Hot water problem

[kentnick]

I hope someone can help.

i have a combi boiler vaillant turbomax, when I turn on the hot tap it just doesn't get hot, it gets warm but never boiling,when I run a bath I have to use just the hot tap because if I turn the cold tap it goes freezing. The only way I can get boiling water is to turn the cold tap on the basin when I'm running the hot tap on the bath.

It's also the same on the mixer shower, I first called the shower manufacturer who said t sounds like a boiler problem rather than the thermostat in the shower as the water comes out hot when restricted flow or cold water from another source is running.

i hope that all makes sense and someone can shed some light on my issues

 

[ianmcd]

when you run a hot tap what temp reading is on the boiler facia ?

 

[kentnick]

It's at 72 then when I turn the tap it drops quickly to 67 then rises up and fluctuates between 79-82

 

[ianmcd]

Ok that sounds normal try and locate the HW outlet pipe below the boiler should be 15mm and feel how hot that gets when you run a tap if it is really hot then it does sound as if you have a blending problem, a check that sometimes works but not always is run the shower you suspect at maximum temp and when it is playing up go to the boiler and with the water still running turn off the cold water inlet isolation valve below the boiler then go back to the shower and if there is still cold water coming out of it then the cartridge is shot doesnt work on all makes

 

[kentnick]

I have just checked and the hot water outlet pipe which is warm not hot i can hold it without having to move my hand when the taps on