In the last year I have replaced the Central Heating Pump, Thermocouple and Electrode. Everything has been hunky dorey until I got home yesterday. The house was warm and I turned up the thermostat to make it more comfortable. An hour later I noticed that the radiators were cold.
I looked through the portal and the Pilot Light was burning nicely. the fan was running. I put my hand over the flue on the exterior of the house to see if the air being vented was cold or warm as an indication as to whether the main jets had just gone out or if they had been off since I upped the thermostat.
The restriction of the airflow by my putting my hand over the end of the flue caused the main jets to ignite, confirmed visually and by the fact that hot air was coming out of the vent. 15 mins later the radiators were heating up nicely. Once my partner arrived home I explained our problem and felt the radiators - they were cooling. I repeated the process and by restricting the air coming out of the flue - the main jets ignite.
Looking at the Maintenance manual I suspected that the cause may be the Overheat Cut-Off Device. I tried changing from Hi to Lo thermostat setting, but it made no difference. Having read through the Forum I now suspect the Air Flow Pressure Switch.
Can anyone confirm my findings and my diagnosis - the Overheat Cut-Off Device or the Air Flow Pressure Switch? Or something else.
The boiler is quite old and I suspect will not go on forever. Can anyone recommend a replacement which will fit in the existing place utilising the existing flue hole and without major re-alignment of pipework etc.
I looked through the portal and the Pilot Light was burning nicely. the fan was running. I put my hand over the flue on the exterior of the house to see if the air being vented was cold or warm as an indication as to whether the main jets had just gone out or if they had been off since I upped the thermostat.
The restriction of the airflow by my putting my hand over the end of the flue caused the main jets to ignite, confirmed visually and by the fact that hot air was coming out of the vent. 15 mins later the radiators were heating up nicely. Once my partner arrived home I explained our problem and felt the radiators - they were cooling. I repeated the process and by restricting the air coming out of the flue - the main jets ignite.
Looking at the Maintenance manual I suspected that the cause may be the Overheat Cut-Off Device. I tried changing from Hi to Lo thermostat setting, but it made no difference. Having read through the Forum I now suspect the Air Flow Pressure Switch.
Can anyone confirm my findings and my diagnosis - the Overheat Cut-Off Device or the Air Flow Pressure Switch? Or something else.
The boiler is quite old and I suspect will not go on forever. Can anyone recommend a replacement which will fit in the existing place utilising the existing flue hole and without major re-alignment of pipework etc.
