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Plumberpro, Home Appliance Technician
Category: Appliance
Satisfied Customers: 634
Experience:  Heating and hot water heating appliances experienced
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I have a Bosch 28cdi combi boiler, no central heating but

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I have a Bosch 28cdi combi boiler, no central heating but both the heating and hot water lights are on permanent and I can get hot water. Also the diverter valve is permanently operating.
Hi, most likely a pcb fault
the pcb should not allow hot water and heating at the same time
Customer: replied 2 years ago.
That's fine but why is the diverter valve permanently operating, that is operating the micro switch?
Hi, when the hot water is on does the heating heat up aswell?
Customer: replied 2 years ago.
No it doesn't seem to
When you say the diverter valve is operating all the time what do mean? Do you mean the pin is out on the hot water microswitch?
Customer: replied 2 years ago.
The diverter valve must be stuck or youve got a massive leak on hot water pipework. Hopefully the former. The diverter will need replacing
Customer: replied 2 years ago.
I can push the pin back but it comes back out again and operates the micro switch which then putes the hot water light on.
Can you turn the mains off either at the stopcock or the cold inlet to the boiler and see if the pin goes in
Customer: replied 2 years ago.
Just done that and the pin still comes out
Ok, the diverter valve must be faulty and will need changing
Customer: replied 2 years ago.
Okay I will change it tomorrow.
Ok, all the best
Customer: replied 2 years ago.
I will let you know how I get on tomorrow. Cheers
Your welcome, all the best
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Customer: replied 2 years ago.
Bought a repair kit for the diverter valve for £27. Boiler now working properly!