shower pump installation - anti gravity loop

I am about to install a Salamander ESP100CPV shower pump. The easiest place for me to put it is in the airing cupboard above the Hot Water Cylinder. The intructions indicate that I can do this as long as I fit an anti-gravity loop at least 250mm in depth.
OK, all well and good but at the risk of sounding foolish, is this something I can buy ready made or do I need to construct one ? If the latter, what is the best way of doing this in 22mm copper, I don't have a pipe bender. I guess what I'm really asking is will there be any problem if I form one out of short straight pieces of pipe with 2x 90degree elbows ?
Thanks.
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The whole point of the loop is to dissuade dissolved air from entering the pumps impellers. I can see any reason why you can't construct one yourself though to retain optimum flow rates a swept 180 deg turn using a spring or pipe bender would be better than 2 elbows.
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yourself
LOL - a point lost on the last plumber we had..
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Fred wrote:

ITYM it is to prevent convected circulation from causing the pump to start all by itself even when the shower is not turned on
(preventing air ingress is one of the reasons for using a dedicated shower flange to feed the shower (Essex / Surrey / Warwix etc))

Yup definately stick to swept bends in this application.
--
Cheers,

John.

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Thanks guys for all the advise. I've just realised that in addition to fitting the anti-graivity loop, if I want to place the pump above the hot water cylinder then I need to use an essex flange which means drilling a hole in the side of the cylinder. I'm not too keen on this and thought I could just replace the existing top fitting with a Surrey flange. I may have to look at other options first, most obvious at the moment is to put the pump under the floorboards, but I'm a little concerned about noise and vibration.
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Kevin wrote:

The exact pump location does not really change the requirements for the tank connection. The pump instructions normally give a range of connection options that start with a dedicated essex flange as the most deireable, to using the existing top connection as the least. Having saif that in the right circumstances using the existing top connection can work fine.
--
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John.

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Thanks John. I've re-read the instructions again. The Essex flange with the anti-gravity loop is compulsory if the pump is fitted above the outlet from the hot water cylinder. If the pump is fitted below the outlet then I can use any other approved top entry flange. These include the Salamander (S) Flange, York Flange and Warix Flange. I thought I had also read Surrey flange but I may be mistaking this with the S flange. I figured it would be easier to use one of the approved top-connection flanges rather than trying to drill a hole in the side of the cylinder and the associated difficulties of fitting it.
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Kevin wrote:

The antigravity loop I can understand being a requirement. However the choice of flange less so. An Essex flange is a good way to do it certainly, but not the only way - even with the pump above the cylinder (but still below the head of the cold tank feeding it)

Surrey and Warwix flanges are pretty similar - I would have no hesitation using either.

Indeed. I have done one before just using the standard output and it worked fine. However that was with an optimal setup with the cold cistern in the loft almost directly above, with a clear run of 22mm swept bend pipework to the cylinder. It was also only using a 1.4 bar pump, had it have been more I may not have tried it! (I also had the option of making up a surrey flange should it prove to not work as well as hoped)
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John.

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Thanks John. I've re-read the instructions again. The Essex flange with the anti-gravity loop is compulsory if the pump is fitted above the outlet from the hot water cylinder. If the pump is fitted below the outlet then I can use any other approved top entry flange. These include the Salamander (S) Flange, York Flange and Warix Flange. I thought I had also read Surrey flange but I may be mistaking this with the S flange. I figured it would be easier to use one of the approved top-connection flanges rather than trying to drill a hole in the side of the cylinder and the associated difficulties of fitting it.
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Kevin wrote:

You should always use swept bends on the piping to pumped showers (read the instructions). If you don't want to bend copper i would use plastic pushfit with the purpose made formers (cold forming bend) that allow you to bend the pipe and hold it in place:
http://www.johnguest.com/part_spec.asp?s B_S1
MBQ
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I'll be interested to know how yours is once you've fitted it. Ours was just put onto the floorboards and consequently these act like a sounding board - it is very noisy. One day I'll try and build an insulation box.
At times I could take a hammer to the unit. It is very sensitive to the slightest drip, which will provoke the pump into action periodically. Unlike it's predecessor, I assume it triggers when the pressure in the pipework drops below a certain amount. Our old pump required a certain amount of flow before triggering.
It's a real PIA when you've gone to bed only to realise that the kitchen tap is dripping *very* slowly and that pump will trigger during the night if you don't go back downstairs..
Arghh!!
Paul
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Paul Andrews wrote:

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Damn, I wish I knew this yesterday. I've been in two minds all week over whether to put the entire hot water supply onto the pump or just put the shower & bath onto it and bypass the pump for everything else. I've now started laying the pipework for the new shower and have gone for the first option. I guess I'm going to have to make sure all the taps are properly closed each night.
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tap
you
Never mind, the family will enjoy listening to it when you're doing the washing up downstairs.. ;-)
(I'm only half joking). Seriously, think about trying to deaden the noise from this beast. Our whole house is powered by this pump, not because I asked for it, but because it made the plumbers life easier..
Paul
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Final question (I hope) and I'm really just looking for reassurance here I've never used plastic pipe before, but I'm thinking that it might make my life a lot easier with the connections from the Hot and Cold tanks to the pump. I assume there are no particular problems with mixing and matching copper and plastic pipe ? I'm thinking that I'll use plastic on the inlets to the pump and copper on the outlet side, simply because most of the pipework on that side is already in place and in copper. Any particular pitfalls I should look out for ?
Thanks.
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For anyone interested, I fitted the pump over the weekend and so far everything's great.
In the end, I decided not to fit the pump above the hot water cylinder, instead I've effectively extended the bottom half of the airing cupboard sideways to allow me to fit the pump next to the cylinder. This meant I didn't need to worry about the AG loop and was able to replace the existing fitting with a Warix flange rather than drilling a new hole for an Essex flange.
The pump is raised off the floorboards with a few small lengths of 3x2 and sat on a piece of 8x1. It came with large foam pads which the pump sit's on to minimise vibration and noise transferrence.
Never having used it before, I was a little wary of using plastic pipe, but I found it extremely easy to use and to bend and had no problems whatsoever with any of the connections. I think in future I will be thinking plastic first as it was so easy to use.
I've put the hot water supply for the entire house onto the pump and have noticed a fantastic improvement already. It used to take an age to fill the bath but took no time at all last night. Not had a chance to test the shower properly yet as I still need to fit the shower enclosure(next weekends job), but at least I know I've no leaks.
Thanks to everyone who offered advise.
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LOL sounds like your is a lot quiter than ours! Glad it went well - nice to see a followup, many can't be bothered.
Paul
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