Thermostatic Shower Valve Problem

[turboizzy]

I recently installed a Thermostatic Shower valve which is fed from a gravity fed system via a shower pump. The valve had been working perfectly for a week but now there seems to be no hot water coming through the valve. The water comes out hot from the taps however it is only cold through the shower. Also I am pretty sure there is noting wrong with the shower pump. I would be glad if someone could offer some advice. Thanks

 

[squowse]

i had a similar system that was very temperamental. it's due to the imbalance between the cold and hot pressures. the valves can't handle it.

i did have a moderate amount of success using isolating valves to adjust the pressures, but ultimately i got a combi so the pressures are the same and now it works great.

i think there might also be pressure regulators or equalisers available.

also - i took it off the wall and removed a couple of tiny pieces of grit from the filters behind the taps and that made a good improvement.

 

[jona]

assuming the hot and cold supplys are both from the tanked supply you shouldnt have any real pressure differential.try disconnecting the flexi hoses from the boost pump the washers have a fine gauze inside it sounds like you have a blockage on the hot.

 

[squowse]

sorry i was assuming that the cold would be fed directly from the mains as i thought this has been the norm for a long time.

 

[stardanny]

If both hot and cold is fed from a cold water tank, how is the hot pipe connect to hot water cylinder? Via a essex flange? or straight off a hot outlet?

you may have airlock.

Show a pic of hot water cylinder and it top pipework.

Dan

 

[turboizzy]

Thanks for reply
I am sure that the it is not a pressure problem. I don't have a flange fitted however I have tested the pipework with the thermostatic valve removed and the water flows perfectly well with and without the pump on. Could it possibily be a problem with the valve ?

 

[squowse]

does the pump pump the hot and cold (4 flexi tails coming out of it) or just the hot?
and is your cold feed come from the mains or a tank as was suggested previously.

 

[mallyplumbob]

What make and model valve?

 

[turboizzy]

I bought the shower valve off ebay which I think was a big mistake but the seller has told me he will send out a replacement. I am about 95% sure it is the valve now. The water pressure on both hot and cold are the same. When I removed the shower head the water seems to respond to the temperature changes on the shower valve. But once the shower head is put back on the water does not change temperature when the valve is adjusted. Any ideas what this could be ? Thanks for your replies

 

[squowse]

well if you won't answer any of my questions then can't help.

 

[turboizzy]

sorry. its pumps both the hot and cold water. The hot water from the cylinder and the cold water from the water tank in the loft. thanks