CH boiler cuts out after 4 mins. HW ok

I’m not joking. Create a demand (heating on) one probe in blue, one probe in orange, if you get 0 volts, then keep the probe in blue and test other orange, if you get less than 240vac on the heating then you have found your issue.
They are 6 way connector blocks and supposed to have a test port but its so tiny I am not convinced my meter probes are correctly in so I used a spare wire hole instead and have 0Vs. I have left the probes in and the heating controls to on and will monitor the meter whn the temp drops and the system fires up like it has been doing.

One thing I noticed is that the orange wire from the motor in question was not fully inserted in the push fit connector but had been this way for 11 years. I have now pushed it fully home.
 
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Well I did not get very far, I pushed my probe into the connector too far and got it stuck and then broke my probe trying to pull it out.:cry:
 
That's the idea of the connector..you push in the wire and the spring clamp locks it in there.
 
Those are supposed to be releasable by twisting and pulling but my probe also had a ridge cut into it which propper got the sprung flap wedged into it.

Anyway I have tested the voltage and it reads 244v when on and then when the motor shuts the valve 3 minutes later the voltage reads zero. And that is when everything ( room stat and timer control ) still asking for heat.

It shut off after 3 mins with the temp on the boiler reading 39 degrees

What is causing the valve to have its power cut after only 3 mins. Is it the 3 mins or is it the 40 ish degrees. Monitoring it the heating water temp has been 39/ 51/57/43 degrees when it has turned off
 
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Where I should your room thermostat located and what temp is it set to? Also is there a boiler thermostat on the front? What’s this set to? (If it has one).
 
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Where I should your room thermostat located and what temp is it set to? Also is there a boiler thermostat on the front? What’s this set to? (If it has one).
The room stat is in the hallway and is usually set about 25 but really never gets anywhere near that as the rad TRVs always kick in first. There is no stat on the boilier - only a facility to set the water temp which is set to 65. The Hot water is fine its the heating side, the boiler tells me the current water temp - either the hot water or heating water. The patten has been the valve gets power at between 29 and 31 degrees - heating water temp as read on the boiler but 3- 4 mins mins later the valve looses its power and closes - at this stage the temp read on the boiler has been anything between 39 and 55 degrees.

I have tried turning the room stat to max also

This boiler https://www.wolseley.co.uk/product/glow-worm-flexicom-hx-heat-only-boiler-24he/
 
Might just be the microswitch inside the valve then, losing contact? You’re getting 244vac on a demand situation, and you can get heating if you latch into manual and use the cylinder thermostat.
 
Might just be the microswitch inside the valve then, losing contact? You’re getting 244vac on a demand situation, and you can get heating if you latch into manual and use the cylinder thermostat.
I get 244v for the first 3 mins then it looses it and i get zero even when heat is still being demanded by the room stat and timer controller. Currently everything is demanding heat and I have zero V at the orange and blue the boiler readout for the central heating temp says 29 degrees right now and the meter is still attached and I am monitoring to see what the the temp is saying on the boiler at the point the valve is given power again.

It could be that it starts up at 27 but I have never been there and by the time I have heard it and ran up the stairs its all ready at 31/33.
Watching it now to see.

To get heating I can leave the heating control off and turn the latch to "man" on the heating valve and then turn on the hot water. So both valve are open at that point.
The hot water side of things is working fine.
 
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Basic T6360 honeywell room stat. with a Honeywell ST9400A / 400c programer
 
Take the cover off your roomstat.
Easy enough to check the roomstat input (and hence the programmer output) and the stat output with your multimeter.
If both as expected the valve is indeed your likely culprit.
 
Before the thread got hijacked and you were told to measure between orange and blue I asked you to measure between brown and blue for the zone valve. That will then confirm whether it's a zone valve problem or programmer/room stat problem.
 
The point being microswitches in the Honey zones valves are better than say the Draytons so the problem is more likely the motor feed. :)
 
This morning the temp readout on the Heating water was 23, set up the meter in blue and brown and get zero V and turned on the heating -- nothing happened. So I turn on and off again + vigorously turn the stat and start thinking maybe I have disturbed some wires and so have a little poke and a wiggle and still nothing and just as I sit back start to get ready to cry -- weeer gos the valve and everything springs to life,and I get 244V at both blue/brown and blue/orange. 17mins and still running all rads up to temp.
I then turn the stat down past the audible click telling me the room temp and the the motor looses power and shuts the valve and releases the micro switch turning the boiler off, pump still runs. Get the Mrs to turn the stat back up and I hear the micro switch in the valve motor click on.

So from that it all seems to be working -- doesn't it :unsure:
 
I have just noticed a rogue brown wire in the connector but cut off without any protection !
Although bad and I will sort it, if it was touching something I dont see how that would explain the behaviour where it would fire for 3-4 mins - cut off - and refuse to fire again until the heating water was down to 23/30. Also the box all the connections are in has not been touched in 11 years. Picture - yes you can see the inner wire and yes it is live and that grey needs pushing in a little more.
IMG_20201002_123242713.jpg


Also a picture of the boiler temp read out, which I think is the temp of the return water from the rads.
IMG_20201002_120900380.jpg
 

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