URGENT Need help on central heating problem

[Rosemi1623]

potterto boiler 23 years old, Drayton mid point actuator.
Central Heating only works when water also on & stat works normally. When CH only, the stat shows a bright light when calling heat and dim light when at temperature.
I changed the stat and it made no difference.
The three way valve seems to work ok (slider moves from W to both to CH) but when you take the head off and use pliers to turn it is very clunky.
Pump seems to be working ok.
Any ideas?

 

[Ric2013]

potterto boiler 23 years old, Drayton mid point actuator.
Central Heating only works when water also on & stat works normally. When CH only, the stat shows a bright light when calling heat and dim light when at temperature.
I changed the stat and it made no difference.
The three way valve seems to work ok (slider moves from W to both to CH) but when you take the head off and use pliers to turn it is very clunky.
Pump seems to be working ok.
Any ideas?

I take it this used to work until recently?

Try turning the heating system off at the isolator and then on again.

If still not working:

I don't think you've proved that the actuator head is working correctly (is it making the right wires live at the right times and is it moving to the right places under motor control?)
If the valve itself is 'clunky' then either it may be preventing the actuator head from doing its job, or it may have been leaking and has caused the head to malfunction.

If you have a good logic for faultfinding and know your way around a voltmeter (not a volt stick), then you may be able to check if the actuator head is working and if it is receiving the right voltage on the right wires. This would help you pinpoint what needs replacing.

Other than that, this really is a job for a skilled plumber or heating engineer. Most electricians won't understand their way around heating controls.

 

[Rosemi1623]

I take it this used to work until recently?

Try turning the heating system off at the isolator and then on again.

If still not working:

I don't think you've proved that the actuator head is working correctly (is it making the right wires live at the right times and is it moving to the right places under motor control?)
If the valve itself is 'clunky' then either it may be preventing the actuator head from doing its job, or it may have been leaking and has caused the head to malfunction.

If you have a good logic for faultfinding and know your way around a voltmeter (not a volt stick), then you may be able to check if the actuator head is working and if it is receiving the right voltage on the right wires. This would help you pinpoint what needs replacing.

Other than that, this really is a job for a skilled plumber or heating engineer. Most electricians won't understand their way around heating controls.

Thanks for reply. Will try tonight. Have added a video to show the clunks.....is this normal. Mike
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Thanks for reply. Will try tonight. Have added a video to show the clunks...is this normal. Mike

Actuator moves to right place at the right time.

 

[Last Plumber]

If the Boiler works for Hot water you can more than likely rule that out.
The chances are it is going to be the programmer, room stat, Motorised valve, wiring etc.
All the component parts can be tested so there is no need to guess and that method will only cost money unnecessarily.
How competent are you with electrical work?

 

[Rosemi1623]

If the Boiler works for Hot water you can rule that out.
The chances are it is Either the programmer, room stat, or Motorised valve.
All the component parts can be tested so there is no need to guess and that method will only cost money unnecessarily.
How competent are you with electrical work?

I am confident to check voltage etc but lack some proficiency and which wires to check. I may have an old programmer so will try that out. I am trying to get hold of a plumber that helped me 6 months ago with a blockage. Thanks for help. Is the noisy valve normal?

 

[SJB060685]

I'd be suspicious of the valve head. But this needs to be tested on certain coloured wires. This really is a job for someone with a good understanding of electrics. I'm sure if you feel confident then someone will guide you through it but ONLY if you're confident

 

[Last Plumber]

I would recommend you ask a heating engineer to look at it. If you're not experienced with heating wiring, you could easily make a mistake.

 

[Rosemi1623]

Thanks for help. Put an old programmer in and problem persists. Checked wiring of mechanical valve (Actuator) and all secure. So down to actuator or 3 way valve or perhaps pump but that works when water/CH on together.

 

[SJB060685]

I'm a bit concerned how you've tried a new stat and programmer. Are you sure you're connecting the right wires to the right place, you could be further complicating things. Really it needs to be tested from programmer to stat and to valve to see what voltage is where. Like I said earlier from what you've described I suspect it is the valve body or head.

 

[Rosemi1623]

Thanks. The programmer is a clip on to a base which holds the wires. Two minute clip on so no wires and stat was 4 simple wires. The valve was clunky when moved with pliers so not sure if that is normal. I changed the actuator about 5 years ago and quite proficient at replacing bits.
Is a clunky valve normal??

 

[SJB060685]

No a clunky sound is not normal. All that should be heard is the slight sound of the motor motoring over.

 

[Rosemi1623]

It’s only clunky when using pliers to turn the spindle (quite stiff). When the actuator does it there is not much noise.

 

[SJB060685]

The spindle could be sticking and preventing the valve from opening fully. The valve has switches inside that depending on what's called for depends what's live and isn't. With everything off and then turn CH only on I would be looking for a feed from programmer, through stat and then to valve, ultimately testing for feed on the orange wire. HW off must be energised as well.

 

[Rosemi1623]

We did have a blockage from expansion tank down to just above pump so would guess three way valve has sludge and will need replacing. Will get a plumber in as pipes may need replacing etc. Thanks for your help.

 

[SJB060685]

A blockage could cause that yes. You would benefit from a power flush if the system is riddled with black iron oxide (sludge). This is something you should have mentioned in original post, would of saved a whole load of trouble lol

 

[Ric2013]

I suspect the clunk in the video is due to the fact that the pump is running as you move the valve? If so, the pressure surge caused by the resistance to flow as you close off the waterway with less resistance may be resulting in a clunk, possibly as the pressure slams the internal thing against the valve seat? That's my hunch anyway. Let me know if this proves to be right.

 

[Rosemi1623]

As I tested programmer using an old one I am going to flush system and change the 3 way valve. I can turn spindle in new one by hand. The old one needs pliers. Probably full of hunk. Hopefully flushing a couple of times leaving water on will help. Once that is done will attach the existing actuator and if still not working will attach the new one. Will update you all next week! Mike
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As I tested programmer using an old one I am going to flush system and change the 3 way valve. I can turn spindle in new one by hand. The old one needs pliers. Probably full of hunk. Hopefully flushing a couple of times leaving water on will help. Once that is done will attach the existing actuator and if still not working will attach the new one. Will update you all next week! Mike

Gunk not hunk!

 

[brown44Elz]

hello,
how to change heating temperature in heater?
Can we monitor temperature using thermostats?

 

[SJB060685]

Brown44elz

You need to create a new thread and ask your question/questions there. Jumping in on an already generated post will not get many views or help. You should also be a bit more descriptive with your post as there are many different sorts of heaters.

 

[Rosemi1623]

All fixed. Fitted a new 3 way valve and the connected existing mid way actuator...same issue of CH only not working and stat showing dim orange light when not calling for heat. Changed the actuator that came as a set with the TWV and now works fine. All done in a hour or so with a bacon sandwich half way through while system filling up again. Thanks for everyone’s help. Mike

 

[SJB060685]

Glad you got it fixed Mike. For future reference just so you know from what you described it sounds as one of the internal switches wasnt activating, the motor was motoring over but the switch was faulty not supplying a live from white wire to boiler feed.
Again well done

 

[Ric2013]

All fixed. Fitted a new 3 way valve and the connected existing mid way actuator...same issue of CH only not working and stat showing dim orange light when not calling for heat. Changed the actuator that came as a set with the TWV and now works fine. All done in a hour or so with a bacon sandwich half way through while system filling up again. Thanks for everyone’s help. Mike

Good to hear your technique of changing parts until you found the right one paid off.

 

[brown44Elz]

Thanks, SJB060685.
I will deffinately ask to new post. thanks for suggestion.
I was talking about room heaters. can we monitor it using thermostats? and where to store its data?