Pta Posted October 12, 2022 Share Posted October 12, 2022 Hi, can anybody assist me with the issue I am having of low flow rates. Below is an explanation of what has been done/tested. Not sure what else to do. Thanks. Flow meters are on the return side as that is how they work need water pushing them up. Manifold is installed roughly 2m above the floor. All i can think of is there is a design flaw with the thermostastic valve flow and return as the return manifold cool water is on the same side as boiler hot flow coming in? The flow side of pipes heat up and so does the return pipe after several hours however i believe due to the flow rates showing zero the flow is going through slower resulting in a longer warm up time. An example is when mixing valve set at 45 after around 3 hours or so return temp is around 25ish so seems to be flow is too slow( insulation was 100mm celeotex and pipe spacing 150mm apart, 16mm pex pipe, most loop lengths under 100m 2 or above at around 107ish). Also to note is if the pump is set to constant pressure which is what i believe it should be set to the pump works slowly i.e only 2 lights would be on. Whereas on proportional pressure i can get 4 and sometimes all 5 light on meaning pump running on full, however neither setting seems to affect flow rate. One more thing to mention is if a smaller zone was open only then the flow meter showed flow to max when fully open however when more loops or zones are open drops back down to show zero, also oddly if only one zone open and I reduce the mixing valve to say 30 the flow rate on that zone would increase and the pump would run on full however if i increased say to 50 flow rate would drop and pump speed also even though set on highest setting. I also did notice that if only 1 zone was open it would heat up much quicker than if more zones were open together both in flow rate showing and from time taken for return temp to be higher. Link to comment Share on other sites More sharing options...
ProDave Posted October 12, 2022 Share Posted October 12, 2022 Basics: Is the manifold pump running? Have you tried adjusting the pump speed? Are you SURE the actuators are energised? Test by unscrewing one, that should result in full flow on that loop. The big question, is this new? i.e. has it EVER worked properly or has it just stopped working properly? Have the UFH loops been properly bled (usually using mains water and a hose)? Link to comment Share on other sites More sharing options...
JohnMo Posted October 12, 2022 Share Posted October 12, 2022 Bit confused by your photos as the flow meter move from top to bottom rail? No flow normally means air in the loops. Also the manifold being higher than the boiler is encouraging air locks. Link to comment Share on other sites More sharing options...
Temp Posted October 12, 2022 Share Posted October 12, 2022 47 minutes ago, JohnMo said: Bit confused by your photos as the flow meter move from top to bottom rail? No flow normally means air in the loops. Also the manifold being higher than the boiler is encouraging air locks. Looks like he has two manifolds, one with actuators/flow at the top and one with the actuators/flow at the bottom. Link to comment Share on other sites More sharing options...
JohnMo Posted October 12, 2022 Share Posted October 12, 2022 5 minutes ago, Temp said: Looks like he has two manifolds, one with actuators/flow at the top and one with the actuators/flow at the bottom. With cold connected to the top each time, or at least the blue isolation valve. So not consistent with the original statement 1 hour ago, Pta said: Flow meters are on the return side Link to comment Share on other sites More sharing options...
Temp Posted October 12, 2022 Share Posted October 12, 2022 @Pta Can you confirm you have two manifolds? Somewhat confusingly... On one manifold you have a blue isolation valve for the actuators. On the other its red. Obviously the colour of the knob doesn't matter but.. Link to comment Share on other sites More sharing options...
Temp Posted October 12, 2022 Share Posted October 12, 2022 (edited) @Pta Would be good to have a photo of the pump end of each manifold. Eg Framed to show one actuator and one flow meter, the pump, the isolation valve and the mixer. Some parts like the pump and mixer may have arrows or letters on them like F and R. If these arent visible in the photos can you mark up the photos in MS paint or similar. Eg like this photo without the bottom cut off.. Edited October 12, 2022 by Temp 1 Link to comment Share on other sites More sharing options...
Pta Posted October 12, 2022 Author Share Posted October 12, 2022 (edited) Sorry to try and clear up only 1 manifold however I switched the flow and acutator bara around to see if that would make a difference however didnt. I dont think the flow was ever high if more than 1 zone was open. I have bled the system so no air. Even though with all zones open it shows zero flow I can feel the flow pipe get hot however the return is too cold i.e 20 to 25 degrees difference between flow and return temperature even after 2 to 3 hours which would mean somehow flow is restricted. Just and fyi for hot water to kitchen sink I used the ssme 16mm pipe under the screed and within 1 min of it on the tiles it runs under get warm. Just not sure what is restricting the flow. Will post some more detailed pics. Thanks Edited October 12, 2022 by Pta Link to comment Share on other sites More sharing options...
Pta Posted October 12, 2022 Author Share Posted October 12, 2022 (edited) The top manifold is return with a C sign on that same line there is an H sign which is hot from boiler and pipe infront is C for cold returning to boiler In other manifolds ive seen both C's are in line and the H is in front. Edited October 12, 2022 by Pta Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 12, 2022 Share Posted October 12, 2022 OK. Can you give us a clear close up of the flow gauges please? Can you support that with some additional info; 1) are they 0 - 5 from top to bottom on the clear body of the flow indicators, and 2) who told you these work by being pushed upwards? Not seen one do that yet, and every single one I’ve done ( lots ) has been pulled downwards by flow generated in the flow manifold rail and never have I done one that pushes the flow gauge upwards. Happy to see that you’re setup is different, but I just need to ascertain.what’s going on there first. One thing is obvious, your installer decided to just put whatever they wanted wherever they felt like it. Actuators up on one, down on the other?!? Who installed all of this?? You say the flow gauges are showing zero, I say they are being forced to zero by the water pushing them to the park position. Link to comment Share on other sites More sharing options...
ProDave Posted October 12, 2022 Share Posted October 12, 2022 Look again at the instructions and at least make sure you have the flow and return manifolds the right way round AND the pump the right way round befoe going much further. Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 12, 2022 Share Posted October 12, 2022 There is also absolutely ZERO way they your pump should be upside down!! This is a mess and I expect the pump / thermostatic valve orientations have been set up in confusion to make a left hand installation suit a right hand arrangement as far as plumbing / pipework is concerned. This needs a major removal and refitting. Stop tweaking, get a plumber, or the person who fitted this badly to come back and do it the right ( correct ) way. 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 12, 2022 Share Posted October 12, 2022 2 minutes ago, ProDave said: Look again at the instructions and at least make sure you have the flow and return manifolds the right way round AND the pump the right way round befoe going much further. Pumps upside down, so it’s a train-wreck. No way the MI’s ever said to fit it this way. Clearly been Frankenstein’d for convenience to the installer. 1 1 Link to comment Share on other sites More sharing options...
Pta Posted October 12, 2022 Author Share Posted October 12, 2022 Pic of flow meter 0 is at the bottom and has writing up to 2.6lpm. Yes pump is upside down to fit from left to right as the flow comes to the lower bar and return to the top. I though a pump could be fitted either way, if not i dont think ive seen anything online for a right side fitting all seem to be left, could you suggest one thanks. This was done 3 years ago so the guy wont come back. Link to comment Share on other sites More sharing options...
Temp Posted October 12, 2022 Share Posted October 12, 2022 All the photos of Reliance manifolds I can find on the web show flow meters on the top flow rail and actuators on the bottom return rail. Example.. 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 12, 2022 Share Posted October 12, 2022 (edited) 58 minutes ago, Pta said: Pic of flow meter 0 is at the bottom and has writing up to 2.6lpm. Yes pump is upside down to fit from left to right as the flow comes to the lower bar and return to the top. I though a pump could be fitted either way, if not i dont think ive seen anything online for a right side fitting all seem to be left, could you suggest one thanks. This was done 3 years ago so the guy wont come back. Ah, OK. Just so you know, written posts on the internet / by folk on here, much as mine do also, can be seen a bit blunt or as if we’re having a bit of a dig. For clarity, any dig is at your installer and absolutely not at you. We will of course help you as much as we can You don’t need any replacement kit btw, just the whole lot needs to be reinstalled / reconfigured. Then you’ll be back up and running in no time. The kit here stands zero chance as it’s simply all installed arse over tit. Do you know a good plumber with some patience? Hopefully the wiring side will need little or no intervention, as long as the actuator cables will all reach the manifold locations after the shuffle. Edited October 12, 2022 by Nickfromwales As not ass :D 1 Link to comment Share on other sites More sharing options...
Pta Posted October 12, 2022 Author Share Posted October 12, 2022 (edited) No worries, appreciate everyones help on this. I do know of a plumber however would need to tell him what to do. Just to clarify do I just need the pump put the right way up and the the mixer valve will be below the pump rather than on top atm? the flow and return from boiler pipes just need readjusting slightly lower. This would result in top manifold being flow and return being the lower one? The acutator cables are long enough to reach both manifolds. Edited October 12, 2022 by Pta Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 12, 2022 Share Posted October 12, 2022 1 minute ago, Pta said: No worries, appreciate everyones help on this. I do know of a plumber however would need to tell him what to do. Just to clarify do I just need the pump put the right way up and the the mixer valve will be below the pump rather than on top atm? the flow and return from boiler pipes just need readjusting slightly lower. This would result in top manifold being flow and return being the lower one? Exactamundo. If you want me to talk this through with your replacement plumber ( easily identifiable by them NOT wearing a straight-jacket ) then PM me. 1 Link to comment Share on other sites More sharing options...
Pta Posted October 12, 2022 Author Share Posted October 12, 2022 (edited) Thanks alot will try this and hopefully will sort the flow rates out. Just do triple check the metal part below the pump going into the manifold can be adjusted to face the opposite way? And same with the top C and H on top? Edited October 12, 2022 by Pta Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 12, 2022 Share Posted October 12, 2022 (edited) 11 minutes ago, Pta said: Thanks alot will try this and hopefully will sort the flow rates out. Just do triple check the metal part below the pump going into the manifold can be adjusted to face the opposite way? And same with the top C and H on top? NOPE! Stop hoping for a quick fix please. The pump needs to be the right way around, the flow and return need to be plumbed to drop down and come in at the level of the lower rail, and the thermostatic valve will, ergo, be at the bottom level too. Sleep well, for tomorrow you will find a new plumber and heating happiness. There is absolutely nothing you can do the the existing arrangement by rubbing some hope ointment into it. Needs a full re-work, prob 2 days work at least for a conscientious plumber. Edited October 12, 2022 by Nickfromwales 1 Link to comment Share on other sites More sharing options...
Fly100 Posted October 18, 2022 Share Posted October 18, 2022 Side note, you should check the temp you set on the white know matches the pipe temp. I had that mixer valve and it was 15c out. Easy fix is to move the knob round on the splines by unscrewing the centre screw. 10 sec job. Link to comment Share on other sites More sharing options...
Pta Posted October 19, 2022 Author Share Posted October 19, 2022 Hi, the mixer valve is set at just above 45 degrees and actual flow temp is around 43 degrees so not too much difference. Have a plumber who hopefully will come this week to correct the pump positioning etc. Link to comment Share on other sites More sharing options...
Pta Posted October 19, 2022 Author Share Posted October 19, 2022 Something i did notice when flushing the system a few days ago was if more than say 4 loops were open then flow rate would show zero even though water was coming out. However when each loop was open 1 at a time all showed full flow. Outside flow rate is above 30 lpm and at around 6 bar. Its almost as though if you have pipe lenghts of 80to 100m there shouldnt be more than 5 loops per manifold as perhaps the pump isnt powerfull enough to produce say 20lpm to give approx 2lpm per ciruit? Link to comment Share on other sites More sharing options...
Pta Posted October 27, 2022 Author Share Posted October 27, 2022 Got plumber to open up mixer valve and was full of sludge and metal debris. The hot pipe from boiler to mixer was also full of sludge/metal. Remove what we could and now ufh working much better getting a delta of 14 degrees rather than 25 Link to comment Share on other sites More sharing options...
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