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...
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