Warix flange, or amend pipework for shower pump

Hi All, Just wondering what your thoughts are on the difficulty level and necessity of adding a Warix flange to this set up.... Looking at adding a STUART TURNER MONSOON S POSITIVE HEAD TWIN SHOWER PUMP 2.0BAR to my new en suite shower valve (yet to be installed). Gravity fed system. Cold tank in loft to bottom of hot cylinder is 2.3 meters in 22mm. There is also a dedicated 22mm off the Cold tank to the shower. Ive traced all 3 dedicated 22mm pipes from the F&E tank and they only supply the HWC, Bath and Shower in the en suite. the rest of the house cold is mains fed.



The horizontal hot is pretty much 90 degrees from the top of the tank and is about 450mm in length to the Tee.

1. How hard is it to fit a Warix flange? (i'll post a better pic of the top of the cylinder later) Any tips please? I dont want to rupture the tank trying to get the old top fitting out (18 years old). should I use boss white/loctite on the Warix flange?

2. Is a Warix flange completely necessary for this set up? I intend to install the pump next to the HWC on the floor. I hoped I could just Tee off the Hot Downpipe but concerned the horizontal pipe needs to be rising more than it is currently....

3. Can I route the hot out the pump back up into the loft and across to the new inset shower valve? Or should I try and follow the cold route under the floorboards for a positive head pump?

4. Any shower valves available that negate the need for any of the above?!!!! The mains pressure is pretty good.

thanks for any help

If your going to stay in the house for a while and you got around £1500-£2000 to spend the consider putting in an unvented cylinder, if not use a negative head pump, warix flanges are not hard to fit but like all things plumbing things can go wrong.

personally i would use an Essex flange for the shower pump and quote for new central heating pump valves

picasso said:

If your going to stay in the house for a while and you got around £1500-£2000 to spend the consider putting in an unvented cylinder, if not use a negative head pump, warix flanges are not hard to fit but like all things plumbing things can go wrong.

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thanks for reply - I dont fancy adding a warix flange to that tank , or rather trying to remove the old fitting..... I think I would rather pay someone whose fitted and removed hundreds of them. the pump is another 350 which may or may not last 10 years. ...so thats 500 quid towards an unvented cylinder... The boiler is probably 18 years old as well - its a baxi solo 2....

Hot&Cold said:

personally i would use an Essex flange for the shower pump and quote for new central heating pump valves

Click to expand...

essex flange easier than trying to get that top thread off?

Essex flange's are not for the faint hearted.

It's a regenerative (peripheral) pump and should be far more tolerant of air bubbles in the hot water from the cylinder.
Therefore you should be ok if you form a 45 degree pipe takeoff from the top of the cylinder...and take the water off a tee facing downwards...see the manuals for details.
Check with ST regarding the warranty conditions though if doing this.

Gasguru said:

It's a regenerative (peripheral) pump and should be far more tolerant of air bubbles in the hot water from the cylinder.
Therefore you should be ok if you form a 45 degree pipe takeoff from the top of the cylinder...and take the water off a tee facing downwards...see the manuals for details.
Check with ST regarding the warranty conditions though if doing this.

Click to expand...

warranty looks fine as long as 45 degrees

Gasguru said:

It's a regenerative (peripheral) pump and should be far more tolerant of air bubbles in the hot water from the cylinder.
Therefore you should be ok if you form a 45 degree pipe takeoff from the top of the cylinder...and take the water off a tee facing downwards...see the manuals for details.
Check with ST regarding the warranty conditions though if doing this.

Click to expand...

warranty conditions are fine doing it this way. thanks for the help. think I will get the flange and the parts to create an upward 45 degree vent pipe. when I cut the existing vent pipe - I will try and undo the top fitting that looks cemented in - and fit the flange if I manage to get it out ok. If not budging - I have the second option of creating a diagonal 45 degree vent pipe.

Can I join the hot out from the pump back into the hot 22mm without running a dedicated new 22mm pipe for the shower hot? Would it just result in a loss of boost to the shower if someone opened up a hot tap downstairs or could it damage the pump? I dont want to damage the pump but it would be nice to boost the hot all around the house - maybe if I upgraded to the 3 or 4 bar ST monsoon version? Ive had one section of floor up and I can tee into the branch that feeds the ensuite only which is just the existing shower hot and ensuite basin.... The floorboards are full chipboard so a pain to get up but I want to do it right.

this is the instruction manual.
http://www.free-instruction-manuals.com/pdf/pa_1001745.pdf

Did the exact same thing today for an aqualisa Q digital shower. I Turned up with a Surrey flange and the cylinder had a male 3/4 outlet at the top. Cylinder was on ground floor. Changed draw off to 45° & then T'd off that to go down then up to feed shower pump in loft.

I'm not a fan of these top mounted flanges...when you look at them they are often flawed...it doesn't take much for the air pathway to block.

When you run just a single hot tap you are effectively running the cold side of the pump under a no flow condition. The kinetic energy from the impeller is transferred into the water contained around the impeller and the water becomes heated and therefore expands and a pressure rise is inevitable. In some cases seals will fail.
It's not clear from the manual whether this pump range can cope with that scenario...other manufacturers design specific pumps for that application. Have a word with technical.
I wouldn't go mad with shower pump spec...even the base models are noisy...and with a standard hot water cylinder you'll soon run out of hot.

picasso said:

If your going to stay in the house for a while and you got around £1500-£2000 to spend the consider putting in an unvented cylinder, if not use a negative head pump, warix flanges are not hard to fit but like all things plumbing things can go wrong.

Click to expand...

thanks for all the replies. Glad I started this thread because I would never have thought about different options available. Its an 18 year old boiler (baxi Solo 2 50 PF)(G Rated efficiency - none condensing) with no service history and open vented HWC. The mains pressure is good. I could spend £500 on a shower pump to get decent pressure to my en suite shower with this old system. I'm now getting quotes together for new boiler and potentially unvented tank (if I need it). Will hopefully save a couple of hundred PA in gas bills with a new A rated system boiler, under warranty and serviced annually.