Maintenance and service
4Maintenance and service
Warning: Always turn off the electrical power supply, turn off the manual gas valve and turn off the manual water control valves whenever servicing.
The unit should be checked once a year by a gas technician. If repairs are needed, the repairs should be done by a gas technician
To remove front cover
BSee instructions to remove front cover on page 8.
Systems and parts that should be checked at least once a year
Reference diagrams on pages 24 and 25. Venting system
Burners
See relief valve manufacture's instruction for pressure relief valve maintenance
Periodic cleaning of the water filter screen, see Fig. 15, chapter 2.10.
Flushing the heat exchanger with a descaling solution if mineral build up is evident. Scale build up will shorten the life of the water heater, descale heat exchanger thoroughly and repeat annually depending on mineral content of ground water.
5Troubleshooting
Introduction
The 250 SXO burner is activated by a water flow valve. Numerous water related problems can cause this water valve to malfunction such as: Insufficient water flow volume to activate the burners at its minimum flow requirement; Dirt in the inlet filter screen; Sediment
Problems stated below in upper case and in bold face should be investigated when there is a problem with the performance of the water heater but there is NO error code on the heater's LCD display or wireless remote control.
Any failures that result in a displayed error code are referenced on page 21. A Functional Scheme of the 250 SXO is detailed on page 23. If there is a problem with the installation, venting or operation of the unit, the heater will communicate the source by these error codes.
BURNERS DO NOT IGNITE WHEN HOT WATER IS TURNED ON
Cold incoming water connection made to wrong side of heater
Make sure cold water inlet connection is plumbed to the right side of heater when facing unit
Water flow rate at hot water tap is too low
A minimum of 0.8 gallon/minute (3 l/m) is required to activate the heater
Cold water inlet filter screen is dirty
Remove water inlet filter screen and clean. The screen is located at the inlet connection to the water heater, disconnecting the main cold supply line at the heater is required. Check and clean faucet aerator screens too.
Crossover in plumbing
The heater activates when there is sufficient water flow through its water valve, a minimum of 0.8 gallon/ minute (3 l/m) is required. If there is a crossover in the plumbing, the necessary hot water flow rate through the unit may not be reached, even though the flow at the hot water tap is sufficient. A plumbing crossover can be caused by a failed washer at a single lever faucet, incorrect plumbing or a faulty mixing valve in the piping. The crossover will create a back pressure on the water heater and prevent an adequate flow of water through it. To confirm there is no crossover in the plumbing, shut off the cold water supply feed to the water heater. Individually open each of the hot water taps. There should be no water flowing under a constant pressure. If there is a constant flow of water then the plumbing crossover must be corrected before the heater can operate properly.
WATER IS TOO HOT
Temperature selection too high
Lower temperature adjustment on heater or wireless remote control accessory, see chapter 3.2.
WATER IS NOT HOT ENOUGH
Temperature selection too low
Increase temperature adjustment on heater or wireless remote control accessory, see chapter 3.2
Btu input is too low due to inadequate gas line sizing
See specifications in chapter 2.8 - 2.9. The 250 SXO requires adequate gas pressure to reach desired temperatures, to compensate for inadequate gas supply or lack of gas pressure the 250 SXO will effectively reach the selected output temperature by reducing the hot water flow rate. Its motorized water valve makes this adjustment
Cold water is mixing with the hot water outlet (crossover)
6 720 607 440 | 19 |
