potterton puma 80e problem

[jonheywood]

My boiler is the type with a non-permanent pilot, the burners are auto ignited when I either turn on the hot water or the central heating. The problem that is happening is that when the system tries to fire up, it trips out the main RCD in my fuse box and consequently disconnects all the electric in the house!

I'm reasonably confident that it's a problem with the boiler as opposed to the RCD (if someone knows otherwise please say so?) and as such will likely be a PCB fault ..... I dout it will be the display board, which leaves the electric modulation board or the sequence control board ..... any ideas ?

 

[picasso]

more likely to be the fan/pump/gas valve, use a dmm to see if you have a short circuit in any of these.

 

[jonheywood]

Sorry, I am neither an electician or a plumber, I do not have a DMM (multimeter??) ..... Fan assembly was replaced a couple of years ago as it had ceased. I replaced the elec mod board myself a year ago as one of the connector had burnt out.

please note : the RCD trips out the instant the boiler tries to flame ..... the fan apears to be running at this time but the pump does not kick in immediately ..... it's not supposed to on this system

Either way, I'll have a look and see if I can spot anything obvious. cheers ...

 

[bengasman]

...The problem that is happening is that when the system tries to fire up, it trips out the main RCD in my fuse box and consequently disconnects all the electric in the house!

Are you sure it is the MAIN RCD that trips?
Do you live out in the country?

 

[jonheywood]

Yes, the main RCD, not the individual trip that the boiler uses ... all of the 7 other trips remain in the on position, just the RCD trips out.... and no, I live in town.

Anyway, Had a quick look at the boiler and when I opened it there was a small amount of water inside the casing .... only a few drops, but there nevertheless. Looking at the pump, there is some corrosion on it's casing .... could be the damn thing has ceased. I have no idea how to tell for sure???

 

[bengasman]

...The problem that is happening is that when the system tries to fire up, it trips out the main RCD in my fuse box and consequently disconnects all the electric in the house!

What do you mean by MAIN rcd?
The only way one rcd can trip the power to a whole house, is when you have a TT installation which you do not find in town.
How many rcd's do you have?
Are you sure it is a RCD that pops and not a MCB?

 

[Agile]

Its most likely to be the pump but thats powered just before the flame is lit.

I have seen a few cases of water leaking from the AAV and dripping on to the gas valve which is conveniently situated below the AAV.

I expect you may need a professional.

Tony

 

[mickyg]

check pcb over. Especially top left corner. Look for scorch/burn marks. Check back of pcb if you can as well, obviously with power off. Also check for water leaks, going near anything electrical. If still nothing then its likely gonna be pump, fan or gas valve in that order of likeliness.

 

[jonheywood]

Bengasman, it's a wylex board with 7 circuit trips plus the main, which has RCD written on it. This is the one thats tripping but if it's an MCB then my mistake .....

Agile ..... in my boiler, the only thing below the pump is the water pressure gauge, the gas valve is on the other side. However, i'm not sre the water came from the pump, there is an electrical connection to one of the pipes above the pump that had a droplet of water on it .... could be that this has got into the conecters on the pump ???

Either way, you could be right in say I need a professional

 

[bengasman]

A bit confusing, a pic of the fuseboard would help.
A tripping rcd could be a different fault from a tripping mcb.

 

[jonheywood]

Bengasmas ..... With the boiler switched off there is no prob with the trips ... lets just say for now its the mains that is tripping.

As the prob is being caused by the boiler I have checked the pcb.... all seems ok , back and front. Btw, Mickyg, the last card burnt out on the 7 pin connector on the top left so paid particular attention to that .....

Nothing seems to be leaking in the boiler so I am gonna leave the cover off and let anything dry out then try again.

I'm pretty sure after all the help here and from what I can see in the boiler itself that the pump is knackered

 

[mickyg]

if you have a multimeter you can check out the pump electrics. disconnect power, remove pump cover and remove electrical connections. Then measure resistance from live to earth, neutral to earth, and check resistance across live and neutral is around about 140ohms.

 

[Agile]

You dont even need to get your multimeter out on this boiler.

Just follow the pump leads and there is a plastic plug/socket which you can pull apart.

Then try boiler on hot water and see if it still trips.

If it does not, then the pump is at fault but you can still have hot water until its replaced.

If it still trips then its not the pump!

Tony

 

[jonheywood]

Well finaly got this resolved today ...... and guess what ..... it was the PUMP.

Called out british gas and the engineer spoke to potterton yesterday and was advised that the fault was either the seq board, the gas valve or the pump in that order.
Today he returned with the board and the pump (someone took the gas valve by mistake at the depot) ..... he tried the board with no luck then thought to do as AGILE suggested and lo and behold ..... knackered pump.

Changed out and all working fine now .... all for the princely sum of £96.89 + service contract (£20 per month).

I don't feel too hard done by as the pump alone would have cost me around £90 on its own, let alone me breaking anything else by changing it myself.

 

[Agile]

That demonstrates a total lack of diagnostic skills by the British Gas man!

If only you had followed my advice from three days ago then you could have had it going far earlier.

You could have still used BG but told them in advance what the problem was.

Anyway at least its going again now!

Tony