Underfloorheating & rads together, help needed please pa

[marklondon]

Hi all, first time poster here, would appreciate some help if possible.

My father in law passed away in Jan and left his flat halfway through his latest project; installing underfloor heating and radiators. He had not fully completed all the pipework required, and I am in the process of finding someone to finish the job. In the front room he has laid the underfloor heating, and also installed a radiator in there too. I have been told by a couple of "plumbers" that it is not possible to run both because one would upset the running of the other, and vice versa. But after reading some old threads from 2005 posted on here I'm beginning to think that it is possble. Does anyone know for sure?

And if so, how would it be done? Would I need valves at certain points on the heating? I did read somewhere that the underfloor heating could run off the return from the rads, is this true?


Any help at all would be appreciated, I don't want to get ripped off or have the job done wrong when I strongly feel that both can run together, or he would not have installed it that way.

The system he has is a Polyplumb manifold, and a water tank that can be heated either via the hot water from the boiler, or electrically. There is no Microconrtol center installed, or thermostats, except one normal stat in the front room that has had the wire run to the point where I think the Control center will go. The flat also has UFH in the kitchen, and pipes running to a rad in the back bedroom (No UFH there) and the loft has been convereted with 2 rads up there (Again no UFH up there)


Thanks in advance

Mark



Replies so far:

marklondon wrote:
In the front room he has laid the underfloor heating, and also installed a radiator in there too. I have been told by a couple of "plumbers" that it is not possible to run both because one would upset the running of the other, and vice versa.

They're saying that because the water in the underfloor pipework needs to be at a lower temperature than the water in the radiators.

Quote:
And if so, how would it be done? Would I need valves at certain points on the heating?

The common method is to run a separate flow to the underfloor manifold, and use a blending valve and a separate pump.

Quote:
I did read somewhere that the underfloor heating could run off the return from the rads, is this true?

This is sometimes done to avoid the expense and complication of an pump
and blending valve. It might work, but you won't have control over the temperature of the water in the underfloor zone.

Quote:
The system he has is a Polyplumb manifold

How many zones does that manifold support?

Does the manifold have a pump attached, and any thermostatic valves, or valves of any kind?

 

[marklondon]

Goldberg, the manifold looks to be supplying 2 zones, the front room and the kitchen. I'm going from memory because I'm not at the flat at the mo.

I'm sure 4 pipes go to the front room and the rest go thru the hall into the kitchen

It has a pump attached to it, but the thermostats or control center have not yet been ordered, or installed. This is how I found it all.

 

[kevplumb]

Quote:
I did read somewhere that the underfloor heating could run off the return from the rads, is this true?

no

you need to run two seperate lines

one for the rads and one for ufh

your rads will run at say 70 deg
ufh needs to go through a blending valve to drop temp to 40/50

the ufh will need its own manifold blending valve and pump

 

[marklondon]

Quote:
I did read somewhere that the underfloor heating could run off the return from the rads, is this true?

no

you need to run two seperate lines

one for the rads and one for ufh

your rads will run at say 70 deg
ufh needs to go through a blending valve to drop temp to 40/50

the ufh will need its own manifold blending valve and pump

With the blending valve in place, would the one thermostat in that room control both the rad and the ufh?
cheers

 

[kevplumb]

no


why do you want a rad and ufh in the same room btw

just curious

 

[marklondon]

no


why do you want a rad and ufh in the same room btw

just curious

The flat has very old single pain windows in it, I think my father in law was installing the rad as well so that the ufh wasnt working overtime trying to heat the room, plus the rad is an old cast iron Windsor style one, fitting with the decor of the flat.

If the one thermostat would not control both how would the room temperature be controlled?

cheers

 

[Goldberg]

Goldberg, the manifold looks to be supplying 2 zones, the front room and the kitchen. I'm going from memory because I'm not at the flat at the mo.

There should be 2 pipes from the manifold to each zone.

I'm sure 4 pipes go to the front room and the rest go thru the hall into the kitchen

It's possible that the living room was split into two underfloor zones, although that would be odd. Best verify your memory of what's what, when you're next there.

It has a pump attached to it, but the thermostats or control center have not yet been ordered, or installed. This is how I found it all.

Does the manifold have any thermostatic valves mounted on it? Or sensors?

I haven't used the PolyPlumb manifold myself, only ones in kits from third party suppliers. But does yours have a blending valve attached to both sides of the manifold?

A photo of the manifold, or a product name/number would help, so that people can look up the installation details and advise you accordingly.

 

[kevplumb]

how about

roomstat for the ufh

and a trv on the rad

 

[Goldberg]

If the one thermostat would not control both how would the room temperature be controlled?

You need to place a thermostat for the u/f system in the room with the u/f heating, which will a much longer latency than the rad system, but you should put the radiator system room stat where you would normally put one, e.g. in a hallway or landing area, and control the radiator either manually or with a TRV.

That way, you could get a fast heat-up when you need it, from the rads, which would then shut off when the u/f system is up to temperature.

 

[marklondon]

how about

roomstat for the ufh

and a trv on the rad

Sorry, what a trv?

I know bugger all about this stufF!

I'm going to the flat tomorrow, I'll take pictures of the manifold and the set up of whats there and upload them when I get back, but thankyou to all of you for your help so far

 

[kevplumb]

how about

roomstat for the ufh

and a trv on the rad

Sorry, what a trv?

I know b*****r all about this stufF!

I'm going to the flat tomorrow, I'll take pictures of the manifold and the set up of whats there and upload them when I get back, but thankyou to all of you for your help so far

thermostatic radiator valve

 

[marklondon]

how about

roomstat for the ufh

and a trv on the rad

Sorry, what a trv?

I know b*****r all about this stufF!

I'm going to the flat tomorrow, I'll take pictures of the manifold and the set up of whats there and upload them when I get back, but thankyou to all of you for your help so far

thermostatic radiator valve

Is that a min to max temperature type thingy that you control the flow to the rad with?

 

[kevplumb]

yes

View media item 11368

 

[marklondon]

Again, thanks. i'll be back tomorrow with some pics, hope you are here!!

 

[marklondon]

Ok, been to the flat today, got pictures of the manifold, and of the 4 pipes for the ufh going into the front room. The only possible reason that there is 4 going to the front room is that he was just making the most use possible from the manifold.

//www.diynot.com/network/marklondon/albums/


Discovered alot today, there was 6 pipes going to the kitchen ufh, but after removing part of the floor, I have discovered that 4 of them were to be for the back bedroom, which was going to be converted into a dining room. So I will now have 4 points on the manifold that won't be used. We are keeping the back bedroom as a bedroom and won't be installing the UFH in there, going to put a double rad under the window.

Decided to fit rads with TRV's as suggested on here, but don't want the rads and the ufh sharing the same water. Anyone know what valves I would need to run the rads at the same time as the ufh, but not on the same water system?

Cheeeeers chaps