Spinny

OK thanks for comments. The supply pipework is 32mm MDPE mains in, connected into 22mm copper (16mm MLCP tee to kitchen, 15mm copper tee to outside tap) through water softener (currently on bypass), then approx 5m of 25mm MLCP pipe to the cylinder location, final 1m in 22mm copper to the reducing combination valve. I was getting 37 l/m from the outside tap, so I know the mains supply is capable of providing a continuous 37l/m through 15mm copper. So the main supply through the 22mm copper and 25mm MLCP should be providing at least that and one would think 40l/m + into the combination valve. Mains pressure 3.5 bar. Unfortunately I can't change the 5m of 25mm MLCP with its press fit connector at each end, because it runs under the suspended floor which now has underfloor heating installed. Had I seen the MLCP connector bore reduction at the time I would have insisted the plumber put in 32mm MLCP. But that is the big unspeakable secret with MLCP and press fittings. I have seen some Wavin Tigris M5 / K5 press fit MLCP connectors which claim ''The new Wavin Tigris K5/M5 with Opti Flow reduces the pressure loss in the installation due to the up to 50% larger orifice..''. Mentioned them to my plumber who promptly claimed they would make no difference, and proceeded to fit cheaper ones he uses. A lot of trade are not interested in using anything except what is available off the shelf at their chosen merchant. System performance for the customer doesn't come into it - in fact I have never seen a plumber measure a flow rate.

I am talking total combined output there - that is Hot Flow + Cold Flow. If it is Christmas and I have family staying - say every year for the next 15 years. Then you have 6 adults in the house, maybe 2 or 3 grandchildren. You want to run 2 showers at the same time. Someone is running taps in the kitchen making breakfast, someone just put the washer on, and someone flushes the loo. So if the system can't handle it, someone is getting a bad shower, and you are into shouting round the house about who can use a bathroom or ensuite. At present the highest simultaneous output I am getting is 34 l/m combined hot and cold downstairs - that is 17 l/m each for hot and cold. Hot flow and cold flow are not separate, they all come through one input pipe and combination valve. I am only getting more like 20-24 l/m simultaneous combined on other outlets. I don't think this is unusual, part of the selling point of UVC vs gravity fed is the ability to run two bathrooms etc. My mains supply should be capable of 40 l/m+. Are we really saying there is no-one here that has ever seen flow problems with a domestic system regardless of how it is plumbed.

I mentioned on another topic, plumber is planning to replace my Caleffi pressure reducing combination valve with a 28mm valve to improve flow (my pipework is 22mm). I am reading some stuff about pressure reducing valves having to be sized correctly for expected flows, and sometimes 2 valves plumbed in parallel may be required - one for low flow, one for higher flow. (I guess I expect flows from say 5/6 l/m with one tap on through to say 35-40 l/m - 2 showers, couple of taps, kitchen appliance all going.) (Seems unfortunate that someone can't design a pressure reducing valve that works well without restricting flow over a wide flow range) PS Do you actually need to have a balanced cold ? What experience and advice can people offer re combination valves for domestic UVC systems and maximising flow ?

Didn't you say on another thread that you were putting traps out for rats ? And had tried poison ? You could perhaps have dead rats somewhere. Got any flies ? What happened with us years ago - rats came up a drain - got into some house voids/cavities/subfloor - wife claimed she could smell something - rat man put down poison - also blocked drain aperture - rats slowly disappear - 2-3 weeks later a plague of flies in the house. When our old extension was demolished - builders found some rat carcases under the floor. (PS Someone I once knew had a distant relative die in their house - body not found for 6 months - had to be identified by DNA. OMG)

Should always chase horizontally or vertically between wall plates/entry/exit points - you will find the electrical safe zones defined on line. That way there is half a chance others won't drill into the cable. Even if it is safe, not actually power, as just a signal cable, nobody wants a severed aerial cable etc. How come you are not just going straight up the wall from subfloor ? What cable is it - Coax, HDMI, Network ?

This seems to me the sort of system plumbers should be using

DIY - nope too busy playing wack-a-mole with various other things. I do just have a plumber currently, maybe ok tbh, but a little frustrated with flow from a different tap he has plumbed in. It is a general problem with trades and differences of objectives between the trade and the customer. Many trades want to be in and out job done - pay me mucho money instantly etc. Most customers have no idea what the plumber is doing. Plumbing should last up to 50 years - that's a lot of people cursing a limited flow rate because a plumber couldn't be bothered to bend pipe etc. One came for a look, as soon as I said a few things about MLCP and connectors and flow rates I had measured, he said, you sound technical, I'll decide whether I want to quote, never seen again. Clearly that type like ignorant customers that never ask a question. Good people want to do a proper job, welcome questions, take some trouble - measure the system performance - leave things right - call customers up to come and fix anything temporary they do etc.

Could it be the drains ? Maybe lift the drain covers and check everything is free flowing. Have all the waste traps in the house got water in them ?

OK Garry, I see you are referring to the white plastic pipe to the outside tap. Sure that bit can be simplified, but really the whole caboodle from the mains pipe coming in forward needs to be reworked. I am wondering whether having the bypass valve mounted vertically would help.

It is actually a right bu***** muddle at the moment under my stairs. (I have had a constant nightmare with plumbers that say they will quote but don't, say they will come but don't, pop in to do something temporary and then never come back, only seem interested in doing the fastest possible rush job using only what is on site/in the van, don't really seem to want to solve issues, and/or want to bill criminal charges.) See photo. If anyone can offer any suggestions for how this should be sorted I would be very grateful. (Sadly I have the electricity main, the gas main & meter, and the water main all coming into an understairs cupboard.) On the left front you can see a 32mm MDPE water main at sub floor ground level, which has been connected to 22mm copper. This runs around in a 90 degree arc out of picture to the left because it still connects to the out of use lead pipe with a stop tap there. Left middle in the photo there is then a 15mm tee down into a blue valve (off) and connector to 16mm MLCP - this MLCP runs as a mains water feed to my kitchen sink location. Next along another 15mm copper tee with blue valve (on) that feeds (1) the outside tap and (2) an MDPE pipe under the floor that runs down to the end of the garden 40m away. The connection to the garden MDPE pipe was made temporarily just to test for leaks - comes vertically down in copper with a blue lever valve (off). Then a bypass valve for a monarch water softener (never yet installed) - bypass valve badly needs moving to the left to make proper room to connect flexihoses to the water softener. Out of the bypass valve into a 25mm MLCP to the cylinder location 5m away (where it connects to 22mm copper to feed the pressure reducing valve). You can also see the mains cable front left, middle is the gas enters through the wall and feeds upward in copper through the meter above and back down to join the yellow gas feed off to the boiler. (Meter man can't touch the gas feed pipe, plumber can't touch the meter etc) Answer welcome for a beer should we ever meet and a donation to the forum.

About a year ago we replaced our lead water pipe with a new 32mm MDPE connection. This resulted in the flow through our outside tap being good at 37 l/m - tap connected off the internal 22mm mains copper pipe using 15mm copper pipe. Since then the piping to the tap was changed as a temporary measure to plastic with various connectors. It now has 5 right angle elbows on the temporary pipe run (see pic). When I measure the water flow it is now 27 l/m - a 27% flow reduction. I therefore conclude that each elbow is reducing flow by about 2 l/m. My plumber has already fitted one 90 degree press fit elbow on another pipe run and the flow there seems lower than other internal taps. I presume I need to tell my plumber to stop using 90 elbows and to use only swept bends if I want to maximise flow ?

Thanks for response John. Yes this is the first creaking/groaning problem. Did the plumber de pressurise the UVC ? Not sure. I think the water was turned off at one point though, so perhaps. The UVC is Gledhill Stainless ES 250L, the expansion vessel is a Zilmet, nominal volume 22. The plumber's colleague has since returned. Said the noises were because of some kind of flutter/oscillation from the pressure reduction valve. He let some air out of the expansion vessel to reduce the pressure in it somewhat - didn't have a pressure meter - so not sure of expansion vessel pressure now. This has stopped the loud creaking/groaning noises whenever we ran the hot water. The system has had release through the tun dish on a regular basis over 3 months or so, relieved by running off hot water through the taps when spotted. The plumber is proposing to replace the pressure reduction valve (currently a Caleffi) with a new 28mm pressure reduction valve, having suggested this may help improve flow through the system. Mains pressure is about 3.5 bar.

Yes, all government schemes seem to get defrauded. Horrendous during covid. Imagine spending £500 Billion to no good effect, and actually doing so much longer term damage. And it is our money not theirs, the politicians waste it like water.

Builder from hell... https://www.bbc.co.uk/news/articles/cvg09n7gj3lo Customer from hell... https://www.dailymail.com/news/article-15761579/Plumber-broken-radiator-row-suing-employers.html

Have a TECE concealed cistern waiting to be fitted so can't comment on any direct experience of it. But on paper looks good and allows the flush volume to be adjusted and provides for a double flush. Cant recall the price but not likely a budget option. Full maintenance through the flush cover plate. Depends what features you want, and on ease of maintenance through the flush plate I guess. I do have a simple cheap plastic cistern on one toilet which is easily maintained by scoring through the right secret grout lines to then remove the worktop above for full access to maintain.