underfloor heating in kitchen - will it be enough?

[beesley121]

hi guys,

cut a long story short, a builder decided to install underfloor heating himself in a kitchen (suspended flooring) and in the living room (screeded floor)

he paid me just to connect up the manifold. now the heating in the livingroom is fine but the kitchen does not heat up at all really. nothing to do with my install, everything working as it should, i just dont think he has installed in correctly using enough pipe and he never put a thin screed over the entire floor, just over the pipework (pipework only in middle off floor due to kitchen cupboards)

anyway, the customer wants it sorting but he's not paying' she is!!

anyway, ive uploaded a plan of the kitchen as they are now going to install a solid concrete floor, put underfloor heating back in and then screed the whole lot. Im worried there just isnt enough space to fit the amount of pipe needed to heat the kitchen and stair well (customer doesnt want door on kitchen)

can you guys tell me what you think? its a old house with no cavitys so insultions values for the whole house are almost non existent

 

[beesley121]

 

[beesley121]

I spoke to nu-heat who told me they just to look on their website for help. It looks like the maximum amount of heat you can possibly get is 100w per m2. ive worked out there is approx 5.5 sqm free space for the underfloor heating, therefore that equates to 550w in total for the kitchen and stair well.

 

[happyflyer]

What centers did the pipe go down at, the smallest center to center is 100 mm because of the return bends and most floor formers are set that as a minimum, I have an infra red camera you can see the centers, if you put them down at 100 mm that the maximum you can get, you do nee to watch the floor temperature does not get too high. 100 w/m2 is about average hope the tubes are not under the cabinets. There should be a flow gauge on the manifold so you can adjust the flow rate on the kitchen coil you will need to look at the manufactures data for that.


Tony

 

[beesley121]

What centers did the pipe go down at, the smallest center to center is 100 mm because of the return bends and most floor formers are set that as a minimum, I have an infra red camera you can see the centers, if you put them down at 100 mm that the maximum you can get, you do nee to watch the floor temperature does not get too high. 100 w/m2 is about average hope the tubes are not under the cabinets

I wasnt there but from what he said the pipe centres werent done at 100mm as he couldnt get more pipe between the joists because of there unusual spacing, plus he said he didnt want to notch them out too much as they were only 4 inch joists.

he's messed up big time but my problem is that even if the suspended floor is removed, filled with concrete and the screeded with the underfloor heating, its only going to give out a maximum of 550w. When doding a rad calc, i would need at least a 600x800mm double rad, double convector @ 1400w. Thats just for the kitchen, but as there is no door on the kitchen, the stairwell has to be taken into account aswell as the poor insulation of the building.

Are my assuptions correct or does underfloor heating not need to be a 'powerful' as a radiator install for the same volume, hope this makes sense

 

[happyflyer]

I can now see its a wooden suspended floor, you need to take great care with this I though it was a concrete beam floor, you need to insulated the floor before you put the coil down and all the edges needs sealing, and jobs I am involved in I always take photographs before the screed goes over, I don't think you have enough floor area 310 x 185 to allow for the heat losses, if you put the kitchen extract fan on and increase the ACR the kitchen will be cold, its a kick heater it needs and I hate them, piping up will now be a problem.

Sorry I can't help more, I have just ripped out a full GF timber UFH system in a £3M house in Knutsford, we ripped the floor up and filled it with stone and 100 mm Kingspan and 75 mm screen, all works perfect 100 mm centre, I have some photos if you want but a bit too late.

Tony

 

[Nostrum]

Has it even been installed correctly under the suspended floor, insulation etc?

550w is 550w no matter how you install.

 

[happyflyer]

Bet it wasn't done like this


Suspended Floor | Robbens Systems Underfloor Heating

 

[markfxy]

most underfloor heating systems are installed at 150 to 200 centers there's no point doing under the units unless you run one pipe around the perimeter wall to stop condensation, the output will be less but should be left on for longer to heat the room did he use spreader plates & selotex insulation?