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Combi Boiler
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my ravenheat boiler 820/20 poilt light is on but the boiler wont fire up so i have no heat or hot water, i have had a new thermocouple put in but still wont work idea please
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Thermocouple failure is very common Alan, as you've obviously found out. I guess it's still possible that the new one has failed.
The trouble is, there are so many little sensors,thermistors etc that can stop a boiler from working.
I guess your's is the type where the t/couple keeps the solenoid open to allow gas in.
I'm no boilerman I'm afraid. Silly question, but is the t/couple in the pilot flame properly?
I remember coming across one where it was out of place, thus never quite warming up.
Otherwise.......... gas valve... even a circuitboard fault.
Sorry that's all I can suggest Alan. Maybe one of Answerbank's proper boiler guys may see this. If not, probably call-out time.
The trouble is, there are so many little sensors,thermistors etc that can stop a boiler from working.
I guess your's is the type where the t/couple keeps the solenoid open to allow gas in.
I'm no boilerman I'm afraid. Silly question, but is the t/couple in the pilot flame properly?
I remember coming across one where it was out of place, thus never quite warming up.
Otherwise.......... gas valve... even a circuitboard fault.
Sorry that's all I can suggest Alan. Maybe one of Answerbank's proper boiler guys may see this. If not, probably call-out time.
The thermocouple (reaching the required temperature) will allow the automatic supply of gas to the pilot light – without the need to manually operate the value (as when the pilot light is first lit).
If your pilot light is lit, the thermocouple is OK.
In operation, when a demand for central heating or direct hot water is made on the boiler, first the fan switches on (to full speed). Once the boiler detects the required air pressure difference between the boiler combustion chamber and the exhaust output (due to the flow of air), the boiler switches on the gas valve supplying gas to the main burner – which is ignited by the pilot light.
All the above happens within a couple of seconds.
Knowing the above sequence can assist with fault finding. Recently my boiler failed to fire-up; the fan was running at full speed – but clearly no gas was being supplied to the main burner.
I removed the boiler cover to discover a split in a pipe to the air pressure sensor – which was an easy fix.
If your pilot light is lit, the thermocouple is OK.
In operation, when a demand for central heating or direct hot water is made on the boiler, first the fan switches on (to full speed). Once the boiler detects the required air pressure difference between the boiler combustion chamber and the exhaust output (due to the flow of air), the boiler switches on the gas valve supplying gas to the main burner – which is ignited by the pilot light.
All the above happens within a couple of seconds.
Knowing the above sequence can assist with fault finding. Recently my boiler failed to fire-up; the fan was running at full speed – but clearly no gas was being supplied to the main burner.
I removed the boiler cover to discover a split in a pipe to the air pressure sensor – which was an easy fix.
I thought Hymie would be able to clear that one up.
Not one of the most respected boilers ever made Alan. Worse still, it's obsolete. I can't even find a downloadable servicing guide.
With the air pressure switch, and the fact that this is a "veteran" model, I think you're getting into "Gas Safe" territory now.
Given the age, and a possible problem with air pressure and flue gases, the only proper advice is to call in the boiler guy.
I know it's a pain, especially when the solution may well be so simple.
Not one of the most respected boilers ever made Alan. Worse still, it's obsolete. I can't even find a downloadable servicing guide.
With the air pressure switch, and the fact that this is a "veteran" model, I think you're getting into "Gas Safe" territory now.
Given the age, and a possible problem with air pressure and flue gases, the only proper advice is to call in the boiler guy.
I know it's a pain, especially when the solution may well be so simple.
While I would advise extreme caution to anyone messing about with a gas boiler – removing the boiler cover is akin to opening the bonnet on a car. But before removing the cover, disconnect the mains power to the boiler.
With the boiler cover removed, regardless of the boiler make, the pressure switch should be accessible and easily identifiable. The two flexible pipes connected to the air pressure switch will be made of translucent silicone rubber (to enable them to withstand the heat) – with an external diameter of 10mm-15mm. Before attempting to replace the pressure switch, inspect the silicone tubes for splits, especially at unions.
When my boiler suffered a split in a pressure switch pipe, there was enough slack to allow me to cut off the perished end section and simply remake the join.
With the boiler cover removed, regardless of the boiler make, the pressure switch should be accessible and easily identifiable. The two flexible pipes connected to the air pressure switch will be made of translucent silicone rubber (to enable them to withstand the heat) – with an external diameter of 10mm-15mm. Before attempting to replace the pressure switch, inspect the silicone tubes for splits, especially at unions.
When my boiler suffered a split in a pressure switch pipe, there was enough slack to allow me to cut off the perished end section and simply remake the join.
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