I'm in the process of having underfloor heating installed as an add-on
to a conventional combi (Alpha CD35C) + zoned radiators. The plumber
has installed the underfloor pipework and the manifold but no pump
(yet). Am I correct in thinking that there should be a separate pump
that circulates the water around the loop that is separate from the
pump that circulates the water around the radiators (that in my case
is integral to the boiler), or is one pump sufficient ?

"aberdeen" wrote in message
...
I'm in the process of having underfloor heating installed as an add-on
to a conventional combi (Alpha CD35C) + zoned radiators. The plumber
has installed the underfloor pipework and the manifold but no pump
(yet). Am I correct in thinking that there should be a separate pump
that circulates the water around the loop that is separate from the
pump that circulates the water around the radiators (that in my case
is integral to the boiler), or is one pump sufficient ?


Hepworth have a new system for SMALL (15 sqm) areas that does not use a pump
or manifold. I've not seen it (only an advert) so can't comment on it.
All others I know of use a pump.

Jb

"Brew" wrote in message
...

"aberdeen" wrote in message
...
I'm in the process of having underfloor heating installed as an add-on
to a conventional combi (Alpha CD35C) + zoned radiators. The plumber
has installed the underfloor pipework and the manifold but no pump
(yet). Am I correct in thinking that there should be a separate pump
that circulates the water around the loop that is separate from the
pump that circulates the water around the radiators (that in my case
is integral to the boiler), or is one pump sufficient ?


Hepworth have a new system for SMALL (15 sqm) areas that does not use a
pump or manifold. I've not seen it (only an advert) so can't comment on
it.
All others I know of use a pump.

Jb


I've used the Hep system in a new bathroom, with some success - it warms the
floor nicely and the room. It uses a lever valve at one end of the floor
pipework, and a thermostatic radiator valve in a special wall mounted
enclosure at the other. With these two it can be regarded as just another
radiator on the system, and does not need a separate pump. It does not use
manifolds, and is just a double spiral of pipe.

I think this simple system works because the pipe resistance is relatively
low. A large UFH system will have much more pipe resistance, and hence the
need for an extra pump.

Charles F

Charles Fearnley wrote:
"Brew" wrote in message
...
"aberdeen" wrote in message
...
I'm in the process of having underfloor heating installed as an add-on
to a conventional combi (Alpha CD35C) + zoned radiators. The plumber
has installed the underfloor pipework and the manifold but no pump
(yet). Am I correct in thinking that there should be a separate pump
that circulates the water around the loop that is separate from the
pump that circulates the water around the radiators (that in my case
is integral to the boiler), or is one pump sufficient ?

Hepworth have a new system for SMALL (15 sqm) areas that does not use a
pump or manifold. I've not seen it (only an advert) so can't comment on
it.
All others I know of use a pump.

Jb


I've used the Hep system in a new bathroom, with some success - it warms the
floor nicely and the room. It uses a lever valve at one end of the floor
pipework, and a thermostatic radiator valve in a special wall mounted
enclosure at the other. With these two it can be regarded as just another
radiator on the system, and does not need a separate pump. It does not use
manifolds, and is just a double spiral of pipe.

I think this simple system works because the pipe resistance is relatively
low. A large UFH system will have much more pipe resistance, and hence the
need for an extra pump.

Charles F


No: the need for an extra pump is because you need to circulate warm
water *independently* from hot CH water. Because you want it timed
differently, or because your CH water is too hot, and needs temp
reduction. Partial recirculation is the way to achieve that.