Boiler Packed Up

[Jimk]

Photocell window sooted up?

[Jimk]

Not IME of over 20 years...

[Jimk]

Time to ring the large company then?

[Mike McLeod]

Just stopped working! No hot water or heating. Just won't fire-up for some reason.

Worcester Greenstar Heatslave 18/25 oil-fired.

Got power to the controller board; no fuses blown. Any suggestions?

[John Rumm]

Start by checking that you are getting a call for heat right through to the boiler. That will prove that the programmer, stats, and valve microswitches are doing their stuff.

[Dave Liquorice]

Locked out? Might be an indicator/button on the burner that is now on, when heat is being called for, that normally isn't on. Try pressing it, should start its ignigtion sequence but if it's still not happy may go back into lock out.

Oil boilers are pretty reliable but do occasionally suffer a lockout for no good reason. If it does go back into lock out, you haven't run out of oil have you? When was it last serviced?

[Andrew]

Pikeys stole your oil :-)

[Mike McLeod]

If by "boiler" you mean the actual burner, I can't get access to its control box because of the bloody stupid construction of the boiler's components. They've made it impossible to get the control box cover off by juxtaposing it with (IIRC) the heat exchanger. If not the HE, then something equally bulky and obstructive. I believe Worcesters are notorious for this kind of poor internal layout.

[John Rumm]

No, just the call for heat to the boiler's input terminal as a starter.

i.e. n point diagnosing a problem with the boiler if its actually a problem with the controls external to it.

Is the pump controlled by the boiler, or is it powered up from the external controls?

[Cynic]

What indicator lamps are lit? John Rumm has asked you to check if there is a call for heat. If there is then examine further links in the sequence. Is the overheat stat tripped? Is there a lockout indicator lit? If you have the boiler installation and service manual it would (should) help you immensely. If not try downloading a copy from one of the internet sources.

[Mike McLeod]

"boiler's input terminal" - sorry, that makes no sense to me.

Very true.

I think the *pump* is running, but it's so quiet I can only hear it via holding a pipe to my ear against it.

[Mike McLeod]

No, the lock-out light hasn't come on and it gets a yearly service under a contract from a large company.

[John Rumm]

So if you have a conventional wiring plan without pump overrun (i.e. the pump runs any time there is a call for heat, then that does suggest a boiler fault. If however the boiler controls the pump, then it suggests it is at least seeing the call for heat even if not firing. So both outcomes suggest a boiler problem.

So either a lockout / fault condition preventing it proving and firing, or something like a valve problem - either not getting an instruction to open, or not responding.

[John Rumm]

Manual here:

[Mike McLeod]

Just the "power" one on the front, as usual.

There's a flow chart in the documentation John kindly linked to.

Can't find it.

Nope

It *should* shouldn't it? Unfortunately Worcester/Bosch's circuit diagram is unreadable for me at any rate (and I'm no stranger to circuit diagrams, believe me).

The main problem is that they've basically prioritised compactness over everything else. So it appears they've taken all the components of the boiler and used some CAD program to determine the best way to fit all these objects into the smallest external dimensions possible with no thought whatsoever into subsequent servicing access. One of the *key* tests in the manual is to check for 40 ohms across the fan motor, but like I said, it's completely inaccessible without taking much of the whole damn thing to bits. Useless! From my researches it's one of the boilers the service engineers most hate working on for this very reason.

[Mike McLeod]

Yep, I just wanted to check I hadn't overlooked anything before calling them.

[Michael Chare]

Does the boiler have a programmer fitted to it, and if so has it been inadvertently changed?

[Michael Chare]

It looks like you can unplug the burner power cable from the boiler chassis. If you do this you could then check whether you have power on pins 1 and 2 when the burner is supposed to be running.

[Mike McLeod]

Nope. Just simple on-off switches. I keep irregular hours.

[Mike McLeod]

Not sure what you mean by "boiler chassis" - one of my major beefs with this design is that it has no frame at all to give it rigidity. It is one shitty design. I'll check out your suggestion, though, if you meant "controller board" instead of boiler chassis. I recall there's a plug/socket on there for it. Not sure why I didn't think of that myself, but I didn't......