How do I fit a hot water boost pump beside a powered shower?

[GTW47]

Just had the bathroom made over and we have very low hot pressure. It's a gravity system, with the 50 gal header tank about 5 feet above the top of the 45 gal Economy 7 hot cylinder.

Bath, basin and WC cold feeds are mains - the only cold-fed item is the shower (more detail in a minute).

The hot supply is through the bathroom then down to the kitchen and shower room below. The pressure downstairs is OK, but a trickle in the bathroom - not enough to operate the bath mixer properly.

So, probably installing a hot boost pump to boost the whole hot supply (maybe Grundfos UPA 15-90 or a Salamander equivalent - any views?)

But one concern. We already have a Mira Vision pumped shower, drawing from the hot cylinder and the cold tank. I'm worried about how to install the boost pump without putting extra pressure through the built-in shower pump, as I assume it would damage it.

The good news may be that the take-off for this shower is a separate feed from the 22mm pipe coming from the top of the cylinder. It is the first outlet on the hot system, a separate 15mm pipe going off before the 22mm pipe goes on to supply the bathroom and downstairs.

What do I need to do to isolate the shower pump from the main boost pump? Is it enough that the boost pump will be 'downstream' of the shower pump take-off, or do I have to so anything extra?

Any help gratefully received
.

 

[Pumpman6]

Hi, if your trying to pump hot only to any type of mixer with cold mains on the other side use a single pressure switch operated pump (negative head also known as a Universal in Stuart Turner)

You will have to seperate the pipework from the Mira Vision pumped shower or you will blow the seals out of the second pump. (damage it)

Pump size/selection will depend on mains pressure, shower requirments, user preferance. 2.0 bar, 3.0 bar etc.

Once pump selected, check installation requirments to ensure installed correctly as most manufacturers require pump located next to hot cylinder, a dedicated hot feed from a anti airation flange fitted to the hot cylinder.

Would recomend taking time to get it right now and you should have many years of trouble free service. So many pump failures are down to incorrect installation.

 

[GTW47]

Thanks Pumpman6.
You confirmed what I thought about the danger to the Mira shower. But as I'm new to this are, how can I isolate the pipework to the shower? Is it enough that it has its own unique feed before any other take-off from the hot, or do I need to do something else?
Thanks.

 

[Pumpman6]

You should have a direct feed from hot and cold tanks direct to Mira shower. With another direct feed from hot tank to pump then off to pumped outlets but NOT linked back into mira shower.

There are various ways to get the feed from the hot water cylinder. Non stop Essex flange, Warix flange, Surrey flange ETC. Check with pump manufacture that you buy.

Hope this helps

 

[GTW47]

Thanks again Pumpman6 - yes it really does help.
Graham