Hello has anybody used or had experience of a Grunfoss upa 15-90 ? I need to improve hot water flow in a small flat so the shower and taps have better hot water pressure. There is a combination cylinder just supplying hot, and all cold is mains. Grunfoss say this pump can be installed inline near the cylinder to give about half to three quarters of a bar improvement, has anyone a better idea without installing mega flow or similar. thanks.