My Potterton Promax 15HE not modulating - the burner is always at max and never modulates down.
Had several engineers scratching their heads. Eventually found a guy who'd do it for a fixed price. He has changed the flow thermister and both the control and ignition pcbs but no fix yet.
From my own research I understand that the gas valve controls modulation by varying gas pressure under the control of the control pcb. Is this true for this boiler?
Can the GV be changed without interferring with the gas supply?
Can it be adjusted?
What else might cause this problem?
Thanks
Had several engineers scratching their heads. Eventually found a guy who'd do it for a fixed price. He has changed the flow thermister and both the control and ignition pcbs but no fix yet.
From my own research I understand that the gas valve controls modulation by varying gas pressure under the control of the control pcb. Is this true for this boiler?
Can the GV be changed without interferring with the gas supply?
Can it be adjusted?
What else might cause this problem?
Thanks