I am having a hard time figuring out why my TRV’s behave a certain way. Overheating is almost constant, and the valve position sometimes cannot be explained.
My setup:
I use 2 Moes TS0601 TRV’s connected with Z2M in Home Assistant with Better Thermostat
Both BT’s are configured with swapping auto/heat, otherwise it does not work. I think this is the right configuration för these TRV’s, as confirmed on this topic.
BT configuration is offset-based
overheating protection in the BT configuration is enabled
I use simple thermostat cards where I also added the Valve position % that Z2M can deliver directly with the integration
the external sensors are Xiaomi BLE sensors flashed with the prvv custom firmware
The boiler itself is controlled by a central thermostat. Due to this it can happen that the TRV would call for heat, but the boiler does not react as the room where the central thermostat is is already at the desired temperature. The central thermostat will eventually be replaced ny a relay switch, so individual thermostats can call for heat on demand.
With all that said, I noticed that the target temperature, the current temperature and the valve position are not in direct correlation. I am having a hard time understanding the connection.
I changed the valve setting on one of the TRV’s to ON/OFF. What I see post that is that the valve position is pretty much 0 or 100%, there is barely anything in-between.
Even so, you see that the valve position is often fully open even though the situation would not call for it (room temp is above target temp)
If I set the valve type to PID on the TRV itself - and this is the setup I use in the bedroom, as it’s the default on the TRV - then the graph looks at least a bit more consistent, but still it overheats big time.
Still, there are situations when the system opens the valve for seemingly no reason. The room temp is higher than the target temp. In this case, even though the simple thermostat card says the state is “idle”, if the valve is open at 25% and the boiler is running (which is the case if the living room calls for heat), it will also heat the radiator.in the bedroom
Is this a case of improper configuration, or this kind of overheating should be acceptable with setups like this? Is it a matter of the TRV reacting too slowly or the BT AI algorithm doing its own thing? If I were to use a more expensive, generally well-received TRV (Shelly, Tado Honeywell etc.) would I experience the same?
From reading around I’ve concluded it’s the hardware of the device, specifically that it uses a measure of resistance in the motor to determine how closed a valve is. For this reason, it fairly regularly gives up closing before it’s done.
Things that might help you, but which didn’t help me:
find a way to lubricate where the TRV contacts the valve pin. I tried lithium grease.
newer valves may be easier to push (but I have brand new and 20 year old valves and multiple brands in my setup and can’t recommend anything specific)
create and automation to fully increase then decrease temp daily, to unwork any valves stuck open
The ultimate hardware solution I think would be some kind if bearing which stops the valve from GRINDING as is presses down the TRV pin, but that’s beyond my DIY skills.
My vague hope is that Moes, Tuya or someone out there produces more robust firmware which compensates for the shiity design and components inside.
I am looking for a good recommendation to replace these, if anyone has one…
I experience the same problem like you with one of the three Moes TRVs I own. All TRVs run the latest firmware and the one which gives trouble is connected to a new valve from China. I also use HA with Z2M.
Everytime the central heating goes on in the morning one TRV overshoots and gives me 23 to 25 degrees Celsius instead the target temp which is 20 degrees Celsius at this time. The overheating problem always shows up with me when the heating goes on in the morning after it was put in eco mode over night. I suppose the pump of the heating creates a lot of pressure which one of my valves cannot withstand. Allthough there is a kind of shunt valve next to the central heating which should prevent that the pressure gets to high. So again: too many question marks…
So far I did no thorough analysing of the situation like you did.
I shall find time to set up a proper analysis and post my findings later.
Hi Wickedy123,
I am facing the same problem like the author of the post and have no real solution yet.
Here are some ideas I got while reading your comment.
I doubt whether greasing the point where the TRV contacts the valve pin helps as the contact point is very small.
I would put the problem rather in the area of the valve. The spring which closes the valve might be rather the problem.
Maybe “training” a new valve by switching the valve from closed to open and back prior setting it to the target temp once a week or so might help. The other not so smart valves I own move the valve once a week to avoid that the closing mechanism of valve gets stuck while the valve is off or no heating is required (e.g. summer time).
The overheating problem always shows up with me when the heating goes on in the morning after it was put in eco mode over night. I suppose the pump of the heating creates a lot of pressure which one of my valves cannot withstand. Allthough, … There is a kind of shunt valve next to the central heating which should prevent that the pressure gets to high. Hmmm…
I have switched over to an A/C unit when it comes to heating, but I thought I would share my findings here - there is a setting on the valve itself that controls the shut-off type with two options: “hard seal” VS “soft seal”.
The exact name of the setting is probably different, but I can’t find the valve’s manual at the moment (it is one of the last settings as you cycle through the options on the valve itself)
Hard seal means essentially that the valve shuts off completely not letting any water through - soft seal on the other hand permits some, that is why the valve status showed to be open, even though the thermostat was supposed to be in “idle” state.
