Hotstart OXM User manual

216311-000 rev1
INSTALLATION & OPERATION MANUAL
OIL CIRCULATING HEATING SYSTEM
MODEL
OXM
OGM

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i
installation & operation manual | oxm/ogm heating system
IOM216311-000
Corporate & Manufacturing
Headquarters
5723 E. Alki Ave.
Spokane, WA 99212 USA
509.536.8660
[email protected]
Oil & Gas Ofce
21732 Provincial Blvd.
Suite 170
Katy, TX 77450 USA
281.600.3700
[email protected]
Europe Ofce
HOTSTART GmbH
Am Turm 86
53721 Siegburg, Germany
+49.2241.12734.0
[email protected]
Asia Pacic Ofce
HOTSTART Asia Pacic Ltd.
2-27-15-4F Honkomagome
Bunkyo-ku, Tokyo
113-0021, Japan
+81.3.6902.0551
[email protected]
NOTE Typical heating
system
identication
plate. Your
identication
plate may vary.
IDENTIFYING YOUR SYSTEM
The HOTSTART heating system is designed to heat uids for use in marine propulsion, diesel-powered generator sets,
locomotives, gas compression or any large-engine applications. The system is pre-wired and pre-plumbed. Each heating
system has an identication plate which includes the part number and serial number.
When ordering replacement parts, be sure to reference your heating system’s model number
and serial number found on the identication plate and following label:
WARRANTY INFORMATION
Warranty information can be found at www.hotstart.com or by contacting our customer service department at
509.536.8660. Have your model number and serial number ready when contacting the warranty department.
COPYRIGHT
Hotstart Manufacturing, Inc. is the owner of all trademarks and copyrightable material contained herein; all rights are
reserved; no form of reproduction is authorized without prior written consent from Hotstart Manufacturing, Inc.

ii installation & operation manual | oxm/ogm heating system
IMPORTANT SAFETY INFORMATION
WARNING
!
Hazardous voltage: Before wiring, servicing or cleaning the heating system, turn off the power and follow your
organization’s lockout and tagout procedure. Failure to do so could allow others to turn on the power unexpectedly,
resulting in harmful or fatal electrical shock.
Electrical hazard: All electrical work must be done by qualied personnel in accordance with national, state and local
codes.
CAUTION
!
Read instructions carefully: The safety of any system incorporating this heater is the responsibility of the assembler.
The safe and proper use of this heater is dependent upon the installer following sound engineering practices. If the
equipment is used in a manner not specied by the manufacturer, the protection provided by the equipment may
be impaired. All applicable electrical safety standards dened by local jurisdictions must be followed. (Reference EU
directive 2006/95/EC in EU countries.)
• Read carefully: Installers and operators of this equipment must be thoroughly familiar with the instructions in
this manual before commencing work.
• Hot surfaces: Avoid contact with the system while it is in service. Some surfaces may remain hot even if the
system is not energized.
• Proper lifting: Proper rigging and safety equipment must be used to move this equipment. Do not lift the
heating system by any cords, electrical conduit or cabling. Create a plan before attempting to move. Proper
lifting locations are identied on each system; use these locations when lifting and mounting the system.
• Rotating equipment: The heating system can start automatically and without warning. Avoid contact unless a
lockout at the service panel has been installed.
• Grounding: The heater must be connected to a suitable ground (protective earthing conductor).
• Overcurrent limiting: The power supply must be protected by a suitable overcurrent
limiting device.
• Power disconnection: A means to disconnect the heater from the power supply is required. HOTSTART
recommends that a power switch or circuit breaker be located near the heater for safety and ease of use.
NOTICE
EU Countries only: Equipment rated for the conditions listed in EN 601010-1 1.4.1 Ingress protection rating IP55.
(Special conditions for specic applications may apply.)

iii
installation & operation manual | oxm/ogm heating system
TABLE OF CONTENTS
1 OVERVIEW | 1
1.1 HEATING SYSTEM COMPONENTS | 1
1.2 OPERATION OVERVIEW | 2
2 PLUMBING INSTALLATION | 3
2.1 OIL PLUMBING INSTALLATION | 4
2.1.1 Oil Supply | 4
2.1.2 Oil Return | 4
2.1.3 Oil Pressure Relief Valve | 4
2.2 PRESSURIZED SYSTEM INSTALLATION | 4
2.3 OIL PLUMBING ILLUSTRATION | 5
2.4 MOUNTING | 6
2.4.1 Tank and Pump | 6
2.5 ELECTRICAL CONNECTIONS | 6
2.5.1 Main Power Supply | 6
2.5.2 Customer Interface Connections | 6
3 SYSTEM COMPONENTS AND
OPERATION | 8
3.1 LOCAL/OFF/REMOTE SWITCH | 8
3.2 50%/100% SWITCH | 8
3.3 PRIME BUTTON | 8
3.4 OIL PRESSURE/TEMPERATURE GAUGE | 8
3.5 PRESSURE RELIEF VALVE | 8
3.6 MOTOR PROTECTION SWITCH (MPS) | 8
3.7 HIGH-LIMIT TCR (TEMPERATURE
CONTROL RELAY) | 9
3.8 CONTROL TCR
(TEMPERATURE CONTROL RELAY) | 9
4 HEATING SYSTEM
START-UP | 10
5 MAINTENANCE, REPAIR AND
TROUBLESHOOTING | 10
5.1 FAULTS | 10
5.2 SYSTEM MAINTENANCE | 11
5.2.1 Plumbing Connections | 11
5.2.2 Electrical Connections | 11
5.2.3 System Mounting | 11
5.2.4 Magnetic Contactors | 11
5.2.5 Pump Seal | 11
5.2.6 Motor Lubrication | 11
5.2.7 Oil Pressure Relief Valve | 11
5.2.8 Oil Pressure/Temperature Gauge | 11
5.2.9 Volatile Corrosion Inhibitor (Vci) | 11
5.2.10 Temperature Control Relay (Tcr) | 12
5.2.11 Resistance Temperature Device (Rtd) | 13
5.2.12 Heating Tank/Element | 14
5.2.13 Reassembly Of Heating Element and Tank | 14
5.3 RECOMMENDED MAINTENANCE | 16
5.4 STORAGE REQUIREMENTS | 16
5.5 TROUBLESHOOTING | 17

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iv installation & operation manual | oxm/ogm heating system

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installation & operation manual | oxm/ogm heating system
1 OVERVIEW
1.1 HEATING SYSTEM COMPONENTS
The OXM/OGM heating system consists of the following main components: See Fig. 1.
NOTE: Component illustrations are for reference only and are not to scale. See part drawings for dimensions
and specications. OGM model shown. OXM model incorporates two heater circuits; 50%/100% switch and
heater lights not available.
Figure 1. OXM/
OGM heating system
components.
H I J
L
K
G
F
D
E
CBA
O MN
A. Element assembly
B. Pressure/temperature
gauge
C. Oil outlet
(1.25″ NPT)
D. prime button
E. local/off/remote
switch
F. 50%/100% switch
G. remote light
H. Lift points
I. local light
J. fault light
K. Oil pump inlet
(OXM: 1.5″ NPT)
(OGM: 2.5″ NPT)
L. Pump/motor assembly
M. Control RTD
(resistance
temperature device)
N. Heating tank
O. High-limit RTD
(resistance
temperature device)

2installation & operation manual | oxm/ogm heating system
1.2 OPERATION OVERVIEW
The OXM/OGM heating system is intended to maintain an engine’s optimal oil temperature while the engine is shut
down. The heating system may be activated locally or by optional remote control (see SECTION 2.6). The OXM/OGM
heating system should be deactivated upon engine start-up.
During heating system operation, a rotary gear pump takes oil from the sump and forces it through the heating tank to
the oil return line. The oil pump will continuously circulate uid. To maintain consistent uid temperature, the heating
elements will cycle on and off at the user-selected temperature control point.
A return line check (non-return) valve (included with the OXM/OGM unit and installed at the outlet) and a supply line
check (non-return) valve (user-supplied, installed near the oil suction port) prevent backow while the engine is operating.
When the engine is shut down, the heating system should be activated locally or remotely to resume maintaining the
uid’s optimal temperature.
Figure 2. OXM/
OGM operation
overview, showing
oil circulation.
While the heating
elements cycle
on and off to
maintain the preset
temperature, the
pump circulates uid
continuously during
operation.
Component
illustrations are for
reference only and
are not to scale.
See part drawings
for dimensions and
specications.
OIL RETURN
OIL SUPPLY

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installation & operation manual | oxm/ogm heating system
2 PLUMBING INSTALLATION
CAUTION
!
Pressure hazard: Power must be turned off and locked out at the service panel when the isolation valves are in the
closed position. Failure to do so may cause damage to heating system components, damage to lubrication oil, uid
leaks and unexpected release of heated uid.
Overheating hazard: After completing line installation, top off the uid levels to compensate for the uid used to ll
the lines and heating tank. Do not operate the heating system without the presence of uid. Position the heating tank
to ensure it is completely full of uid while in operation.
Pump priming: Fill the supply line with uid. Pump is self-priming. However, uid must be present in the pump before
start-up. Trapped air inside the pump will cause pump and seal damage.
Pump seal damage: Do not reduce the oil supply line to an inner diameter smaller than the pump inlet; pump seal
damage will occur.
Check valve: HOTSTART recommends installing a user-supplied swing-type or full-ow check valve (non-return valve)
to prevent oil from owing back into the oil sump. If the pump is installed above the minimum oil level, a check valve
must be installed.
Pressure relief valve: If the OXM/OGM heating system is for use with a closed, pressurized uid system, additional,
user-supplied pressure relief must be installed along the heating system outlet plumbing. User-supplied pressure
relief valve plumbing must be routed back to oil sump, oil tank or atmospheric pressure. Do not route pressure relief
plumbing back to heating system tank.
Isolation valves: HOTSTART recommends installing full-ow ball valves to isolate the heating system in order to
perform service on the system or engine without draining oil.

4installation & operation manual | oxm/ogm heating system
2.1 OIL PLUMBING
INSTALLATION
2.1.1 OIL SUPPLY
Installing a short, straight oil supply line with a minimum
of ow restriction is the most important step toward
ensuring heating system longevity. When installing
the OXM/OGM oil supply line, refer to the following
HOTSTART guidelines:
PUMP
INLET
HOSE INNER
DIAMETER
MAX. LINE
LENGTH
MAX.
ELBOW
COUNT
1-1/2
inch NPT
1-3/8 inch 20 feet
(6 meters)
4
2-1/2
inch NPT
2-3/8 inch 20 feet
(6 meters)
4
• Due to the increased viscosity of lubrication
oil, the oil supply line must be as short and
as straight as possible. Any 90° elbows will
reduce the maximum recommended oil
supply length. See Table 1 for HOTSTART
OXM/OGM oil supply recommendations:
NOTE: Each additional pair of 90° elbows will reduce
the maximum recommended line length
by ve feet (1.5 meters). To minimize ow
restriction, HOTSTART recommends using
sweeping bends or 45° ttings.
• At a minimum, size the oil supply line per the
pump inlet. NOTICE! Do not reduce the
supply line inner diameter; pump seal
damage will occur.
NOTE: To maximize ow and allow the longest
possible supply line, install the largest
practical inner diameter hose; for most
installations, HOTSTART recommends using
a hose with a size larger inner diameter than
the pump inlet.
• Install the oil suction port as low as possible
in the oil sump. NOTICE! Avoid installing
the oil suction port in a location that may
allow debris or sediment to enter the
heating system.
• HOTSTART recommends installing a
user-supplied, swing-type or full-ow check
(non-return) valve to prevent oil owing into
the sump. Install the check valve as close to
the oil supply port as possible.
2.1.2 OIL RETURN
When installing the OXM/OGM oil return line, refer to
the following HOTSTART guidelines:
• At a minimum, size the oil return line per
the heating system outlet. NOTICE! Do not
reduce the return line inner diameter.
• Install the oil discharge port near the engine oil
pump or to the opposite end of the oil sump.
2.1.3 OIL PRESSURE RELIEF VALVE
The oil pump pressure relief valve is internal to the pump
and releases pressure from the discharge side of the
pump to the suction side of the pump at 75 psi (525 kPa).
No plumbing for this component is required.
2.2 PRESSURIZED SYSTEM
INSTALLATION
CAUTION
!
Pressure hazard: The OXM/OGM heating system is
rated for a maximum pressure of 125 psi (862 kPa).
Excessive pressure may cause unexpected release of
heated uid.
If the heating system is for use with a closed,
pressurized system, HOTSTART requires:
• Additional, user-supplied isolation valves
(such as solenoid valves) must be installed on
the oil supply and return lines to isolate the
heating system from pressure greater than
125 psi (862 kPa).
• An additional, user-supplied pressure relief
valve must be installed along the heating
system outlet plumbing. User-supplied
pressure relief valve plumbing must be
routed back to oil sump, oil tank or
atmospheric pressure. Do not route pressure
relief plumbing back to heating system tank.
See Fig. 3.
Table 1. HOTSTART recommended hose inner diameters,
line lengths and elbow counts for OXM/OGM oil supply lines.
Figure 3. OXM/OGM operation in a closed, pressured system.
When the pressurized system is active (left), solenoid valves isolate
the heating system from excessive pressure. When the system is in a
non-pressurized standby state (right), solenoid valves open.

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installation & operation manual | oxm/ogm heating system
2.3 OIL PLUMBING ILLUSTRATION
NOTE: Installation illustrations are for reference only and are not to scale. See part drawings for dimensions
and specications.
OIL RETURN
SECTION 2.1.2
OIL SUPPLY
SECTION 2.1.1
OIL
DISCHARGE
PORT
SECTION 2.1.2
OIL SUCTION
PORT
SECTION 2.1.1
ISOLATION VALVES
CHECK VALVE
(NON-RETURN)
SECTION 2.1.1

6installation & operation manual | oxm/ogm heating system
2.4 MOUNTING
CAUTION
!
Lifting hazard: Proper rigging and safety equipment
must be used to move this equipment. Do not lift
the heating system by any cords, electrical conduit
or cabling. Create a plan before attempting to move.
Proper lifting locations are identied on each system;
use these locations when lifting and mounting
the system.
Overheating hazard: When mounting the heating tank,
position the tank so that it is completely full of uid
while in operation.
NOTICE
Heating system damage: Engine vibration will
damage the heating system; isolate the heating system
from vibration. Never mount the heating system or
components directly to the engine. If the heating
system is installed using rigid pipe, use a section of
exible hose to the supply and return ports to isolate
the heating system from engine vibration.
Improper mounting hazard: Reference heating system
component drawings before mounting the system.
Unless mounted properly, the heating system will be
unstable.
2.4.1 TANK AND PUMP
Mount the heater in a horizontal orientation with the
heating tank directly below the control box and pump.
Reference drawings for mounting position. When
installing the heating system, note that the tank requires
a minimum of 37 inches (94 cm) of clearance to remove
element for maintenance. See SECTION 5.2.12.
2.5 ELECTRICAL CONNECTIONS
WARNING
!
Hazardous voltage: Before wiring, servicing or cleaning
the heating system, turn off the power and follow your
organization’s lockout and tagout procedure. Failure
to do so could allow others to turn on the power
unexpectedly, resulting in harmful or fatal electrical
shock.
Electrical hazard: All wiring shall be done by qualied
personnel in accordance with national, state and local
codes. Each system shall be grounded in accordance
with the National Electrical Code. Failure to properly
ground the system may result in electrical shock.
2.5.1 MAIN POWER SUPPLY
1. Connect the specied power from the user-
supplied circuit breaker to the terminal blocks
located in the main control box. The terminal blocks
are labeled L1,L2 and L3. See Fig. 5.
NOTE: The specied power source must be within
plus or minus 10% of the rated voltage.
NOTE: The circuit breaker must be near the
heating system and easily accessible.
HOTSTART recommends connecting the
heating system to a circuit breaker rated for
125% of the system’s maximum load.
NOTE: The main power supply operates the
heating elements and the circulating
pumps. A transformer is used to operate
the control circuit. The transformer and
control circuits are overload-protected.
2. Connect the main power ground wire to the ground
lug or ground block on the electrical panel located
inside the electrical box.
2.5.2 CUSTOMER INTERFACE
CONNECTIONS
Reference electrical schematic drawing for proper wiring
locations; the following illustrations are typical customer
interface locations. See Fig. 5.
The following customer interface connections are
available for remote control and monitoring:
BA
Figure 4. OLE/OLA underside, showing main power entrance (A)
and customer interface wiring entrance (B).

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installation & operation manual | oxm/ogm heating system
ABD
C
E
Figure 5. Main power supply and customer interface connections as
shown in the OXM/OGM control box. Reference electrical schematic
drawing for proper wiring locations; the following illustrations are
typical customer interface locations.
A. Main power ground block
B. Main power terminal block
C. Fault signal
D. Motor run signal
E. Remote On/Off
24 V DC shutdown
TB2:3
TB2:5TB2:5
TB2:1 TB2:2
TB2:4
TB2:6
K2
K5 K3
K4
24V SHUTDOWN
RUN CONTACTS
FAULT CONTACTS
11 14 21 22
1313 14
A1 A2
• TB2:1/TB2:2
Fault Signal (C)
The fault signal will indicate a heating system
shutdown, triggered by either the high-
limit temperature control relay or the motor
protection switch (see SECTION 5.1).
• TB2:3/TB2:4
Motor Run Signal (D)
A motor run signal indicates the pump motor
is running. If no signal is present, the pump
motor is not running.
• TB2:5/TB2:6
Remote On/Off 24 V DC shutdown (E)
When activated, the remote on/off
connection shuts down the heating system.
When deactivated, normal heating will
resume. Use this connection for remote
operation of the heater when the local/
off/remote switch is turned to remote.
NOTE: The 24 V DC shutdown connection is
wired NC (normally closed) from the
factory; see system wiring schematic
for directions to switch to NO (normally
open) operation.

8installation & operation manual | oxm/ogm heating system
3 SYSTEM COMPONENTS
AND OPERATION
The following is an operation description for the standard
parts located in the system.
NOTE: Parts in the control box may vary depending on
the particular system conguration purchased.
3.1 LOCAL/OFF/REMOTE
SWITCH
• local – The system is on. This mode is
independent of the remote control relay. The
local light will illuminate.
• off – The system is shut off.
• remote – The system will turn on or off via
the remote control relay. See SECTION 2.6.
The remote light will illuminate.
3.2 50%/100% SWITCH
The 50%/100% switch allows manually switching
between employing the unit’s full heating power or half
of the overall heating power when the heating system is
active. This switch can only be toggled locally.
3.3 PRIME BUTTON
Press and hold the prime button to energize the pump
motor in order to remove any air in the heating system
without energizing the elements.
3.4 OIL PRESSURE/
TEMPERATURE GAUGE
The OXM/OGM model features a temperature/pressure
gauge mounted at the outlet of the heating tank. The
gauge will indicate a pressure increase when the pump
motor is engaged by pressing the prime button or
during normal operation. The gauge will also indicate the
current uid temperature.
NOTE: Your system’s operating pressure may vary
depending on the conguration of the engine.
3.5 PRESSURE RELIEF VALVE
CAUTION
!
Pressure relief valve: If the OXM/OGM heating system
is for use with a pressurized uid system, additional,
user-supplied pressure relief must be installed along the
heating system outlet plumbing. User-supplied pressure
relief valve plumbing must be routed back to oil sump
or to atmospheric pressure. Do not route pressure relief
plumbing back to heating system tank.
The oil pump pressure relief valve is internal to the pump
and releases pressure from the discharge side of the
pump to the suction side of the pump at 75 psi (525
kPa). No plumbing for this component is required. The
pressure relief valve cap must always point toward the
inlet side of the pump. See Fig. 6.
The OXM/OGM heating system is designed to not
exceed 125 psi (862 kPa); however, the oil pump will not
exceed 75 psi (517 kPa). In the event the pressure relief
valve is activated, the pump will continue to produce
flow, but will not exceed a pressure of 75 psi (517 kPa).
3.6 MOTOR PROTECTION
SWITCH (MPS)
The motor protection switch (MPS) protects the pump
motor from overloads. See Fig. 7. The MPS will be set at
the full load amperage of the motor when shipped from
the factory. To reset the MPS, the local/off/remote
switch must be switched to off and the operator must
press the MPS reset/on button. See SECTION 5.1.
PRESSURE RELIEF
VALVE CAP
Figure 6. OXM/
OGM pump
assembly. Note that
the pressure relief
valve cap must
always point toward
the inlet side of
pump.

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installation & operation manual | oxm/ogm heating system
3.7 HIGH-LIMIT TCR
(TEMPERATURE CONTROL
RELAY)
The high-limit TCR (TCR2) is a protection device to
prevent oil overheating. The high-limit TCR uses a
resistance temperature device (RTD) located near the
tank outlet. The default setting for the high-limit TCR is
194 °F (90 °C) at 0% hysteresis and should always be at
least 18 °F (10 °C) higher than the control TCR set point.
The high-limit TCR hysteresis is not used in the high-limit
control. See Fig. 7.
3.8 CONTROL TCR
(TEMPERATURE CONTROL
RELAY)
The control TCR (TCR1) is used to control the
temperature of the oil. The control TCR uses a resistance
temperature device (RTD) to sense the temperature
of the uid as it enters the heater and will deactivate
the element when the set temperature is reached. The
standard setting for the control temperature relay (TCR1)
set point is 104 °F (40 °C) at 10% hysteresis. See Fig. 7.
Figure 7. OXM/OGM motor protection switch (above), showing
stop/off (A) and reset/on (B) buttons. To reset the MPS, the heating
system must be switched off and either the reset button or the
MPS reset/on button must be pressed.
OXM/OGM control TCR and high-limit TCR (left). The standard
setting for TCR1 control dial (C) is 104 °F (40 °C).
A
B
C
CONTROLHIGH
LIMIT
A
B
C
CONTROLHIGH
LIMIT

10 installation & operation manual | oxm/ogm heating system
4 HEATING SYSTEM
START-UP
WARNING
!
Hazardous voltage: Before wiring, servicing or cleaning
the heating system, turn off the power and follow your
organization’s lockout and tagout procedure. Failure
to do so could allow others to turn on the power
unexpectedly, resulting in harmful or fatal electrical
shock.
NOTICE
Pump damage: Do not run the motor/pump assembly
dry for more than a few seconds. Running a pump that
is not completely lled with uid will cause damage to
the pump seal.
Proper heating operation: The high-limit temperature
control relay (TCR2) must be set at least 18 °F (10 °C)
higher than the control temperature control relay (TCR1)
for proper heating operation. This will prevent nuisance
tripping of the high-limit circuit.
1. Check and tighten all electrical and plumbing
connections.
2. Ensure isolation valves are open before energizing
the system.
3. Check the pump for proper rotation. NOTICE!
Do not run the motor/pump assembly dry for
more than a few seconds.
hFor three-phase heating systems, press and hold
the prime button while observing the rotation
of the pump motor fan at the rear of the motor.
If the pump motor is not rotating in the correct
direction, switch any two electrical leads at the
main power terminal block. See SECTION 2.5.
hSingle-phase systems are prewired to ensure the
pump motor rotates in the correct direction.
4. Bleed all trapped air from the heating system by
opening a plug or pipe tting at or near the pump.
Press and hold the prime button to evacuate any
remaining air in the lines.
NOTE: When priming the pump, the pressure
gauge should indicate an increase in
pressure. Your system’s operating pressure
may vary depending on the conguration
of the engine.
5. Turn the local/off/remote switch to local or
remote to energize the heating system.
6. Once operation is satisfactory, turn the control
dial on the temperature control relay TCR1 to
the desired temperature setting for engine oil.
HOTSTART recommends a control temperature on
TCR1 of 104 °F (40 °C). The high-limit temperature
setting on TCR2 should be set at 194 °F (90 °C).
See SECTION 3.7 and SECTION 3.8.
5 MAINTENANCE,
REPAIR AND
TROUBLESHOOTING
5.1 FAULTS
The fault light will display if:
• The oil pump motor protection switch is
tripped (MPS1).
• The oil high-limit temperature is exceeded
(TCR2).
A failure in the oil pump motor that
causes the motor protection switch
(MPS1) to trip will shut down the
heating system. A fault signal will be
transmitted and the fault light will
illuminate. See Fig. 8. If this failure
occurs, the local/off/remote
switch must be switched to off and
the operator must press the MPS
reset/on button to reset the fault. (See
SECTION 3.6.)
If there is a failure that causes a high temperature to
occur, the high-limit temperature controller (TCR2) will
shut down the heating system, including the pump
motor. A fault signal will be transmitted and the fault
light will illuminate. To restart the system, the local/
off/remote switch must be switched to off and then
back to local or remote to resume operation once the
oil temperature drops below the high-limit preset (See
SECTION 3.7.)
NOTE: A high-limit fault can only occur when the
heating element is energized.
For additional troubleshooting, see SECTION 5.5.
PRIME
FAULT
LOCAL REMOTE
OFF
Figure 8. Fault
light as shown
on OXM/OGM
control box.

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installation & operation manual | oxm/ogm heating system
5.2 SYSTEM MAINTENANCE
WARNING
!
Hazardous voltage: Before wiring, servicing or
cleaning the heating system, turn off the power
and follow your organization’s lockout and tagout
procedure. Failure to do so could allow others to turn
on the power unexpectedly, resulting in harmful or
fatal electrical shock.
Instructions for the following maintenance procedures
are provided to ensure trouble-free operation of your
heating system. Replacement parts must meet or exceed
original part requirements in order to maintain the
compliance level of the original heating system.
NOTE: After maintenance is performed, refer to
SECTION 4 for system start-up procedures.
5.2.1 PLUMBING CONNECTIONS
Periodically check plumbing connections for leaks and,
if necessary, tighten connections. A loose connection on
the suction side will cause a loss of flow and cavitation in
the pump. It can also pull air into the heating tank and
cause an element failure.
5.2.2 ELECTRICAL CONNECTIONS
Vibration may cause terminals to loosen. At start-up,
tighten electrical connections. Check connections again
in a week. Tighten all electrical connections every three
months.
5.2.3 SYSTEM MOUNTING
Vibration may cause mounting bolts to loosen.
Periodically check and tighten all mounting bolts.
5.2.4 MAGNETIC CONTACTORS
Magnetic contactors are used as voltage switching
controls for motors and heating elements in HOTSTART
heating systems. The contactors use 120 volt or 240
volt coils. To test for failure, check for continuity across
the coil connections; an open or direct-short reading
indicates a failed contactor coil.
The contacts on the magnetic contactor should be
inspected periodically for welding, arc erosion and
mechanical wear. If any of these conditions exist, replace
the magnetic contactor. HOTSTART recommends
contactors be replaced every five years.
5.2.5 PUMP SEAL
Pump mechanical seals are controlled leakage devices
and are not intended to create a zero leak seal. Some
leaking from the seal is expected during normal
operation. If seal becomes worn, replacement pump
seals are available for oil pumps. To ensure pump seal
longevity, ensure the supply line does not restrict flow
excessively (see SECTION 2.1.1) and run the heating
system for 20 minutes monthly during offseason periods
(see SECTION 5.4).
NOTE: Instructions to replace the pump seals are
included with replacement seals.
5.2.6 MOTOR LUBRICATION
Motors are installed with initial lubrication. If your motor
has provisions for relubrication, refer to the motor
manufacturer for recommended relubrication schedule
intervals. For recommended lubrication type, refer to the
motor nameplate.
NOTE: New motors installed on heating systems
placed in extended storage for a year or longer
may require relubrication. See SECTION 5.4.
5.2.7 OIL PRESSURE RELIEF VALVE
The oil pump pressure relief valve is internal to the pump
and releases pressure from the discharge side of the
pump to the suction side of the pump. No maintenance
for this part is required.
5.2.8 OIL PRESSURE/TEMPERATURE
GAUGE
The oil pressure/temperature gauge will indicate a
pressure increase when the pump motor is engaged
by pressing the prime button or during normal heater
operation. The gauge will also indicate the current
temperature of the uid. No maintenance for this part is
required.
5.2.9 VOLATILE CORROSION
INHIBITOR (VCI)
A volatile corrosion inhibitor (VCI) is provided with each
control box and should be replaced once a year.
NOTE: Heating systems placed in extended storage
will require that the VCI is replaced at six month
intervals. See SECTION 5.4.

12 installation & operation manual | oxm/ogm heating system
5.2.10 TEMPERATURE CONTROL RELAY
(TCR)
WARNING
!
Hazardous voltage: Before wiring, servicing or cleaning
the heating system, turn off the power and follow your
organization’s lockout and tagout procedure. Failure
to do so could allow others to turn on the power
unexpectedly, resulting in harmful or fatal electrical
shock.
If the OXM/OGM heating system does not maintain the
desired preset control temperature or signals a high-limit
temperature fault immediately upon system start-up,
the TCR (temperature control relay), the RTD (resistance
temperature device), or the RTD cable may require
replacement. To perform this troubleshooting, you
will need:
• Ohmmeter
1. De-energize the heating system. Verify uid
is present and ow is not restricted. Check
temperature gauge to ensure the liquid in the tank
is below 122 °F (50 °C).
2. Verify the control TCR is set correctly. Verify that
high-limit TCR is set at least 18 °F (10 °C) higher
than the control TCR set point.
3. Using the ohmmeter, measure the resistance
between TCR terminals T1 and T2 (See Fig. 9):
hIf the measured resistance is between 80 and
120 ohms continue troubleshooting. Proceed
to step 4.
hIf the resistance is lower than 80 ohms or
higher than 120 ohms,contact HOTSTART
for further assistance.
4. Using the ohmmeter, test for continuity between
TCR terminals T2 and T3:
hIf there is continuity between TCR terminals
T2 and T3, the TCR, RTD and RTD cable are
functioning correctly. Close control panel.
Allow uid to cool below high-limit preset
temperature. Perform system start-up (see
SECTION 4). If fault or temperature problems
persist after start-up, contact HOTSTART for
further assistance.
hIf there is no continuity between TCR terminals
T2 and T3, locate connected RTD on the
heating tank. Unscrew the RTD plug from RTD.
See Table 2 and Fig. 10, Fig. 11 on following
page.
5. Using the ohmmeter, touch the probes to RTD
pin 1 and pin 3. See Fig. 10. Note the resistance.
Touch the probes to RTD pin 1 and pin 4 to check
for continuity:
hIf the resistance between RTD pin 1 and
pin 3 is between 80 and 120 ohms and there
is continuity between RTD pin 1 and pin 4, the
RTD is functioning properly. Replace the
RTD cable.
hIf the resistance between RTD pin 1 and pin 3
is not between 80 and 120 ohms or there is
no continuity between pin 1 and pin 4, the
RTD is malfunctioning. Replace the RTD. See
SECTION 5.2.11
PIN 1
(BROWN
WIRE)
PIN 3
(BLUE
WIRE)
PIN 4
(BLACK
WIRE)
A
B
CONTROLHIGH
LIMIT
TCR TYPE RTD Position
TCR1 Oil Control 40 °C Tank Inlet
TCR2 Oil High-limit 90 °C Tank Outlet
Table 2. TCR types, default temperature settings and
corresponding RTD positions.
Figure 9. Control (TCR1) and
high-limit (TCR2) TCR showing
terminals T1, T2 and T3.
Figure 10. RTD pins 1, 3 and 4. The resistance
between pin 1 and pin 3 should measure between
80 and 120 ohms. There should be continuity
between pin 1 and pin 4.

13
installation & operation manual | oxm/ogm heating system
5.2.11 RESISTANCE TEMPERATURE
DEVICE (RTD)
WARNING
!
Hazardous voltage: Before wiring, servicing or cleaning
the heating system, turn off the power and follow your
organization’s lockout and tagout procedure. Failure
to do so could allow others to turn on the power
unexpectedly, resulting in harmful or fatal electrical
shock.
High-limit or control resistance temperature devices
(RTDs) sense temperature to either control uid
temperature or protect the system and uid from
overheating. To replace a resistance temperature device
(RTD), use the following procedures.
NOTE: Before removing and replacing an RTD, ensure
the RTD is malfunctioning. See SECTION
5.2.10.
1. De-energize the heating system. Allow uid to cool.
2. Close isolation valves. Drain uid from the oil
heating tank. Locate the RTD that requires
replacement. See Fig. 11.
3. Unscrew RTD plug. Remove plug. See Fig. 12.
4. Unscrew RTD from tank.
5. Screw replacement RTD to tank. When tightening,
ensure plug is aligned with notch toward top of
tank. See Fig. 13.
6. Fit RTD plug to RTD. Ensure plug is aligned
correctly with notch. Push plug in rmly. Screw RTD
plug to RTD to secure in place.
7. To ensure proper installation and temperature
regulation, re-energize and operate heating
system. Refer to SECTION 4 for system start-up
procedures.
A B
RTD PLUG
Figure 11. OXM/OGM high-limit RTD (A) and control RTD (B).
Figure 12. RTDs shown removed from tank
assembly. Unscrew plug and remove to
disconnect RTD prior to removal.
Figure 13. Proper RTD orientation.
Note the notch centered at the top
of the RTD connection.

14 installation & operation manual | oxm/ogm heating system
5.2.12 HEATING TANK/ELEMENT
WARNING
!
Hazardous voltage: Before wiring, servicing or cleaning
the heating system, turn off the power and follow your
organization’s lockout and tagout procedure. Failure
to do so could allow others to turn on the power
unexpectedly, resulting in harmful or fatal electrical
shock.
At least once per year, clean the interior of the heating
tank and the heating element with a wire brush and/or
damp cloth. Periodically check the sediment build-up
around the element loops. Any scaling or build-up will
shorten element life.
To replace the heating element or perform routine
maintenance, use the following procedures. See Fig. 15.
1. De-energize the heating system. Allow uid to cool.
2. Close isolation valves.
3. Drain the uid from the heating tank (F).
4. Open heating element assembly (B) cover.
5. The wire connections inside the enclosure
correspond to one of the phase congurations
shown on the following page. Note your unit’s
phase conguration. See Fig. 17.
NOTE: Replacement elements may be a different
phase conguration.
6. Disconnect the ground (green/yellow) and power
electrical wires from the posts inside the cap.
7. Unscrew cable gland (G) from heating element
assembly (B). See Fig. 16. Remove electrical cable
and wires from the heating element.
8. Unscrew heating element assembly bolts (A).
Detach heating element assembly (B) from heating
tank ange (D). Remove assembly and heating
elements (E) from tank (F).
9. Replace the heating elements (E) or perform the
necessary cleaning procedure. Ensure heating
element gasket (C) is in place.
5.2.13 REASSEMBLY OF HEATING
ELEMENT AND TANK
To reassemble the heating element and tank, follow the
steps listed in SECTION 5.2.12 in reverse order. Make
sure the ground and power electrical wires are properly
reconnected using the provided washers, cup washers
and nuts. Tighten heating assembly bolts (A) uniformly,
using pattern shown. See Fig. 14. Tighten bolts to snug-
tight plus 30°rotation, or 200 lbf · ft (271 N · m)
1
2
3
45
6
7
8
Figure 14. Heating assembly
bolts, showing recommended
tightening pattern.