HSA3 problem.

[Pengwyn]

Hi guys,
any help would be greatly appreciated.

My father-in-laws heating is not working. I hoped it would just be a stuck 3 way valve but no.

I found the actuator stuck in manual. When put back in auto the problem persists.

The motorised valve (HSA3) is operating.
I haven't checked yet (no meter on me when checking) but the boiler is not firing so I assume it is not recieivng a signal.
Pump is running ok.

Am I right in thinking orange is the HW call, and white/brown is heating call ?

Also what other checks can I go through ?

The last problem on this system was a burnt out micro switch on the actuator. If it is this problem again can I buy the micro switch wuthout buying the whole actuator ?

Once again, thanks for the help.

 

[seco services]

if the pumps running then i would check the sw/live to the boiler.
brown is call from room stat.
orange will be live to boiler/pump.
grey is live when hw satisfied or off at programmer.

 

[Pengwyn]

IT is a back boiler and before dismantling that I wanted to see if the actuator was the issue.

Thanks for the suggestion though.

 

[Pengwyn]

Well I tested the control side of things and all was ok.

I have then removed the fire and tested that the signal was getting to the gas valve and it is.
I didn't really want to get this involved but the father in law is without heating and skint .

Once again I went through all of the demand possibilties and the signal switches to the gas valve as it should.

The problem being that the gas valve doesn't open. There is NO activity from the gas valve at all.

So is there any advice ?

The boiler is a Housewarmer 43 back boiler, probably over 20 years old and not regularly serviced.