Water temp for gravity fed shower from boiler and immersion different

[Micro1964]

Hi looking for some advice regarding my shower, it gravity fed and run with a pump. When the water is heated using the immersion tank the shower mixer gives hot water. When the water is heated by the boiler the shower is luke warm, even though the water run from a tap is hot. I've replaced the tank thermostat and the three way valve is working. Does the controller need replacing?

Any advice would be appreciated

 

[MrMeek]

can you post a picture of the set up ?

 

[Micro1964]

can you post a picture of the set up ?

Hi unfortunately not sorry, its lifestyle LP522 programmer and thermostat. The shower is a Bramham temperature stabilised thermostatic shower. It was working fine until the last few weeks. The plumber checked out the three way valve and thats working fine. Odd that its only hot when the water is heated from the emmersion. Both the stats ie emmersion and tank are set to 60o c

 

[SJB6]

If what you said is correct it sounds more like a boiler stat/temperature problem. though the cylinder stat and valve is working correctly if the boiler stat/temperature control has gone out of calibration then the water will be colder.
Is the heating coming up to temperature as normal?
Is the boiler's cylce time the same as before ths?

 

[Micro1964]

Hi, yes the heating is coming up to temperature ok, and no change in cycle time. The boiler is quite old, would say over 10 years.

 

[SJB6]

Ok.
Sorry I did misread the initial thread but if heating is as usual and boiler cycle time is as usual that answers a needed question anyway.
It does sound odd that it's ok when immersion fed and not boiler, especially when hot water is all the same circuit. The fact that it's a thermostatic stabalising shower and was fine up until a few weeks ago makes me think it's probably the shower thermostatic stabaliser side thats at fault.
How old is the shower and pump?
And are you sure the immersion heater stat and cylinder stat are set the same, also is the cylinder stat properly seated against the cylinder? If its a thermostatic stabaliser and the boiler is heating slightly higher it could be enough for the shower to stabalise temperature.

 

[Micro1964]

Ok.
Sorry I did misread the initial thread but if heating is as usual and boiler cycle time is as usual that answers a needed question anyway.
It does sound odd that it's ok when immersion fed and not boiler, especially when hot water is all the same circuit. The fact that it's a thermostatic stabalising shower and was fine up until a few weeks ago makes me think it's probably the shower thermostatic stabaliser side thats at fault.
How old is the shower and pump?
And are you sure the immersion heater stat and cylinder stat are set the same, also is the cylinder stat properly seated against the cylinder? If its a thermostatic stabaliser and the boiler is heating slightly higher it could be enough for the shower to stabalise temperature.

The showere is about 8 years old, it was descaled and the state replaced recently (before the problem occured and was working fine with boiler). The stats are set to the same temp, I haven't check with thermometer but, if I turn up the tank stat to 80, shower is still luke warm. The cyclinder stat is held on with the wire around the tank and appears to be tight, I will try an tighten this up more if I can. Not sure I understand your last comment, should I try turning the boiler stat down?
Thanks for your help and advice.