Hi , Guys I have issue with HOT Water supply ,m Having potterton Performa 24.. ( 10years old not HE only performa 24 )My Heating side is working perfectly fine but when you open hot water tap even after 5 min -10 min no hot water coming out :(
Boiler pressure is just fine btwn 1.5 t 2 as per the requirement. when I start heater ON , I get warm/Hot water in couple of mins but not without heater ON.
I did open the Front white panel but couldnt find out the RED button ( Which was mentioned by Mr. Richard )... Can some one please share pic or image of it? plz.

Vips.., November 2015

If your CH is working fine and just have issue with DHW ( Either slow or nil). Its only Diaphragm issue only! Just get 5111137 Kit and replace diaphragm from diverter valve and problem will be definitely solved. Yes I did it and it works fine now. Please note I am qualified engineer and I have good knowledge in GAS & Boilers particularly. If you are not competent or knowledgeable then simply call the respective company service engineer to analyse and complete the task!!.
Step to do so….fully close the water inlet tap (which may be below to boiler somewhere ) #Isolate the gas and electric supply #Remove the front panel cover # put some bucket below the boiler to avoid spillage # unscrew PCB by removing 2 front screw # Open the HOT water tap and keep it open # cover PCB with proper bags/clothes/protection cover to avoid water contact # Remove the micro switch by unscrew on small screw and properly cover it # remove the front copper pipe carefully (do not touch the other) which is going in potterton part 248063 # unscrew 6Qty of round headed screw from valve# Just keep pressure with your hand as there is spring inside it which can throw cover towards you.# Now gently remove the diaphragm you will find some damage in it for sure # Clean the valve /pin/# replace the new diaphragm and do the reassembly in reverse step as per the company instruction manual .
If you have correctly followed the process , it works!!!!

Vips, December 2015