Do I need a higher performance pump?

[chris202]

Hello.

I've recently installed under floor heating in my house that is for the kitchen only. I've worked some smart electrics and have wired it so it can run completely independently, in other words when the central heating and hot water are off it will run through just the UFH circuit through the use of some two port valves. Although this all seems to work not too bad, the slight problem I am having is as follows....

Because the boiler output is fairly high, when the UFH is calling for heat, the boiler will kick in and out often as it is cutting out on its control stat. Even though the UFH room stat is constantly calling for heat through this time. Now I am guessing that the pump is not able to pump / get the hot water away quick enough. When the boiler does fire on UFH only, it only runs for a short period as the temp of the hot water building up is so rapid.

Im lmost certain that the grundfos 25 / 60 is not pushing it around quick enough and this is te reason for the frequent cycling of the boiler. Would it be as simple as putting a higher performance pump in? If so which one could be recommended, also higher flow rate or higher head pressure?

Any help much appreciated...

Thanks.

Chris.

 

[muggles]

Does the UFH have its own dedicated pump or are you just relying on the one in the boiler? What UFH system have you used?

 

[chris202]

Hi, the UFH system has its own pump.

cannot remember the name but it's 15mm plastic outer flexy pipe with its own manifold / thermostatic valve etc. Approx 20 sq metres.

It's simply teed of the main flow and returns on the main return right next to the boiler. I've lo put. Bypass in to try and help but this didn't seem to do much.

The room does get warm eventually but the boiler is kicking in nd out like. Yo yo when on UFH only.

Thanks....

 

[chris202]

Sorry for terrible spelling on last message. Got one of these iPad things with some sort of auto correct on that I can't seem to switch off!!!!

 

[Dan Robinson]

have you measured the primary flow and return temperatures at the manifold?

Does the manifold have flow guages to check there is the designed throughput?

Do you understand how ufh actually works?

Have you a picture of the setup?

 

[Norcon]

If you're only heating one room then its highly likely the boiler will cycle.

 

[chris202]

Unfortunately, there is no flow gauges. It's a heat miser system - not sure if that helps.

Based on the other response, perhaps I shodnt worry too much at it cyles. It's te just te fact that the flow e gets red hot straight away and te return takes a very long tie o heat up. The boiler is cycling because the flow is hot NOT because the return is up to temp.

Would a higher performance pump not 'push' it through the UFH a little better and hence remove all the heat from the feed of the boiler?