Biasi 24s combi boiler not working

jason_3

Please can someone advise me about my boiler, when I turn the boiler on for heating or hot water it fires up but after a few seconds goes to lockout. I have taken the cover off so I can see the fan and burner, fired boiler up and boiler stayed on but when I put the cover back on the flame goes off and boiler goes to lockout. A friend said it could be the air pressure switch. Can anybody help please.

miniemma

I'm certainly no expert but, do the radiators need bleeding?

jason_3

No the pressure is 1:5 bar which is fine.

flea72

do you have thermostatic valves on all your rads?

i have this prob with my biasi boiler, and the only thing that has cured it, is to have one rad valve, fully open all the time

jason_3

No pressure is at 1:5 bar which is fine.

jason_3

Yes there are TRVs but all the valves are open

jason_3

Did you take the cover off your boiler so you could see inside and did the boiler then stay on.

flea72

are all the valves fully open?

i dont know about removing the cover and it staying on or not. as im not technically minded, i paid for an engineer to come out - he advised having one of the valves fully open, the others i could have at whatever temp i wanted, something about you shouldnt have thermostatic valves on all rads, as it means the system doesnt have a bypass (?)

could be complete twaddle, but it seems to have worked, and ive had no probs since

flea

robowen

flea72 wrote:

are all the valves fully open?

i dont know about removing the cover and it staying on or not. as im not technically minded, i paid for an engineer to come out - he advised having one of the valves fully open, the others i could have at whatever temp i wanted, something about you shouldnt have thermostatic valves on all rads, as it means the system doesnt have a bypass (?)

could be complete twaddle, but it seems to have worked, and ive had no probs since

flea

All boilers should have a bypass. A lot of new boilers have inbuilt bypasses.
Older boilers required a connection from the flow pipe to the return pipe, before the first radiator. This would have a gate valve on it which would be mostly closed off to allow some water to return to the boiler.

It's common to have the bathroon rad valves completely open and this would act as the bypass too. This is why TRV's are not fitted in bathrooms unless a bypass is identified.

rob

robowen

jason wrote:

Please can someone advise me about my boiler, when I turn the boiler on for heating or hot water it fires up but after a few seconds goes to lockout. I have taken the cover off so I can see the fan and burner, fired boiler up and boiler stayed on but when I put the cover back on the flame goes off and boiler goes to lockout. A friend said it could be the air pressure switch. Can anybody help please.

It won't be the air pressure switch.
If it were, then the boiler would not fire up to start with.

When you switch your boiler on, the first thing that happens is the fan starts. If the fan doesn't go.....it won't change the contacts over on the APSwitch and won't fire the boiler.
If the fan goes and the boiler doesn't fire up, it could be the APSwitch.
If the fan goes and the boiler fires up, the APswitch is ok.

I've been to a few where the customer had tried to top up the boiler and had closed off the flow isolation valve. This caused the boiler to lock out after a few seconds.
as you mentioned, there seems to be no bypass with your system, and this could cause the high limit stat to kick in and shut the boiler down.
This will happen when all the rad valves closed at the same time.

I think your boiler man was right.

rob

marc_bell

I have used my boiler over night for central heating then I turned it off in the morning I wanted to turn it back on in the afternoon but it won't light up no hot water either. can anyone help ?