readiescards Posted November 7, 2016 Share Posted November 7, 2016 So although my dwelling won't be passiv hauus standard I'm trying to ensure very little heat escapes into the attic space. Now I'm learning my water pressure is not good enough to run without a cold water tank in the attic. In previous older houses I've seen well lagged cold water tanks be located central in the attic space and have minimal insulation underneath them so some house heat escapes to keep the tank above freezing. Whats the work around for super insulated air tight dwellings to stop the cold water tank freezing please? Link to comment Share on other sites More sharing options...
ProDave Posted November 7, 2016 Share Posted November 7, 2016 I can't see a water tank in the loft solving a low water pressure problem. The pressure has to be enough to reach the tank, otherwise it won't fill. If your problem is low pressure at times but high pressure some of the time, a big pressurised accumulator may be your solution? 1 Link to comment Share on other sites More sharing options...
Ferdinand Posted November 7, 2016 Share Posted November 7, 2016 (edited) Presumably you have to create a blister in the superinsulation over the water tank so that you then leave the trad hole underneath but have a 'hat' over the top. How you create that is an opportunity to be innovative. Interlocking box made out of 150mm kingspan sheets with no bottom? One side easy to remove? Bell shaped frame filled with polybeads, and a winch to lift it like a cloche over a dinner? A Waterbombe Surprise, so to speak, Mr Wint. Or an insulated attic closet with a minimal floor. Edited November 7, 2016 by Ferdinand 2 Link to comment Share on other sites More sharing options...
Onoff Posted November 8, 2016 Share Posted November 8, 2016 (edited) I know some things like pumped showers require a certain size CWS tank, say 50gal to function correctly. Assume it's to do with draw/refill rates. My own place I've got a 25gal tank and had to search around for a shower pump that could live with it. I can't increase the tank size without lowering it's position or modifying the roof! Does "head" not equate to pressure? As in the higher the tank is sited the higher the available head pressure? And does a bigger tank give better head pressure? This is probably Plumbing 101 but it's all a black art to me! Edited November 8, 2016 by Onoff Link to comment Share on other sites More sharing options...
Nickfromwales Posted November 8, 2016 Share Posted November 8, 2016 Put a break tank in the garage and pump into an accumulator / s. No need whatsoever for a tank in the attic unless it's too late to get a pipe in between the house and garage? Just done one exactly like this. Link to comment Share on other sites More sharing options...
Onoff Posted November 8, 2016 Share Posted November 8, 2016 37 minutes ago, Nickfromwales said: Put a break tank in the garage and pump into an accumulator / s. No need whatsoever for a tank in the attic unless it's too late to get a pipe in between the house and garage? Just done one exactly like this. When you get a minute... Can you explain how this set up works please. Just interested. 1 Link to comment Share on other sites More sharing options...
readiescards Posted November 8, 2016 Author Share Posted November 8, 2016 Ditto @Onoff whats a 'break tank'? (I shunted the garage left a couple of metres @Nickfromwales so it is now attached :-) ) Link to comment Share on other sites More sharing options...
PeterW Posted November 8, 2016 Share Posted November 8, 2016 Break tank ensures you can't create negative pressure in the main using a pump. http://uk.grundfos.com/service-support/encyclopedia-search/break-tank.html So a 500 litre break tank is fed with normal mains pressure, then a pump draws from this via a non return setup to pressurise an accumulator that holds water for the house at a "higher" pressure. This is a simplified package version of it all http://www.anchorpumps.com/pump-type/booster-pump-sets/grundfos-home-booster-sets/grundfos-home-booster-240v/grundfos-4-5-bar-home-booster-240v 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted November 8, 2016 Share Posted November 8, 2016 4 hours ago, readiescards said: Ditto @Onoff whats a 'break tank'? (I shunted the garage left a couple of metres @Nickfromwales so it is now attached :-) ) A break tank, as @PeterW rightly says, disconnects you from the incoming mains supply, hence the name 'break tank'. The local water authority will prosecute anyone who creates a deficit on the water network e.g. drawing water in excess of the natural supply flow rate. In Wales the max you can pump at is 11.5-12 litres per minute, anything over that and your in the ?. They can be approached and have to supply a minimum flow rate & static pressure but good luck enforcing that. It's with that annoyance that folk make their own system with what's available. The Grunfos Home Booster linked above is a very good unit which I would recommend as a Plug n Play option, but I'd add a heafty accumulator to compliment it if it were me. It states a 180 litre capacity with the option to double it, but I think I'd go for a 3-500 litre accumulator as you'll only get 60% of the vessel capacity in actual stored water ( the rest of the volume is pressurised air or gas which is compressed to give back pressure as a means of storing energy ). Accumulators will only give the stored volume and will then be exhausted, at which point your water pressure & flow rate will return to whatever comes in from the street.....( you can only get a pint out of a pint pot ). To combat that Achilles heel you simply design the system so the stored volume is rarely / never depleted. Ill give Grunfoss a ring and find out what makes that unit tick, but I'm pretty sure that fitting an accumulator downstream will massively improve its performance, longevity, and the systems ability to deliver high flow rates for longer durations. I am interested in whether it pumps from an open break tank, or if it has a regulated pump which draws off the mains and pumps into an inbuilt, sealed accumulator. @readiescards , what has made you say you need to supplement your cold mains ? Link to comment Share on other sites More sharing options...
readiescards Posted November 8, 2016 Author Share Posted November 8, 2016 I was running a bath the other night when OH was trying to do the dishes but only a dribble of hot water was coming out. And this is in the holiday cottage we are living in that is 500m further nearer to the mains water connection than my new place. which is about 2km away with about 8 properties sharing the same private 40mm ish pipe. My new place will be property number 7. Plus a quick test shows good initial pressure but this reduces after 5 secs. Link to comment Share on other sites More sharing options...
ProDave Posted November 8, 2016 Share Posted November 8, 2016 I remember this one from ebuild now. If the static pressure is good but it is the inability to supply any decent flow rate, then the accumulator is the solution I would try. It will slowly charge up when you are not drawing water, and will supply your demand (as long as it is big enough) 1 Link to comment Share on other sites More sharing options...
Onoff Posted November 8, 2016 Share Posted November 8, 2016 Where are you @readiescards? I've got about 9 bar coming in, you can tap off of that if you want! Link to comment Share on other sites More sharing options...
Nickfromwales Posted November 9, 2016 Share Posted November 9, 2016 10 hours ago, Onoff said: Where are you @readiescards? I've got about 9 bar coming in, you can tap off of that if you want! That's a hell of a hosepipe Link to comment Share on other sites More sharing options...
readiescards Posted November 9, 2016 Author Share Posted November 9, 2016 Lincolnshire - at the end of the line out seems! Link to comment Share on other sites More sharing options...
Onoff Posted November 9, 2016 Share Posted November 9, 2016 39 minutes ago, Nickfromwales said: That's a hell of a hosepipe Flattery will get you everywhere! 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted November 9, 2016 Share Posted November 9, 2016 @readiescards Buy a pressure gauge and fit a non return ( double check ) valve to it. Connect that to your outside tap and leave on for 48 hours. That will capture the peak STATIC pressure available and is critical survey info to ascertain your best cold mains solution. 1 2 3 Test and report back. 1 Link to comment Share on other sites More sharing options...
readiescards Posted November 10, 2016 Author Share Posted November 10, 2016 Cheers @Nickfromwales in the meantime here, this video gives a hint of the water pressure: https://dl.dropboxusercontent.com/u/55058337/2016-11-10 08.06.52.mp4 We are just wondering if we've a leak somewhere so will be checking the water meter (2km away!) first Link to comment Share on other sites More sharing options...
PeterW Posted November 10, 2016 Share Posted November 10, 2016 3 hours ago, readiescards said: Cheers @Nickfromwales in the meantime here, this video gives a hint of the water pressure: https://dl.dropboxusercontent.com/u/55058337/2016-11-10 08.06.52.mp4 We are just wondering if we've a leak somewhere so will be checking the water meter (2km away!) first Confused ... do you own the land between your house and the main 2km away ...??? Link to comment Share on other sites More sharing options...
readiescards Posted November 10, 2016 Author Share Posted November 10, 2016 Half of the land is on our family farm. The pipe was originally put in after the war using metal. I replaced the last 30m of metal last year and it should now be 25mm plastic most of the way now. Link to comment Share on other sites More sharing options...
readiescards Posted November 10, 2016 Author Share Posted November 10, 2016 Checked the meter no leaks will get static pressure kit sorted Link to comment Share on other sites More sharing options...
Nickfromwales Posted November 10, 2016 Share Posted November 10, 2016 ? Link to comment Share on other sites More sharing options...
readiescards Posted November 23, 2016 Author Share Posted November 23, 2016 Got the meter and check valve. Can not work out best way to go from 32mm plastic pipe to 15mm check valve. Any tips @Nickfromwales please? Link to comment Share on other sites More sharing options...
PeterW Posted November 23, 2016 Share Posted November 23, 2016 32mm MDPE..?? One of these http://www.drainagepipe.co.uk/products/mdpe-fittings/mdpe-to-universal-copper-adaptor/32mm-x-15/22mm Link to comment Share on other sites More sharing options...
Nickfromwales Posted November 24, 2016 Share Posted November 24, 2016 1 hour ago, PeterW said: 32mm MDPE..?? One of these http://www.drainagepipe.co.uk/products/mdpe-fittings/mdpe-to-universal-copper-adaptor/32mm-x-15/22mm ? Link to comment Share on other sites More sharing options...
readiescards Posted November 24, 2016 Author Share Posted November 24, 2016 Sorted through a few boxes on the farm and got it connected - easy peazy this plumbing lark! 7 bar static - will see if increases over night. Link to comment Share on other sites More sharing options...
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