I have just fitted a 3.0 bar Monsoon pump adjacent to the bottom of the hot water cyl. Flow to the pump is from the top of the cylinder and the cold comes from a mtr cube tank in the loft.
Pump delivery is upto the loft and to the shower valve. All pipework is 22mm with no restrictions.
Shower pump will not start until the shower rose is lowered level with the shower valve.
Any theories how to get over this will be appreciated.