redtop Posted March 27, 2020 Share Posted March 27, 2020 so I have 32mm mdpe from mains to the house. I went for 32mm as I have to have a sprinkler system and wanted to minimise chance to need a storage tank. I now want to bring it inside the house. So I think... I need a 32mm t connection and then 2 feeds, one for house and one for sprinkler system. Then stop taps for both. But I (think) I have to fit a check valve. We fitted 2 for the taps leading from the mains to the house that fed the outside taps on the way, both have failed probably due to the high water pressure we have (its a bloody fountain) and partly down to the crap build quality (polyfast). The plassen connections have been fine. so my plan was to fit a full bore check valve (minimising flow restriction) and then split into 32mm for house and 32mm for sprinklers. into house and then normal stuff for house and temp on/off for sprinkler system. Can I find a full bore check valve that fits 32mm MDPE nope. Can anyone help advise how I should tackle this? Pleeeese keep it simple as this stuff confuses me. Link to comment Share on other sites More sharing options...
ToughButterCup Posted March 28, 2020 Share Posted March 28, 2020 I sympathise. By chance I'm struggling with the same stuff, without the pressure issues. And need answers to the same questions. Your discomfort at dealing with water supply mirrors mine. To me it's full of arcane nonsense, organised by people whose main concern was their own convenience. Break the problem into bits. You can't find a check valve for 32mm MDPE. ..... because they don't exist or because they can't be supplied? What happened when the taps failed? How did they fail? I've heard of Pressure Reduction Valves (know sod all about): is that a thing worth thinking about? The sprinkler system needs a ' ... temp on/off ...' system. Help us with a bit more detail, please. Slowly slowly catchee monkey. ? Link to comment Share on other sites More sharing options...
redtop Posted March 28, 2020 Author Share Posted March 28, 2020 sooo, I had been n the wine last night ? the two polyfast check valve failed, all the rest of the stuff is plasson and is fine. everything inside house will be temp as the house is so far from finished. really its the check valve. for the house I could step down and then check valve in a smaller diam. for the sprinkler feed I could leave it too the sprinkler installers to provide one and just provide a direct 32mm feed with nothing other than a stop tap between it and the mains Link to comment Share on other sites More sharing options...
PeterW Posted March 28, 2020 Share Posted March 28, 2020 Loads of 32mm Double check valves out there for MDPE..?? Not sure why you are struggling to find them ..?? TBH I would not bother trying to do this in MDPE anyway - terminate the house 32mm with an MDPE stop valve and convert to 28mm copper. Tee the copper into a pair of supplies, put a DCV on each and then a full bore lever valve and a drain tap, then reduce the house supply to 22mm and leave the 28mm to the sprinkler guys. House can then convert back to Hep2O or similar but you’ve essentially got a fireproofed supply at that point using standard parts. 1 Link to comment Share on other sites More sharing options...
Mr Punter Posted March 28, 2020 Share Posted March 28, 2020 If the water is connected, get the sprinkler guys to do a flow test early on, as the system design will assume a minimum delivery rate to the heads. Often the 15mm meter- which is standard for the water companies - is the bottleneck and you may need to get this changed for a higher flow meter. For others, it is worth considering 2 supplies - one for the sprinklers and one for the house supply. Link to comment Share on other sites More sharing options...
redtop Posted March 28, 2020 Author Share Posted March 28, 2020 3 minutes ago, Mr Punter said: If the water is connected, get the sprinkler guys to do a flow test early on, as the system design will assume a minimum delivery rate to the heads. Often the 15mm meter- which is standard for the water companies - is the bottleneck and you may need to get this changed for a higher flow meter. For others, it is worth considering 2 supplies - one for the sprinklers and one for the house supply. I had a special 32mm high flow meter fitted which is approved for sprinkler systems, hence the 32mm mdpe to the house. might still not be enough flow but give me a chance 1 Link to comment Share on other sites More sharing options...
redtop Posted March 28, 2020 Author Share Posted March 28, 2020 17 minutes ago, PeterW said: Loads of 32mm Double check valves out there for MDPE..?? Not sure why you are struggling to find them ..?? TBH I would not bother trying to do this in MDPE anyway - terminate the house 32mm with an MDPE stop valve and convert to 28mm copper. Tee the copper into a pair of supplies, put a DCV on each and then a full bore lever valve and a drain tap, then reduce the house supply to 22mm and leave the 28mm to the sprinkler guys. House can then convert back to Hep2O or similar but you’ve essentially got a fireproofed supply at that point using standard parts. I thought the sprinkler system had to have a direct supply from the mains, with its own stop tap hence wanting to split before the house and then leave the 32mm foor the sprinkler guys. yes I could reduce to copper and then fit DCV Link to comment Share on other sites More sharing options...
redtop Posted March 28, 2020 Author Share Posted March 28, 2020 18 minutes ago, PeterW said: Loads of 32mm Double check valves out there for MDPE..?? Not sure why you are struggling to find them ..?? TBH I would not bother trying to do this in MDPE anyway - terminate the house 32mm with an MDPE stop valve and convert to 28mm copper. Tee the copper into a pair of supplies, put a DCV on each and then a full bore lever valve and a drain tap, then reduce the house supply to 22mm and leave the 28mm to the sprinkler guys. House can then convert back to Hep2O or similar but you’ve essentially got a fireproofed supply at that point using standard parts. and I can find loads of the rubbish polyfast check valves but nothing else Link to comment Share on other sites More sharing options...
PeterW Posted March 28, 2020 Share Posted March 28, 2020 I would use a brass full bore 1 1/2” DCV with a pair of MDPE connectors each end. And what is the definition of 32mm from the mains for a sprinkler system ..? Need to see the spec but I can’t see how splitting underground is any different than splitting as soon as it enters the building ..?? Link to comment Share on other sites More sharing options...
redtop Posted March 28, 2020 Author Share Posted March 28, 2020 3 minutes ago, PeterW said: I would use a brass full bore 1 1/2” DCV with a pair of MDPE connectors each end. And what is the definition of 32mm from the mains for a sprinkler system ..? Need to see the spec but I can’t see how splitting underground is any different than splitting as soon as it enters the building ..?? here is their pic Link to comment Share on other sites More sharing options...
PeterW Posted March 28, 2020 Share Posted March 28, 2020 So reading that you need two dedicated supplies and one from before the meter ..?? What have the water company installed and where is the meter ..?? Link to comment Share on other sites More sharing options...
scottishjohn Posted March 28, 2020 Share Posted March 28, 2020 looking at diagram you get free water down the sprinkler route as it by passes meter --that don,t seem right Link to comment Share on other sites More sharing options...
JFDIY Posted March 28, 2020 Share Posted March 28, 2020 Surely you hope it's never needed. Likewise when the firefighters use a fire hydrant, that is free for firefighting, so the network must accept that? Would he tempting to run the garden Tap off the sprinkler feed though. Link to comment Share on other sites More sharing options...
Mike Posted March 28, 2020 Share Posted March 28, 2020 (edited) Are you looking at the current document? Found a copy here (pdf), probably from 2018 from the file name, and the diagrams differ significantly from the one posted above. Have you considered installing a misting system as an alternative to sprinklers? Edited March 28, 2020 by Mike Link to comment Share on other sites More sharing options...
Mr Punter Posted March 28, 2020 Share Posted March 28, 2020 1 hour ago, scottishjohn said: looking at diagram you get free water down the sprinkler route as it by passes meter --that don,t seem right Correct. The water companies are not allowed to charge for supplies for firefighting / sprinklers. Link to comment Share on other sites More sharing options...
Mr Punter Posted March 28, 2020 Share Posted March 28, 2020 1 hour ago, JFDIY said: Would he tempting to run the garden Tap off the sprinkler feed though And if you were caught you would rightly be prosecuted. Link to comment Share on other sites More sharing options...
redtop Posted March 28, 2020 Author Share Posted March 28, 2020 the diagram I posted is slightly wrong, sorry. you can have one supply for both house and sprinkler provided the right type of meter has been fitted, which has. Havnt really looked at misting systems, thought they were expensive but will take a look, D Link to comment Share on other sites More sharing options...
redtop Posted April 2, 2020 Author Share Posted April 2, 2020 so plan isr 32mm MDPE rising main (that was already there), into house and then stop tap, down to 28mm, DCV, drain and then pressure reducer, 28mm to 22mm tee and will then use the 2 22mm for outside tap and the other to feed stuff around the house. I have split the 32mm before it comes into the house for sprinklers, so that's sorted. got all the stuff except the DCV, seem to be so many types out there does anyone have any recommendations. I have read they cause loss of pressure, and do I need a DCV or single check. argh plumbing. give me electrics any day Link to comment Share on other sites More sharing options...
scottishjohn Posted April 3, 2020 Share Posted April 3, 2020 On 28/03/2020 at 15:27, Mr Punter said: And if you were caught you would rightly be prosecuted. simple they fit meter -read it at same time as normal one -if itshows usage theyt charge you Ican,t see the cost for water on the insurance claim for a burnt house being a big in the scale of things without meter its just asking to be be abused Link to comment Share on other sites More sharing options...
Mr Punter Posted April 3, 2020 Share Posted April 3, 2020 1 hour ago, scottishjohn said: simple they fit meter -read it at same time as normal one -if itshows usage theyt charge you Ican,t see the cost for water on the insurance claim for a burnt house being a big in the scale of things without meter its just asking to be be abused We have a separate 50mm supply for sprinklers and it has its own meter to check water is not used. They don't raise any bill for this. A small amount of usage happens if the sprinkler flow rates get tested. Link to comment Share on other sites More sharing options...
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