Any heating engineers in?

[bd02]

Problem - central heating / hot water programmer reaches 'on' time, lights on programmer come on, boiler sometimes fires, sometimes doesn't - about 50/50. I can sometimes get it going by switching the programmer to 'off' and then back to 'run'. Failing that, if I switch the boiler off and on again then it usually fires.

I've had the boiler serviced and changed the programmer - problem remains. It's as though the message to come on isn't always being received by the boiler... although I believe the message is being 'sent' and the boiler is working OK.

Is there some sort of electrical unit that 'receives' the message from the programme and tells the boiler to fire?? Could this be where the fault lies?

Many thanks.

[tonyvid]

Maybe the gas valve for the main burner is on the way out - what happens if you try and switch it on manually, does it still act funny?

[cjs]

What type of boiler? Combi/ Conventional? What make model?

[ratbane]

Title should read "Any CORGI registered PLUMBERS in?"

[Nic Jones]

ratbane said:

Title should read "Any CORGI registered PLUMBERS in?"

Glad I'm not the only one who gets annoyed by that.

[bd02]

The boiler is a Vaillant Thermocompact - not sure which model as it doesn't say on it but the user manual is for the following: 615/2 E, 620/2 E, 624/2 E, 628/2 E

In terms of maual switching - generally speaking if the programmer is 'on' but the boiler isn't working, I can fire it up by manually switching the boiler off and on again. Doesn't ALWAYS work however!

[bd02]

Nic Jones said:

ratbane said:

Title should read "Any CORGI registered PLUMBERS in?"

Glad I'm not the only one who gets annoyed by that.

My corgi registered plumber refered me to a heating engineer.... who couldn't get out till the new year! Apologies for any offence!

[ratbane]

bd02 said:

Nic Jones said:

ratbane said:

Title should read "Any CORGI registered PLUMBERS in?"

Glad I'm not the only one who gets annoyed by that.

My corgi registered plumber refered me to a heating engineer.... who couldn't get out till the new year! Apologies for any offence!

No offence. That means someone from Vaillant then. Looks like only the manufacturer can help.

[dirkgently]

Is the boiler locking out or just not doing anything?

[bd02]

dirkgently said:

Is the boiler locking out or just not doing anything?

Thats the odd thing - it's not locking out - just intermittently refusing to fire! Once it's going it's fine.

[Hoppy2008]

Hello Mate.

I just had this exact problem.
My mate works for British Gas. Took one look at it and knew what it was right away.
It needed a new PCB. I picked it up locally, cost £120, he fitted it in seconds.
Works like a treat now.

HTH

[bd02]

Hoppy2008 said:

Hello Mate.

I just had this exact problem.
My mate works for British Gas. Took one look at it and knew what it was right away.
It needed a new PCB. I picked it up locally, cost £120, he fitted it in seconds.
Works like a treat now.

HTH

Thanks for that Hoppy - that's a new avenue to look at - sounds like the sort of thing I would expect it to be given the symptoms (not that I'm an expert!)

[cjs]

Is it a Combi or conventional boiler????

[bd02]

cjs said:

Is it a Combi or conventional boiler????

Conventional

[cjs]

bd02 said:

cjs said:

Is it a Combi or conventional boiler????

Conventional

Could be many things but as said before the PCB is a good place to start, you could check for dry joints on the board, I have fixed a few Boiler problems caused by dry joints. Saved £100+ for new PCBs.

Do you have a room thermostat? Bypass this it could be faulty?

[bd02]

cjs said:

bd02 said:

cjs said:

Is it a Combi or conventional boiler????

Conventional

Could be many things but as said before the PCB is a good place to start, you could check for dry joints on the board, I have fixed a few Boiler problems caused by dry joints. Saved £100+ for new PCBs.

Do you have a room thermostat? Bypass this it could be faulty?

No we don't have a room thermostat - just individual thermostats on the rads.

[cjs]

Do you get Hot Water?

[bd02]

cjs said:

Do you get Hot Water?

yes

[cjs]

bd02 said:

cjs said:

Do you get Hot Water?

yes

So you get a tank of HW and the boiler fires up okay to heat this? I'm assuming you have tested the CH with all the rad valves turned up full? Do you have one rad which is fully open all the time? Ie no thermo valve?

[bd02]

cjs said:

bd02 said:

cjs said:

Do you get Hot Water?

yes

So you get a tank of HW and the boiler fires up okay to heat this? I'm assuming you have tested the CH with all the rad valves turned up full? Do you have one rad which is fully open all the time? Ie no thermo valve?

Sorry I think I misled you. Basically, when the problem occurs the boiler doesn't fire up at all. Rads don't warm and presumably no water gets heated. As yet we haven''t run out of hot water but I guess that's cos there is always some left in the tank from the last time the boiler was working (we usually do end up getting the thing to fire up each day). Like I said at the beginning, it's as though sometimes the boiler gets the message to fire and sometimes it doesn't. Which leads me to suspect the fault is electrical. WI've eliminated the programmer (by replacing it) - concensus now seems to be PCB. Question - if PCB was broken, would boiler EVER fire? Because as I say, by switching through the on/off cycles on the programmer eventually the boiler does seem to get the message and fire up.