UFH Problem

Mocrie14

House I recently bought (2000 sq ft) is only 5 years old but underfloor heating (downstairs & rads upstairs) was put in by an amateur and it is useless (I knew about this before I bought). There are only 2 coils (not sure if I'm using correct lingo!) for the entire ground floor when there should apparantly be 10+. As a result the house has proved almost impossible to heat without the boiler being on 24/7 in winter. This resulted in some oil bills of up to €900 per month!

Having examined the retro fitting of rads I have decided thats its too messy as the house is in very good decrative order (incl very expensive floor tiles) and am now looking at installing electric radiators downstairs. Has anyone got any experience of these in general and in particular of the Suka product range www.suka.ie ?

All opinions/thoughts needed and welcome!

Thanks

This may sound silly, but could one of the loops (or part of) be under a section of floor outside the house?

Having only two zones on the ground floor is not a major problem, it depends on where the loops actually are, also does the floor have any insulation under it.

Are the floors concrete? do some areas of floor get warm (or hot) while other parts stay cold?

Is the Manifold (where the ufh pipes connect to the boiler) inside the house and are the radiators connected to the same system.

Is the ufh connected directly to the boiler or is there a hot water cylinder between them?
Is the house well insulated?

It could be there is no thermostatic mixer valve feeding the ufh pipes and the boiler thermostat is set very low making it run very infficiently, boilers work better if they burn at full output for short periods of time rather than on low power for longer periods.

Mocrie14

Deleted User wrote: »

This may sound silly, but could one of the loops (or part of) be under a section of floor outside the house?

Having only two zones on the ground floor is not a major problem, it depends on where the loops actually are, also does the floor have any insulation under it.

Are the floors concrete? do some areas of floor get warm (or hot) while other parts stay cold?

Is the Manifold (where the ufh pipes connect to the boiler) inside the house and are the radiators connected to the same system.

Is the ufh connected directly to the boiler or is there a hot water cylinder between them?
Is the house well insulated?

It could be there is no thermostatic mixer valve feeding the ufh pipes and the boiler thermostat is set very low making it run very infficiently, boilers work better if they burn at full output for short periods of time rather than on low power for longer periods.

Thanks for your reply. There are two loops but only one manifold. It is located in the hall. I was told that the loops can only be about 100ft each (or something like that!) and that just two loops was seriously inadequate. The floors are concrete but I havent really used the UFH since I moved in so I'm not sure how slowly it heats up or where but it is fact that it was horrendously expensive for the previous people who lived here. The house is fairly draughty but I am sorting that out as best I can - being on top of a mountain dosent help!. You sound like you are familiar with the workings of boilers & UFH - know any heating engineers/UFH experts in south east? Think I might get a third opinion.

Thanks

Bazbu

Bazbu wrote: »

Thanks for your reply. There are two loops but only one manifold. It is located in the hall. I was told that the loops can only be about 100ft each (or something like that!) and that just two loops was seriously inadequate. The floors are concrete but I havent really used the UFH since I moved in so I'm not sure how slowly it heats up or where but it is fact that it was horrendously expensive for the previous people who lived here. The house is fairly draughty but I am sorting that out as best I can - being on top of a mountain dosent help!. You sound like you are familiar with the workings of boilers & UFH - know any heating engineers/UFH experts in south east? Think I might get a third opinion.

Thanks

I would say that the draughts are the major issue here, resolving that would be half the battle. Be sure to maintain adequate ventillation.

I'm assuming that the ground floor is approx 1000ft2 (100m2) the pipes should be spaced approx 200mm apart, you should have approximately 450m of pipe in the floor.

I don't have the plan of my ufh system to hand (diy system) but some of the loops were 150m or longer. I have a 200m2 bungalow with about 1km of pipe in the floor.

Insuffucient pipe in the floor is quite likely to result in the house never heating up, but could also result in hotspots as well because the system is constantly running .
The floor could be too thick, all the energy could be wasted in heating up a thick slab and there is nothing left the heat the room above or the pipes could be too deep in the floor.

The only way to really find out how good the pipe layout is, would be to borrow a thermal imaging camera and take photos of the floor with the heating running.

If you're mathmatically inclined you could calculate the length of pipe by draining the system and measuring how much water is needed to refill it, then calculating how many metres of pipe would be filled by "X" litres of water. I can't remember the formula off the top of my head.

On the last point, I can't help, I don't know anyone who could help - I'm sure someone could PM you a name.