Power shower working intermittently

[Bazza4465]

I have a Monsoon 3 Bar Twin pump off which I run two showers, one upstairs and one downstairs, the pump is located downstairs. The shower upstairs does not start straight away it can take a minute or more before starting or not start at all, the shower downstairs work fine and the upstairs shower will run fine if the downstairs shower is running. The pump is 10-15 years old and the problem has only started over the last 2-3 months. I thought the problem was with the pump so I have just installed a new Monsoon 3 Bar Twin pump but I am having exactly the same problem as before with the upstairs not turning on straight away and the downstairs working fine. Any advice would be appreciated.

 

[Ben-gee]

You are probably borderline for a positive head pump on the upstairs shower.
Raise the cws tank in the loft or replace pump with a ‘universal’ (negative head) pump.