John Wood Commercial - 300-400K BTU - Manual (Page 57)

57
alert conditions
When the control system declares an Alert condition it will display
an Alert message on the control system's LCD with a question "?"
mark. The water heater will continue to operate during an Alert
condition but the water heater must be serviced by a qualified
service agent as soon as possible.
resetting control system lock outs
To reset the control system from a lock out condition; turn the
power supply off for approximately 20 seconds and then back on.
keep in mind; if the condition that caused the Fault has not been
corrected, the control system will continue to lock out.
diagnostic checks
Turn off power to the water heater
before performing any service.
Electrical Shock Hazard
•
Label all wires prior to disconnecting
when performing service. Wiring errors
can cause improper and dangerous
operation.
•
Verify proper operation after servicing. •
Failure to follow these instructions can
result in personal injury or death.
•
The following section, Fault And Alert Messages on page 58, lists
some of the messages the control system will display on the LCD
when there are operational problems. This is not a complete list.
Along with each of the Fault and Alert messages described there
will be a list of possible causes and things to check and repair.
Only qualified service agents, as defined in Qualifications on
page 6, using appropriate test equipment, should perform any
service procedures on the water heater.
note:
If you are not qualified and licensed or certified as
required by the authority having jurisdiction to perform a given
task do not attempt to perform any of the diagnostic or service
procedures described in the following section.
If you do not understand the instructions in the following section
do not attempt to perform any procedures.
Call the technical support phone number listed on the back cover
of this manual for further technical assistance or to locate a
qualified service agent in your area.
Jumping out control circuits or components can
result in property damage, personal injury or death.
Service should only be performed by a qualified service
agent using proper test equipment.
•
Altering the water heater controls and/or wiring in any way
could result in permanent damage to the controls or water
heater and is not covered under the limited warranty.
•
Any bypass or alteration of the water
heater controls and/or wiring will result
in voiding the appliance warranty.
Altering the water heater controls and/or wiring in any way
could result in altering the ignition sequence allowing gas to
flow to the main burner before the hot surface igniter is at
ignition temperature causing delayed ignition which can
cause a fire or explosion.
•
• Colder incoming water temperature lengthening the time
required to heat water to desired temperature.
• Hot water piping leaks, open faucets, water heater drain
valve leaking or open.
• Sediment or lime scale accumulation may be affecting water
heater operation. See Maintenance on page 60 for sediment
and lime scale removal procedures.
• Water heater not firing at full input rating. Check manifold
gas pressure, see instructions on page 50. Check actual firing
rate of the water heater, see instructions on page 51.
water is too hot
• Operating Set Point is set too high. See Operating Set Point
And Differential Adjustment on page 44.
• upper and/or Lower Probe Offset settings improperly set -
see Temperatures Menu (cont) on page 45.
• Improper water piping - see diagrams beginning on page 67.
noisy operation
• Sediment or lime scale accumulations can cause rumbling
and pounding noises during heating cycles. See the
Maintenance section of this manual beginning on page 60 for
sediment and lime scale removal procedures.
• Normal operating noise of electrical components;
Combustion blower, transformer hum, relay contact closure.
water leakage is suspected
• Ensure the water heater drain valve is tightly closed.
• Check cleanout opening for leaks - see Figure 4 on page 9.
• Check inlet/outlet water connections and system piping.
• Check the Temperature-Pressure relief Valve.
• Excessive water temperature.
• Excessive water pressure.
• Defective Temperature-Pressure relief Valve.
note:
Excessive water pressure is the most common cause of
Temperature-Pressure relief Valve leakage. Excessive water
system pressure is most often caused by "thermal expansion"
in a "closed system." See Thermal Expansion and Closed Water
Systems on page 14. The Temperature-Pressure relief Valve is
not intended for the constant relief of thermal expansion.
Temperature-Pressure relief Valve leakage due to pressure build
up in a closed system that does not have a thermal expansion
tank installed is not covered under the limited warranty. Thermal
expansion tanks must be installed on all closed water systems.
replacement parts
replacement parts may be ordered from the manufacturer,
authorized service agencies or distributors. When ordering parts
be sure to have the complete water heater Model Number, Serial
Number and Series Number available. This information can be
found on the rating label affixed to the water heater.
refer to the parts list included with the water heater from the
factory for more information or call the parts department or
technical support phone number listed on the back cover of this
manual for further assistance.
fault and alert conditions
fault conditions
When the control system declares a Fault condition it will display a
Fault message on the control system's LCD with an exclamation "!"
mark. The control system will lock out and disable heating operation
until the condition is corrected. The water heater must be serviced
by a qualified service agent before operation can be restored.