Just finished the boiler side of changes (shunt pump circuit)

Background (skip if familiar with thermal stores)


I have a DHW and UFH system connected to a thermal store ...... the
difference to a standard system is that whole contents of store are
circulated around the boiler, not just a transfer loop.
Allows for better efficiency of condensing boiler and allows a storage
of heat which the system runs for some time before calling for boiler cycle.

The DHW is drawn off via a heat exchanger at top of the store via a
TMV, it is fed by mains water - hence mains pressure DHW ... big
benefit. Should you want to it is also drinkable.

The UFH system has a 28mm loop connecting manifolds to a lower heat
exchanger in the store. There is no mixing valve (or any control) of
UFH loop temp, other than by the store stat which is set to 60 degrees.

Each zone has its own digital stat which actuates the floor lop at the
manifolds.

At end of last year I added a PV array on my roof, as well as being paid
for all you generate, any you use is free.
You try to use washing machine, dishwasher etc., but still leaves a lot
of generated power being exported that you could use and still be paid
for it.
To that end fitted a solar diverter switch that dumps any unused
generated power into the immersion

Added complication is that to get continuous DHW you need to stir the
store (De-stratify), in normal use the boiler pump is used for this,
flow switch detects any DHW draw off.

I have added a shunt pump circuit as shown in attached diag which will
provide the de-stratification when boiler is off.
Initially will simply switch off in summer - although assume I will add
a programmer (1day 1ch) to allow me to switch back to boiler once a day
then if there has not been enough heat input from PV boiler can top-up
so plenty of DHW in morning for showers.

http://www.4shared.com/office/RtTLBD...store_TMV.html




To allow me to run store hotter (use more of my PV energy), I need to
install a TMV to ensure the UFH loop cannot exceed 60 degrees.

That is what is shown in the 2nd diagram above.

So I need to fix a TMV to the store connections ......... so started
looking around for suitable 28mm valve, and came across this one:

http://www.renewable-energy-centres....alves-tmv.html

This may be eminently suitable, however it was the text that says that
normal TMV2 valves would not be suitable as they cannot work
continuously at high temperature.
Is this correct, or some hype (my get that valve anyway as price s
reasonable)

Secondly anybody care to recommend a good non-ferrous 28mm TMV ?

rick wrote:
Just finished the boiler side of changes (shunt pump circuit)

Background (skip if familiar with thermal stores)


I have a DHW and UFH system connected to a thermal store ...... the
difference to a standard system is that whole contents of store are
circulated around the boiler, not just a transfer loop.
Allows for better efficiency of condensing boiler and allows a storage
of heat which the system runs for some time before calling for boiler
cycle.

The DHW is drawn off via a heat exchanger at top of the store via a
TMV, it is fed by mains water - hence mains pressure DHW ... big
benefit. Should you want to it is also drinkable.

The UFH system has a 28mm loop connecting manifolds to a lower heat
exchanger in the store. There is no mixing valve (or any control) of
UFH loop temp, other than by the store stat which is set to 60 degrees.

Each zone has its own digital stat which actuates the floor lop at the
manifolds.

At end of last year I added a PV array on my roof, as well as being paid
for all you generate, any you use is free.
You try to use washing machine, dishwasher etc., but still leaves a lot
of generated power being exported that you could use and still be paid
for it.
To that end fitted a solar diverter switch that dumps any unused
generated power into the immersion

Added complication is that to get continuous DHW you need to stir the
store (De-stratify), in normal use the boiler pump is used for this,
flow switch detects any DHW draw off.

I have added a shunt pump circuit as shown in attached diag which will
provide the de-stratification when boiler is off.
Initially will simply switch off in summer - although assume I will add
a programmer (1day 1ch) to allow me to switch back to boiler once a day
then if there has not been enough heat input from PV boiler can top-up
so plenty of DHW in morning for showers.

http://www.4shared.com/office/RtTLBD...store_TMV.html




To allow me to run store hotter (use more of my PV energy), I need to
install a TMV to ensure the UFH loop cannot exceed 60 degrees.

That is what is shown in the 2nd diagram above.

So I need to fix a TMV to the store connections ......... so started
looking around for suitable 28mm valve, and came across this one:

http://www.renewable-energy-centres....alves-tmv.html


This may be eminently suitable, however it was the text that says that
normal TMV2 valves would not be suitable as they cannot work
continuously at high temperature.
Is this correct, or some hype (my get that valve anyway as price s
reasonable)

Secondly anybody care to recommend a good non-ferrous 28mm TMV ?
Horne are reckoned to be the mutts nuts of TMV.
Integrated isolation valves and filters means they can be stripped,
cleaned and new thermostatic cartridge installed without draindown.
It is also rated for "whole house" applications unlike some which are
really intended only for anti scald single point of use.
Quite pricey though.
I've had mine in for 3 years now without complaint (or servicing!)
My triple coil unpressurised store is currently set to dump excess heat
at 93 degrees which it does reach in the summer.

Mine is 22mm but I sure they do a 28mm version here
http://www.horne.co.uk/Products/Ther...Mixing-Valves/

hth
Bob

Mine is 22mm but I sure they do a 28mm version here
http://www.horne.co.uk/Products/Ther...Mixing-Valves/

hth
Bob


Ta I'll follow up on that link ....

On 09/07/2016 16:41, rick wrote:

Just finished the boiler side of changes (shunt pump circuit)


To allow me to run store hotter (use more of my PV energy), I need to
install a TMV to ensure the UFH loop cannot exceed 60 degrees.

That is what is shown in the 2nd diagram above.

So I need to fix a TMV to the store connections ......... so started
looking around for suitable 28mm valve, and came across this one:

http://www.renewable-energy-centres....alves-tmv.html


This may be eminently suitable, however it was the text that says that
normal TMV2 valves would not be suitable as they cannot work
continuously at high temperature.
Is this correct, or some hype (my get that valve anyway as price s
reasonable)

I have not heard of problems running TMV2 style valves continuously...

Secondly anybody care to recommend a good non-ferrous 28mm TMV ?

RWC do some:

http://www.rwc.co.uk/product/heatguard-ufh/


I used one of their TMV valves on the output of my unvented cylinder in
a "whole house" configuration. Been running nicely for 4 years or so now.

--
Cheers,

John.

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On Sat, 9 Jul 2016 17:07:06 +0100, Bob Minchin
wrote:


Horne are reckoned to be the mutts nuts of TMV.
Integrated isolation valves and filters means they can be stripped,
cleaned and new thermostatic cartridge installed without draindown.
It is also rated for "whole house" applications unlike some which are
really intended only for anti scald single point of use.
Quite pricey though.
I've had mine in for 3 years now without complaint (or servicing!)
My triple coil unpressurised store is currently set to dump excess heat
at 93 degrees which it does reach in the summer.

Mine is 22mm but I sure they do a 28mm version here
http://www.horne.co.uk/Products/Ther...Mixing-Valves/

hth
Bob

They do fail. Mine stopped letting hot water through after about 4
years. The TMV 2 repair kit is expensive - £96, and only seems to be
available from Horne directly.

The instructions recommend maintenance - O rings every 3 years, the
element/slide assembly at least every 6 years.

On 7/9/2016 10:23 PM, John Rumm wrote:


RWC do some:

http://www.rwc.co.uk/product/heatguard-ufh/


I used one of their TMV valves on the output of my unvented cylinder in
a "whole house" configuration. Been running nicely for 4 years or so now.



I was surprised by comments about TMV2 being unsuitable.

The HEAT115002 in the link you gave seems suitable. I'll check for price
- thanks.