Apollo 30/50c thermocouple change

[duffsparky]

Similar to many plumbers/heating installers who do a little bit of electrical work, I am an electrician who does a little bit of plumbing work, including CH systems.

Normally I do not touch the boilers except for their electrical requirements, however my boiler pilot started going out in the recent high winds and now goes out on a frequent but irregular basis.

I have a replacement thermocouple for the gas valve pilot control which I would like to fit.

My concern is that to fit the thermocouple I believe I must enter the boiler burner chamber which I seem to remember is illegal unless your CORGI registered also likely as not I will come across an asbestos gasket somewhere or other.

Anyone give me advise on this?

Kind regards.

 

[ollski]

No asbestos anywhere and as its the open flued version (isn't it?), there are no seals to be made really though there will be a red foam seal for the case to sit on. The apollos do come with an interruptor stat which would be worth checking for continuity before anything else though.

 

[pannierstan]

Using your electrical skills I would also check the inline O/H device aswell because they are as likely as the t/c to go

Stan

 

[ChrisR]

an interruptor stat = inline O/H device .

The same thing, you'd think we 're trying to confuddle a sparky!

Not all apollos had this (connects at 2 spades), if yours appears not to, check manual at partsarena.com/baxi.
Needs to be almost 0.0 Ohms between those connections. (short to test)

 

[corgigazza]

I,ve got caught out on that before had one 0.2 ohms that would not work, unless shorted out.

 

[pannierstan]

I,ve got caught out on that before had one 0.2 ohms that would not work, unless shorted out.

The only sure fire way of testing the O/H is to use Millivolts and check the drop across it. If the drops more than 5mv then its stuffed and thats even if its got continuity on resistance scale.

Chris you are right I didnt see Ollies post for some reason but I wasnt trying to cause confusion. Wasnt aware of any appolos without an overheat! How did they manage that with a low water content H/ex?

Stan