cycling problem

[krill]

I have a Ravenheat boiler model CSI 85 A, the water works fine with continuous flame but when the heating is on the the boiler ignites then cuts out cycling about every 20 seconds or less, the radiators all get hot and there's no air in the system, can anyone advise or guide me to what to check first please
Any help would be much appreciated

 

[stem]

I'm not familiar with the model you describe, but it could be working correctly.

The temperature of water leaving the boiler is controlled by the boiler thermostat, which controls the burner to keep the water at the correct temperature. If it didn't, the water would actually boil and anyone touching a radiator would be burned.

If the radiators are at their normal temperature, then it seems to be doing its job. When heating up from cold in the morning, or heating the hot water, the demand is higher and the burner will stay on longer. As the system heats up and demand gets less, the 'on' periods will get shorter and the 'off' periods longer.

Many of the newer boilers have a modulating flame that can vary to meet the demand for heat, but it still may reach a point when the requirement for heat is less than the burner is delivering so that it goes off to prevent overheating.

Someone with knowledge of your model of boiler may be along soon with a definitive reply.

 

[ajrobb]

I'm not sure if it's the right manual but:
"The boiler is fitted with an anti-cycling device on the control board. This delays the boiler from re-firing over a 2/5 minute period."

So cycling every 20 seconds doesn't sound right.

 

[Agile]

A lot of boilers seem to have been sent out with the anticycling turned off!

But it also could be a fault. I assume this is a combi and the DHW is OK and stays on?

Its also possible the boiler has not been correctly commissioned at installation and was not serviced properly every year by a competent engneer.

Tony Glazier

 

[krill]

Thanks for the replies, the boiler was second hand, working when removed, it was commissioned by a corgi heating engineer who said it could take him a long time to find the fault and advised me to try the internet for a solution, the boiler cycles just as fast when the rads are cold so there must be a fault somewhere

 

[ex Teacher]

A lot of boilers seem to have been sent out with the anticycling turned off!

But it also could be a fault. I assume this is a combi and the DHW is OK and stays on?

Its also possible the boiler has not been correctly commissioned at installation and was not serviced properly every year by a competent engneer.

Tony Glazier

How would you go about switching the anti cycling device on if it was sent out with it switched off?
Thanks

 

[Agile]

I would need to read the service manual.

But before that I would be checking that the high and low flame settings on the gas valve are correct.

 

[polesapart]

In the thirteen years since the original post I imagine the second hand Ravenheat in question has long been scrapped.

ex Teacher please start your own thread.​