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Hi i have a archteckt thermostatic shower fitted,the hot water is fed from a cylinder,the water tank is at least 3 mtrs above the shower head,but the cold water is mains fed,the shower will not mix only get warm water,do i
reduce the cold water pressure,with a pressure reducing valve,or would it be best to fit a pump to the hot water

Few mixer showers are designed to use unbalanced feed pressures. I assume the hot water is at low pressure although you leave me to guess this.

I have Googled the shower you mention but got no results so cannot offer advice on how it should be plumbed. The one thing I can say is you cannot fit a pump into just one side of a shower feed. Both need to be balanced properly according to the shower's requirements.

Exactly what make of shower is it? Has it ever worked properly?

as i said the hot is off the cylinder,but the cold is from the mains,so yes the system is unbalanced
this is the spec's for the shower
i'm just not sure the best way to balance it,either by reducing the mains ,or pumping the hot

thermostatic Shower Valve with Kit
Sophisticated minimalistic design
Suitable for unbalanced water pressure (Ratio of 5:1)
Suitable for combination boilers
Minimum pressure required - 0.1 Bar
Features thermostatic control
Individual control for flow and temperature
2 Year Manufacturer's Guarantee
Supplied with the Architeckt Splash Chrome Shower Kit
Twin spray head (Anti-Clogged Spray and Pause)
"Alter-Press" feature
Simple press the side button for Water-Saving pause feature
Supplied with slide rail and hose retainer
1.5m tangle free double interlocked chrome shower hose
Shower Valve Flow Rates:

12.6 L/min @ 0.5 Bar Pressure
18.0 L/min @ 1.0 Bar Pressure
26.0 L/min @ 2.0 Bar Pressure
32.0 L/min @ 3.0 Bar Pressure

What is important, is to keep the hot and cold feeds at constant pressure to avoid the possibility of being scalded or frozen whilst under the shower.

The shower is not designed to be connected to different supplies ie, cold main and separate system of hot water. The instructions mention the connections should be to the cylinder and header tank, which is traditional. This is because should the flow fluctuate, it would do so equally on both feeds therefore maintaining a safe supply. The 5:1 pressure difference is designed to accommodate the fall in pressure across a heating system such as a combi not in the way you have it installed. The difference between your hot and cold feeds is going to be closer to 10:1.

good morning
you could try fitting a water pressure equalizing valve this would bring the cold down to the same pressure as the hot
bob

[quote="bobplum"]good morning
you could try fitting a water pressure equalizing valve this would bring the cold down to the same pressure as the hot
bob[/quote]


so if i fit a pressure reducing valve, to the cold mains ,this should sort this problem out????

hi
it would give a more even balance of water to the shower valve
as is always the problem with questions like this it is not being able to physicaly see it so alot is guess work
i suppose you have nothing to lose except a few more pounds
good luck
bob

personally I would take a new cold feed from the header tank. Cost you pennies as a DIY job (well nearly).

well thx all for your help,i fitted a pressure reducing valve to the cold mains,but no luck,so as the last post suggested i will be runnin a cold feed from the tank,hopefully this will solve the problem,will let you know and thx again

Sometimes mixer showers come pre-installed with pressure reducing washers. If you connect the shower totally to a low pressure system make sure all these are removed (or as the instructions suggest). You quote the shower should work at 0.5 bar, if so, then all will be well.