3 way valve gone wrong

[nuns]

Hello.l We came back from holidays and out CH system is not working. There is hot water, but somehow the pump does not activate itself when the CH comes in.

If I manually pull the lever to the right hand side, it bounces back.

Any ideas of what is going wrong?

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• nuns
• 4 Jan 2012
• 1

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• nuns
• 4 Jan 2012
• 1

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• nuns
• 4 Jan 2012
• 1

 

[D_Hailsham]

Do you get central heating when the hot water is also being heated?

 

[nuns]

no.

But If I hold the lever to the right hand side the pump comes on and I get hot water in the radiators. The minute I let go, it bounces back to mid position and I loose the CH.

 

[D_Hailsham]

no.

But If I hold the lever to the right hand side the pump comes on and I get hot water in the radiators. The minute I let go, it bounces back to mid position and I loose the CH.

That is strange!

The boiler (and therefore the pump) is controlled by the thermostat on the side of the HW cylinder when HW is called and when HW with CH is called. So if the boiler and pump work for HW only it should also work for HW with CH.

Do you have a multimeter (and know how to use it )?

If so, there are detailed fault finding instructions in How a mid-position valve works.

 

[nuns]

Thank you!! I don-t have a multimeter, but my neighbour should LOL. And yes, I know how to use it, so with a bit of luck I can borrow it later on today.

Great link, indeed.

Do you not think it would be the three way valve? The timer works ok and the room thermostat does as well. Hot water comes on, so the cylinder thermostat must be working, right?

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• nuns
• 4 Jan 2012
• 1

 

[nuns]

?????????????????

I was thinking about what you said of the pump not working for HW and CH. I kept it running in the mid position although the radiators were not getting any hot water. Then, after awhile I manually switched it to CH, but with the HW on. If I switch the HW off, the heating comes off as the pump stops working.

At least now I can get the CH and the HW to work together... as long as I don't switch the HW off.

 

[Agile]

Have you tried latching the lever into the slot to hold it open?

Does the valve move at all on its own?

A test meter is the starting point of any fault finding!

Tony

 

[nuns]

Yes, I will get the meter later on.

But no, it doesnt move on its own at all and there is no CH without HW as the pump wont come on.

Thanks a lot for your help!!

 

[cherryred]

Sounds as though the motor within the actuator has possibly burt out.
This can be purchased on its own for around £15. The complete actuator is around £70
The motor is of the spring return type. It drives to open the port to heating and returns under spring action to hot water. Therefore if it is burnt out, you will not get heating.
The lever on the side can be moved to the manual position and usually if you push it all the way it will start the pump and boiler by means of the micro switch within but when latched into position it will move back to about halfway.
http://www.uk-plumbing.com/motorised-valves-honeywell-motorised-valves-c-220_274_276.html

 

[mysteryman]

It is indeed likely to be the motor in the motorised valve.

I am surprised that the two experienced guys in this thread did not point this out!

 

[matt1e]

It is indeed likely to be the motor in the motorised valve.

I am surprised that the two experienced guys in this thread did not point this out!

Not if the valve is moving to mid position its not

Nuns, if as you seem to imply

1) hotwater is working on its own
2) hotwater and central heating work if they are both switched on and in demand
3) central heating does not work on its own (or when the hotwater is satisfied)

then most likey you have a problem with the valve or valve actuator
either the microswitch has gone in the actuator (usual cause)
or the valve is not opening fully to the heating port to operate said microswitch (not as common)

Matt

 

[cherryred]

Yes, I will get the meter later on.

But no, it doesnt move on its own at all and there is no CH without HW as the pump wont come on.Thanks a lot for your help!!

But nuns said the valve does not move on its own.
Also when the lever was pulled over to the right the pump came on. This proves the micro switch is ok.

Therefore it does look very much that the motor is faulty.
Nuns - Take cover off valve head. Turn the cylinder stat down so as not to call for hot water, pump/boiler not running . Turn up room stat. Does motor move valve to heating? Pump/boiler should come on at end of travel. No.
Check 240v between blue and grey, and 240v between blue and white Yes. Renew synchro motor.

 

[matt1e]

Yes, I will get the meter later on.

But no, it doesnt move on its own at all and there is no CH without HW as the pump wont come on.Thanks a lot for your help!!

But nuns said the valve does not move on its own.
Also when the lever was pulled over to the right the pump came on. This proves the micro switch is ok.

but he also said

Then, after awhile I manually switched it to CH, but with the HW on. If I switch the HW off, the heating comes off as the pump stops working.

At least now I can get the CH and the HW to work together... as long as I don't switch the HW off.

unless he means he is manually latching the valve

perhaps Nuns needs to clarify
but anyway easy sorted once he wields his MM

Matt

 

[CombustionGuy]

i would take the metal case off and press the microswitch with a screwdriver if it works its the motor if not its the head simples

 

[cherryred]

i would take the metal case off and press the microswitch with a screwdriver if it works its the motor if not its the head simples

There are two micro switches within the head. I take it you mean the one which switches the pump/boiler. But we have already proved that to be ok.
If you stuck your screwdriver in and the pump started it would not necessarily prove that the motor was faulty. The fault could be that the motor is not receiving the correct voltage. This should be checked before fitting a new motor which may be ok.