Here's the problem.......

I have a oil fired burner heating the rads and hot water cylinder in my house (new self build house). The house heating is divided into 4 zones - Hot water, downstairs rads, upstairs rads and kitchen rads by 4 motorised valves. These valves are actuated by four switches located in the kitchen. I should also mention that the only room thermostat that I have is in the kitchen which will close the motorised valve when it gets to temperature.

So if I wanted HW and the kitchen warm for the morning I have to make sure before I go to bed that the two motorised valves are left open.

The problem that I have is what would happen if the heating was turned on and the only motorised valve open was the one in the kitchen? As far as I can make out the thermostat will close the motorised valve and the the heating pump will keep pumping but the water will have nowhere to go.......

What would be the best solution to this?? I've thought long and hard and the only ideas that I can come up with is ..... (bear in mind that I'm new to this)

A: Wire the power for the boiler through the motorised valves, if they're all closed then the heating will switch of.
or
B: Build in a by pass on the plumbing, but I'm not sure how this will work either. Do I need to add pressure switching valves or what???????

Any help much appreciated

"Fatboise" wrote in message
...

Here's the problem.......

I have a oil fired burner heating the rads and hot water cylinder in my
house (new self build house). The house heating is divided into 4 zones
- Hot water, downstairs rads, upstairs rads and kitchen rads by 4
motorised valves. These valves are actuated by four switches located in
the kitchen. I should also mention that the only room thermostat that I
have is in the kitchen which will close the motorised valve when it
gets to temperature.

So if I wanted HW and the kitchen warm for the morning I have to make
sure before I go to bed that the two motorised valves are left open.

The problem that I have is what would happen if the heating was turned
on and the only motorised valve open was the one in the kitchen? As far
as I can make out the thermostat will close the motorised valve and the
the heating pump will keep pumping but the water will have nowhere to
go.......

What would be the best solution to this?? I've thought long and hard
and the only ideas that I can come up with is ..... (bear in mind that
I'm new to this)

A: Wire the power for the boiler through the motorised valves, if
they're all closed then the heating will switch of.
or
B: Build in a by pass on the plumbing, but I'm not sure how this will
work either. Do I need to add pressure switching valves or what???????

Any help much appreciated

Each valve has a microswitch which closes when the valve is fully open. A
permanent live should run through "each" of these and to the the boiler.
The boiler should not fire if any of these are closed.

The kichen stat energises the kitchen valve. The cylinder stat energises
the DHW valve.

Do you have thermostat radiator valves on all rads?

Fatboise wrote:

A: Wire the power for the boiler through the motorised valves, if
they're all closed then the heating will switch of.

That would be good.

B: Build in a by pass on the plumbing, but I'm not sure how this will
work either. Do I need to add pressure switching valves or what???????


Automatic by-pass/Differential pressure relief valve, I think the
Honeywell one is called something like DU145. The pump differentail
pressure increases as the flow rate decreases, so the valve opens at a
pre-set pressure, allowing water from the flow into the return. It
maintains a flow rate through the boiler & pump until the boiler is
shut down by it's high-temperature thermostat.

The kitchen isn't a good place for the whole-house thermostat. You
could be cooking in the kitchen & the heat would shut off the heat to
the rest of the house.

What operates the other 3 thermostats? A thermostat in each zone is
usual; the boiler & pump start on a demand from any one zone.

Doctor Drivel wrote:

Each valve has a microswitch which closes when the valve is fully open. A
permanent live should run through "each" of these and to the the boiler.
The boiler should not fire if any of these are closed.

To clarify, he means "each in parallel" and not "each in serise". i.e.
only when all are open is the "call for heat" removed from the boiler.
(If the boiler has a call for heat input it is better to use this than
simply using its power connection, since that will let the boiler run
the pump for a while after turning off the burner).

The kichen stat energises the kitchen valve. The cylinder stat energises
the DHW valve.

And the stats in each zone ought to energise those valves.


--
Cheers,

John.

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| Internode Ltd - http://www.internode.co.uk |
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Aidan wrote:
Automatic by-pass/Differential pressure relief valve, I think the
Honeywell one is called something like DU145.

Confirm that. One of these.

http://content.honeywell.com/uk/homes/files/pag115.pdf

"John Rumm" wrote in message
...
Doctor Drivel wrote:

Each valve has a microswitch which closes when the valve is fully open.
A
permanent live should run through "each" of these and to the the boiler.
The boiler should not fire if any of these are closed.

To clarify, he means "each in parallel" and not "each in serise". i.e.
only when all are open is the "call for heat" removed from the boiler.
(If the boiler has a call for heat input it is better to use this than
simply using its power connection, since that will let the boiler run
the pump for a while after turning off the burner).

To clarify. Only when when all zone valves are de-energised will the boiler
be switched off. If one, or more, is open (energised) the boier will fire,
along with the pump.

The kichen stat energises the kitchen valve. The cylinder stat
energises
the DHW valve.

And the stats in each zone ought to energise those valves.

There is none.

Doctor Drivel wrote:

And the stats in each zone ought to energise those valves.


There is none.

Be a good idea to install some then...


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In an earlier contribution to this discussion,
Fatboise wrote:

Here's the problem.......

I have a oil fired burner heating the rads and hot water cylinder in
my house (new self build house). The house heating is divided into 4
zones - Hot water, downstairs rads, upstairs rads and kitchen rads by
4 motorised valves. These valves are actuated by four switches
located in the kitchen. I should also mention that the only room
thermostat that I have is in the kitchen which will close the
motorised valve when it gets to temperature.

So if I wanted HW and the kitchen warm for the morning I have to make
sure before I go to bed that the two motorised valves are left open.

The problem that I have is what would happen if the heating was turned
on and the only motorised valve open was the one in the kitchen? As
far as I can make out the thermostat will close the motorised valve
and the the heating pump will keep pumping but the water will have
nowhere to go.......

What would be the best solution to this?? I've thought long and hard
and the only ideas that I can come up with is ..... (bear in mind that
I'm new to this)

A: Wire the power for the boiler through the motorised valves, if
they're all closed then the heating will switch of.
or
B: Build in a by pass on the plumbing, but I'm not sure how this will
work either. Do I need to add pressure switching valves or what???????

Any help much appreciated

It seems like you have the makings of an S-Plan-Plus system (see
http://content.honeywell.com/uk/homes/systems.htm and scroll down to S Plan
Plus) - but that it hasn't been implemented very well!

The idea behind a zoned system is this:
* Each zone valve is controlled by a timer and thermostat
* The boiler and pump are controlled by the secondary contacts on the zone
valves - all wired in parallel - so that the boiler and pump only run when
at least one zone valve is open

You may or may not need a by-pass depending on whether the boiler needs the
pump to keep running for a bit after it's stopped firing in order to
disperse the residual heat. If so, the pump will be controlled by the
boiler, and only the boiler will be controlled by the zone valves. If you
need a by-pass, install an automatic one between the flow and return pipes -
after the pump.

In order to sort your system out, you need a programmable thermostat
controlling the zone valve in each heating zone. The radiator nearest to the
stat needs to have its TRV disabled - otherwise they will fight. The hot
water valve needs to be controlled by a timer and tank stat.

Once you've done that, you can set it all up for each zone (or hot water) to
be at the required temperature at the right times - and then forget about
it!
--
Cheers,
Set Square
______
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Fatboise wrote:



A: Wire the power for the boiler through the motorised valves, if
they're all closed then the heating will switch of.

Thats is what everybody else does.

controller- thermostats - motorised valves , switches of which are
wire or'ed - boiler.

So any valve ON means 'fire up the boiler and pump'