The water pressure on my Greenstar 25Si Worcester Bosch combi boiler is so low that the shower won`t heat up. Can someone please tell me how to increaese the water pressure as there doesn`t seem to be an obvious valve, and the instruction manual gives no clues to how this can be done. Thanks.

SOURCE: My Worcester Bosch Greenstar Combi

just had same problem.  this apprently happens if the power supply has been interrupted or you switch the power on and off.
• The boiler runs for 15 minutes at minimum heat output to fill the condensate trap, the display (K) alternates between -II-” and the boiler flow temperature. This occurs every time the mains supply has been interrupted.

SOURCE: worcester bosch greenstar 25Si?30Si pressure gauge showing high

a couple of things , is your filling loop disconected ? , and are all your radiators blead from air, have you got a high point where the air can get stuck in system say pipes going into roof etc you may need to fit a air release valve in line at highest point to remove the air from system , your boiler should be around 1.5 bar running preasure average setting . if you are constanly filling with water you could be exceeding the pressure valve limet which releases pressure from system this could be faulty ?

SOURCE: Bosch boiler System

it means that the boiler wants to be serviced, the boiler will still work fine. Once the boiler has been servcied, there are a succession of buttons, that need to be pressed, to tell the boiler that it nhas been serviced. then 365days after it will do it again. Its there to prompt you, to get the boiler serviced

SOURCE: I need to replace a boiler pump

Get connected to the internet and type;
http//www.gumfree.com/london/02/46316802/html;
or you can type Bosch pump Type UPS 15-60 and
you will find other option. God bless you.

SOURCE: We have no pressure on our Greenstar 25Si/30Si

YOU NEED TO CALL THE MAKER