Connecting Drayton Wiser 2 channel (WT724R) to Firebird Combi 90 boiler

[notwiser]

Hi all, I have a Firebird Combi 90 oil boiler that supplies heat and hot water via separate controls on the front of the boiler. There is also a single thermostat in the hall to control the central heating temperature. I don't want to keep the hall thermostat, as the Wiser kit has a wireless thermostat and a couple of TRVs.

I'm hoping I can retain the separate hot water and central heating control with the Wiser system. I tried wiring it up myself, but I'm obviously missing something.

This is the wiring diagram for the Wiser 2-channel kit:

This is the wiring diagram for the Firebird boiler:

Thanks in advance, any help greatly appreciated!

 

[CountryFan]

How did you wire it up? What did you do with the existing room thermostat?

 

[notwiser]

Initially on the wiser connection side I had:
N = neutral from boiler
L = live from boiler
1 = none
2 = none
3 = h/w timer switch live
4 = c/h timer switch live

The 3 and 4 connections were labelled in the firebird manual as external two gang timer, I thought it was looking too easy

I left the room stat in place and turned it up high.

I was able to get the boiler to fire in the wiser app for both the h/w and c/h but the corresponding pump didn't come on.

 

[CountryFan]

Tbh, I’m unsure. I know there’s some on here who know more about oil boilers than me. @Exedon @oilhead. Might be something simple.

 

[notwiser]

Just went over the wiring again to make sure all was in the right place and try some more troubleshooting.

I can control hot water if I just have the wire in slot 4 (connected to h.w. timer switch live on the boiler); if I connect the central heating control wire into slot 5 (connected to c.h. timer switch live) then the boiler is constantly trying to heat the radiators even though there's no schedules in / everything should be off. I have the room thermostat set to max if that makes any difference?

Not sure what I'm missing here.

 

[CountryFan]

As I said, I’m not au fait with oil boilers. It could be the room stat connection on the wiring diagram, it’s looks like there’s a link, or could be faulty Wiser.

I also forgot @stem might understand it better than I.

 

[stem]

I'm not really familiar with oil boilers either, but the wiring diagrams show what control signals it requires, so I would have installed it exactly the same way as @notwiser.

The Wiser does contain two simple on/off switches exactly as required by an "external two gang timer" to give for independent control of the hot water and heating. So is it possible something has been disturbed, or tripped out during the installation?

I see that the pumps are controlled from the relay. So, I would check that all of the connections to it are sound, and if it's a plug in version that it is properly inserted. For someone competent with the use of a multimeter, it wouldn't be too hard to trace the wiring back from the pump terminals via the relay to find out what is failing to work.

Just in case there's an issue with the old room thermostat, it could be disconnected and the link inserted in its place as shown in the manual.

Other than that, maybe wait for the oil guys to have a look.

 

[notwiser]

Thanks for that @stem - I'll check this evening. The physical controls on the boiler are still working for both heating and hot water, so the relays and pumps are operational, I've a multimeter too if need be.

I'll put in the thermostat bypass / link and remove the old room thermostat as soon as I can get the wiser up and running - I've left it in place for now.

 

[stem]

OK, I wasn't aware the timeswitches were fitted to the boiler as they are shown in dotted on the diagram you posted, so I'd assume they were optional and not included. But as they are there and working all seems well with the relay, room thermostat and associated wiring.

However, reading your post again I can interpret it two ways.

3 = h/w timer switch live
4 = c/h timer switch live

As either 'Timerswitch live' or 'Timer, Switched Live' which are different. So I assumed that you mean terminals 3 (and not 4) of the respective timers which would be correct.

Or, ideally the Wiser should be connected in place of the existing timers as shown in the circle in the top right hand corner of the diagram you posted.

 

[notwiser]

Ah yes, there are timers on the front of the boiler (file attached), I have seen photos with similar boilers that have blanking plates where the timers usually are, so maybe it's optional?

As for 3 & 4, I've them wired into the dotted circle on the top right, as you mentioned (connection to "external two gang timer").
3 = "hot water timer switch live"
4 = "heating timer switch live"

I've also attached an alternate wiring diagram if it helps.

Thanks for your help