CH boiler cuts out after 4 mins. HW ok

[aveatry]

flexicom 24hx 11 years old.
From cold when I turn on the heating the motorised valve opens as normal and everything comes to life. But after about 3 or 4 mins the valve looses power and shuts - followed by the boiler shutting then the pump is last to shut. At this stage the rads are only just starting to get warm and the boiler indicates around 45 degrees.

Tried resetting the boiler when it is at this stage and also turning off the heating at the timer then back on. It will not fire up until the indicated temp on the boiler is around 30 degrees.

Honeywell valve, pressurised 2 valve system. When it first starts the valve manual leaver is free indicating the motorised valve is working.

The hot water side of the system works fine and I can get the rads hot by turning on the hot water and manually opening the heating valve.

Running a test now with the timer controller set to on and will see if the system starts when to temp indicated on the boiler drops.

Any ideas

EDIT - There are also no fault codes

 

[Gasguru]

It doesn't sound like a boiler problem. If you are competent check for 240 vac feeding the Honey zone valve motor to see if it's still there once the valve closes after a few minutes.

 

[aveatry]

It doesn't sound like a boiler problem. If you are competent check for 240 vac feeding the Honey zone valve motor to see if it's still there once the valve closes after a few minutes.

So from that is it you think think that for some reason the synchron motor is just giving up even though it still has power. I am confused as to why it should work when the boiler indicates 30 ish degrees until around 45 then gives up and closes.

I have a multi meter and will have a go. But will wait until my "Running a test now with the timer controller set to on and will see if the system starts when to temp indicated on the boiler drops"
Then will turn off power to take the cover off the actuator. Sort out where to poke then turn back on. Dont want to be moving wires around to see whre I have to test when power is on.

 

[Gasguru]

Measure the voltage at the wiring centre...you won't have access inside the zone valve. Brown and blue wires feeds the motor.

 

[aveatry]

Measure the voltage at the wiring centre...you won't have access inside the zone valve. Brown and blue wires feeds the motor.

OH great --------- thanks for that.

 

[polesapart]

240V ac orange to neutral with heating only set at programmer and roomstat calling is what you should get.

Usual safety warnings apply.

 

[aveatry]

So do I stick my meter probes in these two blocks Sorry wrong picture.

 

[CBW]

Ones blue, does the other look orange? It looks like grey to me, with some browns in there. I believe polesapart said, neutral (generally blue) to orange (switched output).

Edit: I’m not 100% you can test the wago, I could be wrong.

 

[aveatry]

These.

 

[CBW]

Yes , and test both, as you probably won’t know which is which

 

[aveatry]

Ones blue, does the other look orange? It looks like grey to me, with some browns in there. I believe polesapart said, neutral (generally blue) to orange (switched output).

Edit: I’m not 100% you can test the wago, I could be wrong.

They are Ideal and supposed to have a test hole https://www.cef.co.uk/catalogue/products/911865-6-port-push-in-wire-connector

 

[aveatry]

Yes , and test both, as you probably won’t know which is which

Dont joke with me, because im not sure now. Are you saying I put the probes one in the orange and one in the blue, and should get 240. Or are you saying both probes in the blue - should be 240 then both probes in the orange - should be 240.

 

[CBW]

Dont joke with me, because im not sure now. Are you saying I put the probes one in the orange and one in the blue, and should get 240. Or are you saying both probes in the blue - should be 240 then both probes in the orange - should be 240.

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.

 

[aveatry]

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.

Ohhhhh I get you now. Yes there are two orange one from each valve.

 

[aveatry]

My other test was completed, this one --- with the timer controller set to on and will see if the system starts when to temp indicated on the boiler drops.

So the temp on the boiler dropped to 33 degrees and valve opened boiler fired up, pump on but only for 4 minutes and by then the temp was 51 degrees.