Plumbing

No hot water from Thermostatic Mixer Shower.

Anonymous user 23/02/2024 - 3.15 PM

I have fitted a brand new thermostatic shower mixer valve (fitted with a Valquest DC70 cartridge) that only gives lukewarm water on the max hot setting even though the inlet elbow downstream of the NRV is very hot as well as the hot inlet to the valve body. My plumber has checked the hot/cold water pressure in the pipes to the mixer valve and they are almost equal as you would expect from a combi boiler. I have been in touch with the manufacturers of the valve who sent me a replacement cartridge along with new Non-return valves but the problem is the same. When the flow control is opened the boiler fires up and the hot water inlet to the valve gets hot but still only lukewarm output on the max setting. I tried with the shower head removed and same thing happens. Of course I have also tried adjusting the temp control to it's max hot setting and still no more than 25C at the output. I have been sent a 3rd cartridge which has also not solved the problem. I was told to check the hot water temp from the boiler as this may be too high and is causing the valve to 'shut down' but my boiler only has a control for the radiator temp. Could this be the problem? I have seen threads on this site with similar issues but not one that has been successfully resolved. Please help!