Glow Worm Flexicom cx gets to temperature then cuts out

[STK]

Hi

My Glow Worm Flexicom cx combi boiler is having some problems resulting in our flat and my pregnant Mrs being very cold and pi**ed off with it and me! Please help!

This is the cycle every 5 mins or so:

Boiler fires up
Temp reaches 85 degrees (highest setting for heating)
Boiler cuts out
Temp drops to 65 degrees
REPEAT

Ive read a few other pages and have got the readings for D40 flow and D41 return:

D40 70 D41 69

So I dont think it is a system circulation problem. I have fitted a new wireless thermostat as it was suggested by an engineer that the previous one was switching it on and off, but the problem persists. If I can avoid having to pay for him to come back again that would be great, any suggestions on other checks I may be able to do? Need to get it sorted asap and for as little as pos.

Thanks in advance.

Ps. No experience with boilers or plumbing so simple terms where possible please

 

[ianmcd]

definately is a circulation problem, sounds like the pump has jammed or failed, if the HW works ok most likely a diverter valve problem

 

[STK]

I can hear a noise that is what I imagine a faulty pump might sound like, Im guessing it shouldnt be making a noise at all.

HW is working fine. So likely diverter valve?

 

[STK]

Only had the boiler serviced 3 weeks ago, no issues reported. Is this coincidence?!

 

[Deleted member 267285]

Only had the boiler serviced 3 weeks ago, no issues reported. Is this coincidence?!

Depends what you mean by service, or was it a safety check? A service should include a bit of a strip down or a full strip down depending on what’s been done previously. A safety check just checks the absolute minimum (sometimes called a poke and go) and just analyses the boiler whole process on just a boiler would be about 20 mins.

 

[Deleted member 267285]

This is the cycle every 5 mins or so:

Boiler fires up
Temp reaches 85 degrees (highest setting for heating)
Boiler cuts out
Temp drops to 65 degrees
REPEAT

Ive read a few other pages and have got the readings for D40 flow and D41 return:

D40 70 D41 69

Im guessing the cycling is with heating on, but does the hot water work, and does it still make the noise?

 

[STK]

Hot water works. I took the cover off last night, the pump is very hot. I checked to see if it was free, it appears to be, but continually spat water at me, is that normal? (Power was off).

I have booked a professional to come this afternoon.

Thanks for your advice.

 

[Deleted member 267285]

Hot water works. I took the cover off last night, the pump is very hot. I checked to see if it was free, it appears to be, but continually spat water at me, is that normal? (Power was off).

I have booked a professional to come this afternoon.

Thanks for your advice.

You should get a small trickle of water, anything more and it usually suggests that the pump seal has deteriorated, so even though pump turns, it’s usually weaker. Let the professional deal with it.