Trouble Shooting

Due to its advanced design the Hotrun does not need any maintenance. A damp cloth can be used for cleaning the cover. Scouring and dissolving agents are not suitable. Regularly clean scale from aerators and hose swivels.

Initial observations

The adequate supply and pressure of the water (min. 100kPa).

  • Make sure the cold water inlet and the hot water outlet are not connected in reverse
  • The main switch or circuit breaker is switched on
  • The fuse/circuit breaker is not blown/triggered
  • Flow rate from cold supply is adequate for the installed Hotrun

Attention: Avoid overheating

Fill the unit completely with water before plugging it in or turning on the mains power supply.  For that purpose: – Open the tap and wait until the water flows out from the spout without any air bubbles. – Close the tap. – Switch-on the mains supply. – Hotrun is ready to use.

Problem 1 – The Hotrun does not switch on when opening the tap fully

Cause – Usually attributed to water supply problems. Ensure the pressure on the cold water supply is   more than 100kPa, while the Hotrun is in use.  – Too much back pressure in outlets or shower heads after the Hotrun causing lack of pressure differential over the Hotrun (backpressure through the cold). – Wrong flow restrictor installed. – Maximum temperature cut-out switches activated, due to air in the Hotrun not cleared before switching on the electrical supply. – Access to the thermal cut-out can only be conducted by a suitable qualified tradesperson.


Remedy – Fix the water pressure problems; remove any flow restrictors in outlets. –  Switch the electric power supply off, check that there is no power on any of the terminals. –   Seek electrical assistance to check power all the way to the elements.

Problem 2 – The water that is coming out of the Hotrun is not warm enough.

Cause – The incoming water is very cold (below 12°C) – The total flow is too high.

Remedy – A flow restrictor should have been installed. If so, an additional ball valve in the water  supply to the Hotrun can enable you to reduce the flow and so increase the temperature (not for Hotrun-T models).

Problem 3 – The heating of water stops when trying to set the required temperature to a colder setting.

Cause – Aerator/restrictor in nozzle of outlet causing too much back pressure.  – Incorrectly balanced flow restrictor in the supply line. – Flow from the cold supply line is less than the requirements for the Hotrun.

Remedy – Remove the restrictors in the tap or aerator fitting. Fit the appropriate restrictor to the cold supply line for the Hotrun. Check that other taps or restrictors inbuilt into the supply line are  not effecting the flow or reducing the pressure too much.

Problem 4 – A Hotrun fitted in an upper floor situation of a building that is gravity fed, the Hotrun doesn’t switch on.

Cause – The pressure is less than 100kPa. The pressure of water under gravity is 9kPa per metre, this equates to approximately 30kPa per floor plus the height of the roof tank. On request we can help to accommodate for most situations, sometimes just leaving out the flow restrictor from the cold water inlet can be sufficient.

Remedy – Remove all restrictors in the tap or aerator and use ‘star’ inserts in spout instead of aerator.  Allowing full flow will often help in low pressure situations.

If the tests above indicate a fault then contact Elwa Technical Support om 08 8353 4040