Split-system air conditioners and heat pumps
- Make sure the thermostat is set to air conditioning (COOL).
- Make sure the outdoor air conditioner unit (condenser) is working.
- Check the circuit breakers in the breaker box or electrical panel. They are usually located on an exterior wall at the back of the house. Are breakers in the ON position?
- Check the main switch of the outdoor unit and make sure it is in the ON position. The power switch is located close to the outdoor unit. Usually it is in a gray metal box 20 cm (8 in.) wide, 40 cm (16 in.) in height and 20 cm (4 in.) deep, wall mounted.
- Make sure the heater fan motor is running. If the thermostat is set to air conditioning (COOL), the heater fan should work.
- Make sure the ON/OFF switch of the heater is in the ON position.
- Check when you last replaced the filter on your heater.
- A clogged filter can interrupt air conditioner operation if airflow is insufficient.
- Your filter should be replaced every 6 months.
- Check the return air grilles and make sure they are not blocked by furniture.
- The return air grilles are normally located on the walls and are wide and flat. Also check all air vents to make sure they are open and air is coming out.
Gas and electric heaters
- Make sure the thermostat is set to the HEAT position.
- Make sure the thermostat set point is higher than the ambient temperature displayed on the thermostat. The set point is what tells the heating system to turn on.
- Make sure the heating system has electric power.
- Try turning the fan on using the fan switch on the thermostat.
- Check the circuit breakers in the electrical panel to make sure they are in the ON position.
- Check the SSU switch (pale gray switch in gray box attached to heater) and make sure it is in the ON position.
- Replace your heater filter if necessary.
- All filters with a thickness of 2.54 cm (1 in.) should be replaced once a month.
- High-efficiency, pleated filters 5 1/4 in. thick can generally be replaced every six months or just twice a year.
- If your system is working, but the filter has not been replaced, it may still need replacing.
- Check return air grilles and make sure they are not blocked by furniture.
The return air grilles are normally located on the walls and are wide and flat. Also check all air vents to make sure they are open and air is coming out.
If these simple solutions don’t resolve the problem, contact Desmair.
Make sure to have the model number ready at hand.