2.8.1 SM50 and SM60 Series Fryers (Except IHOP) 2-27
2.8.2 SM50 Series Fryers, IHOP UFF 50 with Filter Leaf 2-28
2.8.3 SM80 Series Fryers 2-29
2.9 Single Under Fryer Filter (SUFF) Components 2-30
2.9.1 SM50 Series Fryers 2-30
2.9.2 SM60 and SM80 Series Fryers 2-31
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FRYMASTER DEAN MILLIVOLT GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1.1 Functional Description
Frymaster Dean ESG, Super Runner and Super Marathon Series fryers are millivolt fryers, which require
no electricity to operate (systems with built-in filtration and/or other accessories will require electric
power). Frymaster Dean millivolt fryers contain a welded steel frypot (stainless or cold-rolled) that is
heated by gas flames diffused evenly through tubes built into the frypot. The number of tubes varies
from three to five, according to the fryer model and size.
Flames originate from orifices in a burner manifold positioned beneath cast-iron burn ers. The burn ers
are positioned in the tube openings, at the front of the frypot. Diffusers within each tube distribute the
flame evenly throughout the tube. The diameter of the orifices differs fo r natural (CE:G 20/G25) and LP
(CE:G31) gas as indicated in the accompanying table.
An electromechanical millivolt gas valve regulates gas flow to the burner manifold. Frymaster Dean
millivolt fryers use a pilot ignition system to control burner firing.
High-Limit
Thermopile
Operating
Thermostat
Gas Valve
Pilot
Pilot Magnet
Main Valve Magnet
Functional diagram of a typical millivolt system.
Pilot Ignition System
The pilot ignition system is made up of the pilot orifice, pilot hood, and a thermopile or
thermocouple. The pilot serves two purposes: lighting the burner and heating the thermopile/
thermocouple. In operation, the thermopile/thermocouple is in contact with the pilot flame and
generates millivolts. The millivolt output passes through a normally closed high-limit switch and
energizes the gas valve pilot coil, which in turn opens the pilot valve. If the pilot flame is
extinguished, voltage is lost to the gas valve pilot coil and the pilot valve closes.
Thermostats
Frymaster Dean millivolt fryers are equipped with adjustable operating thermostats. The
temperature at which the thermostat opens and closes is adjusted by turning a knob.
Frymaster Dean millivolt fryers are also equipped with a high-limit thermostat. In the event that the
fryer fails to properly control the oil temperature, the high-limit thermostat prevents the fryer from
overheating to the flash point. The high-limit thermostat acts as a normally closed power switch that
opens when exposed to temperatures above 410ºF (210°C) for CE fryers and 435-450ºF (224-232°C)
for non-CE fryers. Once opened, the high limit must be manually reset before operating the fryer.
1-2
1.2 Accessing Fryers for Servicing
DANGER
Moving a fryer filled with cooking oil may cause spilling or splattering of the hot
liquid.
1. Drain all cooking oil from the fryer.
2. Shut off the gas supply to the unit and disconnect the unit from the gas supply.
3. Remove any attached restraining devices.
DANGER
Fryers must be at room temperature, empty of oil, and if fitted with legs, lifted during
movement to avoid damage and possible bodily injury.
DANGER
Hot shortening can cause severe burns. Avoid contact. Under all circumstances, oil
must be removed from the fryer before attempting to move it to avoid oil spills, and
the falls and severe burns that could occur. This fryer may tip and cause personal
injury if not secured in a stationary position.
4. Relocate the fryer for service accessibility. If fryer is equipped with legs, lift the fryer to re locate
it. Damage to the leg or leg support channel can result if the fryer is not lifted when moving.
5. After servicing is complete, reconnect the unit to the gas supply and reattach the restraining
devices.
6. Refill the frypot with cooking oil.
1.3 Cleaning the Gas Valve Vent Tube
1. Set the fryer power switch and the gas valve to the "OFF" position.
2. Carefully unscrew the vent tube from the gas valve. NOTE: The vent tube may be straightened
for ease in removal.
3. Pass a piece of ordinary binding wire through the tube to remove any obstruction. Remove the
wire and blow through the tube to ensure it is clear.
4. Reinstall tube and bend so that the opening is pointing downward.
1-3
1.4 Check Burner Manifold Pressure
WARNING
This task should be performed by qualified service personnel only.
1. Ensure that the gas valve knob is in the "OFF" position (non-CE), or press red button to turn gas
valve off (CE).
2. Remove the pressure tap plug from the gas valve (see illustration below).
3. Insert the fitting for a gas pressure-measuring device into the pressure tap hole.
4. Place the gas valve in the "Pilot" position (non-CE), or press white button and light pilot (CE).
After the pilot is lit (turn non-CE gas valve to "ON" position), set thermostat knob to 350°F
(177°C). When the burner lights and continues to burn, note gas pressure reading for correct
pressure in accordance with the table on page 1-1.
5. To adjust burner gas pressure, remove the cap from the gas valve regulator and adjust to correct
pressure.
6. Place the fryer power switch and the gas valve in the "OFF" position. Remove the pressuremeasuring device fitting from the pressure tap hole and reinstall the pressure tap plug.
7. Repeat step 4 to continue fryer operation.
Pressure tap locations on CE gas valves (left) and non-CE gas valves (right).
1-4
1.5 Adjusting the Pilot Flame
1. Remove the cover shown in the illustration below to access the pilot flame adjustment screw in
the gas valve.
2. Using a small, flat-tipped screwdriver, turn the pilot flame adjustment screw counterclockwise to
3. Reinstall the pilot flame-adjustment cover.
4. Five-tube millivolt fryers: Adjust the trailing pilo t (adjustment valve located on the burner
Pilot adjustment locations on CE gas valves (left) and non-CE gas valves (right).
increase the length of the flame or clockwise to decrease the length of the flame. Adjust the
flame to a length of 1-½ inches (38 mm).
manifold) until a 1-½ inch (38 mm) flame is obtained.
1.6 Replacing Fryer Components
1.6.1 Replacing the Operating Thermostat
1. Drain the fryer and turn the gas off.
2. Remove the thermostat knob by pulling straight out on the knob with a firm, steady pull.
3. Disconnect the wires from the thermostat.
4. Remove the two mounting screws to release the thermostat control from its mounting bracket.
5. Remove the screws and clamp that secure the thermostat bulb to the frypot. Remove spring from
bulb and reinstall on replacement thermostat bulb.
1-5
1.6.1 Replacing the Operating Thermostat (cont.)
6. First, loosen the capillary tube compression fitting until it slides freely on the capillary tube.
Second, loosen the frypot pass-through nut until it slides freely on the capillary tube. Remove
the capillary tube and bulb from the frypot.
7. Install the replacement thermostat capillary tube and bulb in the frypot. Apply a small amount of
Loctite PST567 compound or equivalent to the threads of the frypot pass-through nut and screw
the replacement thermostat securely into the frypot, being careful not to twist the capillary tube
as the fitting is tightened. DO NOT tighten the capillary tube compression nut at this time.
8. Position the thermostat bulb in tube-mounted clamp and replace mounting hardware. Ensure
probe bulb is properly positioned in the clamp (¼" from burner tube) and screws are properly
tightened.
9. Tighten the capillary tube compression nut once the capillary tube is properly positioned.
NOTE: Once the compression nut is tightened, the capillary tube cannot be repositioned. If a
mistake in installation has been made, a new thermostat will have to be installed.
10. Mount the thermostat control to the mounting bracket using the screws removed in Step 4.
11. Connect the wires disconnected in Step 3 to the thermostat.
Compression Fitting
Capillary Tube
Operating
Thermostat
Frypot Fitting
12.Install the thermostat knob on thermostat control shaft.
Thermostat Bulb
1-6
1.6.2 Replacing the High-Limit Thermostat
1. Follow instructions for replacing operating thermostat, section 1.7.1, omitting steps 2 and 12.
1.6.3 Replacing the Gas Valve
DANGER
Drain the frypot or remove the handle from the drain valve before proceeding further.
1. Disconnect fryer from the gas supply.
2. Disconnect wiring from the gas valve terminal block, marking each wire to facilitate
reconnection.
3. Disconnect the pilot gas line fitting from the gas valve and remove the vent tube.
4. Disconnect the union that connects burner manifold and gas valve piping.
5. Remove all pipefittings from old gas valve and install on new gas valve. Apply a small amount
of Loctite PST567 compound or equivalent to pipe threads prior to installing on new valve. Do
not apply compound to the first two pipe threads. Doing so will clog and damage the gas valve.
6. Reinstall new gas valve following steps 1-4 in reverse.
1.6.4 Replacing the Frypot
1. Drain the frypot and disconnect the fryer from the gas supply.
3. Remove the screws from the cabinet back and remove it from the fryer.
4. Remove the screws attaching the flue cap to the frypot and lift the flue cap off the fryer.
5. Remove the door by lifting it upward to disengage the lower hinge pin from the hinge bracket.
Retain any spacers between lower hinge and door for reassembly.
6. Remove the screws from the front cowling and remove the cowling by lifting up and out off the
front lip of the frypot.
7. Remove the screws securing the flue to the frypot and remove it from the fryer.
8. Lift the frypot out of the cabinet, using care not to bump or damage the gas valve/burner
assembly or the thermostat/high-limit. Set the frypot upside down on a clean surface for removal
of the remaining components.
1-7
1.6.4 Replacing the Frypot (cont.)
9. Recover the drain valve, high-limit thermostat, operating thermostat, and burner manifold
assembly from the failed frypot.
10. Clean the threads on the recovered parts, apply Loctite PST 567 or equivalent thread sealer, and
install them on the replacement frypot.
11. Reverse Steps 1-9 to install the replacement frypot in the cabinet.
For SUFF/UFF Filtration-equipped systems, consult the Decathlon Series Gas Fryers
Service & Parts Manual (819-5922), Section 1.7.8, for detailed frypot-removal
instructions.
1.7 Troubleshooting and Problem Isolation
This section is intended to provide technicians with a general knowledge of the broad problem
categories associated with this equipment, and the probable causes of each. With this knowledge, the
technician should be able to isolate and correct any problem encountered.
Problems you are likely to encounter can be grouped into these broad categories:
1. Pilot failures
2. Improper burner functioning
3. Improper temperature control
4. Filtration Problems
5. Leaking
The probable causes and corrective actions for each category are discussed in the following sections.
1.7.1 Pilot Failures
When troubleshooting millivolt systems, always check these areas before performing diagnostic
checks on either the Robertshaw or Honeywell systems:
A. Inspect all wires and component leads for damage (heat, oil, moisture, etc.). On capillary
tube-type thermostats, check for resistance on the thermostat lead wires. Wire nuts and other
connectors cannot be present in a millivolt circuit as they can cause resistance. If resistance
is found, solder the connectors to the wires or replace the wires.
B. Clean and verify that all wire connections and gas valve terminal connections are tight.
C. Check the length of the pilot flame (it should be about 1½-inches (38mm) long) and verify
that it contacts the top one third of the thermopile. Clean the pilot orifice and adjust the pilot
strength if needed.
D. Measure thermopile output with no load (i.e., with the thermopile disconnected from the gas
valve). Measurement must be made with a multimeter having a 0-1000 DC millivolt (MV)
range. Light the pilot and have someone hold the gas cock knob in the depressed position. If
the thermopile is a single lead (coaxial) type, measure from the lead’s end contact to its
screw-in threads. If the thermopile has two leads, measure across the end terminals. The
reading should be within the range of 500-800 millivolts. If not, replace the thermopile.
Performing diagnostic checks on Robertshaw and Honeywell valves are described on the next page.
1-8
ROBERTSHAW-UNITROL 7000 SYSTEM CHECK
1. Complete System Check
With thermostat contacts closed and gas cock
dial in the “ON” position, the main burner
should ignite. Measure the reading between
the 2 & 3 terminals. If the reading is more
than 100MV, replace the gas valve.
2. System Resistance Check
With thermostat contacts closed and main
burner “ON”, measure the millivolt reading
between the 1 and 3 terminals. The reading
should be less than 80MV. If not, recheck the
thermostat leads and connections. Replace
with new or heavier gauge wires if necessary.
If the reading is still greater than 80MV,
replace the thermostat.
3. Automatic Pilot Dropout Check
With the thermostat contacts open, hold the
gas cock knob depressed with the pilot lit until
the maximum millivolt output is observed
between the 1 and 2 terminals. Then
extinguish the pilot and observe the meter.
The sound of the pilot magnet dropping should
be audible. This dropout should occur
between 120MV and 30MV. If it occurs
outside these limits, change the gas valve.
HONEYWELL SYSTEM CHECK
1. Complete System Check
With thermostat contacts closed and gas cock
dial in the “ON” position, main burner should
ignite. If not, measure across terminals 2 and
3 as indicated in the diagram. If the reading is
more than 180MV, replace the gas valve.
2. System Resistance Check
With thermostat contacts closed and main
burner “ON”, measure the millivolt reading
between terminals 1 and 3 as indicated in the
diagram. The reading should be 220MV or
less. If not, recheck thermostat leads and
connections. Replace with new or heavier
gauge wires if necessary. If the reading is still
greater than 220MV, replace the thermostat.
3. Automatic Pilot Dropout Check
With the thermostat contacts open, hold the
gas cock knob depressed with the pilot lit until
the maximum millivolt output is observed
between terminals 1 and 2. Then extinguish
the pilot and observe the meter. The sound of
the pilot magnet dropping should be audible.
This dropout should occur between 110MV
and 36MV. If it occurs outside these limits,
change the gas valve.
Pilot failures fall into one of two categories – failure to light or failure to remain lit.
Pilot Fails to Light
1. Gas is not being supplied to the valve: Check for a closed gas cutoff valve upstream of the gas
valve. Also verify that the gas line quick disconnect fitting at the rear of the fryer (if so
equipped) is properly connected.
2. Blocked pilot orifice: If gas is reaching the valve but the pilot will not light, check for an
obstruction in the pilot orifice, especially in new installations. If the orifice is clear, check to be
sure that the pilot adjustment screw is not completely closed.
Pilot Does Not Remain Lit When Gas Valve Knob is Released
The gas valve used on Frymaster Dean millivolt fryers has a pair of normally open coils
(electromagnetic switches) that close when low voltage is applied to them. If the coils do not close,
the valve will not open to supply gas to the pilot or to the burner manifold. Turning the gas valve
knob to the pilot position and pressing it in bypasses the pilot coil, allowing the pilot to be lit. The
pilot flame heats the thermopile, which generates the voltage required to close the coils. If the pilot
flame goes out when the knob is released, there are four probable causes:
1. Open or grounded high-limit: The high-limit thermostat functions as a normally closed switch.
If the high-limit is open or grounded, the gas valve coil will not pull in and no gas will be
supplied to the pilot or to the burner manifold.
Check and Corrective Action: Detach the high-limit leads from the gas valve and check for
continuity. See page 1-10. If the high-limit fails the continuity check, it must be replaced.
2. Loose/corroded wiring connections on high-limit or thermopile: This has the same effect as a
grounded or open high-limit. If the gas valve coils do not receive the appropriate voltage from
the thermopile, they will not close and no gas will be supplied to the pilot or to the burner
manifold.
Check and Corrective Action: Check wiring connections for corrosion and tightness. Check
terminals to verify that they are securely attached to their leads.
3. Low or no voltage out of thermopile: If the pilot flame does not surround the tip of the
thermopile, it will not generate sufficient voltage to the gas valve coils for them to close. No gas
will be supplied to the pilot or to the burner manifold.
Checks and Corrective Actions: Observe pilot flame located between the middle burners on the
frypot. If the pilot flame is less than 1-½ inches (38 mm) adjust the pilot flame in accordance
with Section 1.6. If the flame is being blown away from the thermopile, eliminate the draft that
is causing the problem.
If the pilot flame correctly surrounds the tip of the thermopile, see D on Page 1-9.
4. Malfunctioning gas valve: If either of the coils in the gas valve fails, no gas will be supplied to
the pilot or to the burner manifold.
Check and Corrective Action: See page 1-10 for check procedures to see if the gas valve has
failed. Instructions to replace the gas valve are found in section 1.7.3.
1-10
1.7.2 Improper Burner Functioning
Fluctuating flame intensity is normally caused by improper or fluctuating incoming gas pressure,
but may also be the result of variations in the kitchen atmosphere. Variation in the kitchen
atmosphere is usually caused by air conditioning and/or ventilation units starting and stopping.
Changes in airflow patterns can also affect flame intensity. If the incoming gas pressure is correct
and stable, check for variations in the kitchen atmosphere.
Flames "rolling" out of the fryer are usually an indication of negative pressure in the kitchen. Air
is being sucked out of the fryer enclosure and the flames are literally following the air. If negative
pressure is not the cause, check for high burner-manifold gas pressure. An obstructed flue, which
prevents the fryer from properly exhausting, may also be the cause.
An excessively noisy burner, especially with flames visible above the flue opening, may indicate
that the burner gas pressure is too high, the gas valve vent tube is blocked, or the tube diffusers are
damaged or worn out. If the gas pressure is correct, the vent tube is unobstructed, and the diffusers
are in good condition, the gas valve regulator is probably defective.
Occasionally a burner may appear to be operating correctly, but the fryer has a slow recovery rate
(the length of time required for the fryer to increase the oil temperature from 275ºF to 325ºF (135ºC
to 163ºC). The primary causes of this are low burner manifold pressure and/or misaligned burners.
If both of these causes are ruled out, the probable cause is a gas valve regulator that is out of
adjustment. Refer to the Check Burner Manifold Pressure procedure in section 1.5.
1.7.3 Improper Temperature Control (i.e., failure to control at set point)
Temperature control is a function of several interrelated components, each of which must operate
correctly. The principal component, however, is the thermostat.
The thermostat must be checked periodically.
Probable causes for temperature problems are damage to the thermostat bulb, kinking of the
capillary tube, and broken or loose wiring. Inspect the thermostat components for visible damage.
If there are dents in the bulb, if the capillary is kinked, or if there is obvious damage to the leads, the
thermostat should be replaced.
If there is no obvious damage to the thermostat, turn off the gas valve and allow the cooking oil to
cool to at least 15 degrees below the thermostat setting. Disconnect the thermostat leads from the
gas valve and check for continuity. If the thermostat fails the continuity check, it must be replaced.
1-11
1.7.4 Filtration Problems
The majority of filtration problems arise from operator error. One of the most common errors is
placing the filter paper on the bottom of the filter pan rather than over the filter screen.
Whenever the complaint is "the pump is running, but no oil is being filtered", check the installation
and size of the filter paper. Verify that the O-ring on the slip-connection is in good condition. A
missing or worn O-ring allows the pump to suck air, decreasing its efficiency.
If the pump motor overheats, its thermal overload will trip and the motor will not start until it is
reset. If the pump motor does not start, press the red reset switch located on the rear of the motor.
Also, reset the filter circuit breaker located under the fryer control panel. If the pump then starts,
something caused the motor to overheat. Maybe several frypots were filtered one after the other and
the pump got hot. Letting the motor cool down for at least a half-hour is all that is required in this
case. More often, the pump overheated for one of the following reasons:
If solid shortening is used: Shortening solidified in the pan or filter lines.
The operator attempted to filter unheated oil. Cold oil is thicker and causes the pump motor to
work harder and overheat.
If the motor runs but the pump does not, there is a blockage in the pump. Incorrectly sized or
installed paper allows food particles and sediment to pass through the filter pan and into the pump.
When sediment enters the pump, the gears bind up causing the motor to overheat, tripping the
thermal overload. Solidified shortening in the pump will produce the same result.
A pump seized by debris or hard shortening must be disassembled, cleaned and reassembled.
1. Disconnect power to the filter system.
2. Remove the front cover of the pump to access the gears inside (see illustration- 8-GPM pump
shown), if the pump is accessible while still inside the cabinet. If the front cover is not
accessible, the pump must be removed from the pump motor (remove input/output plumbing
from the pump prior to removing pump). Remove three setscrews to disengage the pump from
the motor.
Remove bolts to remove
pump cover.
1-12
Remove debris or hardened
shortening to free gears.
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