Is my flat suitable for a Homeboost/Mainsboost?

[Johntheo5]

Sorry for the slow reply, busy week at work.

Not sure I follow this. Are you suggesting the Grundfos pump would only give me 6.75 L/m? What about the Salamander?

Also I'm not quite sure I follow the physics of it, if you wouldn't mind explaining to my layman brain...

Any pump requires a minimum inlet pressure to avoid cavitation, Grundfos state that their's requires 0.2bar, no doubt the Salamander would be similar although IMO the inlet pressure ("cold" water) could probably be as low as 0.05bar, so the pump output is governed by the flowrate that the existing mains can provide, one of your tests showed a flowrate of 5.1LPM with a mains pressure of 0.5bar, the static pressure was 0.9bar so the pressure drop, dP, was 0.9-0.5, 0.4bar, if the minimum pump(s) inlet pressure is 0.2bar then the mains dP will be, 0.9-0.2, 0.7bar, flow is proportional to the sqroot of dP, so max flowrate to avoid cavitation is 5.1*sqroot(0.7/.4), 6.75LPM, IF no cavitation problems down to 0.05bar, then the dP becomes (0.9-0.05), 0.85bar with flowrate of 5.1*sqroot(0.85/0.4), 7.44LPM. The Grundfos & presumably the Salamander can deliver this at a pump outlet pressure of 1.6bar which should be sufficient to overcome the shower resistances.

Management agency have said they're fine with installing the pump on the mains as long as it doesn't cause a noise nuisance to the adjacent flats.

Which it shouldn't do based on its measured noise level, but may see if I can get some neoprene/rubber lined pipework hangers for the bits next do it which are attached directly to the party wall (single skin block) between flats.

I would suggest installing a bypass with a full bore lever valve around the pump and a switch to switch off the pump at night or whatever, this will still give the original unboosted flowrate with no noise while sleeping, etc.