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Andrew Smith
Andrew Smith, Home Appliance Technician
Category: Appliance
Satisfied Customers: 3767
Experience:  Gas cooker specialist
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I have a headline compact boiler, it's not a combi. When it

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Hi I have a headline compact boiler, it's not a combi. When it calls for heating on the time clock,it will not fire up, but if it calls for not water it will

Sounds like a problem with the motorised valve.

Can you confirm the valve opens fully when you have selected heating?

Customer: replied 4 months ago.
Yea valves are open fully
Do they open and close as you turn the heating on and off.
The lever should be slack when open only
Customer: replied 4 months ago.
Yea the valves are perfect
Ok - it is the valve a that fire the boiler.
Do you have a 2 port on the hot water circuit and one on the heating?
An S Plan?
Customer: replied 4 months ago.
It's a system boiler. So their are only motorised valves after the boiler
Ok, but makes no difference.The 2 motorised valves will be wired (via their grey and orange wires) to fire the boiler when opened.
You should check the wiring from the heating 2 port to ensure this is what happens.
Customer: replied 4 months ago.
The valves are perfect
Are you able to check wiring to make sure you are getting 240v back from the valve to fire the boiler when it opens and clicks?
Customer: replied 4 months ago.
Yea, if I turn the time clock on that calls for hot water the boiler will fire, so I heat the rads by having all clocks on at the same time, but if I only call for heating the boiler won't fire
It will be the microswitch in the 2 port head then.
If the valve is opening fully but there is no click then you have to change the head.
When you do, use some WD40 on the valve pin to ensure it gives full movement.
Customer: replied 4 months ago.
The valve is fine,
Not if it won't fire the boiler
It is the valve that fires the boiler
Customer: replied 4 months ago.
just change the head of the valve so.
Customer: replied 4 months ago.
How exactly do I check that, with a multimeter
Can you identify the correct valve?
If so then follow the wire to the junction box.
Check for 240v at the orange and grey wires with nothing on and then with the heating on.
Let me know what you find.
Always check against the earth wire and the one you are checking. Meter set to 500v AC.
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