Can I use a Twin impellar pump to boost hot pressure only..?

[MON5TER]

I have bought a twin impeller pump to boost pressure in a first floor bathroom shower (via mixer tap)

Its a ShowerFORCE Turbo 2 from B&Q.

Having plumbed in the hot, I've just realised the cold is mains fed! (Never assume!!)

Can I just use one side of the pump to increase hot pressure and use a pressure restricter on the cold to help reduce flow? Cold would bypass the pump altogether.

Any advice would be appreciated.

 

[Softus]

The cold side would quickly wear out if you didn't run water through it.

One slightly off-the-wall idea would be to run the hot to and from both impellers. If you do this then include check valves to discourage the flow from one side of the pump from acting against the flow from the other.

The correct solution is, of course, to install a single impeller pump.

 

[Bigburn]

You would be better off changing the mains over to gravity as well and use the pump as per design.
Your going to have a pressure imbalance using the pump in conjuction with the mains which I dont think is a good idea.

 

[Softus]

You could go to the trouble and expense of adding a break tank, but it would be much cheaper and easier to add a pressure limiting device (on the cold supply to any mixer valves).

This kind of thing:

 

[Bigburn]

Softus wrote

You could go to the trouble and expense of adding a break tank,

Why assume the OP has no break tank as in a cold water cistern in his loft ?.
If his hot water is gravity then where is it fed from?.

++++++++++++++++++++++++++++++++++++

And anyway Softus have you ever piped a system up in the manner in which you are suggesting and got it to work successfully.???.

MOD 2

use the edit key

 

[kevplumb]

One slightly off-the-wall idea would be to run the hot to and from both impellers. If you do this then include check valves to discourage the flow from one side of the pump from acting against the flow from the other.

i have done this albeit for an electric shower

worked a treat (customer already had the pump)

 

[Bigburn]

kevplumb wrote

i have done this albeit for an electric shower

Can you explain further ?
Was one side of the electric shower (ie cold side) fed from the mains and the other (ie hot side) from the pump which the customer already had. ?

 

[kevplumb]

they wanted an independent supply to an electric shower so turning on a tap would not affect it

it was a cold feed only job

 

[Softus]

Why assume the OP has no break tank as in a cold water cistern in his loft ?

I haven't assumed anything. Especially I haven't assumed that he has a cistern of sufficient capacity, which you appear to be doing.

If his hot water is gravity then where is it fed from?

I don't know. Is that important?

And anyway Softus have you ever piped a system up in the manner in which you are suggesting and got it to work successfully?

No. Is that important?

 

[Bigburn]

Softus wrote

You could go to the trouble and expense of adding a break tank

without knowing what type of system the OP has and then wrote

I haven't assumed anything.

Really.

Especially I haven't assumed that he has a cistern of sufficient capacity, which you appear to be doing.

Can you point to where I have made an assumption that the OP has a cistern of sufficient capacity. ????
YOU on the other hand advised the use of a prv without even asking if the OP has a cistern.

 

[Bigburn]

kevplum wrote

they wanted an independent supply to an electric shower so turning on a tap would not affect it

Aaah, so the pump supplys a single cold feed of the shower only which was presumably gravity fed to the pump.
So where did you fit the prv then ??.

 

[Bigburn]

Bigburn wrote

If his hot water is gravity then where is it fed from?

Softus wrote

I don't know. Is that important?

Its important if you want to give the correct advise which you dont seem to be capable of doing.

 

[kevplumb]

tank , twin impeller pump teed both sides to provide 1 cold feed to shower

no prv

as i said not exactly the same scenario but it worked

 

[Water Systems]

I have bought a twin impeller pump to boost pressure in a first floor bathroom shower (via mixer tap)

Its a ShowerFORCE Turbo 2 from B&Q.

Having plumbed in the hot, I've just realised the cold is mains fed! (Never assume!!)

Can I just use one side of the pump to increase hot pressure and use a pressure restricter on the cold to help reduce flow? Cold would bypass the pump altogether.

Any advice would be appreciated.

There have been some rather silly ideas here. Run the hot through both side of the pump. Each side will be the same. After the pump install a pressure equalisation valve not a presure reducing valve as some have said. The hot goes through this valve on one side and the cold mains on the other. The valve reduces the highest pressure to the same as the lowest. So the mains will be pegged back to the same pressure as the pumped hot. Then run the outlets of the valve to the mixer.

Sorted.

 

[Bigburn]

Water Systems wrote

Run the hot through both side of the pump

Do you mean in series through the pump ie inlet -outlet -inlet- outlet and then the equalising valve. ??