Gloworm Ultracom 30HXI odd behaviour

[ironsidebod]

Hi,

We have a Glowworm boiler that's behaving a bit odd tonight.

We have underfloor heating downstairs and radiators upstairs (zone valves on each). It's always cycled and not behaved very well with the UFH - it'll surge up to 65deg then switch off and then wait until temp gets down to 40 and then go again. No idea why and nothing seems to make it better. Consequently the rooms take longer than they should to warm up.

However, tonight with both sets of heating on, it's heating to 65 and then dropping the burn rate to the lowest it can (one flame icon) and then sitting with the flow temp at 40deg (return is 32) for ages then firing up again to go to 65deg. This isn't heating the radiators properly, nor is it giving the UFH the required 55deg flow. Both pumps are working, system was checked over in late autumn due to the UFH silliness. Water is clean and so on.

Radiators have always seemed fine and not taking long to heat up.

Anything else to check, any ideas?

TIA

 

[ironsidebod]

For the benefit of anyone else suffering similar, I watched it for a bit and it carried on the same. Powered it off for 30 seconds and it resumed as normal and the burner running as you'd expect for the heating requirement. Seems an odd software problem. Hey ho.

As for the cycling this seems to be a problem people suffer with on the Vaillant this boiler is based on...no way out there possible a new PCB would sort it but no guarantee.

 

[lightning]

Why would a new pcb fix it ????

 

[ironsidebod]

One of the threads I found about the Vaillant mentioned finally getting Glowworm to take the matter seriously and they came and fitted a board with new software which mostly resolved the original complaint. The issues faced by those others I could find related to cycling problems with HW especially where weather compensation in used to lower the flow temp requirement. They never got a follow up or confirmation the prototype board made it to manufacture so it'd be a total gamble to try it.

If you have any ideas to stop the cycling with the UFH I'd be pleased to here them!! I de-rated the boiler to 18Kw and it still did it, suspect the de-rating would have to go so far as to be useless for anything else.