Gas Boiler firing for 5 seconds then switches off for 15 seconds repeatedly
 

Hi

I noticed my my gas boiler doing the following this morning

When central heating was selected the temperature selector in the hall
was set to about 16C the boiler would fire for about 5 seconds then
stop for 15 seconds then it would fire for 5 and stop for 15, it seems
to do this often.
I've read that one point of inefficiency in gas boilers is short burn
time, durning the start up phase not all the is gas burned therefore
you don't get optimum heat from it. If my boiler is doing a start up
4 times a minute then it must be chucking a lot of unburned gas out
the flue.
The boiler is an "Ideal classic 270FF" with a "classic LX" programmer.
Is there anyway I could increase the burn time and hopefully reduce
the start ups.

Thanks Kev

Gas Boiler firing for 5 seconds then switches off for 15 seconds repeatedly
 

On Sat, 24 Feb 2007 03:53:05 -0800, purlpekenny1964 wrote:

Hi

I noticed my my gas boiler doing the following this morning

When central heating was selected the temperature selector in the hall
was set to about 16C the boiler would fire for about 5 seconds then
stop for 15 seconds then it would fire for 5 and stop for 15, it seems
to do this often.
I've read that one point of inefficiency in gas boilers is short burn
time, durning the start up phase not all the is gas burned therefore
you don't get optimum heat from it. If my boiler is doing a start up
4 times a minute then it must be chucking a lot of unburned gas out
the flue.
The boiler is an "Ideal classic 270FF" with a "classic LX" programmer.
Is there anyway I could increase the burn time and hopefully reduce
the start ups.

Is the system heating up OK or is it slow to warm up?

Rapid cycling like this suggests poor circulation: either pump not working
(or running very poorly) or some blockage in the pipework ('Y' in-line
strainer/filters, if fitted, are prone to blocking up). Alternatively you
may have thermostatic valves on all the radiators and they've all shut
down, but if the system is calling for heat with the room thermostat set
to 16C I'd guess the house is too cold for the TRVs to be closed unless
they're all set really low.