Shower pump for can type shower head.

I`ve just installed a new shower with a 8" wide 'can' type head on it. As suspected the water flow through it isn`t that great hence I need a pump. The instructions say the shower will support anything from 0.5bar to 4bar. The system is gravity feed with the CW tanks in the loft and HW tank in the basement. A total of 8m head between bottom of CW tank and top of HW tank. Supply to HW tank is fed in 28mm, feed off HW tank to shower (approx 3m) is in 22mm. HW tank is 200l capacity, not sure on total capacity of CW tanks as I have three plumbed in series next to each other due to the limited space (not big enough for one large CW tank). Shower head is approx 1m above top of HW tank. I have come across a Stuart Turner Showermate 1.8bar pump for a reasonable price. Is this likely to provide me with a decent shower? I must add that this pump may well feed another can type shower in the future. It is highly unlikely they would be used together hence I would prefer not to have to fork out a lot more cash for a 3bar or similar pump at the moment.
Steve
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type of pump will give a quite respectable power shower with a standard head, but with this type you will get an increased volume of water rather than much more of a power effect. That would probably even be true on a 3bar pump, although it would be better.
Presumably you also have a 22mm feed to the shower from the roof tank for cold water?
The main limiting factor, I suspect, will be how long the shower runs for given the flow rate of the tanks and the fill rate from the mains. Before you go and spend money on increasing the flow rate, I would measure how long the shower runs for as is and decide whether that's acceptable, also measuring the flow rate using timing of filling a vessel of known size. That done, take a look at the pump performance - I would expect it to increase the flow rate by a factor of two or three - and decide whether the run time of the shower is going to be enough.
.andy
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wrote:

Yes there will be a seperate 22mm feed from the CW tanks. At the moment the water just dribbles out of all of the holes in the can head. So I suspect the shower would run for a few hours! I think this is due to the design of the head, it seems to have some plastic insert inside the head that evenly distributes the water to all holes in the shower head. I`m not really looking for a power effect, just a decent flow of water to this and possibly one other shower.
Steve
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Wow! That's a tall house!

Your total "head", is therefore 7m. The height of the HWC is not relevent. Only the height difference between the shower head and the cold water cistern is important.

Absolutely.
It would probably run both at the same time anyway, depending on just how much water these shower heads take.
With the head available and the 28mm feed, I suspect you'll get away without using a flange on the hot water cylinder. However, if you do get entrained air, or it sucks the vent dry, then you will need to install one. Ensure that any valves on the HWC feed line are fully open. (If gate valves, don't actually open against the stop, close a tiny amount again to prevent binding).
Also, put the pump as close to the cylinder as you can. Pushing is much better than pulling. Ensure your bath taps are on the pump, too. It makes a bath fill in no time.
Christian.
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