Troubleshoot Therm C 1210 ESC

Burner does not ignite when hot

• If the display is blank, verify power to outlet. (120VAC/60Hz properly grounded circuit required). Verify that the heater power button is pressed ON.
• Verify the fuses in the control board are good. To access fuses, the control board must be removed.
• Make sure cold water inlet connection is plumbed to the right side of heater when facing unit.
• A minimum of 0.65 gallons per minute (GPM) (2,5 l/m) is required to activate the heater. A quart container should fill in 23 seconds or less, from hot water tap only, to activate heater.
• Clean inlet filter screen. Inspect the water path for obstructions. Make sure all showerheads, faucet aerators and whole house filters are clear of debris.
• The heater activates when the water flow through the unit is at or above the required minimum of 0.65 GPM (2,5 l/m). A crossover in the hot and cold plumbing pipes creates back pressure on the water flowing through the heater. Therefore, a higher flow rate than normal is needed to force the heater to activate. To check for a plumbing crossover, shut off the cold water supply to the water heater. Then open all of the hot water taps served by the heater. Wait 10 minutes and check for water flow at each tap. There should be no water flowing. Any continuous flow of water, small or large, indicates a crossover is present and must be corrected. Consult a professional plumber for help in correcting a crossover. Failing single lever faucet mixing valves are common causes of plumbing crossovers.
• With the power button pressed to OFF and the power supply cord unplugged, remove the unit's front cover. Check wire connections between the water valve, control unit and electrode set.
• Water heater in solar mode. If inlet water temperatures exceed the water heater's set temperature, the burners will not ignite and the solar mode indicator will show on the display.

Water is too hot

• Selected temperature on the unit is too high. To lower output temperature, see chapter 5.4, page 32 of the manual.
• Clean inlet filter screen.
• Inspect the water path for obstructions. Make sure all showerheads, faucet aerators and whole house filters are clear of debris.
• Confirm that the heater's gas type coincides with the type of gas being supplied.
• Avoid restrictive outlets. Clean all showerheads and faucet aerators. It may be necessary to upgrade to higher flow rate shower heads if allowable by local code.
• In areas where the water has a high mineral content, periodic descaling may necessary.
• Ensure the outlet temperature sensor is making contact and firmly mounted on the hot water pipe.

Water is not hot enough

• Selected temperature on the unit is too low. To raise output temperature, see chapter 5.4, page 32 of the manual.
• Clean inlet filter screen. See chapter 6.1, page 34 of the manual to increase flow through the heater.
• Inspect the water path for obstructions. Make sure all showerheads, faucet aerators and whole house filters are clear of debris.
• Confirm the heater's gas type coincides with the type of gas being supplied.
• Check inlet gas particle screen for blockage at gas inlet connection on bottom of unit.
• Verify gas pressure is in accordance with specifications in chapter 3.13, page 29 of the manual. A gas pressure reading is needed to proceed further.
• Contact your original installer or a local certified gas technician to obtain this reading.
• Cold water is mixing into the hot water lines (plumbing crossover). A plumbing crossover can unintentionally mix cold water with the hot water leaving the heater. The end result is a cooler water temperature than desired. To check for a plumbing crossover, shut off the cold water supply to the water heater. Then open all of the hot water taps served by the heater. Wait 10 minutes and check all taps for water flow. There should be no water flowing. Any continuous flow of water, small or large, indicates a crossover and must be corrected. Consult a professional plumber for help in correcting a crossover. Failing single lever faucet mixing valves are common causes of plumbing crossovers.
• Ensure the temperature sensor is making contact and firmly mounted on the hot water pipe.