Centrl Heating Not Working

[MANDATE]

The problem could be your 3 way actuator.
In the rest position it caters for hot water only. In the mid position it caters for both hot water and central heating.In the final position it caters for central heating only.
You may find it functions OK in the mid position and you get some heating but as soon as the hot water cylinder is satisfied it is supposed to move to the final position and supply a live feed to the boiler through a micro switch. You need to establish if it works ok in mid positon, you may have to run a bit of hot water off or increase the cylinder stat. Feel at the pipes coming from the 3 way valve (not too near the valve) If the water is being shared then both pipes should be hot. If the pipe going to the radiators is cold(ish) it suggests the valve has not moved to mid position. If everything functions in mid positon you need to establish if the valve moves to the final position. You should be able to hear it move or see an indicator light. If it does move to the final positon you need to establish if the live supply to the boiler exists. You can verify if there is a voltage or not in the wiring terminal box on the terminal containing the 'orange' wire.
Do you know if the actuator head can be removed from the valve, if it can it makes it easier to check, you can see the actuator move according to the various demands.

 

[MANDATE]

If you do manage to remove the actuator head, try twisting the spindle with finger and thumb to make sure it turns easily. The W M H markings are Water, Mid way and Heating and I presume the lever mentioned acts as a indicator to show which position the valve is in. If the valve does not move from W (rest positon) to mid positon then either the actuator needs replacing or a wiring fault ( check voltage on terminal holding 'white' wire in terminal box).

 

[espee]

The valve indicator does move to M but the radiators are still cold. All the pipes seems equally hot.

 

[kevplumb]

remove the screw from the pump again and stick a screwdriver in the hole see if the pump is actually running

 

[espee]

With CH and HW both switched off from the control panel I opened the screw on the pump. Water started dripping out of it but when I inserted screw driver in it, I could not sense any movement. Should I expect the pump to be running only when CH and HW is on.

 

[kevplumb]

yes the pump should be running try again with the screwdriver there is a slot in the top of the shaft to turn it might only be stuck

 

[espee]

Do you mean the pump is running 24 hours a day. It might have tired by now.

I could not rotate the pump after removing the screw. Should it rotate clockwise or anti-clockwise (looking from the front) anyways, I could not rotate it at all. Does it need a lot of force or should it be easily rotatable?

 

[kevplumb]

sounds like a new pump its seized
it runs thro the programmer and the three port valve
so it shouldnt be running 24/7

 

[espee]

Shall I try and see if the pump moves with heating and hot water switched on or is it unsafe?

 

[kevplumb]

help yourself
at this stage of the game anything is worth a try
no its not unsafe

 

[espee]

A big thanks to all of you who helped me. At least when the plumber / heating engineer arrived, I knew he was not talking rubbish. The plumber came in yesterday, did the job within an hour. Within the first 5 minutes, he was right on the track and said the pump needs replacing. The plumber was a nice huy actually, much better than expected. (Did I have low expectaions?) The pump replaced, and now I am warm again, ready for christmas.

Thanks

 

[Gambituk]

Hi , just wanted to say thanks for this post, i used it to diagnose a sticky pump in my system that was causing my boiler to start, boil over like a kettle and then stop within a few minutes.. I inserted screwdriver and rotated manually for a minute or so, and when i restarted my boiler, the pump made a whirring noise that it hadn't made before. i removed the screw again and inserted screwdriver to feel it going round. it didn't spray me with water as expected.
Now, everything is thawing out and i'm a lot more relieved.

Thank you to all involved in this post.
Crighton

 

[espee]

Glad it helped you.