Zoe1979

There is on the underneath of the boiler a hole where a t-key goes. Insert it and twist to lock it in. Then there is a twist knob which will allow you to increase the pressure. I have found that if the boiler is losing pressure then there may be a leak somewhere in the system. What boiler do you have? If a Bosch Worcester, let me know which model as i have downloaded all the instruction and engineer manuals, so i could e-mail whichever one you need.