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Plumberpro
Plumberpro, Plumber
Category: Plumbing
Satisfied Customers: 634
Experience:  Heating and plumbing answers. 20 years experience
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Ravenheat Boiler over heating red lamp lights up 3 seconds

Customer Question

Ravenheat Boiler over heating red lamp lights up 3 seconds after calling for either hot water or central heating,
The pump runs for a few seconds only.
Then the overheating indicator lights up and the pump stops stops.
No power is switched to the fan but the fan is OK when I have disconected it and tested it worked no problems.
I thought this pointed to the fan controller PCB but I had swapped this out but the same problem remains.
I am certain somebody has repaired this fault before. So what is the cause of the combi-boiler not working properly. Thank you in anticipation of your help.
Submitted: 2 years ago.
Category: Plumbing
Expert:  Plumberpro replied 2 years ago.
Customer:

Hi . it is probably the temperature thermistors. Replace the heating and the domestic hot water one at the same time