pumped hot water!

Homesafe · 4 Jan 2012

Was looking at a system today with a 2 port pump connected to a cylinder on an open vent system feeding a shower (cubicle), the problem is that the mixer on the bath is not balanced cos when both hot and cold are drawn the hot starts to get cold upto the cylinder feed off (reverse flow).

Is there a fix for this on the mixer?.
Do'nt know if thats comprehendable but I'm tired today so can I be forgiven

Onetap · 4 Jan 2012

newgas said:
Do'nt know if thats comprehendable but I'm tired today so can I be forgiven

New pump, I'd suspect, unless you can dismantle the hot side and replace the impeller. I'd think that the impeller on the hot side has possibly become detached or has been shredded by cavitation, which is more likely with hot water. It would also suggest some defect that caused the cavitation, water too hot, excessive resistance on the inlet, inadequate head, etc..

Homesafe · 5 Jan 2012

The connection to the pump is direct from top of cylinder and after the tee that feeds off the other taps, this is wrong iirc it should be via a boss from top of cylinder below the top connection.

The cylinder was insulated with foam as usual the question I have is what is the best way to sort a boss out in cylinder -never done this before plumbing is'nt my usual thing.

The pump is only a to connection one-1 port in 1 out, first time i have seen 1 tbh.

seco services · 5 Jan 2012

newgas said:
this is wrong iirc it should be via a boss from top of cylinder below the top connection.

Depends what pump it is.

The cylinder was insulated with foam as usual the question I have is what is the best way to sort a boss out in cylinder -never done this before plumbing is'nt my usual thing.

use a surrey flange is the easiest.

The pump is only a to connection one-1 port in 1 out, first time i have seen 1 tbh.

Single pump, so your saying the cold is mains fed ?
thought the pump was only supplying the shower or is it on the bath mixer to ?

matt1e · 5 Jan 2012

Maybe I read it wrong (it's late/early) but it sounds more of a mixer problem to me or knackerd non return valve if external to mixer

The mains is forcing its way up the hot

Homesafe · 5 Jan 2012

matt1e said:
Maybe I read it wrong (it's late/early) but it sounds more of a mixer problem to me or knackerd non return valve if external to mixer

The mains is forcing its way up the hot

Yes thats whats happening it's mains cold with hot from cylinder not pumped to the mixer on the bath , no non return fitted it's a bodge job done some years back by unknowns

.
The pump sounds like it is taking air in from top of cylinder.
Seco the pump is only suppling the shower upstairs, and it only has 2 connections on (not to

).
Pump wants changing imo and a surrey flange in cylinder, will prob. sort out the shower problem but the mixer?

Onetap · 5 Jan 2012

matt1e said:
The mains is forcing its way up the hot

Agree; ignore my previous post, I'd thought it was a twin-impeller pump.

Surrey or Warix flange; an Essex flange involves drilling the side of the cylinder. A twin impeller pump with a cold feed from the loft tank would be better (equal pressures). I believe you can get mixer valves that will cope with unequal pressures, or single impeller pumps intended to pump the mixed out let of the shower valve.

seco services · 5 Jan 2012

Stick nrv's on the mixer.

Homesafe · 5 Jan 2012

I've heard of essex flanges but surrey?? Are they different install methods?

I am looking at a single salamader pump at the moment for about 200 quid with a boss into cylinder.

Seco , NRV's on both hot cold ,, will this sort the pressure issue??

I was thinking along the lines of pressure reducing valve on the cold inlet to mixer, what you say?

Jake1886 · 5 Jan 2012

newgas said:
I've heard of essex flanges but surrey?? Are they different install methods?

Yep, Surrey is easier to fit imo, no drilling. Some going cheap on fleabay I think.

newgas said:
Seco , NRV's on both hot cold ,, will this sort the pressure issue??

Yeah, as long as you fit them the right way round

Homesafe · 5 Jan 2012

Even getting the nrv's the right way round may not stop the problem cos then the cold will only push the hot upto the nrv on hot pipe ,,, or am I wrong in that presumption??

The pump I'm looking at is a salamder with a flow activation switch or summat, it looks the right one, I do'nt like the idea of getting it wrong on the surry essex boss, it might be a costly mistake.

Any tips on putting them in??

Homesafe · 6 Jan 2012

newgas said:
Even getting the nrv's the right way round may not stop the problem cos then the cold will only push the hot upto the nrv on hot pipe ,,, or am I wrong in that presumption??

The pump I'm looking at is a salamder with a flow activation switch or summat, it looks the right one, I do'nt like the idea of getting it wrong on the surry essex boss, it might be a costly mistake.

Any tips on putting them in??

??? Wheres everyone gone all of a sudden??

Charnwood · 6 Jan 2012

newgas said:
Wheres everyone gone all of a sudden??

To bed and then to work, probably.

chris1337 · 6 Jan 2012

if you can get to the pipework under the bath , you can fit a pressure equalising Valve.

http://www.bathtek.com/pressure_equalising_values.htm

it will reduce the higher pressure pipe to the same pressure of the lower

this should stop the cold going back up the hot when its mixing as now you have equal pressures

Chris

Homesafe · 7 Jan 2012

What about a pressure reducing valve on the cold pipe under bath??

Will that work??

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pumped hot water!

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