16
Troubleshooting
Troubleshooting
Symptom
Possible Causes
Burner does not ignite even if hot
water is opened.
Make sure that the ON/OFF button on the Control Panel has been turned ON.
If the monitor on the Control Panel is blank, make sure the power cord is plugged in and
fuses on the main controller are good.
Make sure that water flows to the unit. The heater will be running when the inlet water flow
sensor detects flow over 0.5gpm.
Make sure the cold and hot water pipes are not plumbed in reverse.
Make sure that water and gas supply lines are opened.
Make sure that water lines are not frozen.
Outlet water is not hot enough.
Make sure that the temperature setting on the unit is not too low.
Make sure that the filter in the cold water inlet line is not clogged with debris.
Make sure that the gas supply type is correct.
Check if the supply and manifold gas pressures are in accordance with specifications.
Make sure that the water flow sensor with three wires has been properly connected on the
top of heat exchanger.
Outlet water is too hot.
Make sure that the temperature setting on the unit is not too hot.
Make sure that the filter in the cold water inlet line is not clogged with debris.
Make sure that the gas supply type is correct.
Hot water temperature
Make sure that the filter in the cold water inlet line is clean.
Check if the supply gas pressure is sufficient.
The blower is still operating after the
combustion stops.
This is normal because the blower keeps operating for 3 minutes.
I can’t change the temperature
setting above 125°F on the Control
Panel.
This is a safety device to prevent scalding. Hot water temperature over 125°F can cause
severe burns instantly or death.
Abnormal sounds come from unit
during operation.
A leak of combustion gas between sealed chamber and exhaust duct inside the unit.
Improper venting termination, make sure that the venting termination complies with
specification.
Check if the supply gas pressure is sufficient. Insufficient gas pressure can cause unstable
burner flame and noise.
Summary of Contents for Marquis TWH180
Page 24: ...22 Error Codes 1 Flame Detection ...
Page 25: ...23 Error Codes 2 Gas Detection 3 Sensing air pressure ...
Page 27: ......