Firebird Combi C26 strange goings on

[Mathemagic]

Hi I wonder if anyone can help.

I've recently moved into a house with one of these. Water and heating all seem to work ok with one notable exception.

Every now and then one radiator, and sometimes a second start to heat up even if the heating is completely switched off. The don't get to full heat. The first one isn't even the first radiator to get hot when I switch the heating on.

We don't have a hot water storage tank - taps and heating are both on demand. However, the system does seem to have a built in feature where it starts up and runs for a period of time (some minutes) even though there is no demand for heating or hot water at all. I'm only guessing that this is related. I have heard that some systems keep an amount of water heated up in reserve. Our usage means this just uses heating oil for no reason.

Any suggestions (and even how to turn this feature off if it is the cause) are very gratefully received.

Thanks

 

[Mike Jackson]

Not familiar with the boiler but my guess is a hot water preheat and the diverter valve passing.

 

[lame plumber]

some firebirds have stored water in combi hence need to turn on and run up at times, and diverter is probably passing hence warm rads, need an engineer preferably oftec to carry out investigation

 

[Mathemagic]

Hi both,

Thanks for the quick reply.

Just looking at the instructions and it seems that the system has a "Twin circulating pump – no diverter valve required".

Would your replies then point to the pump as the problem?

 

[lame plumber]

you have a hw heat store as i thought, which stores ready use hw and will kick in when the temp drops, so your probably getting some gravity feed to rads warming them as the hw is warmed up.

 

[Mathemagic]

Thanks lame plumber - The gravity feed bit would make sense with the radiator that is getting warm not being the normal first one in the sequence when using the heating. I don't suppose you know if the preheat / hw heat store feature can be turned off? Otherwise I think we will just live with things for the time being until we next get it serviced.

 

[kimbo]

These boilers have a check valve in the pump outlet if its a condensing boiler and if it isnt there will be one on the heating flow at the top of the boiler and one for the hot wster. It sounds like the check vslve is stuck open which is quite common. It will neef an engineer I am afraid.

 

[lame plumber]

These boilers have a check valve in the pump outlet if its a condensing boiler and if it isnt there will be one on the heating flow at the top of the boiler and one for the hot wster. It sounds like the check vslve is stuck open which is quite common. It will neef an engineer I am afraid.

its an old conventional fm the sound of things