Glow Worm Flexicom 15HX - F25 roughly every 24 hrs

[jimmeebee]

Hi,

I have a Glowworm Flexicom 15HX which I am getting an F25 (Circulation fault) about once a day. Once it's reset it seems to work ok for about 24 hrs before the fault arises again.

I've tried bleeding all of the radiators and none of them seemed to have any air in them. Is there anywhere else I should be looking to bleed it? I've looked at the manual and googled around but haven't found anything helpful.

Grateful for any help with fixing this.

Thanks,

Jim

[thescruff]

Is the pump sticking when in fault mode.

[moderator2]

Moved to CH & B

[jimmeebee]

I've reset it now, so will have to wait until next time it faults. How will I tell whether the pump is sticking?

[thescruff]

You'll probably hear it running or feel it if you stick a hand on it. (May be very Hot)

What motorized valves do you have.

Does it fault in the hot water mode or heating mode, or both

Perhaps a pic or 2 around the cylinder

[jimmeebee]

The pump feels quite hot now. The boiler has stayed on this evening, so haven't been able to check what's happening when it faults.

The valve is a Honeywell V4043H 1056

I think it's the heating mode that's the problem as it seems to go wrong when the heating turns back on (either in the evening or morning). Hot water is on constant.

A few photos in case it helps...

[Razor]

The pictures aren't clear enough really. We need to know what happens to the pipe under the pump. It goes to an upside down tee which splits to go to two, two port valves (the silver boxes). Are there any other pipes tee'd off between the pump and the valves?

There isn't a bypass in your pictures. That would cause overheating when both valves are shut

BTW

[thescruff]

Yes you need to zoom right out so we have more detail

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[jimmeebee]

Thanks. You might be able to see a bit more from these photos....

[thescruff]

The red plastic knob in the 2nd pic is there a name on it anywhere.

Looking like the MV for the heating is playing up if it works ok in the dhw mode. Thats the lower one

[jimmeebee]

No name on the red knob.

Is there some way to test the lower MV to see what the problem is?

[thescruff]

You could remove the actuator and check the shaft is turning 1/4turn either way without resistance or use of tools

[jimmeebee]

Ok, thanks. I'll give that a try tomorrow.

[jimmeebee]

I've not yet removed the actuator, but have just checked the manual lever on the lower MV and it feels stiff. The lever on the other MV feels loose when the power is on.

Is this likely to indicate some issue with the lower MV, before I try anything more drastic like pulling it apart?!

Also, the boiler had an F25 again during the day. I note that when I reset it the temperature reading quickly rises to 83, but every so often it drops to 40ish and quickly climbs back to 83 again.

[thescruff]

When the htg is on there should be no resistance on the lever

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