Jackson TEMPSTAR TGP Service Manual
Jackson MSC, Inc.
P.O. BOX 1060
BARBOURVILLE, KY. 40906
FAX (606) 523-9196
PHONE (606) 523-9795
Company
DUAL TEMPERATURE, GAS HEATED
DOOR-TYPE DISHMACHINES
TECHNICAL MANUAL
INSTALLATION MANUAL FOR EXPORT UNITS
SERVICE MANUAL FOR DOMESTIC UNITS
FOR JACKSON MODEL:
TEMPSTAR TGP
June 24, 2004
P/N 7610-001-98-99 (Revision C)
An
HWY. 25E
www.jacksonmsc.com
GENERAL PAGE
Specifications ............................................................................................. 1
INSTALLATION
Unpacking................................................................................................... 2
Plumbing Connections................................................................................ 2
Electrical Connections................................................................................ 2
Gas Connection.......................................................................................... 3
OPERATING INSTRUCTIONS
Preparation.................................................................................................. 4
Power Up.................................................................................................... 4
Initial Fill...................................................................................................... 4
Preparing the Dishes.................................................................................. 4
Daily Machine Preparation.......................................................................... 4
Washing a Rack of Ware............................................................................ 4
Shut Down and Cleaning............................................................................ 4
OVERVIEW OF OPERATION................................................................................... 5
THERMOSTAT ADJUSTMENT PROCEDURE........................................................ 7
AUTO-CALIBRATION PROCEDURE....................................................................... 8
ELECTRONIC CONTROL BOARD (ECB)............................................................... 9
TESTING THERMISTORS........................................................................................ 10
CONTROL BOARD LED LIGHT INDICATIONS...................................................... 11
TROUBLESHOOTING.............................................................................................. 12
DIMENSIONS............................................................................................................ 19
TABLE DIMENSIONS............................................................................................... 20
PHOTOGRAPHS
Main Assembly............................................................................................ 21
Control Box Assembly-Front View.............................................................. 22
Control Box Assembly-Top View................................................................. 23
Hood Assembly........................................................................................... 24
Cantilever Arm Assembly............................................................................ 25
Tub Assembly.............................................................................................. 26
Back of Tub, & Drain Assembly.................................................................. 27
Lower Assembly (Right Side)..................................................................... 28
Incoming Plumbing Assembly..................................................................... 29
Gas Pack Assembly.................................................................................... 31
Upper Wash, & Rinse Arm Assembly......................................................... 32
Lower Wash, & Rinse Arm Assembly......................................................... 33
Steam Coil Assembly.................................................................................. 34
Rinse Tank Assembly.................................................................................. 36
Electronic Control Drawer Components...................................................... 37
METRIC CONVERSION........................................................................................... 38
SCHEMATICS
208/240 Volt Schematic.............................................................................. 39
TABLE OF CONTENTS
i
1
PERFORMANCE/CAPABILITIES
OPERATING CAPACITY (RACKS/HOUR)
RACKS PER HOUR 57
DISHES PER HOUR 1425
GLASSES PER HOUR 1425
OPERATING CYCLE (SECONDS)
WASH TIME 45
RINSE TIME 11
DWELL TIME 2
TOTAL CYCLE TIME 60
TANK CAPACITY (GALLONS)
WASH TANK (MINIMUM) 8.0
BOOSTER TANK 3.0
TANK CAPACITY (LITERS)
WASH TANK (MINIMUM) 30.28
BOOSTER TANK 11.36
WASH PUMP CAPACITY
GALLONS PER MINUTE 150
LITERS PER MINUTE 567.81
TEMPERATURES
WASH ---°F (MINIMUM) 150
WASH ---°C (MINIMUM) 65.56
RINSE ---°F 180
RINSE ---°C 82.22
ELECTRICAL REQUIREMENTS
WASH PUMP MOTOR HP 3/4
CIRCULATOR PUMP MOTOR HP 1/12
VOLTS PHASE AMPS
208 - 240 1 6.7
WATER REQUIREMENTS
INLET TEMPERATURE 70 -140°F
INLET TEMPERATURE 21.11-60°C
GALLONS PER HOUR 52.0
LITERS PER HOUR 196.84
WATER LINE SIZE I.P.S. (Minimum) 3/4”
WATER LINE SIZE I.P.S. (Minimum) 1.9 CM
DRAIN LINE SIZE I.P.S. (Minimum) 1-1/2”
DRAIN LINE SIZE I.P.S. (Minimum) 3.81 CM
FLOW PRESSURE P.S.I. (Optimum) 20
GAS REQUIREMENTS
BTU INPUT RATE 55,000
INLET LINE PRESSURE (T
OWN GAS) 4-6” wci
MANIFOLD PRESSURE (MINIMUM) .25 wci
(MAXIMUM) 2.3 wci
FRAME DIMENSIONS
WIDTH 25 3/4”
WIDTH 65.4 CM
DEPTH 25 1/4”
DEPTH 64.14 CM
HEIGHT 56 3/4”
HEIGHT 144.15 CM
STANDARD TABLE HEIGHT 34”
STANDARD TABLE HEIGHT 86.36 CM
MAXIMUM INSIDE CLEARANCE 17 1/4”
MAXIMUM INSIDE CLEARANCE 43.82 CM
RACKS
DISH 20” X 20” (50.8 CM X 50.8 CM) OPTIONAL
GLASS & SILVER 20” X 20” (50.8 CM X 50.8 CM) OPTIONAL
SPECIFICATIONS OF THE TEMPSTAR TGP
VISUAL INSPECTION: Before installing the unit, check the container and machine for damage. A damaged container is an indicator that there may be some damage to the machine. If there is
damage to both the container and machine, do not throw away the
container. The dishmachine has been inspected and packed at
the factory and is expected to arrive to you in new, undamaged
condition. However, rough handling by carriers or others may
result in there being damage to the unit while in transit. If such a
situation occurs, do not return the unit to Jackson; instead, contact
the carrier and ask them to send a representative to the site to
inspect the damage to the unit and to complete an inspection
report. You must contact the carrier within 48 hours of receiving
the machine. Also, contact the dealer through which you purchased the unit.
UNPACKING THE DISHMACHINE: Once the machine has been
removed from the container, ensure that there are no missing
parts from the machine. This may not be obvious at first. If it is discovered that an item is missing, contact Jackson immediately to
have the missing item shipped to you.
LEVEL THE DISHMACHINE: The dishmachine is designed to
operate while being level. This is important to prevent any damage to the machine during operation and to ensure the best
results when washing ware. The unit comes with adjustable bullet
feet, which can be turned using a pair of channel locks or by hand
if the unit can be raised safely. Ensure that the unit is level from
side to side and from front to back before making any connections.
PLUMBING THE DISHMACHINE: All plumbing connections must
comply with all applicable local, state, and national plumbing
codes. The plumber is responsible for ensuring that the incoming
water line is thoroughly flushed prior to connecting it to any component of the dishmachine. It is necessary to remove all foreign
debris from the water line that may potentially get trapped in the
valves or cause an obstruction. Any valves that are fouled as a
result of foreign matter left in the water line, and any expenses
resulting from this fouling, are not the responsibility of the manufacturer.
CONNECTING THE DRAIN LINE: The drain for the TempstarTGP is a gravity discharge drain. All piping from the 1 1/2 ” FNPT
connection on the waste accumulator must be pitched (1/4” per
foot) (2.083 cm per meter) to the floor or sink drain. All piping from
the machine to the drain must be a minimum 1 1/2” I.P.S. and shall
not be reduced. There must also be an air gap between the
machine drain line and the floor sink or drain. If a grease trap is
required by code, it should have a flow capacity of 5 gallons
(18.93 liters) per minute.
WATER SUPPLY CONNECTION: Ensure that you have read the
section entitled “PLUMBING THE DISHMACHINE” above before
proceeding. Install the water supply line (3/4” pipe size minimum)
to the dishmachine line strainer using copper pipe. It is recommended that a water shut-off valve be installed in the water line
between the main supply and the machine to allow access for service. The water supply line is to be capable of 20 PSI “flow” pressure at the recommended temperature indicated on the data plate.
In areas where the water pressure fluctuates or is greater than the
recommended pressure, it is suggested that a water pressure regulator be installed.
Do not confuse static pressure with flow pressure. Static pressure
is the line pressure in a “no flow” condition (all valves and services
are closed). Flow pressure is the pressure in the fill line when the
fill valve is opened during the cycle.
It is also recommended that a shock absorber (not supplied with
the Tempstar-TGP model) be installed in the incoming water line.
This prevents line hammer (hydraulic shock), induced by the solenoid valve as it operates, from causing damage to the equipment.
PLUMBING CHECK: Slowly turn on the water supply to the
machine after the incoming fill line and the drain line have been
installed. Check for any leaks and repair as required. All leaks
must be repaired prior to placing the machine in operation.
ELECTRICAL POWER CONNECTION: Electrical and grounding
connections must comply with the applicable portions of the
National Electrical Code ANSI/NFPA 70 (latest edition) and/or
other electrical codes.
Disconnect electrical power supply and place a tag at the disconnect switch to indicate that you are working on the circuit.
The dishmachine data plate is located on the right side and to the
front of the machine. Refer to the data plate for machine operating requirements, machine voltage, total amperage load and serial number.
To install the incoming power lines, open the control box. This will
require taking a phillips head screwdriver and removing the one(1)
screw on the front cover of the control box. Install 3/4” conduit into
the pre-punched holes in the back of the control box. Route power
wires and connect to power block and grounding lug. Install the
service wires (L1 &L2) to the appropriate terminals as they are
marked on the terminal block. Install the grounding wire into the
lug provided. Tighten the connections and perform the “pull test”.
The tightened wires should remain in place after giving the wires
a moderate pull to see if they will come loose.
It is recommended that “DE-OX” or another similar anti-oxidation
agent be used on all power connections.
VOLTAGE CHECK: Ensure that the power switch is in the OFF
position and apply power to the dishmachine. Check the incoming
power at the terminal block and ensure it corresponds to the voltage listed on the data plate. If not, contact a qualified service
agency to examine the problem. Do not run the dishmachine if the
voltage is too high or too low. Shut off the service breaker and
mark it as being for the dishmachine. Advise all proper personnel
of any problems and of the location of the service breaker.
Replace the control box cover and tighten down the screws.
INSTALLATION INSTRUCTIONS
2
It is very important that the type and inlet pressure of the gas used corresponds to the machine data plate. This machine is equipped
with a 1/2” female line for connection of gas. The gas line used should be of the type approved for use with natural gas or propane,
depending on the gas selected to be used in this machine. The gas line should be sized to carry the maximum flow of 55,000 BTUs.
Too small of a gas line will result in poor performance. A manual gas shut-off valve must be installed in the gas line, located within an
accessible area of the machine. The gas line should be kept as short as possible and installed in a way to protect it from damage.
When making pipe connections, use an AGA approved pipe dope, being careful not to use excessive amounts as to foul the gas valve
or clog the gas line. When tightening the gas line always support the gas valve to avoid damage to the gas train.
When making the connection to the booster unit, take care to start the gas line fitting by hand and tighten by hand to avoid cross threading. Tighten fitting with a wrench, taking care not to damage any internal components of the unit.
After making a final connection of gas, with power to the unit turned off, check all gas line fittings for leaks, using a liquid test solution.
GAS CONNECTION
3
WARNING
ENSURE THAT THERE IS NO ELECTRICAL POWER APPLIED TO THE MACHINE WHEN MAKING GAS CONNECTION.
CHECK ALL GAS CONNECTIONS FOR LEAKS PRIOR TO APPLYING POWER.
THE GASES USED FOR COMBUSTION IN THIS DISH MACHINE ARE HIGHLY FLAMMABLE.
DO NOT SMOKE AROUND THIS MACHINE.
ENSURE THAT THE AREA WHERE THIS MACHINE IS TO BE INSTALLED IS WELL-VENTILATED TO PREVENT THE
BUILD-UP OF COMBUSTIBLE GASES.
ENSURE THAT ALL LOCAL HEALTH, FIRE, AND BUILDING CODES ARE BEING ADHERED TO WHEN INSTALLING THIS
MACHINE. VERIFY WITH LOCAL OFFICIALS IF THERE ARE ANY QUESTIONS.
INSTALL A SHUT-OFF VALVE AT THE GAS SOURCE AND SUPPLY THE MACHINE USING A 1/2” LINE. CONNECT TO THE
1/2” NPT FITTING ON THE MACHINE.
PREPARATION: Before proceeding with the start-up of the unit,
verify the following:
1. The pump intake, and wash tank strainers are in place
and is clean.
2. The drain stopper is installed.
3. That the wash and rinse arms are screwed securely
into place and that their endcaps are tight. The wash
and rinse arms should rotate freely.
POWER UP: To energize the unit, turn on the power at the service
breaker. The voltage should have been previously verified as
being correct. If not, the voltage will have to be verified.
FILLING THE WASH TUB:Ensure that the delime switch is in the
NORMAL position, and place the power switch into the ON position. The Tempstar-TGP should fill automatically and shut off
when the appropriate level is reached (just below the wash tank
strainer). Verify that the drain stopper is preventing the wash tub
water from pouring out excessively. There will probably be some
slight leakage from the drain hole. Verify that there are no other
leaks on the unit before proceeding any further. The wash tub
must be completely filled before operating the wash pump to prevent damage to the component. Once the wash tub is filled, the
unit is ready for operation.
The water level was set at the factory. If the water level is not at
the level noted above, it will require adjustment. Check to ensure
that the recommended water pressure is being supplied to the
machine (20 PSI). If the water pressure is correct then the fill
valve will need adjustment. Use the following steps to adjust the
cam. Turn power off at the machine circuit breaker. Open the
control box cover. Locate the timer fill valve cam (Cam 4 from the
timer motor). Locate the spanner wrench taped to the electrical
panel. The spanner wrench is used to adjust the cam.
WARE PREPARATION: Proper preparation of ware will help
ensure good results and less re-washes. If not done properly,
ware may not come out clean and the efficiency of the dishmachine will be reduced. It is important to remember that a dishmachine is not a garbage disposal and that simply throwing
unscraped dishes into the machine simply defeats the purpose
altogether of washing the ware. Scraps should be removed from
ware prior to being loaded into a rack.
Pre-rinsing and pre-soaking are recomended, especially for silverware and casserole dishes. Place cups and glasses upside
down in racks so that they do not hold water during the cycle. The
dishmachine is meant not only to clean, but to sanitize as well, to
destroy all of the bacteria that could be harmful to human beings.
In order to do this, ware must be properly prepared prior to being
placed in the machine.
DAILY MACHINE PREPARATION: Refer to the section entitled
“PREP ARATION” at the top of this page and follow the instructions
there. Afterwards, check that all of the chemical levels are correct
and/or that there is plenty of detergent available for the expected
workload.
WARM-UP CYCLES: For a typical daily start-up, it is recommended to run the machine through 3 cycles to ensure that all of
the cold water is out of the system and to verify that the unit is
operating correctly. To cycle the machine, ensure that the power
is on and that the tub has filled to the correct level. Lift the doors
and the cycle light will illuminate. When the light goes out, close
the doors, the unit will start, run through the cycle, and shut off
automatically . Repeat this two more times. The unit should now be
ready to proceed with the washing of ware.
WASHING A RACK OF WARE: To wash a rack, open the doors
completely (being careful for hot water that may drip from the
doors) and slide the rack into the unit. Close the doors and the
unit will start automatically . Once the cycle is completed, open the
door (again watching for the dripping hot water) and remove the
rack of clean ware. Replace with a rack of soiled ware and close
the doors. The process will then repeat itself.
OPERA TIONAL INSPECTION: Based upon usage, the wash tank
strainer may become clogged with soil and debris as the workday
progresses. Operators should regularly inspect the wash tank
strainer to ensure it has not become clogged. If the strainer does,
it will reduce the washing capability of the machine. Instruct operators to clean out the wash tank strainer at regular intervals or as
required by work load.
SHUTDOWN AND CLEANING: At the end of the workday, close
the doors. When the unit completes the cycle, turn the power
switch to the OFF position and open the doors. Manually remove
the drain stopper from the tub and allow the tub to drain (NOTE:
the wash tank water will be hot so caution is advised). Once the
wash tub is drained, remove the wash tank strainer and the pump
suction strainer. Remove soil and debris from the strainer and set
to the side. Unscrew the wash and rinse arms from their manifolds. Remove the endcaps and flush the arms with water. Use a
brush to clean out the inside of the arms. If the nozzles appear to
be clogged, use a toothpick to remove the obstruction. Wipe the
inside of the unit out, removing all soil and scraps. Reassemble
the wash and rinse arms and replace them in the unit. The arms
only need to be hand tight, do not use tools to tighten them down.
Reinstall the strainers and close the doors.
OPERATION INSTRUCTIONS
4
The Tempstar TGP heating system is designed to heat and maintain the wash tank water temperature at a minimum of 150
°F (65.56 °C) as well as providing a constant 180 °F (82.22 °C) rinse water temperature. Incoming water is supplied at a pressure of
20psi and between 70-140 °F (21.11 - 60 °C). Incoming gas pressure should be between 4.0-6.0 WCI for town gas. The sequence of
operation is as follows (please refer to the above diagram):
When the power is turned on at the ON/OFF switch the water level control board will sense a low water level in the wash tank
and the unit will begin to fill. This occurs as the rinse solenoid valve opens, allowing connected water to fill the booster tank, heat
exchanger and the rest of recirculating system, once the booster tank is full, water will fill the wash tank until the water level control system is satisfied. Simultaneously with the fill, the rinse recirculating pump and the gas burner assembly is energized, to begin heat up
of the unit. A transformer in the main control box supplies +12vdc to the electronics control drawer location in the lower section of the
unit. The electronics control board (ECB) is the brain of the system. The ECB receives various inputs and determines the amount of
heating required.
When energized the ECB receives input from the T-mid thermistor indicating a low water temperature in the recirculating system. The ECB will power the ignition relay on the board, which in turn provides +12vdc to the direct spark ignition board (DSI). The DSI
sends +12vdc to the combination gas cutoff valve to open it. This will supply gas to the burner assembly. The DSI begins sparki ng the
igniter probe, and monitors the flames presence. If the flame is not sensed during the ignition attempt, then the DSI will lockout until
the software resets the DSI approximately 60 seconds later.
OVERVIEW OF OPERATION
5
VACUUM BREAKER
PRESSURE
GAUGE
CHECK VALVE CHECK VALVE
BOOSTER
TANK
BURNER
ASSEMBLY
COMBINATION GAS
CUTOFF VALVE
WASH TANK
COILS
RECIRCULATING
PUMP
RINSE ARM
HEAT
EXCHANGER
FILL / RINSE SOLENOIDREGULATOR
WASH TANK
T
RINSE TEMP
>180 °F (82.22 °C)
T
WASH TEMP
150-165 °F
(65.56 - 73.89 °C)
TS
THERMOSTAT
WL
WATER LEVEL
PROBE
T-MID
ECO
MODULATING
VALVE
The operator may turn the power off at the ON/OFF switch for approximately 5 seconds, and then back on. This will also reset the ECB
and the DSI. If flame is lost during normal burn, the DSI will attempt a reignition.
The ECB monitors the 12vdc signal from the DSI to the combination gas cutoff valve. The software in the ECB also reads the
temperature at the middle of the heat exchanger with the T-mid thermistor. After the 5.5 second ignition time, the software will increase
gas flow to the burner to minimum burn by increasing voltage to the modulating valve (MV). If the heat exchanger temperature is far
away from the stabilization temperature, the software will increase gas flow to maximum burn.
Once the heat exchanger temperature nears the stabilization temperature the gas flow is slowly reduced until the minimum
burn is attained. The software will keep the unit in minimum burn until the heat exchanger temperature exceeds stabilization temperature when the gas will be shut off. Over many minutes, the software will turn the burner off and on repeatedly until all the water in the
system reaches the stabilization temperature. At this point the software will only turn the burner on every 1-2 minutes to maintain the
stabilization temperature. Now the unit is ready for operation.
As the dishwasher pulls water from the tank, the water is replaced with cooler water. The need to heat the new water is sensed
by the software and the burner is turned on. The software will modulate the gas flow between minimum and maximum gas flow attempting to recover the stabilization temperature and always keeping the tank temperature above the required temperature.
The stabilization temperature may be adjusted by means of a potentiometer located on the ECB. This is referred to as the Tset. (normally 4.25vdc)
The recirculating pump draws water from the rinse booster tank and circulates it through the wash tank coils where it will heat
the water residing in the wash tank. The water then returns to the heat exchanger where it is reheated. This hot water then flows back
to the rinse booster tank and repeats the cycle.
The thermostat,(in conjunction with the wash temp relay) is used during idle times to prevent wash tank temperature from
exceeding 170° F (76.67°C), during normal operation the wash tank will self regulate between 150-165° F (65.56-73.89 °C). However,
when idle, the temperature in the wash tank will slowly rise towards booster tank temperature until the temperature reaches 170° F
(76.67°C). The wash tank thermostat will cycle the heat exchanger & recirculating pump off. When the wash tank temperature lowers,
the heat exchanger and recirculating pump will energize. This will continue during all idle time. At any time that the unit is placed into
operation, the wash
temp relay will energize and immediately power the heat exchanger and the recirculating pump, regardless of the thermostats position.
Excessive high temperatures in the system are avoided by the following: 1. high temperature limit control by input from T-mid
thermistor, 2. energy cutoff temperature lockout (ECO) by means of a bi-metallic switch independent of the microprocessor which will
break voltage to the combination gas cutoff valve if temperature in the system exceeds 210 F (98.89°C).
Excessive high pressures that potentially could be created in the system are vented directly to atmosphere by means of the
rinse booster tank and rinse arms.
OVERVIEW OF OPERATION (CONTINUED)
6
THERMOSTAT ADJUSTMENT PROCEDURE
7
1) Start up unit
2) Allow to fill, and start warm-up
3) Turn thermostat trim screw Counter Clockwise (CCW) 2 full revolutions
4) Allow wash temperature to reach 170# F on Wash Temperature Gauge
5) Turn thermostat trim screw Clockwise (CW) until flashing Green LED on control board turns off. (The recirculating pump
will also turn off).
6) To ensure that the trim screw has not been turned too far CW, turn CCW very slowly until Green LED turns on and once
again turn CW very slowly until Green LED goes out.
7) Start normal operation and monitor wash tank temperature.
8) If readjustment is needed repeat steps 5 - 7 until wash tank temperature maintains at 170#F (76.67°C),during idle time.
AUTO-CALIBRATION PROCEDURE
8
Model: TEMPSTAR GP, & TEMPSTAR TGP
This procedure must be completed every time you replace either a control board or a modulating valve.
AUTO - CALIBRATION
1. Turn the unit OFF at the main power switch and let stand for one minute.
2. Remove the lower front panel and set aside.
3. Remove the cover of the rectangular control box.
4. Locate the control board (see figure 1).
5. Locate and remove the jumper labeled ACAL (see figure 1) from the control board. Be careful to remove
metal jumper not just the plastic insulator. Make a note of the exact position the jumper was located.
Set jumper aside for later reinstallation.
6. With your multi-meter set on DC volts, attach to the molex plug going to the modulating valve.
NOTE: Do not disconnect molex plug. Insert probes in the rear of one side so the contact is made with
the metal pins inside of the plug. (see figure 2).
7. Turn dishmachine ON. Burner will ignite and run through a series of steps. Watch the readings of your
multi-meter. They will run approximately 11.9 VDC (23 VDC for the TGP) at the highest flame, step down
to about 6.0 VDC (12 VDC for the TGP) and then step down again slightly to 5.7 to 5.8 VDC (11.4 to 11.6 VDC for the TGP) before shutting the burner off. This whole process takes about 1 - 2 Minutes.
8. Once the burner goes out, turn dishmachine OFF.
9. Wait one minute.
10. Replace jumper on control board in the exact same place it came off.
11. Turn the dishmachine back ON.
Figure 1 Figure 2
ELECTRONICS CONTROL BOARD (ECB)
9
The Control Board regulates the temperature of the water in the heat exchanger system. This water is also used as the rinse water
for the rinse cycle of the dishwasher. It does this by regulating the flame of the burner by increasing or decreasing the voltage to the
modulating valve. The modulating valve, in turn, increases or decreases the gas pressure going to the burner manifold depending on
the voltage it is getting from the control board. From time to time it may be necessary to check or adjust the setting of this water temperature. To test the setting or to reset the temperature of the rinse water, make sure the unit is on and the green LED on the board is
flashing steadily. Insert the NEGATIVE (Black/Common) probe of a multi-meter set on DC volts in the BLACK test point (see above).
Insert the POSITIVE (Red) probe of the multi-meter in the BLUE test point. The reading will indicate the set point temperature. The factory setting is 4.25 VDC which corresponds to 198#F (92#C). Adjustments to the set point are made on the BLUE POTENTIOMETER
directly below the BLUE test point. With a very small slotted screwdriver rotate the trim screw on the potentiometer clockwise (CW) to
increase the voltage (and Temperature) and counterclockwise to decrease.
Testing and Setting the Set Point Temperature
TESTING THE THERMISTORS
10
There are two thermistors that are used in controlling the temperature of the water in the heat exchanger system. The T- in that samples the temperature of the water going into the heat exchanger and the T-Mid that samples the temperature halfway through the heat
exchanger. The Control Board constantly monitors the temperature at the T-Mid Thermistor and adjusts the burner pressure by way of
the Modulating Valve according to how far away that temperature is away from the set point temperature.
Thermistors are devices that change their resistance value with changes in temperature. By running a constant voltage through the
thermistor, one can read the change of voltage caused by the change of resistance thus determining the temperature of the thermistor. There are test points on the control board (see above) that can be read with a multi-meter on the Direct Current Volt (DCV) scale
for each thermistor.
T
o test the temperature at the T-in Thermistor
There is a BLACK test point along the top edge of the control board on the right side of center. This is where the NEGATIVE
(Common/Black) probe of a multi-meter is inserted. There is an ORANGE test point along the top edge of the control board on the left
side of center. This is where the POSITIVE (Red) probe of a multi-meter is inserted. A DC voltage reading is then taken. Find
the voltage on the chart below and find the corresponding temperature.
To test the temperature at the T-Mid Thermistor
Using the same BLACK test point with the NEGA TIVE probe of the multi-meters in testing the T-in thermistor above, also find the YELLOW test point on the left side of the board just under the large plug (see above). Insert the positive probe of the multi-meter and read
DC Volts. Since the two thermistors have the same values, the same chart is used.
Gas Pack Thermister Conversion
0
0.5
1
1.5
2
2.5
3
3.5
4
50(10)
60(15.6)
70(21.1)
80(26.7)
90(32.2)
100(37.8)
110(43.3)
120(48.9)
130(54.4)
140(60)
150(65.6)
160(71.1)
170(76.7)
180(82.2)
190(87.8)
200(93.3)
210(98.9)
Temperature °F (°C)
Voltage DC
CONTROL BOARD LED LIGHT INDICATIONS
11
The Electronic Control Board (ECB) has two LED light indicators that can be seen at its upper left hand corner.
The following conditions for each light may be seen during operation of the unit.
1) Green LED is off.
A) Dishmachine is turned off, therefore no power to ECB.
B) Wash thermostat has cycled off, therefore breaking power to 12 volt transformer in the main control box.
This will also disrupt power to the ECB.
C) ECB may have never recieved an AUTO CALIBRATION.
D) ECB may be damaged due to high voltage.
E) Control chip in ECB may be misaligned, not fully inserted, or damaged.
2) Green LED is a illuminated and steady.
A) ECB has been damaged in some form.
3) Green LED is illuminated and flashing.
A) This is the normal operating condition.(whether the LED flashes rapidly, or at a slower rate).
4) Red LED is off.
A) This is the normal operating condition.
5) Red LED is illuminated and steady, or flashing.
A) This is an indication of a malfunction of the T-MID Thermistor. Thermister may be unplugged, grounded, have frayed
wiring, or other damage.
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