Banging Thorne Apollo Boiler!

Rookery · 10 Jan 2005

I've got an Apollo 15/30 boiler and it hasnt worked this year. When I turn it on, it fires up then after approx 10 secs makes a whole load of banging noises and then shuts down again.

I changed the pump and it worked for around 2 hours then when I turned it off and tried turning it on again about an hour later, the same thing started happening again.

This boiler must be over 10 years old if not older. The hot water is working OK but not the CH. Can anyone help? It's freezing!

kevplumb · 10 Jan 2005

try locking the three port valve mid position it sounds like a curculation problem

croydoncorgi · 11 Jan 2005

Pump is supposed to be driven from the pump terminals on the boiler. Check that the wiring is actually correct. Then check that when you switch the boiler on, the pump live connection on the boiler is actually live. If not, maybe pump overrun stat on boiler not working. If it is and the pump's definitely OK, check for live at the pump end. Fix wiring, pump or stat in boiler accordingly. Or better still, get in a CORGI engineer, who'll be quicker and probably cheaper in the end.

Rookery · 11 Jan 2005

Thanks for your replies guys.

Croydon I am speaking to a plumber but I think he's trying it on as he's telling me I need a new boiler without even looking at it. He hasnt made any of the recommendations that you fellas have.

Does this unit have a 3 way valve then? As you can probably tell I'm a layman when it comes to these matters and I wouldnt do the work myself unless it was very straightforward.

Does it sound like a new boiler job to you?

croydoncorgi · 11 Jan 2005

The boiler is certainly old but not necessarily dead - it fires up and presumably doesn't leak, which is a good start! Thant said, it's definitely NOT worth spending serious money on.
See //www.diynot.com/forums/viewtopic.php?t=18640 , this sounds very much like the same problem.

Rookery · 11 Jan 2005

Corgi it's different in that there is no click as such. It's an almighty crash, bang, wallop then off.

I dont trust my plumber. Gonna try and fix it tonight. Wish me luck.

kevplumb · 11 Jan 2005

1st make sure the pump is runnung as croden suggests

Rookery · 11 Jan 2005

Right this was the sequence of events:

1) Turned on CH. Confirmed that pump working fine. After 10s loud banging noises and boiler turns itself off. Switched off CH.

2) Turned on CH again but this time the HW also. Pump still working fine. Boiler stays on but rads dont warm up. Pipes to rads cold also. Plenty of HW though.

Note that the 3 way diverter valve was cold before we turned on the HW but heated up almost straight away when the HW was switched on.

Also note that the HW/CH switches are both connected to a programmer unit which allows you to differentiate between the CH and HW. (two seperate sliding paddles).

Hope this is enough info. Does it throw any extra light on the matter?

kevplumb · 11 Jan 2005

the valve has a lever to open it manually sounds like its shot hw is the default position on a spring return valve

try opening it with the lever

croydoncorgi · 11 Jan 2005

A feature of the 3-port valve is that it cannot block completely, so if the boiler is happy in HW mode it should also be happy when the valve diverts flow to the rads..

From your description, there may well be nothing wrong with boiler or valve. There is probably a blockage or (more likely) an airlock or lack of water in some part of the plumbing to the radiators.
Have you actually checked that there is water in the small F&E tank that the system has (somewhere!) and have you bled ALL the radiators?

Recheck (with the system OFF) that you get water dripping out of the bleed screw on each of the rads when you loosen it. (When you say

Confirmed that pump working fine

did you mean that you could hear it running? If so, was it making a consistent, quiet humming noise? whooshing as if full of air, what? How did you know it was 'fine'?

kevplumb · 11 Jan 2005

cc if the pump wasnt running the same would occur on hot water

you have a point the valve could be full of crud

croydoncorgi · 11 Jan 2005

I was sorta hoping to hear that the pump was 'quiet' when on HW but went 'whoosh, whoosh' on CH - indicating low water or airlock....

kevplumb · 11 Jan 2005

would make sense

Rookery · 12 Jan 2005

CC you ask how do I know the pump was working fine. Well to my untrained eye I thought it was as I could feel it rotating and the pipework either side was hot. Am I wrong in assuming then that this indicates correct functioning?

I never had the HW on on its own. It was either the CH on its own or both. When just the CH was on the boiler fell over. Not the case when both were on.

Interestingly the pump did sound a lot quieter when both HW/CH were on than for the few seconds when just the CH was on.

I haven't tried bleeding the rads yet and this is my next step. There is no F&E tank in the loft. In fact there are no tanks in the loft - yet it appears I have one big one in a cupboard above the pump / valve.

In addition last night the pipes to the rads weren't really warming up which I've heard could discount the posibility of air in the system. (Although they were slightly warmer). Is this correct?

On the other hand when I had the system on the other day and it worked for a short space of time after I changed the pump, the rads did heat up but not by as much as I'd expect them too.

Lots of info there. Thanks for perservering with this fellas. Really appreciated.

Rookery · 12 Jan 2005

...some extra info:

it seemed as though the arm/lever on the valve was loose/broken. Any use?

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Banging Thorne Apollo Boiler!

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