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Perform Gas Leak Test
WARNING
Fire or Explosion Hazard.
Can cause severe injury, death or property
damage.
Check for gas leaks with soap and water
solution any time work is done on a gas system.
CAUTION
Water Damage Hazard.
Can damage electrical components in the
WT8840.
Do not spray soap and water solution on the
WT8840 housing. Do not use an excessive
amount of soap and water to perform the gas
leak test.
Gas Leak Test
1. Paint pipe connections upstream of the water
heater control with a rich soap and water
solution. Bubbles indicate a gas leak.
2. If a leak is detected, tighten the pipe connection.
3. Stand clear of the burner while lighting to prevent
injury caused from hidden leaks that could cause
flashback in the appliance burner compartment.
4. With the burner in operation, paint the pipe
joints (including adapters) and the control inlet
and outlet with a rich soap and water solution.
5. If another leak is detected, tighten the adapter
screw, joints, and pipe connections.
6. Replace the part(s) if a leak cannot be stopped.
Check the gas input and burner
flow rate
WARNING
Fire or Explosion Hazard.
Can cause severe injury, death or property
damage.
Follow these warnings exactly:
1. Do not exceed input rating stamped on
appliance nameplate or manufacturer
recommended burner orifice pressure for
size of orifice(s) used. Follow instructions of
appliance manufacturer.
2. IF CHECKING GAS INPUT BY CLOCKING
GAS METER: Make certain there is no gas
flow through the meter other than to the
appliance being checked. Other appliances
must remain off with the pilots extinguished
(or that consumption must be deducted
from the meter reading). Convert flow rate to
Btuh as described in form number 70-2602,
Gas Controls Handbook, and compare to
Btuh input rating on appliance nameplate.
3. IF CHECKING GAS INPUT WITH
MANOMETER: Make sure the manual gas
shutoff switch is in the OFF position before
removing outlet pressure tap plug to connect
the manometer (pressure gauge). Also, move
the manual gas shutoff switch to the OFF
position when removing the gauge and
replacing the plug. Also shut off gas supply
before disconnecting manometer and
replacing plug. Repeat Gas Leak Test at plug
with main burner operating.
WT8840 TRADE WATER HEATER CONTROLS
Procedure to check the gas input
and burner flow rate
1. Check the full rate manifold pressure listed on
the appliance nameplate. Water heater control
full rate outlet pressure should match this
rating.
2. With burner operating, check the water heater
control flow rate using the meter clocking
method or check pressure using a manometer
connected to the outlet pressure tap on the
water heater control. See Fig. 5.
MAINTENANCE
WARNING
Fire or Explosion Hazard. Can cause severe
injury, death or property damage.
Do not attempt to take apart or clean the gas
valve inside the WT8840 control. Improper
cleaning or reassembly can cause gas leakage.
The maintenance program should include regular
checkout of the control as outlined in the Startup and
Checkout section, and the control system as described
in the appliance manufacturer literature.
Maintenance frequency must be determined individually
for each application. Some considerations are:
1. Cycling frequency. Appliances that may cycle
10,000 times annually should be checked
monthly.
2. Intermittent use. Appliances that are used
seasonally should be checked before shutdown
and again before the next use.
3. Consequence of unexpected shutdown. Where
the cost of an unexpected shutdown would be
high, the system should be checked more often.
4. Dusty, wet or corrosive environment. Since these
environments can cause the control to
deteriorate more rapidly, the system should be
checked more often.
The system should be replaced if:
• It does not perform properly on checkout or
troubleshooting.
• The control is likely to have operated for more
than 150,000 cycles.
• The control is wet or looks as if it has been wet.
TROUBLESHOOTING
Troubleshooting With Status
Indicator Assistance
1. Pilot burner must be lit. If not, push and hold
Pilot knob and light pilot with piezo. Error code
will be displayed when thermopile heats up.
Error code can be recognized by counting the
number of flashes of the status indicator after a
three second pause. One single flash (with set
point knob in PILOT position) indicates that the
control is in normal operation.
2. Observe status indicator on control; check and
repair the system as noted in Table 3 on page 6.
Flash codes are displayed with a three-second
delay between cycles. A continuous solid light
indicates system shutdown when knob is turned
from a temperature setting to OFF position.
5
34-00013EF—01
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Troubleshooting
