L2 Troubleshooting & FAQ

Troubleshooting & FAQ

General troubleshooting and answers to the most frequently asked questions

Troubleshooting

Water leaking from safety valve, or water on the floor by the water heater
Possible cause 1: Excess coming into the property causing pressure reducing valve to fail. Alternatively, the cold water pressure in the home is too high during the day.
Solution: Install AX expansion tank which takes up expansion during heating and mounting / adjusting pressure reducing valve for stable water pressure into the home. The Pressure Reducing Valve (PRV) should be adjusted in relation to the expansion vessel preprint (usually 5 bar). Contact authorised installer.

Possible cause 2: The heaters safety valve is worn or there are particles between the membrane and valve seat due to unclean water.
Solution: try to flush through the R valve with water. Open the valve for about 1 minute. If the valve is stile dripping after closing the valve must be replaced. Contact authorised installer.

Possible cause 3: leakage by electric heating element.
Verify by:
1. Break electrical supply
2. Unscrew the lid in front of the electrical exchange
3. Visually check if the leak comes from the heating element.
Solution if YES: change gasket / heater. Contact authorised installer.

There is no hot water
Possible cause 1: The power supply to the water heater is broken.
Solution: Verify by:
1. Check the fuse is in the fuse box
2. Plug from the heater is plugged into the wall socket
3. Including plug (earth) has not broken out in the fuse box

Possible cause 2: The electrical thermostat has turned off for security function.
Solution: Press the “RESET” button on the safety thermostat.
1. Disconnect power
2. Disassemble the electric lid with a screwdriver.
3. Press the red “RESET” button.

Possible cause 3: The thermostat DHW is defective.
Solution: Replace heating element. Contact authorised installer.

Possible cause 4: Leakage on hot water pipes in the property
Verify by:
1. Shut off mixing valve
2. Wait 3 hours while the heater warms water.
3. Touch the mixing valve to see if it is hot
If YES, there is leakage on hot water pipes or other leaks.
Solution: contact authorised installer.

There is not enough hot water
Probable cause is that there is a lot of consumption of hot water in the home.
Solution 1: Adjust the temperature on the thermostat up to 80°C (see user manual):
1. Disconnect the power supply
2. Remove the electrical junction box cover using a screwdriver.
3. Adjust the temperature on the thermostat.
4. Refit the electrical junction box cover before connecting the power supply.

Solution 2: Change to a larger volume OSO Hotwater heater. Contact authorised installer.

The water temperature is too low
Possible cause 1: The mixing valve on the heater is set at too low a temperature.
Solution: adjust the temperature on the mixing valve (see user manual):
1. Turn the adjustment knob fully towards“+”
2. Turn knob towards “–” until desired temperature

Possible cause 2: The electrical thermostat is set too low.
Solution: adjust the temperature on the thermostat up to 80 °C (see user manual).
1. Disconnect the power supply
2. Remove the electrical junction box cover using a screwdriver.
3. Adjust the temperature on the thermostat.
4. Refit the electrical junction box cover before connecting the power supply.

Fuse for water heater shuts off repeatedly
Probable cause is incorrect wiring or fault in the water heater electrical system.
Solution: Verify by:
1. Turn off power supply to water heater
2. Remove electrical junction box cover
3. Inspect junction box for any visually detectable faults (loose, crossed or overheated wires etc.)
If any faults are visible or the problem persists, contact authorised electrician. Refit junction box cover.

It takes a long time before hot water reaches the tap
This is normal if the distance from the water heater to the tap is significant due to water cooling in pipes between use.
Possible solution:
1. Install hot water circulation pipe (pump and extra pipe required – contact installer)
2. Fit an electric heater cable on pipe – contact installer.
Another option is to install a point of use heater (OSO Nano) at the tap location.

Rattling noise from pipes when closing hot water tap
Probable cause is the pipes shake and rattle due to the sudden change in water pressure.
Over time this can cause fatigue fractures in pipes and should be rectified.
Possible solution:
1. Fit extra pipe clamps in problem areas to fasten pipe better to wall to avoid excess pipe movement.
2. Fit an expansion vessel if the problem persists. Contact authorised installer.

FAQ

How to adjust the temperature on the mixing valve? 
This operation varies between different products and is explained in the user manual supplied with the water heater.
If the manual is missing contact OSO Hotwater.

How to adjust the water temperature in the water heater?
The temperature inside the water heater can be adjusted by turning the internal thermostat up or down:
1. Turn off power supply to the water heater
2. Remove electrical junction box cover
3. Adjust the temperature on the thermostat – see user manual
4. Refit the junction box cover before turning power supply back on.
NOTE: It is not recommended to set the temperature below 65°C due to danger of bacterial growth inside the water heater. It is also not recommended to turn the temperature up higher than 85°C due to excess water expansion.

How to reset the electric thermostat?
Thermostats in OSO products have an emergency cut-off which will activate if the temperature in the water heater gets too high or the water heater is exposed to high power input caused by lightning strikes, power supply surges etc. To reset the thermostat (see manual):
1. Turn off power supply to the water heater
2. Remove electrical junction box cover
3. Press the red ‘RESET’ button on the upper part of the thermostat. A distinct ‘click’ should be heard if the cut-off has been activated.
4. Refit the junction box cover before turning power supply back on.
If the emergency cut-off activates repeatedly without any of the power input problems mentioned above occurring the thermostat might need replacing. Contact authorised installer.

How to drain the water heater?
This process varies between different OSO product series, see user manual for instructions.
If the manual is missing, contact OSO Hotwater.