I think it has to be a double pole, in the uk for isolation purposes.
Unfortunately for you.
But it could be fitted “upstream” of your existing DP fused spur and then the immersion heater could be electrically isolated (DP switched) which is a requirement but you could then use your “smart” immersion heater automations using the zigbee switch.
Just my take on it. I am not an Electrician just an OLD electrical engineer.
Hi, apologies in advance, I am a newbie here so please forgive me if I’ve mis-posted this.
I’m looking to install the Drayton Wiser and hook it up to HA. Problem is, I currently have four zones - hot water, upstairs, downstairs, underfloor. The three heating zones are currently controlled by Honeywell wireless timer/stats and the hot water is on a 7 day timer. All are hooked up to motorised valves (four in all, and yes, I’ve changed a lot of motors).
Wiser comes closest at three zones and is clearly great value. My current thinking is use the three Wise zones for the heat circuits, and dream up something else for the hot water. This could be a simple switch in HA to drive the motorised valve (which will in turn create demand at the boiler) of maybe use one of the Wiser electrical switches? I only really need a timer on the hotter, there is already a thermostat in the control circuit.
Any thoughts/views on how best to take this very gratefully received. Thank you!
I believe with the three channel hub, one of the channels has to be used for hot water i.e. on/off, so you only have the other two channels for heating control, which would take care of your upstairs and downstairs zones and hot water. If your underfloor heating is electric, you would add the Electrical Heat Switch and if it’s wet/water then you would add the Underfloor Heating Controller.
Aha, thank you, that’s very useful. One option I’m considering is actually to wire the underfloor and ground floor together, I will have a ponder as to how sensible that is.
Pretty sure you can add multiple Electrical Heat Switches if your electric underfloor heating is more than one zone, but only one Underfloor Heating Controller (as that controls multiple zones anyway). Do your due diligence checks to confirm.
Thanks. I’m waiting on my electrician calling me to confirm what the regulations require regarding SP and DP fused spurs for situations such as this.
If DP is needed, I am now considering a slightly modified version of what you’ve suggested. TBH, this might be a better solution anyway. Instead of installing it as a second “upstream” fused spur, I think a frient Smart Cable might be a better option. It’s rated at 16A and has the added benefit of power monitoring. I actually have one of these sitting unused in an unopened box that I bought for something else, but ended up going with a different solution for in the end. Obviously, this only works if you have exposed flex connecting from the dumb fused spur to the immersion heater, which I do. 
I’ll discuss both options with my electrician and feedback here when I have confirmed what the regulations require.
Is there a method in HA to simulate toggling off the ‘Follow Schedule’ button that is shown in the wiser app for a TRV ?
I searched and found a suggestion it is done by setting the climate mode to ‘heat’ - but when I do that the toggle is still on in the wiser app, and it shows 16’c until 9.30 (next time my schedule is due to change).
What i’m trying to do is automate lowering the set point to 16 and temporarily disabling follow schedule whilst a window is open in the given room… currently the manual setpoint works fine, but looking at the wiser app it seems it’ll get overridden when the room schedule changes.
It’s a room characteristic that needs changing. Using packet capture I’ve looked to see how the Wiser app flips the setting. The value to change is the room “Mode” from “Auto” to “Manual”. I’ll leave it to Mark how it’s done via HA.
I just set the room to off when a window is open.
‘Heat’ is essentially manual mode. If climate is set to heat, the schedule won’t be followed. When I select heat, follow schedule is toggled off in the wiser app.
Thanks for the replies, however for me at least the mode “heat” is still following the schedule. I had a window open on vent last night and the climate.wiser entity for that room was set to 16’c and heat mode. Just checked it now and it has followed the schedule and is heating the room up to 19’c 
I will try “off” and see what that does.
{"temperature":16,"hvac_mode":"heat"}
As the data for the set_temperature service call… but it seems that doesn’t actually change the mode, a separate call to set_hvac_mode does the job and does indeed disable ‘Follow Schedule’ 
I’ve just remembered my quick test with a “2250~3000 Watt kettle” and a Wiser Smart Plug…
Schneider forum
@ 236V, it actually drew 12.91A or 3046W - which the Wiser plug reported - briefly - before powering itself off! Other devices operating close to the limits might do the same.
I’d be much happier, if you were using a 16A device 
Rob
How about leaving the existing 2 pole as isolation device
use a solid state relay of suitable rating to do the switching.
control would be via HA controled light weight relay so it can be incorperated.
with these you can switch on and off or pulse the relay so it just keeps the “load” at corect temperature
this is used in all sorts of comercial machines whe constant set temperatures are required.
an example of one Solid State Relays | UNDER CONTROL INSTRUMENTS LTD
I’ve just started using passive mode and I think I may have found a bug with it.
TL; DR; I think that in a 3 channel wiser setup, demand on one heating channel can cause rooms in passive mode on the other heating channel to demand heat.
I have a three channel wiser heat hub, one channel for hot water, and the other two for central heating.
The first heating channel has Radiator Thermostats and Room Thermostats and covers several rooms and it controls a gas boiler (not using opentherm).
The second heating channel has a single Room Thermostat in one large-ish room and controls a second gas boiler (not using opentherm).
Today I turned passive mode on for two rooms on the first channel. It seemed to be working fine. Later in the day I took a look at the graphs to see what was happening and saw that for heating channel 1, there were exactly two rooms calling for heat, and they were the two rooms in passive mode, and both rooms were above their minimum temperatures. After some head scratching I happened to look at channel 2 and then it became apparent that the passive mode rooms on channel 1 were only calling for heat when there was demand on channel 2.
In this picture, there are demand levels on the left (climate.wiser_bathroom_down.percentage_demand) and on the right, temperatures (climate.wiser_bathroom_down.current_temperature & climate.wiser_bathroom_down.displayed_setpoint)
The two rooms in passive mode are “Bath Down” (min 17.5 max 19) and “Ensuite” (min 18.0 max 19.5).
In the displayed period, two other rooms (“Hall” and “Master”) show demand between 9:59 and 10:35, but otherwise the only rooms on channel-1 with demand are the two passive mode rooms.
I am not sure it’s been tested with a three channel hub. I only have two channel hub. Not sure what @msp1974 has. So could well be a bug when using with a three channel one. Will need Mark to advise on what to do to troubleshoot and potentially gather more information from you.
Yes it doesn’t factor 2 channel heating - good point. I don’t have a 3 channel hub so not thought about that. We can add channel checking in however. Will add to the to-do list - and I thought I had just cleared it! 
@msp1974 does the wiser API allow to only control the iTRV motors, by this i mean, could you add a another option like “passive mode”, but when enabled and room temp is below target temps, it will simply just open the TRV valve to allow the radiator to heat when the boiler is fired up next. As ATM “passive mode” effects the CH1 Demand and this effects the OpenTherm flow temp curve. It would be good have an option so that it does not.
No the api cannot control the TRV valves, only the target temp for the room.
If you do not want it firing the boiler when below the min set point, just set the min to 5C. Then when the boiler is firing (caused by another room), it will also heat upto the max setpoint but it is unlikely that it will itself cause the boiler to fire.
EDIT: Sorry just worked out what you are saying. No, you cannot open the valve and not impact the opentherm demand.
thanks @msp1974 , I have just spoken to Wiser Tech, and they have taken on board my request and he has passed to the developer team for future consideration. Let hope it gets added, as this would give OT more efficiency.
I’ve been getting these sorts of errors daily for a long while now.
Leaving my diag file down here.
I don’t detect any errors in use most of the time. Heating works, and I have completely stopped using the Wiser app altogether. But it bothers me seeing constant errors in the log.
Is there something I can do to fix them?
Thanks!
Diag file: Pastie
