32mm MDPE to internal pipework?

[Ben Weston]

Hi all,

 

New build. We have 32mm MDPE coming up under the sink. From the sink, we need 15mm feeds (Hep2O) to the kitchen appliances and a connection to the 25mm MDPE pipe that goes to the rest of the house – water cylinder, heat pump, bathrooms, etc. I'm trying to simplify this but am struggling. It's a LOT to fit in an under-sink cabinet currently. I've attached a diagram of the simplest way I can think to do the pipework but I know it's not right.

 

Can anyone much cleverer than I advise how to take a 32mm MDPE and terminate to 25mm MDPE and 15mm Hep2O?

Edited December 7, 2023 by Ben Weston

[jayc89]

Do you need to reduce to 25mm MDPE? What's supplying your hot water?

I have 32mm MDPE coming in, converts down to 28mm copper, full bore lever as a stop tap, them up to the unvented cylinder multi-bloc before teeing off and reducing down to 15mm/10mm for outlets.

 

Plastic's quite bulky, IMO copper is far better for tight spaces. 

[RichJ]

If you're willing/able to swap the 32mm JG stop tap for a Plasson 32mm (compression) stop tap instead, you can use a Plasson 32mm to 25mm reducing set in the outlet of the Plasson stop tap to go straight from 32mm MDPE to 25mm MDPE in one fitting. So you wouldn't need the 32mm to 25mm JG reducer in that case.

 

See https://plasson.co.uk/product-category/mechanical/line-7-grey/valves-line-7-grey/compression-stoptap-valves-line-7-grey/ and

 

https://plasson.co.uk/product-category/mechanical/line-7-grey/conversion-and-adaptor-sets-line-7-grey/reducing-set-conversion-and-adaptor-sets-line-7-grey/

 

The only thing about the Plasson 32mm MDPE stop tap is it's huge (174mm long). I don't know how that compares to what you already have.

[Russell griffiths]

What stage is the house at ?

if it’s possible I would re think your watermain location and bring it up in the area that has the tank and the majority of the plumbing stuff. 

 

[Ben Weston]

Thanks for the replies :-) 

 

  On 08/12/2023 at 08:25, Russell griffiths said:

What stage is the house at ?

if it’s possible I would re think your watermain location and bring it up in the area that has the tank and the majority of the plumbing stuff. 

 

Expand  

 

Yes, in hindsight this would have been a much better idea. Unfortunately, floors are all down now so we have to deal with the MDPE as it is. 

 

  On 08/12/2023 at 00:42, RichJ said:

If you're willing/able to swap the 32mm JG stop tap for a Plasson 32mm (compression) stop tap instead, you can use a Plasson 32mm to 25mm reducing set in the outlet of the Plasson stop tap to go straight from 32mm MDPE to 25mm MDPE in one fitting. So you wouldn't need the 32mm to 25mm JG reducer in that case.

 

See https://plasson.co.uk/product-category/mechanical/line-7-grey/valves-line-7-grey/compression-stoptap-valves-line-7-grey/ and

 

https://plasson.co.uk/product-category/mechanical/line-7-grey/conversion-and-adaptor-sets-line-7-grey/reducing-set-conversion-and-adaptor-sets-line-7-grey/

 

The only thing about the Plasson 32mm MDPE stop tap is it's huge (174mm long). I don't know how that compares to what you already have.

Expand  

 

I'd be happy to replace the stop tap – the JG one is 220mm!!! It's why I'm concerned about how I fit it all under the sink! This definitely simplifies things a lot, thank you.

 

It also looks like I might need a drain tap directly after the stop tap but I've not been able to find a single 32mm drain tap! Is this the case?

 

Edited December 8, 2023 by Ben Weston

[cherryfountain]

Buy a 32 MPDE to 28mm copper fitting and a 28mm stop cock or lever valve .You can then tee off with a reducer tee for a drain down valve. You can also use a reducer tee for 25MPDE to a 22mm copper fitting. You could then reduce the 28mm copper tail to 22mm or 15mm for the supplies that need them. If I was doing this I would use end-feed copper fittings, but you could also use push-fit. You need to remove the sink base back and clip all plumbing back to wall. You can always fit a removable back with access later if required.

[Gone West]

Isn't it a requirement to have a double check valve on entry into the property.

[cherryfountain]

It is a good idea to fit one there , as then covers you when you fit other appliances  that need a check valve.ie water softener,outside tap and other appliances.

[RichJ]

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Edited December 8, 2023 by RichJ

[RichJ]

  On 08/12/2023 at 14:08, cherryfountain said:

Buy a 32 MPDE to 28mm copper fitting and a 28mm stop cock or lever valve .You can then tee off with a reducer tee for a drain down valve. You can also use a reducer tee for 25MPDE to a 22mm copper fitting. You could then reduce the 28mm copper tail to 22mm or 15mm for the supplies that need them. If I was doing this I would use end-feed copper fittings, but you could also use push-fit. You need to remove the sink base back and clip all plumbing back to wall. You can always fit a removable back with access later if required.

Expand  

 

With the Plasson 32mm MDPE stop tap you can go to 28mm copper using a copper conversion set in the outlet..

https://plasson.co.uk/product-category/mechanical/line-7-grey/conversion-and-adaptor-sets-line-7-grey/conversion-set-for-copper-pipe/

[markocosic]

32mm mdpe to 1" BSP

 

1" full bore ball valve with female threads as the isolator

 

Then cooper with a male 1" thread on the beginning 

 

Don't forget inserts on the MDPE