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VL BOILER BASE SERIES CONVECTION STEAMERS - SERVICE PROCEDURES AND ADJUSTMENTS
8.
After performing steps 1-5A and verifying the
water level control boards operation, if the control
is not functioning as described, then replace it
and check for proper operation.
Electro Mechanical - Low Level Cut-Off &
Differential Control
THE FOLLOWING STEPS REQUIRE
POWER TO BE APPLIED TO THE
UNIT DURING THE TEST. USE
EXTREME CAUTION AT ALL TIMES.
1.
Ensure that water is filling the boiler.
A.
Confirm that water supply valve(s) is turned
on.
B.
Observe boiler water level in the water level
gauge.
C.
Verify boiler fill solenoid valve is receiving
120VAC and water is flowing through it.
2.
Check for correct voltage being applied to the low
level and differential water level controls.
A.
Turn the water supply valve off then turn the
power switch ON. Check the input voltage
across terminals 1 and 2. Meter should read
120VAC. If voltage is correct proceed to
step 2B. If voltage is incorrect, find the
source of the problem and repeat this step.
B.
With the boiler empty, check the voltage
across terminals 9 and 10. Meter should
read 300 to 350VAC. If voltage is correct
proceed to step 3. If voltage reading is
approximately 30VAC then the internal
contactor is energized but the probes are
scaled over and moist and/or have a
damaged insulator giving a false reading.
See WATER LEVEL PROBES listed below
for inspecting and cleaning, and BOILER for
procedures on boiler inspection, clean-out
and deliming. If you do not read any voltage,
then contactor coil on the water level control
is bad and the control should be replaced.
Check for proper operation after
replacement.
3.
If water is in the boiler but is not being detected
by the water level probes, the probes may need
cleaned and/or boiler delimed. See WATER
LEVEL PROBES listed below for inspecting and
cleaning, and BOILER for procedures on boiler
inspection, clean-out and deliming.
F24650 Rev. A (1017)
4.
Turn the power switch OFF and disconnect the
lead wire from each probe. Note the location of
the probes and the number of the wire connected
to it.
A.
Check the resistance between the probe
terminal and boiler shell. An open circuit
should be present when the boiler is empty.
If resistance is present, remove and inspect
the probes as outlined below under WATER
LEVEL PROBES. A resistance reading
should only be measurable between the
probes and boiler shell (ground) when the
boiler is full of water.
NOTE: The actual resistance reading will depend on
water quality and probe condition.
5.
If after performing steps 1 through 4 and the
control is not functioning properly, verify the
water level controls operation as outlined in
WATER LEVEL CONTROLS.
6.
After checking the above items, if the low level
cut off or differential water level control does not
appear to be functioning as described, then
replace the control and check for proper
operation.
Water Level Probes
1.
Remove the cover over the water level probes
and disconnect the lead wire from each probe.
Note the location of each probe and the number
of the wire connected to it. Remove each water
level probe for examination.
2.
If lime scale buildup is evident on the probe,
thoroughly clean it removing all deposits from the
probe and insulator. Do not use anything
abrasive on the insulator; use a soft cloth.
3.
Inspect the probes for a cracked or damaged
insulator. If a probe appears to be damaged,
replace it with a new one and proceed to step 5.
If a probe does not appear to be damaged then
proceed to step 4.
Page 26 of 93
DISCONNECT THE ELECTRICAL
POWER TO THE MACHINE AT THE
MAIN CIRCUIT BOX. PLACE A TAG
ON THE CIRCUIT BOX INDICATING
THE CIRCUIT IS BEING SERVICED.
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