Underfloor Heating question

I have reviewed previous post re: underfloor heating but I have a question.

I noticed that some of the heating pipes in my UFH system are not heating up at the manifold. I have bled the system of any air but it still does not help.
Any Ideas why?

assuming there are no underground kinks ,blockages and the water flow is correctly running from the boiler into the return manifold.

are the circuits switched off. my rehau manifold has twist valves (red - plastic) that allow circuits to be switched on-off quickly.
are the actuators matched to the wrong circuits - try labelling them all and disconnecting them.

if the pipe runs are long , it might take a long time before you notice heat returning from the floor, that is quite normal.

Get your installer back ASAP - it could be any number of things: room thermostats, leak, bad balancing...

xt40 said:

assuming there are no underground kinks ,blockages and the water flow is correctly running from the boiler into the return manifold.

are the circuits switched off. my rehau manifold has twist valves (red - plastic) that allow circuits to be switched on-off quickly.
are the actuators matched to the wrong circuits - try labelling them all and disconnecting them.

if the pipe runs are long , it might take a long time before you notice heat returning from the floor, that is quite normal.

Click to expand...

Some of the pipes don't seem hot in the pipes leaving the manifold, not to mind returning. other pipes are very hot leaving the manifold.

All circuits are on. I will check the actuators as the sparky couldn't read the labelling system left for him so had to chance it this way....... Is this probably the reason?

Just a quick question to anybody with underfloor heating, i was going to install the underfloor heating in my new self build with a 75mm screed ground floor, and a 50mm screed first floor, to get a quicker reaction time upstairs. I heard from a mate though that he thinks he heard some place that you can install the screed less than 60mm due to the risk of cracking, is this true has anybody got the full story.

JoeHooker said:

I heard from a mate though that he thinks he heard some place that you can install the screed less than 60mm due to the risk of cracking, is this true has anybody got the full story.

Click to expand...

It will crack somewhat, especially at door opes, but what are you planning on heating the UFH with? If geothermal, you'd be better with thicker screed than 50mm anyways, as you don't want a quick reaction time, more a better thermal store. Not sure about pellets or oil.

People can get carried away with bleeding the system. My advice is to get a plumber in as soon as possible to sort it out.

Anyone run UFH run off a condensing gas boiler? I'm curious to know the monthly running costs.

Our site has natural gas, we're builiding a 2800sqft house. Our engineer is sceptical of ufh running off gas as he reckons the boiler will keep kicking on and off, therefore using a lot of energy and working out very expensive.

We were considering GeoTh but as we need to go for the vertical version as the site is small the costs are out of our budget, we've been quoted 20 - 26k...should we have rads upstairs and what's the difference between a combi & a condensing gas boiler?
Any info greatly appreciated as we are just boggled with the conflicting information we're receiving from suppliers...