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Ask Jerry Your Own Question
Jerry, HVAC Technician
Category: HVAC
Satisfied Customers: 422
Experience:  Epa universal certification, hearth products specialized.
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My vaillant thermocompact boiler is approx 5 years old but

Customer Question

My vaillant thermocompact boiler is approx 5 years old but has started to come on at times when the controller( lp241) indicates it should be off ie at night, the controller light is off but the boiler is heating up and pumping.
Is there my other cause except a faulty controller unit?
Submitted: 4 years ago.
Category: HVAC
Expert:  Andrew Smith replied 4 years ago.
Is the boiler in the garage or somewhere cold?
Customer: replied 4 years ago.
No the boiler is inside the house and never gets too cold. The controller light indicates the boiler should be off but it is pumping and heating up.
Expert:  Andrew Smith replied 4 years ago.
It sounds like your motorised valve is stuck in the open position. Are you able to find it in the airing cupboard?
Turn off your heating and hot water and then see if you can find it