Troubleshoot Therm 660 EF/EFO

Unit does not attempt to ignite when water is running

• Check for reversed plumbing or crossed pipes.
• Check the water drain valve filter.

Unit attempts to ignite but fails

• Reset unit and try again. There may be air in the gas line.
• Have a professional check the gas supply pressure.

Hot water is not available when a fixture is opened

• Are the gas and water supply valves fully open?
• Is the water supply cut off?
• Is the hot water fixture sufficiently open?
• Is the gas being cut off by the gas meter? (Can other gas devices such as stoves be used?)
• (For LP) Is there enough gas in the tank? (Can other gas devices such as stoves be used?)
• Is the water drain valve filter clogged?
• (Using the remote controller) Is the power button turned on?

No water is available when a fixture is opened

• Is the water supply cut off?
• Is the heater frozen?

The hot water is not the correct temperature

• Is the hot water fixture sufficiently open?

Water takes time to become hot when turning the hot water fixture

• Have you allowed enough time for the cold water in the pipes to drain out?

Water is too hot

• Is the water supply valve fully open?
• (Using the remote controller) Is the water temperature setting appropriate?
• If the water supply temperature is high, it is possible for the temperature to be higher than the temperature set on the remote controller.
• If only a small amount of hot water is demanded, it is possible for the temperature to be higher than the temperature set on the remote controller.

Water is not hot enough

• Is the gas supply valve fully open?
• (Using the remote controller) Is the water temperature setting appropriate?
• If the amount of hot water required is very high, it is possible for the temperature to be lower than the temperature set on the remote controller.
• Decrease the amount of hot water passing through the unit and the temperature should stabilize.

The water is cold when only a single fixture is open

• The unit will not heat the water if the flow rate is less than 0.5 GPM (2L/ min.). Open the fixture more or open other fixtures so that a greater flow passes through the unit, and the unit should begin heating again.

Fluctuations in hot water temperatures

• Clean the water filter of any debris.
• (Using the remote controller) Set water temperature at 115°F (48°C) to 120°F (50°C). This will allow you to use a higher flow of hot water thus meeting the minimum flow requirement of 0.5 GPM (2L/min.)

Setting temperature can not rise

• Is the maximum temperature setting appropriate?

The amount of hot water at a certain fixture is not constant

• When hot water is demanded at other fixtures, the amount available may be reduced. The maximum flow available from the 660 EF, 660 EFO is 5.3 GPM (20.0L/min.) at a 45°F ( 25°C) temperature rise.
• Pressure fluctuations and other plumbing conditions can cause the temperature and pressure at a fixture to be unstable, but it should stabilize after a short time.
• There are some types of hot water taps that discharges large volumes of hot water at first but stabilize after time.
• To keep the temperature stable, the heater limits the amount of water that can flow through it to a small amount initially, but the amount increases over time.

The amount of hot water in the tubis less/more than the set amount

• When hot water is used for other fixtures while filling the bath tub, the tub will not fill as much.
• If there is water in the tub already, or when filling is stopped and restarted, the tub will fill more.

The flow meter alarm does not sound even when filled to the set amount

• The flow meter alarm is set to sound when hot water is continuously discharged for the set volume of water. If mixing valves are used, or if cold water is mixed with hot water at the fixture, the tub will fill more than the setting of the flow meter alarm.

Amount of hot water available has decreased over time

• Is the water filter clogged?

The light on the power button does not come on

• Has there been a power failure?
• Is the power connected properly?

The water temperature changes after a power failure or when the power is disconnected

• The temperature setting and the flow meter alarm setting may both need to be reset after a power outage.

The plastic on the surface or buttons of the remote has torn, pleeled, or air bubbles inside

• The surface of the remote controller is affixed with aprotective sheet (to prevent surface scratching, etc.) at time of shipment. This sheet can be removed or left as it is. When leaving the protective sheet on, areas frequently touched may tear or peel. However, the remote controller will not malfunction from water entering such torn or peeled areas. To restore the appearance of the remote controller surface, simply remove the protective sheet.

The fan can be heard after operation is stopped. A motor can be heard when turning the unit ON or OFF, when opening or closing a fixture, or after the unit has been running for a while

• These noises indicate the proper operation of devices which are designed to let the unit reignite more quickly, and ensure the water temperature is stable.