Potterton Prima 40f - ignites, and then... goes out :(

dangel · 28 Oct 2010

Any help from anyone most welcome

1 Fan is running, constantly throughout the whole process. As is pump upstairs (this was replaced not so long ago).
2 Sparks and ignites pilot fine.
3 Main burner comes on OK
4 After a short period of time main burner goes off
5 Pilot burner is still ON, there is NO sparking at this time
6 After a while main burner reignites and we go back to (4)

How would you diagnose this? If it's air pressure related can I bridge the APS temporarily to find out if the burner remains on for example?

Agile · 28 Oct 2010

You should not be opening the combustion chamber or touching the APS if you are not gas registered.

You dont say how long the flame stays on for as that could indicate a PCB fault.

However, the obvious advice is to call a registered engineer.

Tony

dangel · 28 Oct 2010

I'd say generally up to a couple of minutes. You're right - I shouldn't

The obvious advice is solid and yes, I'm going to inevitably do that but just wanted to get a clue on any known issues. Reading round PCB s are often suggested for this boiler.

I know a decent engineer and i'll phone him in a tick, in the meantime thanks for taking the time and I will post up whatever the end result was/is just so that it might help some other inquisitive soul like myself

kevplumb · 28 Oct 2010

1 Fan is running, constantly throughout the whole process. As is pump upstairs (this was replaced not so long ago).

are you sure the pump is running

dangel · 28 Oct 2010

kevplumb said:
1 Fan is running, constantly throughout the whole process. As is pump upstairs (this was replaced not so long ago).

Click to expand...

are you sure the pump is running

I'll double check this tonight but it certainly was last night when I was looking at it. Presumably without the pump being on the boiler would shut-down to prevent overheating? Would this mean the reset button on the bottom would pop out and be 'hard' to when pushed (I did hit this last night and there was no resistance from the button at all).

How long should a boiler last? Over the years i've replaced the actuator and pump upstairs and had one of the pipes kink (top rubber pipe [red] to APS) causing a similar fault (engineer fixed that one in five minutes lol)).

Agile · 28 Oct 2010

At two minutes it does rather indicate a flow problem external to the boiler.

That model if the temp knob is too high will operate the o/h stst first if there is no flow.

You can get an idea by feeling the flow and return pipes at the boiler. With a correct flow rate they should soon both become warm. If the return stays cold that indicates a probably lack of flow.

How do you know the pump is running correctly?

Tony

dangel · 28 Oct 2010

Agile said:
At two minutes it does rather indicate a flow problem external to the boiler.

That model if the temp knob is too high will operate the o/h stst first if there is no flow.

You can get an idea by feeling the flow and return pipes at the boiler. With a correct flow rate they should soon both become warm. If the return stays cold that indicates a probably lack of flow.

How do you know the pump is running correctly?

Tony

Interesting - thanks - learning all the time here

Well, the pump upstairs was running (vibration, sound etc) or so I thought last night.

Now you've raised the above i'll double check this. The one thing i've stupidly not said (sorry) is that last night by just running the hot water alone I managed to get a tank of hot water - so either the fault is intermittent (which is possible) or.. is it possible that with intermittent heating over time it would heat the water in the tank?

I didn't double check to see if the actuator is diverting correctly (we first noticed something was awry when the rads weren't getting hot) but i'm sure the main burner ought to stay lit for a more substantial amount of time regardless?

Just waiting to find out when the engineer can come round. Given the cost of parts for these things (having checked) this isn't going to be cheap regardless!

At work so I can't really try anything till later. Was all a bit late last night when this surfaced so my time was limited after spending a while reading through the manual online.

StevenJames125 · 28 Oct 2010

could be a rectification problem or gas valve fault even

i'd checdk pump first - se if it's running properley - what speed is it on?

dangel · 28 Oct 2010

StevenJames125 said:
could be a rectification problem or gas valve fault even

i'd checdk pump first - se if it's running properley - what speed is it on?

2 AFAIK - in fact, i'm sure.

StevenJames125 · 28 Oct 2010

when the boiler goes to lockout - does the pilot always stay on?? or does that go out too?

dangel · 28 Oct 2010

StevenJames125 said:
when the boiler goes to lockout - does the pilot always stay on?? or does that go out too?

It stays on (but I can't see any sparking or hear it either which probably means it knows the pilot is lit). I presume that if it's meaning to shut down the mainburner the pilot should also go out until a relight is necessary?

StevenJames125 · 28 Oct 2010

I haven't seen your boiler or manul - is it a permanent pilot or does the pilot come on only when a demand is to be made? I suspect it is this type?...

Could be a gas valve (solenoid) fault
or a PCB fault

But usually the pilot will go out and boilert to lockout if no ignition is made within a few attempts

dangel · 28 Oct 2010

StevenJames125 said:
I haven't seen your boiler or manul - is it a permanent pilot or does the pilot come on only when a demand is to be made? I suspect it is this type?...

Could be a gas valve (solenoid) fault
or a PCB fault

But usually the pilot will go out and boilert to lockout if no ignition is made within a few attempts

You can view the manual for this boiler here:

http://www.partsarena.co.uk/baxi/System/DATA/Dx/DS1/installation/2072/I01-2072/I01-2072.htm

Re-reading it myself!

EDIT: the fault finding chart seems to suggest the pilot remains lit?

dangel · 28 Oct 2010

Small update: engineer called and told me to check circulation and also the expansion tank in the loft to see if water is going into the system..

Going to check this when I get home (along with other suggestions) and give him a ring back in the morning.

dangel · 28 Oct 2010

Got home to find the pilot light on, no sparking btw, and the main burner out. I believe i've got water flow, upped the pump to position 3 to make sure (was on 2) and i've also checked the expansion feeder tank in the loft to make sure there's water in it (there is and the inlet pipe is sitting in water).

Tried pressing the reset button on the boiler and the main burner clunks and briefly lights and then goes out - a few times in a row and then it just clunked.

So i've got a permanent pilot light - which looks pretty - but def. got 'issues'

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Potterton Prima 40f - ignites, and then... goes out :(

Similar threads