Can I use the HW in my bathroom radiator rather than the CH ?
I'd like warm towels all year round
of is the only option to fit an electric rad ?
--
Vass

"Vass" wrote in message
...
Can I use the HW in my bathroom radiator rather than the CH ?
I'd like warm towels all year round
of is the only option to fit an electric rad ?
/\
or
--
Vass

In an earlier contribution to this discussion,
Vass wrote:

"Vass" wrote in message
...
Can I use the HW in my bathroom radiator rather than the CH ?
I'd like warm towels all year round
of is the only option to fit an electric rad ?
/\
or

You haven't told us enough your system to be able to give a proper answer.

If you have an oldish gravity HW and pumped CH system, you could connect the
bathroom radiator into the HW circuit and it would get hot whenever the
boiler was running.

If you have a more efficient fully pumped S-Plan or Y-Plan system - with
zone valve(s) and a cylinder stat - putting the bathroom rad in the HW
circuit is not very clever because it will only get hot when the HW is
actually being heated - which isn't very often.

In this case, you would do better to connect it after the pump but before
the zone valves. That way, it would get hot whenever the boiler is running -
either for HW or CH or both.
--
Cheers,
Set Square
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On Tue, 29 Nov 2005 10:42:55 -0000, "Vass"
wrote:

Can I use the HW in my bathroom radiator rather than the CH ?
I'd like warm towels all year round
of is the only option to fit an electric rad ?


Well you *could*. The problem would be that the radiator would
corrode rather quickly.


Apart from the electric suggestion, there are three ways to do this
from the heating.

1) Use the bathroom radiator as a bypass for the boiler. If you look
at your system, you may find a pipe between the flow and return
from/to the boiler before the motorised valve(s) with something like a
radiator lockshield valve on it. The purpose of this is so that if
the CH and HW thermostats are satisfied and the boiler is in full
burn, there is a path so that the pump can continue to run and
dissipate the heat. You could take this out and replace it with the
connections to the radiator.

2) If there is no bypass, then connect the radiator to the equivalent
positions - i.e. after the pump but before the motorised valve(s).

Either 1) or 2) will heat the bathroom radiator when either the CH or
the HW comes on. It won't when neither is on.

3) Create a separate heating zone. This would need for the system to
be changed to using an S plan configuration - one motorised valve for
HW, one for existing CH and one for bathroom. (see Honeywell content
site for info on this). This would allow completely separate
control for the bathroom but would mean that a suitable thermostat for
a bathroom would be needed.

--

..andy

"Andy Hall" wrote in message
...

1) Use the bathroom radiator as a bypass for the boiler. If you look
at your system, you may find a pipe between the flow and return
from/to the boiler before the motorised valve(s) with something like a
radiator lockshield valve on it. The purpose of this is so that if
the CH and HW thermostats are satisfied and the boiler is in full
burn, there is a path so that the pump can continue to run and
dissipate the heat.

This is how my towel rail is configured and I wish it wasn't! When it pumps
through the towel when all other rads are off it makes quite a noise and
stops me from sleeping at night.

On Tue, 29 Nov 2005 11:56:55 -0000, "Mark Hewitt"
wrote:


"Andy Hall" wrote in message
.. .

1) Use the bathroom radiator as a bypass for the boiler. If you look
at your system, you may find a pipe between the flow and return
from/to the boiler before the motorised valve(s) with something like a
radiator lockshield valve on it. The purpose of this is so that if
the CH and HW thermostats are satisfied and the boiler is in full
burn, there is a path so that the pump can continue to run and
dissipate the heat.

This is how my towel rail is configured and I wish it wasn't! When it pumps
through the towel when all other rads are off it makes quite a noise and
stops me from sleeping at night.


You may be able to alleviate this by changing the pump to a Grundfos
Alpha.

These automatically back off their power as the flow resistance
increases, which I suspect here is the reason for the noise.


--

..andy

In an earlier contribution to this discussion,
Andy Hall wrote:


You may be able to alleviate this by changing the pump to a Grundfos
Alpha.

These automatically back off their power as the flow resistance
increases, which I suspect here is the reason for the noise.

Is there any danger of them backing off so much that there's insufficient
flow to cool the boiler during pump over-run conditions?
--
Cheers,
Set Square
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Set Square wrote:

In an earlier contribution to this discussion,
Andy Hall wrote:


You may be able to alleviate this by changing the pump to a Grundfos
Alpha.

Or turning the existing pump down, as long as it still gives satisfactory
circulation at a lower setting.


These automatically back off their power as the flow resistance
increases, which I suspect here is the reason for the noise.

Is there any danger of them backing off so much that there's insufficient
flow to cool the boiler during pump over-run conditions?

Yes, I have heard that caveat (though I haven't come across that situation
in practice, but then I've come across vanishingly few Alphas)

On Tue, 29 Nov 2005 13:05:38 -0000, "Set Square"
wrote:

In an earlier contribution to this discussion,
Andy Hall wrote:


You may be able to alleviate this by changing the pump to a Grundfos
Alpha.

These automatically back off their power as the flow resistance
increases, which I suspect here is the reason for the noise.

Is there any danger of them backing off so much that there's insufficient
flow to cool the boiler during pump over-run conditions?


There is a control to set the operating speed/power.

In any case, though, there is not a need for a very great flow for
bypass purposes - only enough to stop the water boiling if it were to
otherwise stop flowing. Also, remember that this is more of an issue
with cast iron boilers than those with low mass heat exchangers


--

..andy

In an earlier contribution to this discussion,
John Stumbles wrote:

You may be able to alleviate this by changing the pump to a Grundfos
Alpha.

These automatically back off their power as the flow resistance
increases, which I suspect here is the reason for the noise.

Is there any danger of them backing off so much that there's
insufficient flow to cool the boiler during pump over-run conditions?

Yes, I have heard that caveat (though I haven't come across that
situation in practice, but then I've come across vanishingly few
Alphas)

Yes, I wonder how well they work with automatic by-pass valves. AIUI, an
automatic by-pass only opens on the pressure rise resulting from low flow
through the rads when all the TRVs are closed. If the Alpha backs off so
that the pressure *doesn't* rise, the by-pass may not open and the boiler
may overheat.
--
Cheers,
Set Square
______
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On Tue, 29 Nov 2005 15:00:38 -0000, "Set Square"
wrote:

In an earlier contribution to this discussion,
John Stumbles wrote:

You may be able to alleviate this by changing the pump to a Grundfos
Alpha.

These automatically back off their power as the flow resistance
increases, which I suspect here is the reason for the noise.

Is there any danger of them backing off so much that there's
insufficient flow to cool the boiler during pump over-run conditions?

Yes, I have heard that caveat (though I haven't come across that
situation in practice, but then I've come across vanishingly few
Alphas)

Yes, I wonder how well they work with automatic by-pass valves. AIUI, an
automatic by-pass only opens on the pressure rise resulting from low flow
through the rads when all the TRVs are closed. If the Alpha backs off so
that the pressure *doesn't* rise, the by-pass may not open and the boiler
may overheat.


You just make sure that the pump is set at a point that it always
overcomes the ABV.


--

..andy

In an earlier contribution to this discussion,
Andy Hall wrote:

On Tue, 29 Nov 2005 15:00:38 -0000, "Set Square"
wrote:

Yes, I wonder how well they work with automatic by-pass valves.
AIUI, an automatic by-pass only opens on the pressure rise resulting
from low flow through the rads when all the TRVs are closed. If the
Alpha backs off so that the pressure *doesn't* rise, the by-pass may
not open and the boiler may overheat.


You just make sure that the pump is set at a point that it always
overcomes the ABV.

I probably need to educate myself about Alpha pumps. How many parameters can
you change on them?

As we known, a conventional pump operates on a curve (per speed setting)
whose two ends are at max pressure/zero flow and max flow/zero pressure. In
a heating system with TRVs, it would seem to be desirable to have a pump
which provided a constant pressure regardless of flow. Then, when one or
more TRVs closed, the flow through the remaining radiators would be
unaffected. I presume that an Alpha goes some way - but not all the way -
towards this, so that there is still *some* pressure rise to open the ABV
when all the TRVs close?
--
Cheers,
Set Square
______
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On Tue, 29 Nov 2005 17:23:31 -0000, "Set Square"
wrote:

In an earlier contribution to this discussion,
Andy Hall wrote:

On Tue, 29 Nov 2005 15:00:38 -0000, "Set Square"
wrote:

Yes, I wonder how well they work with automatic by-pass valves.
AIUI, an automatic by-pass only opens on the pressure rise resulting
from low flow through the rads when all the TRVs are closed. If the
Alpha backs off so that the pressure *doesn't* rise, the by-pass may
not open and the boiler may overheat.


You just make sure that the pump is set at a point that it always
overcomes the ABV.

I probably need to educate myself about Alpha pumps. How many parameters can
you change on them?

This one just has one knob to turn for the setting.

If you look on their web site there is a procedure for setting the
pump and ABVs.

There is a more sophisticated one - UPE 15-60, which has a choice of
two modes of automatic operation plus a head control. You can have a
remote for it if you want....




As we known, a conventional pump operates on a curve (per speed setting)
whose two ends are at max pressure/zero flow and max flow/zero pressure. In
a heating system with TRVs, it would seem to be desirable to have a pump
which provided a constant pressure regardless of flow. Then, when one or
more TRVs closed, the flow through the remaining radiators would be
unaffected. I presume that an Alpha goes some way - but not all the way -
towards this, so that there is still *some* pressure rise to open the ABV
when all the TRVs close?


--

..andy

On Tue, 29 Nov 2005 11:34:24 +0000, Andy Hall wrote:

On Tue, 29 Nov 2005 10:42:55 -0000, "Vass"
wrote:

Can I use the HW in my bathroom radiator rather than the CH ?
I'd like warm towels all year round
of is the only option to fit an electric rad ?


Well you *could*. The problem would be that the radiator would
corrode rather quickly.

If you put it through one of those ladder type towel warmers they are made
of copper or brass I think.

This idea is not new. Some of the 1930s mansion flats with central
heating (in the very original and precise use of the term), put the DHW
through the towel warmer. I discovered this when trying to change a washer
on a basin tap. Only some of the flow to the bath & basin went through the
towel warmer.

The OP will also introduce a substantial delay to HW arriving at the taps.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://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

On Tue, 29 Nov 2005 20:12:02 +0000, Ed Sirett
wrote:

On Tue, 29 Nov 2005 11:34:24 +0000, Andy Hall wrote:

On Tue, 29 Nov 2005 10:42:55 -0000, "Vass"
wrote:

Can I use the HW in my bathroom radiator rather than the CH ?
I'd like warm towels all year round
of is the only option to fit an electric rad ?


Well you *could*. The problem would be that the radiator would
corrode rather quickly.

If you put it through one of those ladder type towel warmers they are made
of copper or brass I think.

This idea is not new. Some of the 1930s mansion flats with central
heating (in the very original and precise use of the term), put the DHW
through the towel warmer. I discovered this when trying to change a washer
on a basin tap. Only some of the flow to the bath & basin went through the
towel warmer.

The OP will also introduce a substantial delay to HW arriving at the taps.


Hmmm.... I can't imagine that this would be very good though. THe
volume of water in the rail is not going to be large, and if it's just
a basinful of water, the towels are not going to get very warm during
ablutions. Running a bath would mean heat being supplied for a bit
longer.


I suppose another variant would be to put the towel warmer across the
cylinder coil. At least that would heat the towel rail while the
cylinder is recovering from delivering the bath water.


--

..andy

The message
from Andy Hall contains these words:

Is there any danger of them backing off so much that there's insufficient
flow to cool the boiler during pump over-run conditions?


There is a control to set the operating speed/power.

In any case, though, there is not a need for a very great flow for
bypass purposes - only enough to stop the water boiling if it were to
otherwise stop flowing. Also, remember that this is more of an issue
with cast iron boilers than those with low mass heat exchangers

Boiling is not really an issue for me. Firing the overheat cutout is. I
don't have an Alpha but I occasionally get the boiler isolated by the
overheat stat which could be a problem if it ever happened when I was
away from home in the depths of winter. However AFAICT it only happens
when the boiler is heating the DHW shortly after the central heating has
turned itself down for the night and then only so occasionally that I
can't be bothered to bugger about with the flow rates though the heating
coil and the automatic bypass.

--
Roger Chapman