I have a fully pumped system with an Apollo 30/50b boiler and in 12 years use it has only had two faults. The first was a faulty thermocouple and the second a faulty pump. They were fixed.
It has been OK now for 2 years but recently it has become very noisy, here is the story:
The boiler stat is set to LOW or HIGH
The pump speed is set to HIGH
The programmer is set to MANUAL
When I switch on, and the system is calling for heat, the boiler fires up and the pump kicks in.
The radiators begin to heat up.
After about ten minutes, I hear a swishing sound from the boiler, which lasts for about six seconds, and then all hell breaks loose!
A loud hammering, about five or six sharp raps, is heard from the boiler, (which is downstairs in the kitchen).
The noise then migrates upstairs, through the pipes, to the expansion tank area and can be heard hammering and banging it’s way up to the tank itself.
The expansion overflow ejects some water.
The gas in the boiler switches off, (but the pilot remains lit).
The pump cuts out.
The noise stops.
Then the whole process repeats but becomes progressively more frequent.
Any suggestions?
It has been OK now for 2 years but recently it has become very noisy, here is the story:
The boiler stat is set to LOW or HIGH
The pump speed is set to HIGH
The programmer is set to MANUAL
When I switch on, and the system is calling for heat, the boiler fires up and the pump kicks in.
The radiators begin to heat up.
After about ten minutes, I hear a swishing sound from the boiler, which lasts for about six seconds, and then all hell breaks loose!
A loud hammering, about five or six sharp raps, is heard from the boiler, (which is downstairs in the kitchen).
The noise then migrates upstairs, through the pipes, to the expansion tank area and can be heard hammering and banging it’s way up to the tank itself.
The expansion overflow ejects some water.
The gas in the boiler switches off, (but the pilot remains lit).
The pump cuts out.
The noise stops.
Then the whole process repeats but becomes progressively more frequent.
Any suggestions?