What shower pump do I really need

[Richard C]

I’m in a quandary about what size shower pump to fit; I need to feed 2 showers, each fitted with a 200mm drencher head - but rarely likely to be used at the same time. Salamander are pointing me towards a 2.2 bar, 22mm feed pump & I’ve been trying to imagine exactly what delivery flow rates of 20 litres/min @ 2 bar will mean! I’m wondering if it may be a bit OTT? Would a 15mm feed pump, giving 12 litres/min @ around 1 bar do all I want! Or will I be disappointed?

The flow rate of our current, totally naff shower is only 2 lites/min @ sort of ‘drip’ pressure but I’m not sure if I need a shower that’s going to provide 10 times that; 1 tank of hot water for a 10 minute shower! I don’t want to drill holes in my head or surf on the water going down the plug hole but I have no previous experience of what to expect; can any of you guys advise? Will I be disappointed if I go for the lower output pump?

 

[simond]

If you have fitted an 8" drench heads then you have pretty much already determined the flow rate. The smaller pump will be crap through this.

Either fit a smaller head or buy the larger pump.

Hope you've got a v large hw cylinder and cold water tank. And a fast flow waste in the shower tray.......

 

[Richard C]

Nothing in the tech info of the drench heads, do you have any idea what sort of flow rate a 200mm head will require? Perhaps I should be thinking of something smaller? I haven’t actually bought any kit yet; I want is a decent shower to replace the dreadful gravity fed Mira unit we currently have but obviously I don’t want to install something the current H/C water systems won’t cope with.

Re the water tanks; we have a solar heating system so there are 2 x interconnected CW tanks about 400 litres total & 2 x HW cylinders around 180 litres each (only one is usually operational in winter). The dedicated shower waste will be 50mm, the other is a shower/bath unit in 40mm but both waste pipes will exclusively feed to the stack. It’s the capacity of the HW system that’s making me have second thoughts about the pump size that’s been recommended as it will give 10 minutes max at the higher flow rate of the 22mm pump!