Under Floor heating

[paulpa]

When trying to balance the manifold i am having issues.
One room has two loops running as one zone on one thermostat.
One loop heats the return pipe quickly and is within 7 degrees of the flow pipe. The other loop however takes a while and even fully open (flow regulator) i struggle to get it within 12 degrees of the flow pipe.
The other loop is on about 1.5 ltrs / minute the other as far as i can turn it maximum flow.
Any ideas?
Also should i be trying to get all loops in the system having return pipes roughly same temp, or aim at this 7 degrees temp difference between flow and return?

 

[DeltaT2]

You may still have air in that one loop, or (shock horror!!!) A kink in a pipe!!!

If it's just air & you purge it, fine. The surface floor temperatures are more important than the ΔT.
HTH

 

[paulpa]

The floor temp on the good loop is much higher than the other loop.
what IS THE BEST WAY/CORRECT WAY TO PURGE IT?

 

[DeltaT2]

The floor temp on the good loop is much higher than the other loop.
what IS THE BEST WAY/CORRECT WAY TO PURGE IT?

OK, so your manifold has main iso valves, right? So turn off the UFH & Boiler. Shut the main iso valves at the manifold. Then shut off all other valves on the manifold, bar the dodgy loop. Fit a garden hose onto one of the manifold drain c.cks & a 'drain' hose onto the other. Open the drain hose first, then put mains pressure through the loop via the garden hose until you get a good flow through the drain hose..............Job done, disconnect hoses, open all valves & stick £20 in a kids charity box for my fee.
Thank you

 

[paulpa]

Thanks. Should i allow the heating to cool down over night then do it.
So turn off all loops at flow meter and valve, turn off the valve on main flow and thermostat head( on manifold), do i turn the allen key off on pump to to stop the flow through pump?