I have microbore with 2 valves per rad - is this right?

[mk2phil]

I seem to have a bit of a hybrid heating system in my house according to a friend;

My radiators are all supplied by microbore (mostly 8mm, but one or two are 10mm) from feed and return manifolds. My mate reckons that microbore usually only has one valve and that both feed and return enter through this single valve. Mine however have 2 valves per rad, 1 for the feed and the other for the return.

Is this normal practice for microbore?

This also leads onto my second question. I'm planning to remove one of the radiators and use its feed and return to run a conservatory underfloor heating kit that Hep20 make. Apparantly it can run off the existing rad curcuits as opposed to its own pump/manifolds that normal installations require - you just connect it up like an additional rad. It comes with an inline temperatire sensor to control the temp by stopping the flow (I presume). It also comes with an isolating valve. Is this so you can turn that curcuit off if you dont want it running - much the same as with a normal radiator? If so, wouldn't I need 2 valves - 1 for the feed and one for the return as with rads?

Should you close both valves on either ends of radiators to turn them off, or is 1 sufficient?

Thansk in advance.

 

[ChrisR]

2 valves is fine, for one rad.

Run a conservatory underfloor off a pair of 10mm's in parallel with a radiator? Not a snowflake's chance!

 

[TicklyT]

Turn one valve off to turn off the radiator. The other usually has a blank cover and is preset to control the maximum flow through the rad. (See system balancing)

Turn both off if you need to isolate the rad so you can drain and remove it for decorating etc.

 

[pannierstan]

I seem to have a bit of a hybrid heating system in my house according to a friend;

My radiators are all supplied by microbore (mostly 8mm, but one or two are 10mm) from feed and return manifolds. My mate reckons that microbore usually only has one valve and that both feed and return enter through this single valve. Mine however have 2 valves per rad, 1 for the feed and the other for the return.

.

Your mate is talking about the old Terrier twin entry valve which uses a spreader inside the rad and goes in one end only.
This is just a variety on the 8mm theme.

Stan