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Andrew Smith
Andrew Smith, Home Appliance Technician
Category: Appliance
Satisfied Customers: 3768
Experience:  Gas cooker specialist
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Had a new boiler fitted also Drayton 2 way motorised valve

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Had a new boiler fitted also Drayton 2 way motorised valve on central heating only? makes a banging noise every time boiler shuts down? valve does not have direction arrow on it but has A and B on end ports? flow is from B to A which makes me think it is wrong way round? closing flap is at A port? bypass gate valve is open about 1/3 on a turn? thanks in advance Tom.

Do you have the make and model of the boiler.

Strange to hve 2 port on the heating only?

No 2 port near the cylinder?

Customer: replied 4 months ago.
Worchester Bosch 30 ri 1 valve on central heating 2 port? And 2nd valve on hot water 2 port? Only central heating was change recently when boiler was fitted?
Ok, S Plan then.
It's a good control system but does not work very well with a boiler that has a pump overrun.
The bypass should be open a lot more or you will give the pump problems.
The correct option is a differential pressure bypass valve;
https://www.screwfix.com/p/compression-differential-bypass-valve-22mm/40437
Customer: replied 4 months ago.
thanks for your help
No problem.
Come back if you need anything else.
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