Heating and Water not switching.

[Kimberley88]

I have just moved into a house with a Thorn Apollo boiler and the gas pressure valve has been changed recently as well as hi and lo stats and the pump replaced in 2001.

My problem is, when its switched to hot water only, the radiators are on and the pump is on all the time, if I switch to water and central heating nothing changes and if I turn up the thermostat nothing happens.

Any ideas, it has a switch in the airing cupboard part no. HSA3 that looks like its supposed to switch between the two, could this be faulty?


Also I want to replace the honeywell thermostat with a Drayton Digistat 1

The honeywell is wired as

red = 1
yellow = 3
blue = 2

The digistat requires

1 to be common
2 to be satisfied
3 to be demand

How do I work out which wire is which? I guess red is common.

Any help appreciated.

Chris

 

[ChrisR]

Sounds like the HSA3 is dud - could be just the motor in the head, the head itself or the body too. I think you can change the motor by itself. Could also be a faulty programmer...
1 to 3 stays 1 to 3, Isolate blue.
Skip the Digistat1 and use a Digistat3. Put your existing progremmer on 24hr CH and use the D3's ability to give you what temp you want when you want it, each day different if you want. COntact me if you want one for £20 (same for a Digistat1)
(Motor for your valve £5 - I'll check if it's changeable)

 

[Kimberley88]

Thanks for that would be interested in the parts
Regards

Chris

 

[oilman]

Hmmm..... so would I at those prices