Home boost pump to run 2 showers?

[daiking]

Our hot water is run off a 33kW Baxi combi  boiler. There isn’t enough water pressure to run 2 ‘nice’ showers at once.

 

If we had a boost pump on the incoming cold water main to boost pressure when needed, would this solve the problem? (I.e. the boiler would be man enough to supply hot water for 2).

 

If so, any recommendations?

 

[PeterW]

Can’t use a booster on mains where it could create negative pressure or draw more than 12l/min - have to use an accumulator. Two showers running will be more than that flow I expect. 

[SteamyTea]

Won't the boiler size be a bit marginal, works out at 16 kW/shower, so about 15 litres/minute.

Actually that is not a bad flow rate if it is actually achieved, mine is 11 litre/minutes and quite nice.

[daiking]

20 minutes ago, PeterW said:

Can’t use a booster on mains where it could create negative pressure or draw more than 12l/min - have to use an accumulator. Two showers running will be more than that flow I expect. 

Ok I’ll look into that

[daiking]

26 minutes ago, PeterW said:

Can’t use a booster on mains where it could create negative pressure or draw more than 12l/min - have to use an accumulator. Two showers running will be more than that flow I expect. 

Just looking up some pumps, they themselves are limited to 12m/min?

 

https://www.anchorpumps.com/blog/buying-home-booster-pump-complete-guide/

 

https://www.bathroomsandshowersdirect.co.uk/mains-pumps/mains-pumps/salamander-homeboost-pump?gclid=EAIaIQobChMIm4qdj6_U7AIVVOvtCh0JMwEiEAQYAiABEgIwgPD_BwE
 

So you could legally fit one of these?

 

The question then, is whether that 12litre would provide enough of a increase in performance? And if this is worth the effort?

[daiking]

19 minutes ago, SteamyTea said:

Won't the boiler size be a bit marginal, works out at 16 kW/shower, so about 15 litres/minute.

Actually that is not a bad flow rate if it is actually achieved, mine is 11 litre/minutes and quite nice.

No idea what the flows are. I think I will need to measure them and explain to the wife where we are with current flow and max potential flow with a 12l/min limit. 

[PeterW]

As above, boiler could cope (just check the flow curve to get a decent heat input at 20l/min) but I expect your issue is primary flow and you’ll be maxed out at 12 anyway so consider low flow shower heads first before you spend on pumps. 

[Temp]

I recommend checking what flow rate is available from the cold main. Perhaps its the pipe layout around the house causing the issue not the mains flow rate.

 

Partially blocked filter on the inlet to the Baxi? Or would that give error codes?

 

 

[daiking]

2 hours ago, PeterW said:

As above, boiler could cope (just check the flow curve to get a decent heat input at 20l/min) but I expect your issue is primary flow and you’ll be maxed out at 12 anyway so consider low flow shower heads first before you spend on pumps. 

 

I'll have a play with the current fittings to see what the normal flow is when running singly and double.

 

1 hour ago, Temp said:

I recommend checking what flow rate is available from the cold main. Perhaps its the pipe layout around the house causing the issue not the mains flow rate.

 

Partially blocked filter on the inlet to the Baxi? Or would that give error codes?

 

 

 

Layout etc, won't be ideal but there are no issues running a single shower. I don't think there's anything wrong, its just wanting 2 good flow showers simultaneously is beyond a standard capability.