HELP NEEDED. Tearing my hair out. Hot water not circulating. Both up and down stairs manifolds purged. All loops purged. All accuvators operating. New boiler and heating pump renewed. No pressure loss or spikes. (1 1/2 bar) Only thing I`ve now discovered is that underfloor heating expansion tank is full of water. Could this be my problemplease. It`s a Uponor system. Obviously need to sort the tank but not sure whether that`s going to solve my problem.
Underfloor heating problem.
- Thread starter jddevel
- Start date
Need to step through the different components to narrow down circulation issues > pump > mixing valve > manifold airlock > zone valves if fitted > actuators
The EV shouldn't interfere with circulation, just give PRV lifting issue when system was hot enough.
The EV shouldn't interfere with circulation, just give PRV lifting issue when system was hot enough.
OK so spent most of today making sure all air purged from underfloor loops. All activators open and flow valves fuctioned correctly whilst purging. Purged pumps ( UFH pump new and boiler pump circulating correctly) HOWEVER whilst running system still no flow through any flow meters even though all actuators open. So currently system currently at 1 1/2 psi what would be the problem of raising this to say 3 1/2 psi in case there is a air lock somewhere before the manifolds. The system has been working correctly for around 15 years. Any advice please welcome.
Start with the parts that don't cost anything.
If there's no flow then either the loops/manifolds are restricted or the pump isn't circulating.
Do the manifolds have isolating valves on the inlet of the flow and return end of the manifold? Do they also have inlet/drain valves for filling/draining at the other end of the manifold? If so, isolate the manifold from the system on both sides, attach a hose to the flow fill valve, open the outlet on the return and take one of the actuators off with the flow meter set to max, is there circulation through that loop? Try that with each loop. This checks that the loops are flowing freely and there's no blockages. Then take all the actuators off and check they'll all run at the same time making sure the flow meters are open.
If the loops run freely then it's over to the pump.
I presume you mean 1.5bar, not PSI? No, raising it to 3.5 bar wouldn't make any difference, 1.5bar should move any airlock.
If there's no flow then either the loops/manifolds are restricted or the pump isn't circulating.
Do the manifolds have isolating valves on the inlet of the flow and return end of the manifold? Do they also have inlet/drain valves for filling/draining at the other end of the manifold? If so, isolate the manifold from the system on both sides, attach a hose to the flow fill valve, open the outlet on the return and take one of the actuators off with the flow meter set to max, is there circulation through that loop? Try that with each loop. This checks that the loops are flowing freely and there's no blockages. Then take all the actuators off and check they'll all run at the same time making sure the flow meters are open.
If the loops run freely then it's over to the pump.
Thanks Rob. Yes Isolater for in and out on the manifolds. Not for the first time I`ve performed a purge. Isolaters off closed all flow valves and all actervaters off. Then as you suggested undid one flow and related actuvater. Mains hose to inlet (drain end) of flow (top) of manifold and hose to bottom (actuvater) and ran water through until totally clear of air. Did this with all 19 circuits ( 10 downstairs and 9 up) All flow valve indicators dropped to bottom of sighting tube in each case showing flow. Even removed some of the flow valves to make sure they were operating correctly. Regarding pump it`s a NEW Grunfos replacing the old one (6 mtr head). Inspected old pump and "propeller " etc all OK so didn`t really need a new pump. Hot water gets to inlet of upstairs manifold but fails to indicate flow in flow valves. Luke warm to bottom manifold and again no indication of flow in valve. All activaters indicating open. Have removed a couple of them to check that they are not "jammed "shut. Pressing down physically on the "pin" move freely. Yes I did mean bar sorry stupid mistake.
It sounds like it's pumping the wrong way...
New boiler as well so potentially flow and return was reversed there during install!
Edit: for both manifolds not to be working, having worked previously before for many years, the problem lies upstream and what has changed recently! The boiler! Would be my first port of call. What model boiler before and what is there now?
Lots of heat only boilers have differing f&r connections... Been there, done that
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That is a good point but I have also seen a pump going the wrong way on an UFH manifold totally stop all flow in a system when it was running. Either way it shouldn't be too hard to findNew boiler as well so potentially flow and return was reversed there during install!
Edit: for both manifolds not to be working, having worked previously before for many years, the problem lies upstream and what has changed recently! The boiler! Would be my first port of call. What model boiler before and what is there now?
Lots of heat only boilers have differing f&r connections... Been there, done that
OK so to clarify. This is a system designed by Uponor. It has run correctly for nearly 16 years and following a course with Uponor it is a DIY installation. When it first started failing to circulate correctly I initially purged the system believing that to be the problem. No success so called out a local engineer. He discovered that the mixing valve was siezed ( it is a Esbe Motor Valve ( 3 way mixer with actuator) supplied by Uponor. Freed it off and following a quick test believed it was working OK. Following further running it was obviously not the case. Believing the engineer for various reasons (mostly intuition) was not really conversant with UFH I employed another recommended by a previous Uponor engineer who no longer dealt with Uponor. But before doing so changed both boiler pump and UFH pump. Engineer spent a considerable time checking the system including purging all loops. Having at least got heat to the upstairs manifold and with time pressing he said "seems OK now " left. NOT the case no obvious flow through the flow meters. New pump is a UPS2 25-80.180 which is an exact replacement model previously fitted. It`s installed in the flow pipework and with the arrow indication flow towards the mainfolds. IT IS NOT A NEW BOILER. Hope all this answers the questions.
That is a good point but I have also seen a pump going the wrong way on an UFH manifold totally stop all flow in a system when it was running. Either way it shouldn't be too hard to find
But it's both manifolds so 2 pumps!
No, I got called out to a job where a mate had changed a pump on one manifold out of the four in the house and just that one running backwards pretty much stalled all the heating side of the property
Can you post a photo of this manifold with the pump running showing its LEDs, can then see what mode&setting its on, do they compare with the other correctly operating manifold's pump LEDs?, unfortunately, the UPS2 doesn't display the pump power which is quite useful as the flowrate can be derived from it, I've often attached a plug in energy monitor to these type of pumps including the UPS3 to get this info.
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