New Member: Underfloor Heating

[ANDY WALKER]

Hi,

Thanks for having me. I own a B&B in the far NW of Scotland in the village of Durness on the NC500 route.

I have an Encompass underfloor heating system connected to a Grant oil burner and associated with a Santon Premier Plus unvented hot water system. I keep losing pressure in the hot water system and in turn the underfloor heating system(when I put pressure back into the hot water system the pressure increases on the underfloor heating). The main problem that I have just now is that there is a water leak coming from the top of the oil burner at the hot water pipe just below the automatic air vent. Is this a common problem or is it likely there is a leak elsewhere that is building pressure in the system as a whole? Both the hot water and undefloor heating gauges are reading 1 bar.
Thanks for any help as it is so difficult to find a plumber that is available this far north!

Regards

Andy

 

[ShaunCorbs]

How much does the pressure drop ish ?

 

[chris watkins]

Hi Andy
I am no good with oil boilers but just to clear something up your unvented hot water system is not directly connected to the heating system, what we mean by that is the water that comes out of the hot taps is not the same water in the heating system, so if you have 2 gauges both showing the same pressure then chance are they are both on the heating system. (unvented hot water should be at a high pressure then 1 bar)
How often if the system loosing pressure ?
We are looking to do the NC500 next year so if you can hang on I will bring me tools.

 

[ANDY WALKER]

How much does the pressure drop ish ?

Depends really on usage but can drop from 1bar to 0 in the space of a few days. I've a feeling the expansion tanks may need re-energised?

 

[ANDY WALKER]

Hi Andy
I am no good with oil boilers but just to clear something up your unvented hot water system is not directly connected to the heating system, what we mean by that is the water that comes out of the hot taps is not the same water in the heating system, so if you have 2 gauges both showing the same pressure then chance are they are both on the heating system. (unvented hot water should be at a high pressure then 1 bar)
How often if the system loosing pressure ?
We are looking to do the NC500 next year so if you can hang on I will bring me tools.

Possibly my mistake and the pressure gauge next to the hot water tank is connected to the central heating upstairs as it sorted itself out for a while when I bled the upstairs radiators. It is this gauge that sits at 1 bar, the same as the gauge downstairs next to the underfloor heating. I think optimal is 1-1.5bar.
Look us up if you are doing the NC500, Bae Seren B&B,Durness.

 

[EvilDrPorkChop]

Look us up if you are doing the NC500, Bae Seren B&B,Durness.

Funnily enough I think I stumbled across your B&B only last week. We were looking at doing the NC500 this summer but left it a bit late for bookings and didn't fancy the midges.

Back to your original question. When the Underfloor heating and hot water are running and reheating (So the whole system is hot) what does the pressure go up to.

 

[ANDY WALKER]

Funnily enough I think I stumbled across your B&B only last week. We were looking at doing the NC500 this summer but left it a bit late for bookings and didn't fancy the midges.

Back to your original question. When the Underfloor heating and hot water are running and reheating (So the whole system is hot) what does the pressure go up to.

The hot water pressure remains around about 1 bar and the underfloor heating sits around 1.5 bar

 

[chris watkins]

Can you post a couple of photos of the leak & the gauges please?

There will be a slight difference in the heating system pressure depending on the height they are within the building (1M = 0.1 bar) but there shouldn't be a 0.5 difference.
At the moment best advice is fixed the leak & hopefully stop topping up the system because the more fresh water you keep putting in the more corrosion the system will suffer.

 

[ANDY WALKER]

Thanks for all the help guys so far. Update is that after replacing the thermostatic head and sensor probe and surprisingly bleeding radiators upstairs and resetting the pressure on the hot water tank, the UFH started working again with good heat in all downstairs rooms. However after the boiler was serviced and the automatic air vent was replaced on top of the boiler, the hot water flow is now longer going past the thermostatic head into the mixing valve! The pump has been checked and is working fine, the thermostat pin has been checked and is fine and the system has been bled and is maintaining pressure. The system is calling for heat, room thermostats appear to be working and the actuators and the flow rate indicators suggest all is good. However no matter what the engineer tried yesterday the hot water is just not getting past the themostatic head into the mixing valve. I will add some pictures tonight to illustrate setup but in the meantime does anyone have any ideas? The mixing valve was checked and appears clean as is the water in the system with no evidence of sludge? thanks again for any help