Im in the process of fitting a chrome radiator to the other side of the
bathroom, now when the plumbers were in fitting my combi they removed the
old radiator at my request and capped of the feeds under the floorboards,
now when ive come to fit the new radiator ive just got two identical looking
How do i figure out which is the in and out for the new radiator
You can tell on a working radiator because the feed is hotter than the
return - but with no flow, these blanked-off pipes probably won't ever get
Does it really matter? What sort of valves are you fitting. If manual, each
valve can be either user-controllable or a lockshield depending on which
type of top you put on. If using a thermostatic valve, it would be a good
idea to get one which doesn't mind whether it is in the flow or the return.
If you *really* want to know which is which before fitting the new rad,
you'll have to trace the pipework and see where each of blanked-off pipes
Possible simple way - but laborious:
fit a simple bridge between the two pipes - compression joints and a 'U'
bend of pipe - refill the heating and turn it on and feel the pipes - one
will get hot first. Then remove, and fit your radiator. This does invlove
draining the system again.
This is only if you don't have radiator valves which work both ways.
Even if your valves are nominally one way flow you can fit the radiator and
feel which leg warms up first, then swap the valves round if they are wrong.
In all this it helps if your 'in' and 'out' valves are the same size -
otherwise swapping them round may be a problem.
Worth considering fitting a couple of isolating taps onto your capped ends
to make taking the radiator on and off an easy task without draining the
However, as suggested elswhere the best option is just to buy a pair of
valves which can flow both ways.
It may hurt to buy more valves if you already have some, but the extra cost
will probably be small compared to the hassle of trying to fit and remove
valves until you get it right.
Did the old rad have a TRV fitted ?
The rad in our bathroom doesnt (its the only one in the house that
doesnt). I understand that this is normal practise. It is used as a
'by pass', so that of all the rads get up to temp then the water still
has a route back to the boiler. If your system is the same i.e.
doesnt have a by pass fitted, then just fit 2 lock shield valves.
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