Can anybody tell me whether a thermostatic shower valve will be of any
benefit in a system fed by a pump with twin impellers.

My, maybe nieve, understanding is that the pump will balance the flows
and prevent any temperature fluctuations due to surges etc in either
the hot or cold supply.

I do not want to pay the extra for a thermostatic valve if a simple
manual valve would suffice.

On 18 Dec 2004 12:10:06 -0800, "jdi" wrote:

Can anybody tell me whether a thermostatic shower valve will be of any
benefit in a system fed by a pump with twin impellers.

Yes it will.



My, maybe nieve, understanding is that the pump will balance the flows
and prevent any temperature fluctuations due to surges etc in either
the hot or cold supply.

Not really, the valve will balance in order to maintain the required
temperature.


I do not want to pay the extra for a thermostatic valve if a simple
manual valve would suffice.

You can use a manual valve, but the water temperature will tend to
drift - especially if the water in the cold tank has been standing for
a while and has warmed slightly. When cold from the mains comes in
to replace it, the mixed water temperature will fall with a manual
valve.




--

..andy

To email, substitute .nospam with .gl

Showers are feed type specific,ie gravity or combi mains pressure or pumped,
most good manufactures do a model for the above feed types.I do not think
that a pump alone would give a safe temp hold.

I recentley purchased a aqualisa quartz shower and the product and support
from them has been quite exceptional,so would recommend them as a good
manufacturer

I guess my logic was flawed, thanks for your replies and advice guys.

My, maybe nieve, understanding is that the pump will balance the flows
and prevent any temperature fluctuations due to surges etc in either
the hot or cold supply.

There are two types of automatic valve commonly found in shower mixers. The
best mixers have both types of operation.

The pressure balancing type ensures that the water pressure is identical for
hot and cold. It is rapidly responsive to changes in pressure caused, for
example, by taps/toilets being used elsewhere.

The thermostatic type measures the temperature of the outlet water and
adjusts the flow of the hot or cold accordingly. The response is much
slower, but it enables an exact output temperature to be set regardless of
the temperature of the hot and cold water supplies, which may fluctuate over
time. This means that you don't have to adjust the mixer several times
during the shower.

I would only buy a mixer with both types of operation, even with pumped
operation. I would also ensure that there are independent temperature and
flow controls, with the temperature graduated in Celcius. Some types have a
single control, which is hopeless, as you lose the temperature setting every
time you turn off and the flow is often too strong to be comfortable.

Christian.