Spinny

Just made some dynamic pressure measurements… Static Pressure on 15mm outside tap coming off nr the mains stop cock is 3.4Bar if I put the outside tap full on (20l/m) and take pressure at 15mm toilet cistern connected to the same 15mm pipe branch the pressure falls to only around 1 bar. Pressure at outside tap when running upstairs taps is… 1 cold tap on = 2.4Bar 2 cold taps on = 1.7Bar 2 cold & 2 hot taps on = 1 Bar Q1 So I guess the issue is fairly major dynamic pressure drop from current lead mains feed? Q2 If I get say a 32mm MDPE pipe put in will I get less pressure drop for a given dynamic flow ? Q3 Any way to estimate it ? Q4 Is the 22m distance from the mains a significant issue and would some other type of low friction pipe be better than MDPE ? Q5 Do water companies limit the size of the pipe connection you are allowed to have to the mains ? (Will they not connect 32mm, or effectively choke it down through a 25mm connector ?) Q6 Does type of stopcock make an appreciable difference ? (My current stop cock tends to start drip leaking if you try to open it too far.) Sorry, too many questions. Thank you for any and all help you can give. Been fighting endless issues since my builder started a one storey extension 1.5 YEARS ago!

Thanks I tried the water company, but they will only do short runs and mine is 22m from pavement stop tap to house stop tap. So I am going to have to pay and contract someone myself.🙄

Another pic showing stop tap & water softener pipework.

Can anyone comment on the use of MLC pipe and tell me what bore they are restricted down to at the crimped connectors ? (The mains pipe needs sorting, but connecting a new one onto the 25mm MLC which is effectively perhaps only 17mm internal diameter seems a bad idea. As is 16mm MLC with an effective bore of 10mm going to kitchen taps etc.)

Thank you. I have just found the cylinder design & install instructions for the gledhill cylinder online. It seems the cylinder is supplied with a tun dish - so wonder where it is ? I see the discharge pipework has to be metal (presumably copper?) so the plastic waste pipe presumably isn’t going to be good enough. Very worried now on a number of fronts. It may be that some u/floor heating will have to be taken up for access. why aren’t some gas safe people apparently either competent or trustworthy ? Sigh.

Wow, thank you. Plumber is gas safe registered - not sure if you can check G3? presumably a Ton Dish something like red lines on this photo then ? Presume it can be made to discharge into same drainage outlet as boiler condensate ? The wiring is temporary, sparky still to tidy up/complete moving onto new circuit. Got two Heatmiser wiring hubs, manifolds & Pumps down there. One heating a concrete slab, t’other omnie u/floor heating. lead to copper join photo attached. This join has not been changed so is at least 30 years old. I am currently trying to get quotes to mole in a new 32mm MDPE mains pipe. (If you can suggest any contractors for moling in the Bristol area I would be grateful.) is there a way I can check the dynamic pressure on the outside tap ?

PS I have recently been made aware that MLC pipe is not necessarily what it might seem. That is: 16mm MLC is only 12mm internal bore, but worse every crimped join restricts bore further (suppliers brochures don’t seem to say ?!?) but 10mm ? 9mm ? Likewise even 25mm MLC is 20mm internal bore but restricted to what at crimped joins 18mm ? 17mm ?

PS I have recently been made aware that MLC pipe is not necessarily what it might seem. That is: 16mm MLC is only 12mm internal bore, but worse every crimped join restricts bore further (suppliers brochures don’t seem to say ?!?) but 10mm ? 9mm ? Likewise even 25mm MLC is 20mm internal bore but restricted to what at crimped joins 18mm ? 17mm ?

Old gravity fed water system has been removed and a new mains pressured UVC system has been installed by the builders plumber. ATAG Gas Boiler, 250L Gledhill Stainless ES Cylinder plus expansion tank. Mains supply currently via lead pipe connected to 15mm copper. Static mains pressure about 3.5Bar at outside tap connected directly to mains via 15mm copper/plastic. Flow rate from tap 20l/m. System has 3bar PRV fitted. Cylinder has 4.5Bar/95C over pressure/temp relief valve. System is fitted on ground floor. Questions/Issues 1/ Should there be a Tundish fitted as there is currently none. The overp/t relief valve has nothing connected to it at all and would discharge onto the floor ?! 2/we wanted to be able to run 2 showers simultaneously and still flush a toilet/use kitchen tap. Currently B/room shower gives static pressure of 2.8Bar and flow rate of 10l/m (hose only) or just 6.6l/m(from shower head/flow destructor removed). Noticeably weaker than old gravity system with 3bar(2.5bar at 9l/m) monsoon pump. If another tap is fully opened upstairs, shower static pressure drops to 1.4bar. Shower flow drops to 5.5l(hose only), 4.6l/m(through shower head). Hardly likely to support 2 decent showers at once. So what pipework should the plumber have installed ? Is the problem the pipe bores used, the pipe bends and Tees, the cylinder plumbing, the pipe lengths ? Very concerned now that plumber hasn’t installed adequately and not fit for 20 year use. How to know what exactly is wrong and how to fix it ? PS Current Pipes in sequence… 20m lead into property 15mm copper stop tap 22mm copper to water softener (not yet fitted bypass valve operating) 25mm MLC pipe to cylinder/boiler area 22mm copper to PRV, cylinder, and 22mm copper hot and cold to first floor landing. Then 15mm copper feeds from the 22mm pipe to upstairs taps and showers. 15mm Tee, 3 or 4 15mm right angles to shower mixer.

Maybe we can get round that problem if we design and 3d print a special joining piece. 🫣😵‍💫

Just a man that foolishly decided to improve and not move.