Help! my heating died

[BALLISTIX]

Any help would be great

Worcester 9/14 cbi boiler
Honeywell st699 programmer
Honeywell room stat

Straight to the point, boiler not operating when heating required, have turned boiler on/off, re-set programmer, checked fuses/connections, all good.

Programmer heating light illuminates so bypassed/bridged room stat still no go, boiler silent, no fan no pump.

Hot water is fine btw.

Possible PCB failure is my guess, I take it the PCB has seperate heating and hot water circuits?
Any suggestions welcome.

Thx
Andy.

 

[Breesey]

How's your three port valve looking?

 

[BALLISTIX]

Hi Breesey

I pushed the little leaver over to off/manual (it was half way between auto and off/manual) and the pump started, ran downstairs and boiler is still asleep.

Ive put the lever all the way back to auto, is this correct?

Hot water still working fine.

Thx
Andy

 

[Breesey]

If the boiler's working for hot water there's a good chance its the valve head. What make is it?

 

[BALLISTIX]

I just did it again, pushed lever to off/manual, pump started, ran down stairs boiler fan was on, but no ignition, just the fan and pump running.

Went back upstairs and lever had moved back to half way between auto and off/manual by itself, is this ok?

Went back downstairs and boiler is again silent.

It is a Honeywell sundial y plan?

Thx
Andy

 

[hi-spec plumbing heating]

check the motor in the valve is getting power if so the motor has gone.

 

[BALLISTIX]

check the motor in the valve is getting power if so the motor has gone.

Am i correct in thinking, if I pushed the lever over to manual and hooked it under the 'tab' so it stays there, should the boiler not ignite though? as it does not atm.

 

[Breesey]

check the motor in the valve is getting power if so the motor has gone.

Quite!!

 

[hi-spec plumbing heating]

check the motor in the valve is getting power if so the motor has gone.

Am i correct in thinking, if I pushed the lever over to manual and hooked it under the 'tab' so it stays there, should the boiler not ignite though? as it does not atm.

pushing the lever across don't mean it will make the microswith

 

[hi-spec plumbing heating]

switch it to heating and stat up check if you have live at the orange wire in your wiring centre

 

[BALLISTIX]

And just when you need your circuit tester!

Yup I off to being screwed for it

 

[BALLISTIX]

Ok, just checked and have 230v supply to wiring box, I take it you were both correct in diagnosing a duff 3 port motor then?

 

[Breesey]

With heating only calling for heat you should have 240v on the grey and white. When heating satisfied you should have about 100v on the orange only, assuming you had only had heating on.

Change the head mate

 

[D_Hailsham]

Ok, just checked and have 230v supply to wiring box

Do you mean the box on top of the valve or the one on the wall? You may find that you need to remove the cover of this box to do a proper check

Read How a 3-port valve works

It explains what voltages you should have on which wire and when.

The easiest way to check that the motor is working is to turn the room thermostat up and down and listen to the motor whirr. Motors are standard parts and can be bought from B&Q.

If the motor is OK and you don't get the correct voltages then the actuator is faulty. Provided your valve is not too old, these are also replaceable parts (on some makes at least e.g Honeywell)


Edit: The manual position on the valve is purely for refilling the system. It must be in Auto when the system is running. The position of the lever does not indicate where the valve is.

 

[Breesey]

I explained in my last post what voltages to expect at the valve and when, I did assume that Ballistix was talking about the valve head, thanks for clarifying that D Hailsham, btw do have shares in B&Q?!