MASCOT MSTWW, Installation And Operation Instructions Manual

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Mascot ST Tankless Water Heater Page 47
6.1 Error Codes
Section 6,
Error Codes
Error
Code Error Code Description
Possible Remedies
Recover
methods
11
Ignition has Failed
10 (Ten) Times
Press the Power button to clear the Error Code.
If Error happens again:
1. Monitor the gas pressure to the water heater while in operation. Ensure pressure is between 3.5 and 14” WC.
2. Check gas valve wire. Ensure connection is secure.
3. Check flame detection sensor. Ensure connections are secure. Normal operating settings are more
than 2.5DC before ignition, less than 2.5DC after ignition.
4. Check igniter transformer for proper connection.
5. Clean the spark igniter with steel wool to remove oxides. Ensure proper separation (3-4 mm).
6. Replace the spark igniter if damaged.
7. Assure that the flame is stable when lit.
8. If the problem persists, replace the main control.
Hard Lock
16
Operating
Temperature Sensor
or DHW Sensor
detects Water
Temperature Greater
than 199 ° F (93 ° C)
This Error Code will go away when the DHW temperature decreases.
If Error happens again:
1. Check if dip switch MAX Fire setting is ON. Switches 6 and 7 should be OFF for normal operation.
2. Check if DHW pipe is blocked. Ensure there is enough water flowing to the water heater.
3. Check DHW sensor at DHW outlet. If resistance is zero, replace the sensor.
4. Check Operating Temperature sensor at the heat exchanger. If resistance is zero, replace the sensor.
5. If the problem persists, replace the main control.
Soft Lock
20
High Limit Overheat
Switch – Closed is
Normal, Open is
Fault
Press the Power button to clear the Error Code.
1. Inspect the High Limit Overheat switch. Ensure proper connections.
2. Check High Limit Overheat switch resistance. If resistance is zero, replace the switch.
3. If the problem persists, replace the main control.
Hard Lock
29
APS/Condensate
– Closed is
Normal, Open is
Fault (Condensate
Drain Trap)
Press the Power button to clear the Error Code.
1. Check APS/Condensate and main controller connections. Ensure all are secure.
2. Check APS/Condensate resistance. If resistance is zero, replace the switch.
3. Check APS/Condensate hose. Ensure it is connected and in good condition.
4. Check condensate line and termination for blockages.
5. Check exhaust vent for blockages.
6. If the problem persists, replace the main control.
Hard Lock
31
Inlet Water Sensor
Open or Short
This Error Code will go away when inlet water temperature decreases.
If Error happens again:
1. Check inlet water temperature sensor. Ensure connections are secure.
2. Check sensor resistance. If resistance is zero, replace the sensor.
3. If the problem persists, replace the main control.
Soft Lock
32
DHW Sensor Open
or Short
This Error Code will go away when outlet water temperature decreases.
If Error happens again:
1. Check DHW outlet temperature sensor. Ensure connections are secure.
2. Check sensor resistance. If resistance is zero, replace the sensor.
3. If the problem persists, replace the main control.
Soft Lock