I had a new boiler (Potterton 80 combi) fitted about 5 years ago & had
TRV's fitted (on all radiators) at the same time. Subsequently
someone said to me that I should have at least 1 radiator without a
TRV. When I mentioned this to the British Gas engineer doing my
annual service during the summer he removed the one from my bathroom
(he didn't seem to check whether or not I had a bypass).

The problem now is that my bathroom is very warm - uncomfortably so at
times, so I'd like to put the TRV back on. As I don't actually know
for sure whether or not I've got a bypass fitted I don't know whether
I can safely put the TRV back on. As the pipework around the boiler
is boxed in I can't tell if there's a bypass there without slightly
trashing the 'boxing-in'.

Any advice on whether or not it's likely I've got a bypass or how I
could find out would be useful.

Many thanks,

Michael

In an earlier contribution to this discussion,
Michael D wrote:

I had a new boiler (Potterton 80 combi) fitted about 5 years ago & had
TRV's fitted (on all radiators) at the same time. Subsequently
someone said to me that I should have at least 1 radiator without a
TRV. When I mentioned this to the British Gas engineer doing my
annual service during the summer he removed the one from my bathroom
(he didn't seem to check whether or not I had a bypass).

The problem now is that my bathroom is very warm - uncomfortably so at
times, so I'd like to put the TRV back on. As I don't actually know
for sure whether or not I've got a bypass fitted I don't know whether
I can safely put the TRV back on. As the pipework around the boiler
is boxed in I can't tell if there's a bypass there without slightly
trashing the 'boxing-in'.

Any advice on whether or not it's likely I've got a bypass or how I
could find out would be useful.

Many thanks,

Michael

There seems to be some muddled thinking here! The idea of having one
radiator without a TRV is that you must *also* have a room stat in the area
served by that radiator, which switches the *whole lot* off when it gets up
to temperature - otherwise known as a boiler interlock.

Have you got such a room stat? Without it, there was no point whatsoever in
removing the TRV!

Whether or nor you need a by-pass depends on a number of factors. Does your
boiler have a pump over-run stat, and is the pump connected to it? Do you
have an S-Plan (2 x 2-port zone valves) system or a Y-Plan (3-port
mid-position valve) system? If the latter, and if one rad is always on,
there should always be a flow path open - thus not needing a by-pass.
--
Cheers,
Set Square
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On Fri, 29 Oct 2004 02:01:53 -0700, Michael D wrote:

I had a new boiler (Potterton 80 combi) fitted about 5 years ago & had
TRV's fitted (on all radiators) at the same time. Subsequently
someone said to me that I should have at least 1 radiator without a
TRV. When I mentioned this to the British Gas engineer doing my
annual service during the summer he removed the one from my bathroom
(he didn't seem to check whether or not I had a bypass).

The problem now is that my bathroom is very warm - uncomfortably so at
times, so I'd like to put the TRV back on. As I don't actually know
for sure whether or not I've got a bypass fitted I don't know whether
I can safely put the TRV back on. As the pipework around the boiler
is boxed in I can't tell if there's a bypass there without slightly
trashing the 'boxing-in'.

Any advice on whether or not it's likely I've got a bypass or how I
could find out would be useful.

Many thanks,

What do the installation instructions say?
A way of implementing a bypass is to have a permanently open radiator
although dedicated pipework with a gate valve or pressure sensitive bypass
valve is better.



--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

Whether or nor you need a by-pass depends on a number of factors. Does
your
boiler have a pump over-run stat, and is the pump connected to it? Do you
have an S-Plan (2 x 2-port zone valves) system or a Y-Plan (3-port
mid-position valve) system?

Very unlikely, as it is a combi boiler...

Christian.

In an earlier contribution to this discussion,
Christian McArdle wrote:

Whether or nor you need a by-pass depends on a number of factors.
Does your boiler have a pump over-run stat, and is the pump
connected to it? Do you have an S-Plan (2 x 2-port zone valves)
system or a Y-Plan (3-port mid-position valve) system?

Very unlikely, as it is a combi boiler...

Christian.

Fair point - I had overlooked the "combi" reference. It is likely,
therefore, with no zone valves and one permanently-on rad, that a by-pass
*isn't* required.

I was more concerned (in the part of my post which you didn't quote) with
the fact that a TRV had been removed, but that there was no mention of a
room stat.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

I was more concerned (in the part of my post which you didn't quote) with
the fact that a TRV had been removed, but that there was no mention of a
room stat.

Indeed, although it might be better to switch the TRVless radiator to the
lounge. A room thermostat in the bathroom could be less than ideal.

Christian.

"Christian McArdle" wrote in
et:


Indeed, although it might be better to switch the TRVless radiator to
the lounge. A room thermostat in the bathroom could be less than
ideal.

Christian.

As long as there isn't a gas fire in the lounge, like mine.

(Apologies to respondents, but it may not be that obvious to the OP)

mike

"Christian McArdle" wrote...

Indeed, although it might be better to switch the TRVless radiator to the
lounge. A room thermostat in the bathroom could be less than ideal.

Christian.

Thanks for the replies - I haven't got a room stat, either in the
bathroom or in any other room... which is obviously why the room's
getting so warm. I'd like to put the TRV back on, but I don't want to
if it's going to cause problems if I don't have a bypass fitted (I
seem to remember that I did have a pump go about 18 months ago).

The installation instructions for the (Myson) TRV's say that a bypass
should be fitted - the problem is that I don't know if there is one.

The plumber who fitted the boiler fitted the TRV's on all the
radiators (at the same time as installing the boiler). I don't know if
that means that it's fair to assume that it's very likely that he
would have fitted a bypass.

Regards,

Michael