The majority of problems are usually simple installation problems, relating to the wiring or plumbing, or design problems with regards to the limitations of UFH and its suitability for the purpose intended.

In all cases where an electrical fault is reported it is always prudent to check the obvious before replacing components.

  • Is there an electrical supply?
  • Is it switched on?
  • Are there any fuses that may have blown and need replacing?
  • Are any components overloaded?
  • Is everything wired correctly?

Under no circumstances replace a fuse with a higher rating than stated for the piece of equipment.    

If the water arriving at the manifold (prior to entering the mixing valve) is either cold or below the design temperature, check:

  • The boiler is firing
  • The primary pump is fitted
  • The primary pump is working
  • The boiler is of adequate size
  • The primary pipework is sufficiently sized
  • The primary pumps are large enough

Operating Problems?

If a loop or loops fail to warm, when other zones are working correctly.

General things to look for:

  • Check that the corresponding manifold valves are open
  • Check that there is a demand from the corresponding room thermostat and/or the thermal actuator is open on demand.
  • There may be an air lock in the loop, which will require purging, either shut down all other loops by closing the valves at the manifold or turn down all other room thermostats. This will concentrate all pump pressure to the problem lip and may shift the air blockage.

If all else fails the loop can be flushed through with high-pressure water following the instructions details in Filling, Venting and Pressure testing.  If circulation is apparent but poor, it may be that the regulating control valve on the manifold required adjustment.

  • Check that all pump isolating valves are fully open.

The UFH / Room is not getting Warm?

General things to look for:

  • That the room thermostat fitted is calling for hear and that the valve has opened using the visual window on the actuator.
  • That the room thermostat is connected to and communicating to the correct actuator(s).
  • That the room thermostats are not operating in temperate set-back mode.
  • That the floor temperature is correct as it enters the floor loops. Although typical design water temperatures are suggested through this guide, there is some element of a learning curve with UFH, as on some occasions the design water temperature may need to be raised after commissioning and once the system has been in operation during a heating season.
  • That the primary flow and return connections are installed correctly and not crossed over at the UFH manifold.
  • That the primary water temperature is not too low. This needs to be at least 15°C higher than the UFH system water temperature, especially when using a Pump Control Pack.
  • That the high limit thermostat on the V5 Compact Control Pack is not set too low.
  • That the lockshield valve on the V5 Compact Control Pack is set correctly.
  • Thermal resistance of floor covering is not too high, as this could reduce the floor heat output.

If the system is too noisy?

General things to look for:

  • There is no air in the system
  • That all pipes are firmly clipped in place and that the manifold brackets are tight.
  • That the UFH pump speed is not set too high.
  • The excessive pressure from another circulator in the system is not interfering (hence the importance of having a primary bypass)

 If the running costs are high?

General things to look for:

  • That the UFH system is correctly electrically connected to the boiler to prevent short cycling and to ensure that the boiler is not running when it is not required.
  • That the room temperatures and thermostat settings are not too high (typical comfort temperatures are 20°C in living quarters and 18°C in bedrooms)
  • For any open windows or draughts, it is not unknown for windows to be open in cold weather, as the internal comfort remains constant with thermostatic controls.
  • That the boiler is running correctly. Has it been serviced and/or commissioned by an approved engineer.
  • That the floor downward losses are high due to inadequate level of floor insulations.

The design water temperature is not met?

General things to look for:

  • Check all control valves are correctly installed in their correct orientations and that any remote sensors are installed and located in suitable position.
  • Check the temperature settings are as per design and adjust as necessary, depending on the water temperature control system used.
  • Check the primary water temperature is not too low. This needs to be at least 15 degrees in excess of the UFH system temperature.

The system is losing pressure?

General thing to look for:

  • If the system is losing pressure either during testing and or after the system has been filled, but the flooring has not been laid, simple visual manual checks around the manifold and along each look of pipe should identify the problem area.
  • If there are no clear visual signs, each loop circuit may require a separate pressure test to identify the exact location.
  • If the floor has been laid, identification of the fault can be traced through signs of a wet patch around the leak. Obviously to make the repair, the floor will have to be raised, in screed floors, excavated carefully in the centre of the wet patch.
  • Any leaks on the manifold are generally due to the connection and any loose nuts and unions will require tightening.


To make repairs to the pipe, follow the process below:

Repairing the pipe:

  • Isolate the damaged pipe loop at the manifold.
  • Cut out the damaged section of pipe.
  • Prepare both ends of pipe using pipe cutters. For MLC Pipe use a bevelling tool.
  • On panel systems, remove a small section of the floating panel or fixed tracked panel, to accommodate the compression fittings.
  • Slide the compression adaptor nut over each end of pipe together with olive on PEX pipes, prior to inserting the insert sleeve into each end.
  • Offer both ends of pipe/inserts to the compression coupler and tighten both nuts.
  • Ideally, the joint will require and inspection chamber in case further maintenance is required. However, in practice this is often not practical, and the fitting is wrapped in suitable tape before burying in the screed (ensure approval with the building inspector is ought prior to doing this)
  • Pressure test the system again before laying the floor covering.


Multipipe Ltd.
Unit 12 Great Hayes Business Park,
Lower Burnham Road,
Stow Maries,

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