unnderfloor heating

paul303

Underfloor heating eating oil!!
I have underfloor heating downstairs, each zone controlled by a wallstat, radiators upstairs. I'm finding it almost impossible to control the system, but i notice the rads warm up even when upsairs is off, I suspect this is heat overflow from down stairs, anyone help??

sanbrafyffe

paul you must have a stat for to control upstairs circut via a motorised valve(mv) on the branch at the hotpress(normally),,,this will open and close as you require by the stat,,maybe that is knackered


is there massive heat up stairs in the rads or just luke warm,,,if its just luke warm,,,it might be the heat travelling through the metal pipework(copper)


you need to find out if your circuit control unit(mv) is working,,,,,these can be operated manually as electrically

paul303 wrote: »

Underfloor heating eating oil!!
I have underfloor heating downstairs, each zone controlled by a wallstat, radiators upstairs. I'm finding it almost impossible to control the system, but i notice the rads warm up even when upsairs is off, I suspect this is heat overflow from down stairs, anyone help??

corkgsxr

Our half stainless oil boilers can't go to low enough to condense properly and to the pooint can't go low enough to do underfloor heating. So has to use a mixer to bring the heat down, your upstairs might be the circuit it uses to cool the water.

I think underfloor heating is only for if you don't care about cost

Outkast_IRE

corkgsxr wrote: »

Our half stainless oil boilers can't go to low enough to condense properly and to the pooint can't go low enough to do underfloor heating. So has to use a mixer to bring the heat down, your upstairs might be the circuit it uses to cool the water.

I think underfloor heating is only for if you don't care about cost

I would say underfloor is only if you have a incredibly well insulated house, and good airtightness would be essential too.
Also most irish homes dont have the right level of control for underfloor, i would install literally every room as a zone linked to its own thermostat.

Most homes with underfloor are one off homes, alot of these homes dont have anywhere near the right insualtion levels or airtightness.

Outkast_IRE

paul303 wrote: »

Underfloor heating eating oil!!
I have underfloor heating downstairs, each zone controlled by a wallstat, radiators upstairs. I'm finding it almost impossible to control the system, but i notice the rads warm up even when upsairs is off, I suspect this is heat overflow from down stairs, anyone help??

have the rads upstairs always warmed up or is it a recent thing.

corkgsxr

Outkast_IRE wrote: »

I would say underfloor is only if you have a incredibly well insulated house, and good airtightness would be essential too.
Also most irish homes dont have the right level of control for underfloor, i would install literally every room as a zone linked to its own thermostat.

Most homes with underfloor are one off homes, alot of these homes dont have anywhere near the right insualtion levels or airtightness.

You need a full stainless boiler too so you can run it down at 30 odd degrees. Extremely expensive here. You don't need mixers and the boiler runs at most efficient. Try that with our boilers and it'll rot to pieces in under 6 months

And kingspan the feck out of the house

shane0007

Have to disagree totally here! I have UFH & I care greatly about cost. For the size of my home, I use relatively low amount of oil & my missus loves heat! I just have excellent controls.

UFH if installed, set up and controlled correctly is not an expensive option to run. Flow temperatures into the UFh is ideally 45C with a return of 34C, therefore it does take a lot of energy to reach that temperature. It also does not mean that the return is lower back to the boiler. Bypass mixing valves installed at the boiler ensure that the boiler can be set to whatever flow & return temperatures is required as it can be mixed to ensure the boiler is condensing at all times.
Throw in a modulating circulating pump and this is ensure the correct delta T is maintained as more and less circuits are in use, especially when the system is combined with convector radiators in another zone.
Then you have controls, most are set up completely wrong. All UFH heating systems should have motorized valves in conjunction with the manifolds and all other circuits should have them also, including the DHW circuit. These should be interlocked with each room thermostat and each actuator, whether 24v or 230v.
Proper instructions on how to use the system correctly & efficiently should be shown to the homeowner.
UFH will however, benefit more greatly by modulation. This can be achieved through a buffer tank or indeed changing to a gas boiler, either natural gas if available or LPG. This will allow the boiler to modulate down to low demand when the system reaches temperature and can be easily maintain at minimal cost.

I completely agree that every home should be extremely well insulated. No point in generating all this heat, only to have it lost quickly to outside atmosphere.

Now, the rads heating up to warm because the heat is travelling through the copper pipes itself is nonsense. If they are heating up only marginally, it is either one of two things, a motorized valve that is stuck partially open or it is reverse circulation.

paul303

Thanks all for taking the time to post.Each room downstairs is zoned and the stats are linked to valves on the manifold which all seems to be working fine,however the lag time makes control very difficult , resulting in too much or too little heat. The rads heating upstairs is a new trick so I will check the "upstairs" valve for a fault.