So it’s the mechanical linkage that you think has the problem ?
So just update 1 off the valve bodies (£13) and see if your eTRV can close the valve
Problem solved - else get rid
If you ‘old’ trv’s are that old they should be replaced anyway
The TRVs are not “old old” - moreover just the ‘previous’ ones. Standard mechanical ones bought between 2 to 3 years ago from Screwfix. They work fine. Just wanted to avoid having to mess around turning them up/down through hours of the day as rooms are used/unused and automate warming up rooms through the seasons. Nothing out of the ordinary. But these eTRVs are just resulting is so much energy wastage and unnecessary duty cycles of the boiler.
New valve bodies means more work and draining the system - with no 100% guarantee of resolution with these eTRVs.
Also, eTRVs are not ideal as a temperature sensor given they sit right next to the rad, consequently not an appropriate reflection of the true ambient room temp.
Cutting my losses and changing approach is logical.
@ninjaef Just came across this thread as I am just exploring smarter control of my heating.
My system is different to yours, but the way I get around the multi-room situation is as follows.
Each room has a TRV (Zwave in my case with 15 min cycle), a temperature sensor and a generic thermostat. The generic thermostat controls an input_boolean called something like “room 1 needs heat” rather than the eTRV. There are then 3 node-red flows.
-
monitors the setpoint on the thermostat and sets the TRV to be a defined degC above (to allow for the calibration of the TRV). (This is the place to put intelligence in)
-
does a logical OR of each rooms “room x needs heat” and sets another input_boolean “We need heat”.
-
actually controls the boiler.
It looks complicated having the third flow but it gives me a bit more control over the boiler.
Ok. So @Mutt …
I wanted to explore your suggestion a bit with you if I may please…
I’m coding this up. I have ordered 5 smart temp sensors that I will place in each room (one in each of my 5 rooms mounted on walls in the coolest spot of each room). In HA I have setup two sensors from the min_max platform, one avg and one max. The entities for these will be the 5 temp sensors.
Q: What is the benefit / advantage / logic , of using the midpoint between avg and max values and then comparing this with a single generic_thermostat setpoint - as opposed to having 5 generic thermostats each with its own setpoint and sensor input (each smart temp sensors) and simply turning on the boiler if any one of the rooms needs heat (generic_thermostat heater output is ‘on’)?
Bear in mind I have now refitted the mechanical TRVs and ditched the eTRVs.
my current config snippet:
sensor:
# AVERAGE OF ALL ROOM TEMP SENSORS
- platform: min_max
name: house_temp_avg
#round_digits: 1
type: mean
entity_ids:
- sensor.trv_7922_temperature
- sensor.trv_8005_temperature
- sensor.trv_8008_temperature
- sensor.trv_8206_temperature
# MAX OF ALL ROOM TEMP SENSORS
- platform: min_max
name: house_temp_max
#round_digits: 1
type: max
entity_ids:
- sensor.trv_7922_temperature
- sensor.trv_8005_temperature
- sensor.trv_8008_temperature
- sensor.trv_8206_temperature
# MIDPOINT BETWEEN AVG AND MAX HOUSE TEMP
- platform: template
sensors:
house_temp_midpoint:
value_template: "{{ (states('sensor.house_temp_avg') | float + states('sensor.house_temp_max') | float) / 2.0 }}"
input_boolean:
# HEATER DEMAND SWITCH - HOUSE
thermostat_heater_house:
name: "Thermostat heater House"
climate:
# HOUSE THERMOSTAT
- platform: generic_thermostat
name: house
heater: input_boolean.thermostat_heater_house
target_sensor: sensor.house_temp_midpoint
#target_sensor: sensor.thermostat_dad_hysteresis_temp
target_temp: 18.0
min_temp: 5
max_temp: 23
cold_tolerance: 0.0
hot_tolerance: 0.0
initial_hvac_mode: "off"
precision: 0.1
away_temp: 18.0
…and…
Please can you explain this algorithm.
Sorry but I’m not following - never come across this ‘typical’ logic.
Not quite gasping the concepts:
- delay - what’s this?
- input_number - for what?
- overshoot - what’s this? overshoot what?
- undershoot - I figure that’s inverse of the overshoot
- hunting - what’s that?
- pretty close - to what / using what ?
Bear in mind that :-
- I am not using the eTRVs.
- Will be using new smart temp sensors in each room.
- The new smart temp sensor have a cycle time of around 15 minutes , so the issue of a delay in reporting the actual temp is still prevalent, causing the actual room temps to be higher than the temp reported by the room sensors, due to the delay in reporting.
- Manual TRVs have been refitted to each radiator and each has been set at some value between 0 and 5 depending on size of rooms/desired temp in each room. By the way , as a result of this , the rooms are now not getting above 24C like they were with the eTRVs fitted because they were not closing the valve fully. Each room is between 17 and 20C now. I’m just toggling my boiler switch on and off via HA front end - until I get your algorithm understood. So saving energy already
Thank you.
There’s a lot to deal with here, I’ll have to deal with it in bits.
I can only do 2 consecutive replies so you may have to respond occasionally with “and go on” so I can continue.
I’m on a tablet.
The benefit was - given the leaking valves, when a room shuts off (temp reached) it does not actually shut off so continues to add heat to the house. You also have no ‘individual’ control - all you can do is turn the boiler on and off. So it’s an averaging system so you have to use ‘average’ data. This may mean you have temperature variance across the rooms concerned.
The last bit (of this) "if any one of the rooms needs heat (generic_thermostat heater output is ‘on’ " is exactly how I propose my new system to be (see earlier posts). As it relates to you is that it’s predicated on being able to fully close valves. If you can, go for it. Else you are back to averaging for the house. Traditionally you don’t really care about the house average, it’s more the temp of the living room. Establishing ‘some heat’ in the rest of the house - either way in any of the above - you need to ‘balance’ all the radiators with the isolation valves (an arcane art as it’s endless tweaking of the valves).
Yes, sorry, I kept adding to the post here and there.
Ah, OK. I see.
Might help if I break this down into numbered questions:-
-
Is it the case I do not need the averaging algorithm - given my new plan? Which is… I will setup 5x generic_thermostat, 5x room temp sensors, and group the 5x generic_thermostat heater outputs then mode on the group (on/off) to fire the boiler. The valves are now closing correctly - using the manual TRVs.
-
Nevertheless, my temp sensors will only report every 15 mins or so , so there is still going to be a delay in reporting the true room temp, so is there any other advice you can offer based on my new approach and this delay fact? - was this not the point of the ‘mark’/cycle duration you alluded to?
-
One thing I have wondered, is when using non-smart TRVs and manually setting these, is there not a flaw in using these types of TRVs within a smart-home environment?. Allow me to explain by means of an example:-
- Let us assume for simplicity I have just one room. In that room I have a smart temp sensor wall mounted. The room has a rad with a non-smart TRV fitted. I rotate the TRV slider to position 3 (range is 0 to 6 so 3 is midpoint).
- Then, in HA I use a generic thermostat climate component where its target_sensor is the smart temp sensor device output, and generic_thermostat heater output is used to mode my boiler on/off. Simple so far!
- Let us also imagine that for this single room I set the generic_thermostat target temp (using lovelace thermostat card) to say 21C.
- In this single room, the smart temp sensor is reporting current temp of 16C ; consequently through HA my heating comes on to warm this room up. So far so good.
- The temp rises gradually in the room. Recall that the TRV is set midpoint (position 3) and thus the room warms up ever so slowly, (because the TRV is not on setting 6), never quite getting to 21C, maybe 19C at best. The boiler fires for a long period of time, an hour, two hours - whatever - but crucially much longer than it probably needs to. The room temp is not quite getting upto 21C.
This his is a somewhat pessimistic scenario - but possible nevertheless. Given the above, is there not an issue here, wherein I need to somehow calibrate/determine what setting to put the TRV on in order to achieve an optimal setup such that the target temp is achieved in the most efficient way, i.e quickly, with minimal boiler on time, but also remaining cognisant that I do not want the room temp to exceed 21C. ??? Am I overcooking this ? It seems a valid feasible condition ? and this issue would be repeated for all 5 rooms I have**
BTW, Yes, the rads have all been balanced and the drop across each is 12C (between feed and return on each rad). It’s not permanent and lasting of course due to thermal dynamic laws and environment, weather, and so on - but it’s good enough.
I do appreciate your support on this, I am learning HA - slowly - and its a good interesting dialogue.
I wouldn’t be engaging otherwise.
Background: I’m an electrical engineer with a control system background. A lot of the concepts I use were from industry (heavy, pharmaceutical, food and water) So your reading will probably will not find examples, just tips plucked from the hedgerows of experience (ie from the good engineers I have worked with, that resulted in solutions) most times the context for which is longer than the suggestion. I you don’t find merit - don’t do it.
1a. If you have balanced your radiators then taking one sensor reading will be tha same for all (don’t worry that’s nearly impossible)
1b. The multiple sensors will help you balance the radiators
1c. Run all the sensors in the same room for a week to see comparitive calibration (or agreement of values)
1d. Ultimately you have an averaging heating system (modified by the TRV’s) so you need to have a sensor representative of that average OR more probably just of your living room an then use the isolation valves to throttle (or not) the other rooms. It also depends on if you keep internal doors shut, open or ‘cracked’ (don’t modify people’s behaviours, that’s just temporary, try to go with ‘normal’. 20 years of ‘explaining the mechanics’ hasn’t modified the wife’s behavior at all.
2a. Your ‘current’ sensors report every 15 minutes
2b. You new sensors will update on two bases, the first will be time based and may well be every 30 minutes (I dunno) the second will be on a delta T ie if the temperature changes more than x in t (time) then report T (temperature) this is the best way to to do it (the reading will ALWAYS be representitive.
2c. The mark-space suggestion is more applicable to the long duration feedback basis so that the average of one is moderated by the average of the other. This is a poor solution unless you have the inertia of tosion’s system (for which, I imagine huge insulated walls and a huge thermal mass to stabilise - ie NOT your average house)
3a No need to explain, I understand completely hence my thoughts on creating individual thermal zones with ‘local’ controls
3b. No. mid point does not mean half open, 1st there’s a non-linear relationship between valve position and flow. Second, setting a trv to ‘mid’ when it’s cold will result in fully open same as ‘mid’ in hot weather would be closed. You have to consider the inside of the valve, it has a chamber that expands the hotter it gets pushing down on the pin that closes the valve. The valve does have an asymptotic approach (starts quickly but approaches slower the closer it gets) So if your ‘mid’ position equates to 21 degrees it will stop there at 21 (21 is very warm, current recommendations are 19 degrees for living areas) each degree higher equates to (about) 20% more energy required (so 21 requires (about) 44% more energy than 19, wear a jumper). Each valve has manufacturing tolerances so don’t assume 3 on this one is 3 on that one (use the sensors to check)
A 12 degree drop is fiction as it depends on the btu value of the radiator, the total flow verses the flow in the radiator and the kW rating if the boiler and the losses in the transport system (pipes). All you can ever hope for is a reasonable balance from a ‘cold’ start
Digest and respond
Wow. So you’ve spend many years in the industry, a guru in every sense of the word then.
Digest well it certainly had multiple tastes on the palate … wasn’t able to swallow a few so will have to come back on them…
1b what do you mean by this? balancing - to my uneducated mind - is achieving a nominal 12C drop across the rad? - deviation due to environment / home style / thermal fluid dynamics accepted.
My impression what that the TRV setting (rotate head to open more, close more) would ‘throttle’ the rad in a given room. They are all set at different settings as I do not want to heat some rooms at certain times of the day. For example, I heat the kitchen in the morning upto 10:00. I heat the boxroom “office” from 18:00-21:00. I heat the lounge from 12:00 to 21:00. Different on weekends. Hence why I have mutliple generic_thermostat components with corresponding lovelace cards.
So within HA are you advocating…
- I should just use the one generic_thermostat using midpoint sensor input?
or - I should use multiple generic_thermostat each with its corresponding room temp sensor input and a thermostat lovelace card?
or - something else?
Sorry - you may have deduced that I’m getting in a tiz with this particular concept. 
Can you elaborate please.
The new temp sensors are Xiaomi LYWSD03MMC . I have no idea - yet- what their reporting rate is. But can you elaborate please on what delta T ie if the temperature changes more than x in t (time) then report T (temperature) this is the best way to to do it (the reading will ALWAYS be representitive means, in layman terms .
So I’m not going to need that algorithm to do with ‘mark’ and delay? If so great because I did not comprehend anyway.
The 21C was just for explanation in the use-case I provided.
As I mentioned, the room TRVs are now all set to different settings - for example my Daughter likes airy rooms so her TRV is set to 2. I feel the cold so my room is set to 5 (!). The lounge is set to 3 which is currently heating to around 19.1. On this topic, in concert with your comments around throttling, is this range of TRV settings not right - should they all be on max and I use the lock shield valve to increase/reduce flow (thus temp) ?
Thanks for coming back to me. Back to you fountain of all knowledge 
Each room has a btu requirement based on size, floor type, window area, outside vs inside walls, and ceiling insulation. So two adjoining rooms can have different btu needs (obvious) say 3200 and 3900 btu. BUT the desisign aesthetic needed ‘these’ radiators (and you can never get radiators spot on the btu you want. So ‘if’ they were correctly calculated and the calculations were valid (rarely are due to variations in actual building materials, damp ‘in that corner’, gap in insulation etc.) then a 12 degree drop would mean you are outputting a btu fraction aligned to each radiator. But what you want instead is for the rooms to heat at approximately the same rate, which may be different from your 12C drop.
Plumbers want to spend as little time on this as they can hence the rough and ready 12C
1d. With the manufacturing tolerances and 2 valves set to ‘3’ one may control at 20C and the other at 21C, (so tweak one of them to 2.98) yes they raise and lower as you say,. The point is to set the trv to the temp requirement in that room and the isolation valve so that all the rooms achieve it at about the same time. This is less critical with modern valves (as is 1b ultimately) as the trv can shut off any radiator that has reached its value. So it’s possible to allow a race as those that have crossed the finish line are no longer drawing resource. But ‘balance’ is better as the house heats as a unit so you don’t get a furnace in this part and an ice box in that - the sensors (I assume are battery operated so you can move them around to try to get the rooms to heat at the same rate. You won’t achieve this but get close. So that the ‘race’ is a fairly close one. The room you may want to win though is the living room. The problem with this is if that is the master thermostat then the boiler goes off and the other rooms are carried to wherever their current temperature and their thermal inertia take them. This is why ‘some people’ put the master in say a hallway. This cooler location will allow all the other rooms to pass the post before shutting down the boiler. Again the closer this race is the better. The whole house will be ‘warm’ so heat lost will be even and the next top up will probably have to address just (say) 6 of 10 rooms. You no longer have the eTRV’s that allow heating to continue past setpoint. As a result of all the above you need to determine whether you (say) set the hallway to master with a lower setpoint of say 18C but have allowed the rooms to get to 20C or have the master set in the kitchen at 19C but because you have created such an even race that you KNOW that if the kitchen is 19C then the chances are that the living room is at 19.2C
You no longer have an averaging problem (with the eTRV’s) so your sensors don’t need to average either. Though you ‘may’ want to try something like the average of two ‘living areas’ or the maximum of the two or the minimum of two different ones.
How you heat your house is up to you but the multiple sensors allow you to understand how your heating works, which rooms are too hot, which are too cold and that bed room 4 “just seems to need a bigger radiator” etc.
Ah, didn’t know. Thought all plumbers were honest hard working and dedicated 
. How do I ensure all rooms heat up at the same rate - as in , what is the procedure please?
And your responses to my other questions if you would indulge me please 
I’m trying to answer one set of questions before you embark on the next.
There are different ethos’s here, read the lot before choosing one, but ultimately having flows to all rads, good TRV’s and a sensor in the right place will get you a pretty damn good heating system
The procedure is that (and this is hard in winter when the family “just want some heat”) you heat the house from cold (so about 15C but you have to work with what you can get). And compare the data for the five sensors over the five rooms monitored. If you get (say) 15 to 19 degrees in 35, 33, 32, 36 and 38 minutes, then I’d call that a win. Move 3 of the sensors rinse and repeat, if you get an outlier of 17 minutes or 1:10 then you have an issue and need to throttle/open. Also remember that a half open valve allows 85 (ish) percent flow, so margins in the (non-linear) control area are VERY tight, just a nudge each time.
When you have your house balanced, you will have a) a very angry household (from all the messing about, anther reason why the plumbers don’t do it) b) a good basis for your control.
In all your monitoring and looking at profiles you should develop a gut feel for where the control sensor should be, though not necessarily the value. ie 17C on the shelf may become 19C when mounted on the wall in its final position. Location (room) is more important than position (above the shelf, below the shelf, to the left/right of the door) but you should try to ensure a draught free position.
In actual fact you can do most of this with a live house, it just takes longer. You can leave say two sensors in the same positions and use one for control and the other for living space monitoring.
If you balance 9 of the 10 rooms in your house (as I said above) you may need a bigger radiator but it may just be that the preferential flows are starving that one, so nudge down ALL the other radiators and start again (very LONG and laborious) it’s long, laborious and boring which is why ‘just getting close’ and then allowing “a race to set point” is so much simpler. At least the 12C drop ensures there’s a pretty good flow through most of the rads, the rest is handled by the TRV’s
1 Like
The manual for the sensor should tell you the specifics (try searching for a downloadable pdf for the ones you are buying)
If the sensor reads 17 degrees at 2 o’clock and gives you an update 5 hours later that it’s still 17 degrees then you have assurance that it was always 17 degrees (this is the time base, though it may be a different time base 15 mins, 30 mins or 5 hours are just random examples, the lower the frequency the longer the battery lasts)
If it reports at 2 o’clock that it’s 17 degrees but at 10 past 2 the temp raises to 17.5C then the sensor reports at 2:10 (ie after 10 minutes but the time is not important, it’s the delta T (change in temp)) if it continues to fluctuate you will receive continuous reports (though this will punish the battery) This is very unlikely in an environment where the whole point is to maintain a stable temperature. (a house)
If I have a room that because of heat loss (given an outside temp of say 4C) needs 422 W to maintain a temperature of 17C
My heater is 1000W and its either on or off so basically I need 1000W to be on 42.2% percent of the time (the figures were to make the the maths easier)
But the outside temperature changes to 2C which means that instead I need the heater on 56% of the time
Then I pick an overall duty cycle say an hour (3600 seconds) so every hour I start my duty cycle with a mark-space.
The longer the duty cycle the higher and lower the peaks and troughs will be but this is just an example (before we were taking a bout a 10 minute cycle) but aiming at a 50% mark and minimum peak/trough I should switch the heater on for a second and off for a second and on for a second and … You get the idea
This means the contactor would be ‘chattering’ quite noisy and VERY BAD for the contractors like expectancy, so you pick a longer duty cycle
So the cycle starts with a room temp of say 15C (average for the last hour) so we add to the mark value (which automatically means the space value is reduced. After a few cycles the mark space is at 57% which results in a temperature of 17.1C this is above target so let’s reduce the mark value
Thus the ‘mark’ wanders around the 56% point so maybe 2012 to 2020 seconds in an hour constantly hunting for when the outside temp needs more or needs less.
This is based on the paucity of frequency in the sensor data (which is what you had)
This is not recommended for TRV’s that work and when you have real time sensor data, you can respond much better than this.
This method assumes the environment factors and setpoint will be the same in the next hour as they were for the last hour. Whereas a house is a dynamic environment.
I think this is the end of my allowed responses
You will need to respond with a question before I can elaborate any further
Edit : except I read further
Absolutely NOT. the isolation valve is for isolation and roughly balancing flows only Not temperature regulation as it can not compensate for ‘your daughter demanding less flow or you demanding more’ so a radiator balanced thus will be VERY fragile in the set of components/elements.
@Mutt please accept my apologies for “embarking on questions” , borne out of (a)the fact that I didn’t realise you were editing existing posts (b)each of your responses are detailed with lots of concepts and theories for which I am ignorant on; this in turn generates more confusion and misunderstanding this end, for which I then need to understand by posting follow-up questions. Much of your last posts have gone right over my head. I am not a heating engineer but I am a design/programmer. So my lack of comprehension is my fault rather than of education your insightful detailed posts
So,change of tact. Keeping it simple, can I ask one question at a time, and deal with that until I understand, then move to other questions? Asking several as I have/am is getting me nowhere and confusing me further each time. I perhaps need to move away from trying to understand the theory/rationale and instead, agree simple steps with you in programmatic terms. Keeping it dead simple and easy:-
So question 1 - “Balancing”.
My desired room temps across the house are all different. Lowest is 16C. Highest is 19.5C. These correspond to various settings on the non-smart TRV, i.e. 0 to 6. Lets assume I have calibrated all 5 of the Xiaomi temp sensors and determined the best place for them in each room (just to keep things simple in this thread). Now, for the balance test/action, is the following pseudo-algorithm correct? no explanation need but would super appreciate help on the procedure.
# Let us for this test assume we are not using HA. This is a non-smart home. This test is simply to balance radiators.
Start:
LET all rooms be "cold" #-- i.e. first thing in the morning after waking with no heating all night.
SET all radiator TRVs to max setting #-- i.e. rotate TRV head to position 6).
SWITCH boiler ON
FOR each room DO
record how long it takes to warm the room to 19C
END DO
#-- so now I have a list of warm-up times for each room to get to 19C
#-- lets assume (just for example) :-
#-- Room1 = 50 minutes
#-- Room2 = 55 minutes
#-- Room3 = 40 minutes (smallest room, small rad)
#-- Room4 = 53 minutes
#-- Room5 = 65 minutes (biggest room, with 2 rads)
FOR EACH room DO
#-- The following is to balance radiators.
#--
#-- One thing I did not understand is what conditions need to be met
#-- in order to adjust the lockshield valve on a radiator
#-- and at what point would the radiators all be in balance
#-- so need help , what are the {{conditions}} below please?
IF {{condition}} THEN
Adjust the radiator lock shield valve to *increase* flow
ELSEIF {{condition}} THEN
Adjust the radiator lock shield valve to *decrease* flow
END IF
END DO
IF {{condition}} THEN GOTO Start #-- i.e. what condition would mean that all rads are NOT balanced and I need to repeat the next day (when cold house).
Apologies about the colouring and font weight, that’s not me but HA forum doing something to the post. Can you help fill in the blanks/conditions and/or correct. Thank you.
Yes
BTW I’m not a heating engineer either, I’ve just had to control a lot of “stuff” in my time.
I also ‘need’ to know how stuff works (engineer OCD issue) so when I see anything I don’t understand - I ask questions, then dissatisfied with any bland answers I research the topic (if it’s interesting enough)
Balancing
No your premise is wrong it doesn’t matter what temp each trv is set to (as long as its not artificially low or high) but a ‘reasonable value’, your quoted 16 to 19.5 is fine.
[The following paragraph has been heavily edited]
Put the heating on to get the pump running,
Open each lock shield, then close it till it starts to hiss then back off a quarter turn.
The 12C drop per rad is a good starting point so look to achieve this.
Then close all the doors, get those rooms to and maintaining those temperatures by adjusting the TRV’s (you can just stop there if you like, no further balancing required)
This is the race mode where each valve steals what it can and damned the rest, finishes in ten minutes but shuts the boiler off because the sensor is placed in the wrong room and bed 4 is still at 5C (place the sensor correctly though and you are laughing)
Or you can switch the heating off and let the house cool.
Then you can start the boiler and monitor the temps, your aim is to get from start temp to (say) ‘set temp’ minus 1/2 degree (due to the asymptotic approach) within the same time frame, so (say) 20 minutes plus or minus 5 - this means that all those rads are capable of doing that duty and in a balanced manner. You don’t have sensors for all the rads but keeping 2 in place and moving 3 means that you are then balancing 8, rinse, repeat 11, etc.
Thus each room is actually controlled by its local TRV and they are balanced so you can reasonably expect that when one room achieves ‘temp’ the others will also be there plus or minus half a degree or so, before the boiler shuts off. [this is the most efficient use of your boiler] [also with a condensing boiler you get most heat efficiency if you boiler temp is below a temp to allow full condensing to occur, I think that’s generally accepted as 54C but it depends on your boiler]
In a group a group of rads being tested, If the BTU has been calculated correctly and you managed to find a nice looking radiator in the right colour that fits under the window but not too wide it stops the door opening etc. (And is available with a BTU value ‘just above’ calculated (they come in “stepped” sizes so ‘never’ spot on) they should all warm up together or to their set point (your choice) in about the same time
From your examples, I’d be very worried about the biggest room with two radiators, taking so long. But given the pattern, nudge back the fastest radiator ‘only’ ! This will redistribute the flows. Rinse repeat.
[Edit: there are differing views on multiple rads heating the same space. If they have the same set point they can be controlled using the same valve but this means you are splitting the Hot Water temp difference across 2 rads, not what the calculations are designed for. On the other hand if you have two valves they are possible to set at slightly different values (or a lot different if you have a kid that ‘plays’) regardless this is the better way of doing it even if on radiator shoulders slightly more of the load]
Keep doing this till the times are all comparable. You can see why this can take a long time and the more sensors the less time it takes.
As you can see the ‘flow split’ (this is a loose term because as you said ‘there are other factors involved’) but what you are after is the temps to rise in concert. The 1/2 degree offset is to allow some room for your daughter to get ill, need the heat at 20 and the rad still to supply it (the last few tenths of closing is very non linear so this is an approximate method of discounting that)
Thanks @Mutt. Ok, I misunderstood the premise. The figures and timings were arbitrary - they were just for example purposes.
Right, staying with this single 10 char current question, I simply do not understand the rest of your reply following the quoted text …
…so I will focus on your quoted text - as in using all TRVs to balance.
Right, so I could set all TRVs to maintain 16C. However, there are two issues with this:
-
Going forward, after balancing, I want some rooms at 16C for sure, but I also want the lounge at 19.5C and the office at 18.5C. So once all rooms are at 16C I will then need to increase the TRV settings in lounge and office, after which the balancing will be out. That’s what TRVs are for anyway, no?
-
It’s a 3 storey newbuild house. The heating rises ground up (obviously). The heat from the kitchen on the ground floor contributes to heating the lounge above which in turn contributes to heating the office above that. Getting any room to maintain a steady temp for long is nigh impossible, and getting all rooms to maintain a consistent 16C is going to be difficult.
So…what now?
Yes they do final balancing so there’s no need to run the system with ALL at 16C just each room anywhere between 16 and 21 is fine, this will distort your timings (a 21 degree room will inherently take longer to heat than a 16 degree room even with a big difference in BTU capability because the BTU calculation is based on a ‘given value’ to achieve not just what the occupant wants that day.
I edited the post however please Re read (though I’m going to edit it again to achieve some clarity)
I hear you but we are taking about heating not over heating the rise through the stairs is impossible to control all you can reasonably expect is to ensure you don’t freeze and that if your family closes the fire doors on each floor (as they should) then the individual rooms will control according to the room TRV
Tall buildings generate a lot of waste heat, you can either vent it (an incredible waste) or duct it back down to the ground floor to rise again (hard to do as a retrofit)
Bear in mind most houses of this type do not heat the stairs and the ground floor is often biggest culprit in the heat contribution causing the other floors to suffer the consequences.
Close the doors - stop the heat getting out AND coming in
It’s an education issue and as I’ve said, I lose that battle almost daily
Lockshields are not hissing. Opened fully, closed slowly, to full - no hissing. Got my ear on the hot lockshield (ouch!). Tried three rads. All same. Boiler is on, pumping, rads getting hot, no hissing. Definitely no hissing
What I do have, is 12C -ish drop across all rads. I’ve got TRVs set to maintain 17C - ok right job done - then I turn the TRVs up in some rooms, down in others. Voila, so I’m back to where I was before I started this thread. Argggh.
Right , forget the balancing (please) - it’s too complicated and I need simple, concise, easy steps 'cos I’m dumb.
Lets move on.
Question 2.
I have set TRVs to maintain the desired room temps as best I can.
So now in HA, is it better to:
- Set TRVs to maintain room temps desired. Create 5 off generic_thermostat components, each using its individual room temp sensor, and use a lovelace thermostat card to set setpoints, thereby any of the generic_thermostat.heater outputs will command the boiler on/off as needed by room(s).
or
- Do what I have currently which is to take all 5 room sensor inputs, calculate the average, determine midpoint between average and whatever the max sensor reading is, and use that as the “house current temp”. Then, using a single generic_thermostat component where its target_sensor input is “house current temp”, and its heater output controls the boiler, use a single lovelace card to set a target temp which is in essence then the desired temp “for the house”?
or
something else?
Your system is obviously a lot newer, would it also be rum in microbore pipe ?
Both will reduce noise
But at close to shut off the valve should give a hint of vibration due to the flow restriction (oh well never mind !)
Regardless, if you have a consistent 12C drop you are pretty close so good enough.
The aim of the rest of the balancing is to : -
- Be assured that if room A is comfortable then room B will also be comfortable (without actually checking that room) if it’s race to finish was ahead of the room you were in the it stopped heating 2 minutes ago and if it lost that race it was only by 2 minutes, so is ‘just off’ comfortable.
- Minimise the overall boiler on time as well as well bed 3 needs a top up run boiler for 10 mins, oh now the office needs a top up run boiler for 12 minutes etc. With a sensor for each room this becomes (say) 10 off heating systems sharing a common boiler rather than a house needing heat input as an entity to maintain a given profile.
The danger with the former could be TRV set to ‘3’ which gives 17. 5C sensor reads 17.8 with a setpoint of 18C so the rad is off but the boiler called to action
[Which is why I’m toying with sensor and solenoid, to change set points in any room on any time profile and be assured of control]
You can’t do this you don’t have anything to control apart from the boiler
With the individual rooms shutting off when they reach their desired temperature you just need 1 sensor to act as the spokesman for all in the coldest room.
Or you could take the lowest of 5 and run until set point achieved in all (best to have 4 setpoits close to trv values and the 5th just a bit lower (so it generally controls on that)
Just had a thought : -
I have not made it clear enough that you probably shouldn’t be using these sensors as thermostats, just get the sensor values from them then you can feed the desired on into the generic thermostat that controls the boiler
[This is what I do]