I have a conservatory which is fitted with a radiator. The conservatory
never gets warm as the house heats up faster and reaches the room thermostat
temperature and cuts off before the conservatory can get warm. The room
thermostat is in the hall which also has a radiator. I have TRV's on all the
radiators in the house bar the one in the hall. My plan is to fit a trv to
the hall radiator and turn it down, along with the other room radiators. I
will leave the conservator one turned up thus allowing the conservatory to
warm up before the rest of the house reaches the desired temp. What I am
asking is if there is any sort of problem with this. I have read that there
shouldn't be a trv in the same room as the room thermostat.

Thanks for any advice offered.

Mark.

My plan is to fit a trv to the hall radiator and turn it down,
along with the other room radiators.

This won't work. If the hall TRV is set above the room thermostat, than the
TRV will never operate. If the TRV is set below the room thermostat, the
heating will never turn off and is the equivalent to shorting out the room
thermostat. This will keep the conservatory warm. However, the boiler will
remain on constantly, even when no heat is required, costing you a fortune
if the boiler cutout doesn't operate.

The only solution that will really be satisfactory in your situation is to
have a separate zone for the conservatory. This means that the conservatory
will have its own programmable thermostat totally independent from the rest
of the house. It also allows different time scales to be used. If, for
example, the conservatory is used as a dining room, the timer can be set to
only heat it for the early evening, saving you loads in keeping a poorly
insulated conservatory hot for the entire day and evening.

Another alternative is to have TRVs in every room and remove the room
thermostat. Then an automatic bypass loop is used (any old manual one
removed) with a flow switch that can turn off the boiler when the automatic
bypass opens. This solution is not as good, as there isn't separate timing
for the conservatory. However, it may be easier to implement if the pipework
isn't conducive to sub zoning.

Christian.

Christian McArdle wrote:

My plan is to fit a trv to the hall radiator and turn it down,
along with the other room radiators.


This won't work. If the hall TRV is set above the room thermostat, than the
TRV will never operate. If the TRV is set below the room thermostat, the
heating will never turn off and is the equivalent to shorting out the room
thermostat. This will keep the conservatory warm. However, the boiler will
remain on constantly, even when no heat is required, costing you a fortune
if the boiler cutout doesn't operate.


But they do.

I ran my old house like that for 6 years no problem. TRV's on all rads
except bathroom, and stat on max. the PUMP runs all the time. The boiler
does not...eventually there is just one super hot bathroom, and the
pipes going to it, and the boiler occasionally firing up to keep it that
way.

Short of a zone for every room with its own thermostat, its actually the
best way to do it. You CAN balance everything and hope that the heat
losses stay teh same, and the master stat will do everything right, but
its a darned sight cheaper to TRV everything, so you can turn down
certain rooms when not in use.



The only solution that will really be satisfactory in your situation is to
have a separate zone for the conservatory. This means that the conservatory
will have its own programmable thermostat totally independent from the rest
of the house. It also allows different time scales to be used. If, for
example, the conservatory is used as a dining room, the timer can be set to
only heat it for the early evening, saving you loads in keeping a poorly
insulated conservatory hot for the entire day and evening.


I disagree..



Another alternative is to have TRVs in every room and remove the room
thermostat. Then an automatic bypass loop is used (any old manual one
removed) with a flow switch that can turn off the boiler when the automatic
bypass opens. This solution is not as good, as there isn't separate timing
for the conservatory. However, it may be easier to implement if the pipework
isn't conducive to sub zoning.


That is pretty much what I suggested. Except why remove the stat? Just
whack it up to full...and the auto bypass? That's a neat idea..except
that without the pump running all the time, and using the boiler to
monitor flow temp, how does it know when to cut in again?

All I can say is the bodge described WORKS. Short of re-engineering
everything, its a good compromise between economy, cost of installation,
and pump life.

Its IMHO the best compromise to upgrading an existing system to get
better control over room temps without going to a proper fully zoned
system complete with loads of motorised valves and thermostats, which
need a lot of wiring as well as re-plumbing.




Christian.

The boiler does not...eventually there is just one super hot
bathroom, and the pipes going to it, and the boiler occasionally
firing up to keep it that way.

It is against the building regulations to install such a system. It keeps
the bathroom too hot and the central heating pipes hot when they could be
cold. Central heating pipes do lose a lot of heat.

You CAN balance everything and hope that the heat losses stay teh same,
and the master stat will do everything right, but its a darned sight
cheaper to TRV everything, so you can turn down certain rooms when not in
use.

You can TRV every room except the room thermostat one. Balance the system
properly and then turn down the room thermostat room half a turn. This
ensures that other rooms warm up quicker and the TRVs shut off before the
room thermostat is satisfied. Then, when this happens, the boiler interlock
cuts in, preventing the central heating pipes being kept warm for no reason,
which can be very wasteful, particularly on a marginal day when heating is
only really required in the morning and late evening, but is selected on all
day.

Christian.

"Christian McArdle" wrote in message
t...
The boiler does not...eventually there is just one super hot
bathroom, and the pipes going to it, and the boiler occasionally
firing up to keep it that way.

It is against the building regulations to install such a system. It keeps
the bathroom too hot and the central heating pipes hot when they could be
cold. Central heating pipes do lose a lot of heat.

You CAN balance everything and hope that the heat losses stay teh same,
and the master stat will do everything right, but its a darned sight
cheaper to TRV everything, so you can turn down certain rooms when not in
use.

You can TRV every room except the room thermostat one. Balance the system
properly and then turn down the room thermostat room half a turn. This
ensures that other rooms warm up quicker and the TRVs shut off before the
room thermostat is satisfied. Then, when this happens, the boiler
interlock
cuts in, preventing the central heating pipes being kept warm for no
reason,
which can be very wasteful, particularly on a marginal day when heating is
only really required in the morning and late evening, but is selected on
all
day.


Sounds right to me. So as a compromise, how about putting a wireless stat in
the conservatory and replacing the stat in the hall with a TRV on the hall
radiator? The timer would ensure that you're not trying to heat the
conservatory all the time. And you might need to set the conservatory stat
down a bit lower than you'd have set it were it still in the hall. Seems to
me it would be easier than rejigging the CH to add an additional zone, and
avoid having the system running all the time.

Just my 2p

Cheers
Clive

Sounds right to me. So as a compromise, how about putting a wireless stat
in
the conservatory and replacing the stat in the hall with a TRV on the hall
radiator?

Whilst this would work, it has the very serious problem that the radiator in
the thermostat room shouldn't not be controllable (i.e. should have
lockshields both ends). By putting an unzoned thermostat in the
conservatory, you are basically removing the ability to turn off
conservatory heating.

OK, will some of the other solutions you don't have independent timing, but
at least you could manually control it.

Christian.

Christian McArdle wrote:

The boiler does not...eventually there is just one super hot
bathroom, and the pipes going to it, and the boiler occasionally
firing up to keep it that way.


It is against the building regulations to install such a system. It keeps
the bathroom too hot and the central heating pipes hot when they could be
cold. Central heating pipes do lose a lot of heat.



Firstly I don't think its against regs, secondly it doesn't keep the
pipes hot. As the TRVs close the loops to which they are attached ****
down, flow stops, and the pipes cool..only the bathrom loop stahs hot,
and in my case, this was a positive advantage, cos it kept the bathroom
floor warm as well.



You CAN balance everything and hope that the heat losses stay teh same,
and the master stat will do everything right, but its a darned sight
cheaper to TRV everything, so you can turn down certain rooms when not in

use.

You can TRV every room except the room thermostat one. Balance the system
properly and then turn down the room thermostat room half a turn. This
ensures that other rooms warm up quicker and the TRVs shut off before the
room thermostat is satisfied. Then, when this happens, the boiler interlock
cuts in, preventing the central heating pipes being kept warm for no reason,
which can be very wasteful, particularly on a marginal day when heating is
only really required in the morning and late evening, but is selected on all
day.



Well for a start I had assumed we were time clocked anyway, secondly
what the heck? As long as teh pump has somewhere to pump, you cabn even
have a trickle bypass on it so that all teh rads are TRV'ed.

There is absolutley NO problem with the pump running all the time,
because the TRV';s will stop the flow in unwanted pipe sections. That
is, after all, what they do.Ther will be far less loss through a few
lagged pipes than vast areas of radiator heating unused rooms needlessly
anyway.

No mate. I don't buy it.



Christian.

Ok quite a few ideas for me to consider there !! And all much more
knowledgeable than I !

Thanks for all your ideas, that'll give me something to pick through and
start to investigate. Oh, and sorry for the double post.

Cheers all,

Mark.

In article ,
(Mark) writes:
I have a conservatory which is fitted with a radiator. The conservatory
never gets warm as the house heats up faster and reaches the room thermostat
temperature and cuts off before the conservatory can get warm. The room
thermostat is in the hall which also has a radiator. I have TRV's on all the
radiators in the house bar the one in the hall. My plan is to fit a trv to
the hall radiator and turn it down, along with the other room radiators. I
will leave the conservator one turned up thus allowing the conservatory to
warm up before the rest of the house reaches the desired temp. What I am
asking is if there is any sort of problem with this. I have read that there
shouldn't be a trv in the same room as the room thermostat.

As others have said, this won't work.

It sounds like, barring gross faults with system balancing (i.e.
conservatory radiator is noticably cooler than the others), then
then problem is inadequate heat input to the conservatory for
the heat loss. You can fix this either by adding another radiator
(or swap for a higher output one), or by reducing the heat loss
from the conservatory.

--
Andrew Gabriel

Ther will be far less loss through a few lagged pipes than vast
areas of radiator heating unused rooms needlessly anyway.

But what turns the boiler off? The approved document requires a boiler
interlock that turns the boiler off when no heat is required. You may think
it OK to reduce your overall efficiency by around 10% by running the boiler
when all the radiators are off, but the government disagrees.

Christian.

Christian McArdle wrote:

Ther will be far less loss through a few lagged pipes than vast
areas of radiator heating unused rooms needlessly anyway.


But what turns the boiler off? The approved document requires a boiler
interlock that turns the boiler off when no heat is required. You may think
it OK to reduce your overall efficiency by around 10% by running the boiler
when all the radiators are off, but the government disagrees.



I don't know what turns *your* boiler off. In my case it turns itself
off when the temperature of the water in the return path matches its
internal thermostat settings.

Actually, in this house, one heating zone comprises a suite of TRV
equpped towel rails, and a series of fan blown heat exchangers all with
their own thermostats. There is no master thermostat at all on that zone.

The boiler, needless to say, does not run continuously, but the pump does.

Since all boilers I have found do the same. I don't really understand
what the problem is.


Christian.

I don't know what turns *your* boiler off. In my case it turns itself
off when the temperature of the water in the return path matches its
internal thermostat settings.

The boiler has to turn off properly and allow the circulating water to cool
down. This is for energy efficiency. In very cold weather this won't have
much effect, as the water won't have much chance to cool down anyway.
However, in marginal weather, where the heating might not be required for
hours in the middle of the day, considerable savings can be made.

In order to promote this, hot water cylinders have to be reasonably rapid in
recovery, so that the pipes don't remain hot for long periods.

Christian.

"The Natural Philosopher" wrote in message
...

I don't know what turns *your* boiler off. In my case it turns itself
off when the temperature of the water in the return path matches its
internal thermostat settings.

Yes, but the point is that it then turns itself *on* again when the boiler
itself has cooled to below its stat setting - regardless of whether any
heating is needed in the house. This is clearly wasteful.

Roger

Christian McArdle wrote:

I don't know what turns *your* boiler off. In my case it turns itself
off when the temperature of the water in the return path matches its
internal thermostat settings.


The boiler has to turn off properly and allow the circulating water to cool
down. This is for energy efficiency. In very cold weather this won't have
much effect, as the water won't have much chance to cool down anyway.
However, in marginal weather, where the heating might not be required for
hours in the middle of the day, considerable savings can be made.


Yes. You switch of everything, including the pump, on a time clock...



In order to promote this, hot water cylinders have to be reasonably rapid in
recovery, so that the pipes don't remain hot for long periods.


Thats why they are lagged.



Christian.

Roger Mills wrote:

"The Natural Philosopher" wrote in message
...

I don't know what turns *your* boiler off. In my case it turns itself
off when the temperature of the water in the return path matches its
internal thermostat settings.


Yes, but the point is that it then turns itself *on* again when the boiler
itself has cooled to below its stat setting - regardless of whether any
heating is needed in the house. This is clearly wasteful.



Er, no, it doen't. The fact that heat has been taken out of the water
indicates that the house has cooled enough for some TRV's to open...
Ok there is marginal loss through hot water pipes under floors etc that
set a base level of heating that the system never drops below, but I
would suggest that anyone who runs their heating at all when they don't
actually need their radiators on is a bit of a plonker.

In more normal situations, the slight heat loss through the pipework is
far more than compensated by not having UN TRV'ed radiators overheating
rooms that are not in use, or need to be set at lower temperatures.

TRV'ing everything and ruinning the whole sytem on a time clock is far
more energy efficient than having a master thermostat and no TRV's


Roger

Yes. You switch of everything, including the pump, on a time clock...

Only if you want to break the law (on a recently installed system)

Part L1

1.41 Gas and oil fired hot water central heating
system controls should switch the boiler off
when no heat is required whether control is by
room thermostats or by thermostatic radiator
valves:

a) The boiler in systems controlled by
thermostats should operate only when a space
heating or vessel thermostat is calling for heat.

b) Where it is proposed to effect control by
thermostatic radiator valves, a room thermostat
(or other device such as a flow switch) should
also be provided to switch off the boiler when
there is no demand for heating or hot water.

Christian.

TRV'ing everything and ruinning the whole sytem on a time clock is far
more energy efficient than having a master thermostat and no TRV's

Both of these systems would not be not permitted. You may have a master room
thermostat and TRVs, or all TRVs and a flow switch to detect the TRVs are
all closed. You may not use all TRVs and then pump hot water through the
bypass all afternoon.

Christian.

"The Natural Philosopher" wrote in message
...
Er, no, it doen't. The fact that heat has been taken out of the water
indicates that the house has cooled enough for some TRV's to open...
Ok there is marginal loss through hot water pipes under floors etc that
set a base level of heating that the system never drops below, but I
would suggest that anyone who runs their heating at all when they don't
actually need their radiators on is a bit of a plonker.

In more normal situations, the slight heat loss through the pipework is
far more than compensated by not having UN TRV'ed radiators overheating
rooms that are not in use, or need to be set at lower temperatures.

TRV'ing everything and ruinning the whole sytem on a time clock is far
more energy efficient than having a master thermostat and no TRV's


I wasn't aware that anyone was suggesting having just a stat and no TRVs.

The *ideal* system - from an energy efficiency point of view - would have a
separate zone valve and room stat for each rad - an would be wired so that
the boiler and pump would only run when one or more zones required heat.
Better still, the room stats would be programmable - so that each room could
have a heating profile to match its likely use.

Failing that, the next best solution is:
* a timer to turn the whole lot on and off at pre-defined times
* TRVs on all but one radiator
* a room stat in the room with the non-TRV radiator (whose lockshield should
be turned down a bit to make this the last to get hot)
* an interlock which ensures that the boiler and pump both stop when the
room stat is satisifed

My understanding is that new systems would have to have all of these
features in order to satisfy the new building regs. Your solution (whilst
legal for an existing system) wouldn't comply with the new regs - because
you have no interlock which turns the boiler off when all demands are
satisfied.

Roger

Christian McArdle wrote:

TRV'ing everything and ruinning the whole sytem on a time clock is far
more energy efficient than having a master thermostat and no TRV's


Both of these systems would not be not permitted. You may have a master room
thermostat and TRVs, or all TRVs and a flow switch to detect the TRVs are
all closed. You may not use all TRVs and then pump hot water through the
bypass all afternoon.



Tough, cos my fan blown heat exchangers have their own stats, which work
the fans, not the flow.

Its on right now. The boiler hasn't fired up (tho the pump is running)
for about 1/2 hour.

If you have enough hysteresis in the boiler thermostat, it stays hot a
long time (with properly lagged pipes) before it cuts in again for a
five or ten minute burn..



Christian.