thermostat and underfloor heating

lunacyfoundme

I built a house during the summer and am starting to use the underfloor heating now for the first time really. I've noticed that the thermostats (digitial) never go above 13 or 14 degress.

I have tried increasing the temperature up to say 27 degrees but it never goes any higher on the thermostats and doesnt feel any warmer. There is a little burner symbol on the thermostat indicating it is requesting more heat from the oil boiler.

There are two manifolds for the underfloor heating control and the dials on these always read around 35 degrees. There also seems to be another hand dial set to about 45 degrees, I presume this is a maximum temperature limiter of some sort.

The thermostats are not programmable so i cant see anything that would be limiting the temperature from going higher.

Can anyone tell me if this is normal given the extremely cold weather or should the underfloor definitely be able to produce a higher room temp. I should note that my house is a two story house, underfloor heating on ground floor radiators on first floor. Also the attic is not yet insulated. Not sure if that would have such a drastic effect on it or not.

Frowzy

I'm not a plumber or electrician but I'll try a few suggestions that might help. We put underfloor heating in our house 9 years ago, both upstairs and downstairs and it works perfectly.

Firstly did you get somebody who knows enough about the system to put it in? did you properly insulate under the heating and put a heat deflector underneath the pipes to ensure that the heat is not absorbed by the sub-floor underneath the pipes?

Has the pipe been laid in one continuous flow, i.e. no joins anywhere therefore no leaks. Was the system pressure tested before it was commissioned?

Lastly there is no need for the heating to be at 27 degrees. 13-15 degrees is adequate to be comfortable, because the underfloor distributes the heat more evenly you don't need it as high.

The attic will have a huge effect on the heat of the house. I bet on an icy morning your roof defrosts quickly. Anyone who doesn't have an icy roof on a frosty morning is loosing all their heat straight through an inadequately insulated roof. The apex needs to be insulated with reflective/foil back insulation to reflect the heat back into the house and you need to pump insulation into the floor.

Do you have individual thermostats in each room? is the problem in every room? Where is the manifold in relation to the house? (e.g. if it's in a garage that's not attached to the house you will loose heat between the garage and the house).

Just a few suggestions. As Phil and Kirsty would say it's all about insulation, insulation, insulation :-)

Frowzy

Now that I'm home I've consulted my husband - who also happens to be the electrician who set up our underfloor system.

He says that you need to bypass the solenoid for each zone on the top of the manifold (usually by unscrewing them) this will cause a constant flow of water to every zone. Once you're happy that the rooms have heated up, which could take some hours, start to reconnect 1 solenoid at a time and take notice does room stay warm as sometimes during wiring the thermostat for a zone does not match up at manifold leading to a thermostat in one room controlling different room which can lead to problems controlling temperatures.

Let me know how you get on!

kdunderfloor

lunacyfoundme wrote: »

I built a house during the summer and am starting to use the underfloor heating now for the first time really. I've noticed that the thermostats (digitial) never go above 13 or 14 degress.

I have tried increasing the temperature up to say 27 degrees but it never goes any higher on the thermostats and doesnt feel any warmer. There is a little burner symbol on the thermostat indicating it is requesting more heat from the oil boiler.

There are two manifolds for the underfloor heating control and the dials on these always read around 35 degrees. There also seems to be another hand dial set to about 45 degrees, I presume this is a maximum temperature limiter of some sort.

The thermostats are not programmable so i cant see anything that would be limiting the temperature from going higher.

Can anyone tell me if this is normal given the extremely cold weather or should the underfloor definitely be able to produce a higher room temp. I should note that my house is a two story house, underfloor heating on ground floor radiators on first floor. Also the attic is not yet insulated. Not sure if that would have such a drastic effect on it or not.

hi,i work at ufh,if the maximum temp on the dials at the manifolds are 35 degrees then your stats will not heat above roughly your temps at the minute!you must have 50 degrees running through your manifolds in order for the rooms to reach 20+....to do this the thermostatic mixing valves on the manifolds must be set at 50!

heinbloed

The OP wrote:

.... I've noticed that the thermostats (digitial) never go above 13 or 14 degress.

I have tried increasing the temperature up to say 27 degrees but it never goes any higher on the thermostats and doesnt feel any warmer....

Get professional help in. Start with asking questions like " What is the difference between a thermostat and a thermometer? "

Ask for a proper set-up of the heating system. An optimisation of the CH system.