Boiler only turns on with hot water not with CH

[Palmist]

Hi Guys, hoping someone will guide me in the right direction. I have recently bought a new place and heating seem to be working ok till a couple of days ago. I have been doing a lot of reading to familiarize myself with heating system.

Problem:

CH comes on when HW is water and once water is heated, boiler goes off. I have checked thermostat and its set to max.

Boiler: Greenstar Ri condensing

I have been reading up on such issues and have finally locally the valve in airing cupboard, it says Honeywell F4 0540 D. This valve has a lever kind of thing which says Auto on left hand [my left] and MAN on right. Nothing in middle. I have tried moving it to MAN and AUTO but it makes no difference. Valve stays in same position AUTO when I turn HW on or OFF.

I would really appreciate if you can help me out here. Boiler is still under warranty but when I called the guys they said that its not the boiler but something else in the system.

thanks

 

[adlplumbing]

three port vavle has gone most likly

check it by feeling the return pipe as it get`s warm if it hot then it tell`s the boiler to shut down

also check the rads when it does this at the bottom

 

[Palmist]

thanks, its gone off and everything seems cold, probably because water has reached its highest temperature.

Lever has little or no resistance when I try and move it from AUTO to MAN and back.

You will need to tell me which one is return pipe please

 

[Palmist]

After reading other forums, I have figured out that the actual model is V4073A1039

Is it worth replacing this valve on my own ?

 

[adlplumbing]

are the rads hot yes or no
and return pipe take pic boiler and we shall tell you

 

[Palmist]

radiators were hot and stayed for about an hour but all gone cold now. Boiler not firing up staying on blue, no green light.

Does the VALVE setting need to be in middle or on AUTO [far left]

Pics below and all pipes are cold

Untitled

• Palmist
• 17 Nov 2011
• 1

 

[Palmist]

I have been flicking the valve to MAN and AUTO a few times.

Did a little tap with a mallet a few as suggested in another thread.

HW is off and CH is on and the boiler has fired up. Been like this for last 15minutes. Radiators are warming up and I now which pipe you were on about, its really hot.

Fingers crossed, How can I avoid it from happening again. I normally switch hot water and CH off most of the time. Is it better to leave it on timer than manually switching off.

 

[adlplumbing]

it possibly the one with gate vavle on but i can not tell on that pic

 

[D_Hailsham]

It sounds as if the valve is sticking.

Is there a small bump on the top of the cover - it looks like it from the pic?

If so you can remover the actuator - that's the metal box.

Turn the power off to the system.

Lock the lever in the notch at the MAN end
Remove the cover (screw at the end)
Remove the actuator (two screws in opposite corners). No water will come out.

You will then see the valve spindle.

This should be able to turn easily by hand - but less than a quarter circle.

If it is hard to turn, apply a small amount of silicon lubricant to the spindle and use a pair of pliers to free the shaft.

Replace the actuator and cover.

Release the lever, which should move over to the Auto end with a whirring sound.

Push the lever to the Man end - you should feel resistance - and let go. It should return to the Auto end.

If this is OK, turn the power ON and check the boiler works for HW, HW and CH, CH.

You will not see the lever move from the Auto end, but when you have CH on (with or without HW) the lever will feel floppy when you move it to the MAN end.

 

[Palmist]

It has been working alright now since the "fiddle". HW and CH both come on separately and together.

However I was woken by loud pump noise yesterday, lowered the thermostat on boiler and it went quiet.

 

[Palmist]

back to how it was

I am going to try what you said about turning the spindle.

 

[Palmist]

It sounds as if the valve is sticking.

Is there a small bump on the top of the cover - it looks like it from the pic?

If so you can remover the actuator - that's the metal box.

Turn the power off to the system.

Lock the lever in the notch at the MAN end
Remove the cover (screw at the end)
Remove the actuator (two screws in opposite corners). No water will come out.

You will then see the valve spindle.

This should be able to turn easily by hand - but less than a quarter circle.

If it is hard to turn, apply a small amount of silicon lubricant to the spindle and use a pair of pliers to free the shaft.

Replace the actuator and cover.

Release the lever, which should move over to the Auto end with a whirring sound.

Push the lever to the Man end - you should feel resistance - and let go. It should return to the Auto end.

If this is OK, turn the power ON and check the boiler works for HW, HW and CH, CH.

You will not see the lever move from the Auto end, but when you have CH on (with or without HW) the lever will feel floppy when you move it to the MAN end.

Found the spindle, it doesn't seem sticky at all and moves a tiny bit on each side not much, even with pliers in only moves a tiny bit.

Put actuator back on and CH worked fine on its own for 10 mins before we went back to square 1.

So opened it up again and it seems that spring action only works when actuator case is at an angle. So I put some wire bit to give it bit of a tilt and not the lever is all springy and goes back to auto [not all the way back though]

Now I have only hot water; CH doesn't come on even with HW.

 

[D_Hailsham]

How a mid-position valve works has fault finding instructions.

 

[Palmist]

vavle seems to be moving fine so I am going through the wiring.

Couldnt get past the first CH only test:

white wire is connected to T4, I have moved it to T1 which was empty

grey wire was on T3, as soon as I moved grey wire, I heard something moving in the valve. I have set it to T1 as well.

Now when I got mrs to turn CH on , the valve moves, I could see it as I have the cover open. And I can see switches. no light on Boiler though

Again when I switch HW on with CH boiler light comes on, but not only on CH.

I have attached a picture of wiring box to make I am reading the numbers correctly. Is T1 the blank one on top of red wire or the red one itself or both ?

thanks

Untitled

• Palmist
• 24 Nov 2011
• 1

 

[D_Hailsham]

I have attached a picture of wiring box to make I am reading the numbers correctly. Is T1 the blank one on top of red wire or the red one itself or both ?

Let's clear this up first. The terminals are in pairs as they are the same block of brass. T1 refers to the first (left) pair, and so on.

Couldnt get past the first CH only test:

white wire is connected to T4, I have moved it to T1 which was empty

grey wire was on T3, as soon as I moved grey wire, I heard something moving in the valve. I have set it to T1 as well.

Now when I got mrs to turn CH on , the valve moves, I could see it as I have the cover open. And I can see switches. no light on Boiler though

It sounds as if T1 only goes live when you turn CH ON. For the test, the white and grey need to be connected to a terminal which is permanently live. This is usually T1, but may not be - it all depends on the installer's preferences.

Do you have a multimeter?

Can you post a list of what each wire is connected to, for each terminal pair? (Warning: Green/yellow cables may not be earth cables, they could be carrying 240Vac.)