Underfloor Heating Troubleshooting

by UFH1

1. If you have a fault once the system is up and running, the first thing to check is the flow rate in the flow meters. Make sure they are set between 1.5L/min and 2L/min for boiler use and 1L/min for heat pump use. If there is no reading (the red indicator is at the top) nothing is flowing around the loop.

2. Then take off your actuator heads, if you then get a flow or your system then works you know it is an electrical problem. If after taking all the actuators off you still have problems then it will be a flow fault

Symptoms Checks/Remedies
No circulation

Check flow meters are open

Check thermostats / actuators on

Flow pipe gets hot, return stays cool, even after many hours running, temperature on flow side not increasing.

Check flow meters are open properly

Air lock – flush through by repeating the filling up process.

Insufficient flow from boiler to manifold turn up speed of boiler or                 manifold pump.

Flow & return pipes both hot, but temperature on floor low.

Too much flow. Too fast a flow rate will not transfer the heat properly in the room. Set the flow meters to 1.5-2 for boiler system and 1 for heat pump use.

No rooms getting hot

Check the thermostat is calling for heat and switching the heat source/pumps on. If ok, check flow meters (red indicator) have a flow running through and check all valves are open.

Room stat calling for heat, but no power to the pump.

Safety stat on the manifold (if fitted) locked out or faulty, electrical connection problems.

One room warm, other cold.

Check correct actuators on correct manifold ports.

Insufficient flow for all circuits required

One room not getting warm.

Air lock – flush through by repeating the filling up process.

Check the thermostat is calling for heat and opening the correct actuator

Noise in system.

Manifold fitted on stub partition, reverberating and acting like a sound box. Tension on copper flow & return pipes.
Air in system – due to incorrect filling procedure

Too high pressure in the system

Room gets too warm.

No thermostatic control. 

Not connected to correct manifold port.  Thermal head faulty/broken.  

Room stat faulty/broken.  


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