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Page 52
Section 7 – Troubleshooting
Before calling for service, review the following diagnostic steps first for saving time and money.
Question & Answer
Indicate
Burner does not ignite even if hot
water is opened.
Outlet water is not hot enough.
Outlet water is too hot.
Hot water temperature
The blower is still operating after the
combustion stops.
Abnormal sounds come from unit
during operation.
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 and
fuses on the main controller in the units are good.
Make sure that there is water supplied to the unit. The heater will be running when the inlet
water flow sensor detects the flow over 0.5gpm.
Make sure the cold and hot water valve are not plumbed in reverse side.
Make sure that cold water and gas supply lines are opened.
Make sure that water lines are not frozen.
Make sure that the setting temperature 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.
Make sure that the setting temperature 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.(Check the provided gas with the water
heater model)
Make sure that the filter in the cold water inlet line is clean.
Check if the supply gas pressure is sufficient.
This is normal because the blower still keeps operating for 3 minutes. If a BLDC motor is
not running in 120VAC, replace the BLDC motor.
A leak of combustion gas between sealed chamber and exhaust duct inside the unit.
Immediately call a qualified service technician for evaluation.
Improper venting termination, make sure that the venting termination complies with
specification.
Check if the supply gas pressure is sufficient. Insufficient gas pressure will cause unstable
burner flame and noise.
LAARS Heating Systems
7.1 Diagnostics
Indicator
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