mrcool.com
Troubleshooting
52
A0
Watch Dog Circuit
Failure
MCU internal failure.
Change the controller.
A1
MCU PC Command
Failure
MCU internal failure.
Change the controller.
A2
Instruction
Compilation &
Execution Failure
MCU internal failure.
Change the controller.
A3
MCU RAM Failure
MCU internal failure.
Change the controller.
A4
MCU ROM Failure
MCU internal failure.
Change the controller.
A5
MCU Register DC
MCU internal failure.
Change the controller.
Corrective Action Recommendations
No electrical power to the
water heater.
Is the plug on the power supply
cord unplugged from the electrical
outlet?
Reset the plug.
Reset the circuit breaker.
If the display panel is blank,
unplug the unit & contact a
qualified installer or service
technician.
Has the electrical panel’s 10 Amp
circuit breaker been tripped?
Is the fuse on the circuit board
good?
Is there a power outage?
Contact the power company.
Issue
Possible Causes
Possible Remedies
No water is available when
the faucet is turned on
or opened.
Is the water supply valve shut off at
the meter (are the cold water
faucets still working)?
Open the closed supply valve.
Open the water valve.
Turn OFF the unit, close all water
valves and the gas valve. Then,
contact a qualified installer or
service technician.
Is the watter supply valve near
the unit opened?
Is the water pipe frozen?
Is the main water valve jammed?
Check to see if an E9 code has
been triggered in the error code
history of the after-sales mode. If
the water supply is OK, and there
is no water flow at the hot water
outlet, change the main water
valve.
Hot water is not available
when the faucet is turned on
or opened.
Does the water heater have power
(is it plugged in)?
Restore electrical power to the
unit.
Press & hold the power button to
turn the unit on.
Refer to the error codes &
solutions section on the previous
pages.
Open the gas supply valve.
Is the water heater turned on?
Is an error code flashing on the
display panel?
Is the gas supply valve shut off at
the meter (are other gas devices
operating)?
Содержание MHWH199NC U Series
Страница 8: ...mrcool com 3 Product Overview Accessories 7 Fig 3 1 1 5 3 6 4 2 7 8 10 9...
Страница 24: ...23 Measuring The Inlet Gas Pressure Fig 9 1 Fig 9 2 Fig 9 4 mrcool com Fig 9 5 Fig 9 3...
Страница 65: ...Electrician and or HVAC Technician License Installation Date Installation location Serial number...