Installation of Drayton Wiser system

[garyslater]

My first post in this thread. I wanted better control of a panel heater in main bedroom. Downstairs is heated by ASHP to water underfloor heating. Upstairs by panel heaters with no timing facilities. Space limitations meant I couldn’t find the right size panel heater with a timer for replacement.
The Drayton Wiser system was mentioned to me and after research decided to install this.
I installed the hub and electical heat switch.
The exisiting timer for heating is linked to the heat pump, meaning I had to install the backplate with an associated FCU - fused at 3amp, from scratch, taking the power from the adjacent FCU serving the ACHP controller.
Working reasonably well but the Wiser App is not the best, but gives useful heat related data.
The App doesn’t seem to remember the heat source for the app. When the Heat Switch is activated by the thermostat I can hear it clicking on and off - I think that this may be related to the hub cycle rate but not certain.
I have set the heatswitch to relay mode but would like to try pilot wire mode (heater has pilot wire and I have connected this to the relevant terminal) but can’t find any information on how this would work with the thermostat. Drayton support went quiet on this after a couple of e-mails.
There is competition between the heater thermostat and Wiser thermostat meaning that even if the setpoint is reached the heater doesn’t provide heat because the in built thermostat doesn’t think it is cold enough.
On the whole I am pleased and nice to have better control finally. Some tweaking of schedules and knowing where to set the inbuilt thermostat so it doesn’t compete needed.
If anybody knows more about how the pilot works gratefully received- does it overide the heater thermostat for instance

 

[CBW]

If you only wanted a time control, why didn’t you just fit a single channel time switch?

 

[garyslater]

Because I wasn’t sure how it would work. Both single and dual on sale at Screwfix for same price and thought dual channel might have higher resale value if I needed to sell it!

 

[ericmark]

Interested in your project, did not realise the Drayton Wiser had the heat pump requirements. I use an old STC-1000 for beer brewing, the main difference between it and a normal room thermostat is one it uses a sensor, which I can stick on side of fermenter, and two it has a delay function for working with heat pumps. The fridge is a type of heat pump.

I am not sure about the heat pumps used today, it was back in 1980 when living in Algeria when I started working with heat pumps (Air conditioners) and we were instructed when swapping generators we must wait 5 minutes before turning the power back on. The reason was so the AC could drop in pressure before restarting, as starting a single phase motor under load could cause it to stall, the overload would trip, and it would auto reset and try again latter, but the overloads would fail if used too often, so better to allow pressure to drop before trying to restart.

With three phase motors the problem is the huge start current, so again not good to start under load, however today we have the inverter drive, these can soft start some motors under load, and can also run refrigeration units at a variable speed, commercial freezers don't switch on/off but adjust motor speed. (Domestic freezers even with three phase motors and inverter drives still switch on/off) So one has to be careful with the control for refrigeration be it a heat pump, fridge, freezer or AC.

I can set the delay start with my STC-1000 for cooling, but it does not have option for heating, reason we used them they were super cheap, today the Inkbird ITC-308 is used, as all built in, I have looked at the Drayton Wiser with thoughts of using it myself, I can't see any delay settings. Maybe no required, or maybe I have simply not found instructions on how to set them?

I use a lot of smart devices, and at 5 amp see no problem, however at full 13 amp not sure I would want to trust them. Thinking now of your upper floor heaters, I think to be use the unit can take the power, likely immersion heater timers are best option if not using the trigger wire. As I am sure they can take the power.

Thermostats is hard, how much is inferred and how much convection? Inferred is line of sight, and heats the thing it hits not the air it passes through, i.e. like the sun, so control needs to bring in more or less heaters, not switch whole lot on/off. And colour of the thermostat matters, and position. Controlling convection is far easier, if the air develops a circulation then just before it returns to the heater is an ideal place to measure, as said before the location of the TRV is ideal. So in your case built into the heater.

I don't have the option of using electric heating, there is only a 60 amp supply for all my needs, but today we call the people who install heating and ventilation engineers, and I consider an engineer as some one with a degree.

 

[CBW]

Because I wasn’t sure how it would work. Both single and dual on sale at Screwfix for same price and thought dual channel might have higher resale value if I needed to sell it!

Are you on about the dual channel thermostats? I’m on about time switches, completely different thing. That way you wouldn’t have a thermostat vs a thermostat.

 

[garyslater]

Oh OK - yes - sorry - I was talking about the dual channel hub. I saw the programmable time switches. I wanted more accurate temperature control. I agree I have probably over engineered it!

 

[garyslater]

Oh OK - yes - sorry - I was talking about the dual channel hub. I saw the programmable time switches. I wanted more accurate temperature control. I agree I have probably over engineered it!