Problem with underfloor and central heating systems

vzx3t1

We recently had some renovation work done and we now have a problem with the heating system that I was hoping someone could advise on.

We have water based underfloor heating downstairs which is connected to the boiler. We also have a central heating system with radiators upstairs and downstairs. The central heating radiators and underfloor heating have separate room thermostats. There is a programmer for the hot water and radiators and a separate programmer for the underfloor heating.

If the underfloor heating is switched on, then the radiators downstairs are coming on. They start to get hot one hour after the underfloor heating is activated. The central heating and hot water programmers are set to OFF. I can see four separate valves (one for hot water, one for upstairs radiators, one for downstairs radiators and another for the underfloor). When I switch on the underfloor heating, I can only hear the underfloor heating valve activating.

The installer suggests that this is happening because the hot water being returned from the underfloor heating circuit is trickling down to the downstairs radiators circuit on the way back to the boiler. Does this sound right?

Too me, this sounds as though the whole design of the heating system is incorrect – the central heating and underfloor heating systems should be independent.

Any advice would be appreciated.

frisbeej

Maybe the downstairs radiators valve is stuck partially open?

WentworthFox

I would agree with you the 2 systems need to be seperate.

It sounds like the hot water is been pushed round the underfloor heating and ground floor radiators.

Have you tried (while its summer) to turn off the other valves apart from the underfloor heating and see if the radiators warm up then?

If it does then the 2 systems are connected when they shouldn't be and you should get who installed them back to lok at the system.

Hatrick24

Firstly, apologies, as I know this response does not actually solve your problem, however, just in case you are told, this is just the way it works... We appear to have an identical set up, water underfloor heating with its own programmer. Rads, hot water on a separate programmer, all being supplied off one boiler. Ours works perfectly and I can confirm that the rads etc. do not heat up when the underfloor heating comes on. So, there is obviously something wrong with the way the system has been set up.

Hope this helps in some small way!

southcoastrgi

What work did you have done ?
Was it like this before the work was done ?
Has someone left the valve locked in the manual open postion ?

Ianwzzz

I also have the same system but I have another extra circuit which just feeds the towel rails in the bathrooms. I had this problem when I installed the system and it turned out to be the heat was going back up the return which heated the radiators when the towel rails or underfloor heating was on. I just fitted a single non return valve on the return to the radiators just before it connects to the boiler return. This fixed the problem.

vzx3t1

Thank you for all the replies.

I can confirm that this is a brand new installation (new radiators, new boiler, new valves etc).

The valves are in the AUTO position.

I shall check on what has been suggested but I just wanted to make clear that the downstairs radiators are not coming on immediately after the underfloor heating has been switched on. Rather, it takes about an hour before they get hot.

The installer suggested that we just turn down the radiator thermostats when using the underfloor but that just sounds like a botch to me and it is good to see that you agree that the two systems should be independent.

Ianwzzz

vzx3t1 wrote: »

Thank you for all the replies.

I can confirm that this is a brand new installation (new radiators, new boiler, new valves etc).

The valves are in the AUTO position.

I shall check on what has been suggested but I just wanted to make clear that the downstairs radiators are not coming on immediately after the underfloor heating has been switched on. Rather, it takes about an hour before they get hot.

The installer suggested that we just turn down the radiator thermostats when using the underfloor but that just sounds like a botch to me and it is good to see that you agree that the two systems should be independent.

If the radiators are taking an hour or so to heat up that is by gravity up the return. A non return valve will resolve this.

JohnB47

This might not help but your description almost suggests that the under floor heating is upstairs. Is that the case?

Also, if it's all brand new, including under floor heating, then I think it's not been installed properly and no amount of 'just turn this off ...' is acceptable.

ronkeddy11

Installation of floor tile whether it is ceramic tile or porcelain tile , it should be done by proffessional only. If done in a proper way then it is the long lasting option. And Centura Tile can help you with that. Porcelain tile can work for you as it is fired at high temp becoming 30% harder than natural stone.

southcoastrgi

ronkeddy11 wrote: »

Installation of floor tile whether it is ceramic tile or porcelain tile , it should be done by proffessional only. If done in a proper way then it is the long lasting option. And Centura Tile can help you with that. Porcelain tile can work for you as it is fired at high temp becoming 30% harder than natural stone.

I think the words sod & off spring to mind