Mr. Heater MHU 80, MHU 50 User Manual

OPERATING INSTRUCTIONS

Model #

AND OWNER’S MANUAL

READ INSTRUCTIONS CAREFULLY: Read and follow all instructions. Place instructions in a safe

place for future reference. Do not allow anyone who has not read these instructions to assemble, light, adjust or operate the heater.

For model serial numbers, see page E16.

LANGUAGES

ENGLISH

Pages E1 — E16

SPANISH

Pages S1 — S16

COMPACT UNIT HEATER FOR COMMERCIAL USE COMPACT UTILITY HEATER FOR RESIDENTIAL USE

FRENCH

Pages F1 — F16

MHU 50 MHU 80

WARNING: Improper installation, adjustment, alteration, service or maintenance

can cause injury or property damage. Refer to this manual. For assistance or additional information consult a qualified installer, service agency or the gas supplier.

—

WHAT TO DO IF YOU SMELL GAS

• Open Windows

• DO NOT try to light any appliance.

• DO NOT use electrical switches.

• DO NOT use any telephone in your house. Immediately call your local gas supplier from a

neighbor’s telephone. Follow the gas supplier’s instructions.

• Do not touch any electrical switch; do not use any phone in your building.

• Installation and service must be performed by a qualified installer, service agency or the gas supplier.

• If you cannot reach your gas supplier, call the Fire Department.

FOR YOUR SAFETY: Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.

WARNING: If the information in these instructions are not followed exactly, a fire or explosion may result causing property damage, personal injury or loss of life.

02/12 Rev. 12A #60185MR. HEATER, INC., 4560 W. 160TH ST., CLEVELAND, OHIO 44135 •800-251-0001

WARNING:

YOUR SAFETY IS IMPORTANT TO YOU AND TO OTHERS,

SO PLEASE READ THESE INSTRUCTIONS BEFORE YOU OPERATE THIS HEATER.

GENERAL HAZARD WARNING:

FAILURE TO COMPLY WITH THE PRECAUTIONS AND

INSTRUCTIONS PROVIDED WITH THIS HEATER, CAN RESULT IN DEATH, SERIOUS BODILY INJURY AND PROPERTY LOSS OR DAMAGE FROM HAZARDS OF FIRE, EXPLOSION, BURN, ASPHYXIATION, CARBON MONOXIDE POISONING, AND/OR ELECTRICAL SHOCK.

ONLY PERSONS WHO CAN UNDERSTAND AND FOLLOW

THE INSTRUCTIONS SHOULD USE OR SERVICE THIS HEATER.

IF YOU NEED ASSISTANCE OR HEATER INFORMATION

SUCH AS AN INSTRUCTION MANUAL, LABELS, ETC. CONTACT THE MANUFACTURER.

THE STATE OF CALIFORNIA REQUIRES THE FOLLOWING WARNINGS:

WARNING:

FIRE, BURN, INHALATION, AND EXPLOSION HAZARD.

KEEP SOLID COMBUSTIBLES, SUCH AS BUILDING MATERIALS, PAPER OR CARDBOARD, A SAFE DISTANCE AWAY FROM THE HEATER AS RECOMMENDED BY THE INSTRUCTIONS NEVER USE THE HEATER IN SPACES WHICH DO OR MAY CONTAIN VOLATILE OR AIRBORNE COMBUSTIBLES, OR PRODUCTS SUCH AS GASOLINE, SOLVENTS, PAINT THINNER, DUST PARTICLES OR UNKNOWN CHEMICALS.

WARNING: Combustion by-products produced when using this product contain carbon monoxide, a chemical

known to the State of California to cause cancer and birth defects (or other reproductive harm).

WARNING: This product contains chemicals, including lead, known to the State of California to cause cancer and

birth defects or other reproductive harm. Wash your hands after handling.

CONTENTS

UNIT DIMENSIONS ................................................................E-4

SHIPPING ...............................................................................E-5

REQUIREMENTS .....................................................................E-5

UNIT HEATER INSTALLATION..................................................E-6

COMBUSTION & VENTILATION AIR ........................................E-6

VENTING .......................................................................... E-6-10

ELECTRICAL CONNECTIONS ................................................. E-10

GAS CONNECTION ...............................................................E-11

LEAK CHECK .........................................................................E-11

START-UP OPERATION ...........................................................E-11

HEATING SEQUENCE OF OPERATION ................................... E-12

IGNITION CONTROL LED ...................................................... E-12

ADJUSTMENTS..................................................................... E-12

SERVICE ............................................................................... E-13

WIRING DIAGRAM ............................................................... E-13

PARTS LIST ........................................................................... E-14

WARRANTY ......................................................................... E-16

Compact Unit / Utility Heater Operating Instructions and Owner’s Manual

E-2

AIR

FLOW

HEAT EXCHANGER

(ALUMINIZED STEEL)

HANGING BRACKETS

MHU 50/MHU 80 UNIT DIMENSIONS

(N-NATURAL GAS, P-PROPANE)

MOUNTING SLOTS (Typical) 5/16 x 3 Inches (8 x 76 mm)

DIMENSION 50 80

A 12 (305) 17 (432)

B 5-1/2 (140) 6-1/2 (165)

C 4-1/4 (108) 6-3/4 (171)

TOP VIEW

START–UP AND PERFORMANCE CHECK LIST

Job Name: __________________________________________ Job Location: ________________________________________ Installer: ____________________________________________ Unit Model No.: ______________________________________ Electrical Connections Tight? _______________________________________________ Supply Voltage ___________________________________________________________ Gas Piping Connections Tight & Leak-Tested? __________________________________ Motor Amps _____________________________________________________________ Furnace Btu Input ________________________________________________________ Line Pressure ____________________________________________________________ Manifold Pressure w.c. ____________________________________________________

Job No.: ______________________________________ City: _________________________________________ City: _________________________________________ Serial No.:_____________________________________

HANGING

BRACKETS (2)

ADJUSTABLE

SERVICE

ACCESS PANEL

LOUVERS

SIDE VIEW

Date: _______________________________________ State/Province: _______________________________ State/Province: _______________________________ Service Technician: ____________________________

Flue Connections Tight? __________________________________________________ Fan Timer Operation Checked? _____________________________________________ THERMOSTAT Calibrated? _____________________________________________________________ Heat Anticipator Properly Set? Level? _________________________________________________________________

E-3

Operating Instructions and Owner’s ManualCompact Unit / Utility Heater

SHIPPING

The heater is completely assembled. Installation instructions, two mounting brackets (shipped loose), and a flue transition are included. Check the unit for shipping damage. The receiving party should contact the last carrier immediately if any shipping damage is found.

REQUIREMENTS – CSA IN THE USA

Installation of gas unit heaters must conform with local building codes or, in the absence of local codes, with the current National Fuel Gas Code ANSI Z223.1.

Installation in aircraft hangers must be in accordance with the current Standard for Aircraft Hangers ANSI/NFPA No. 409.

Installation in parking structures must be in accordance with the current Standard for Parking Structures ANSI/NFPA No. 88A.

Installation in repair garages must be in accordance with the current Standard for Repair Garages ANSI/NFPA No. 88B.

These units are approved for residential applications. For installation in a residential garage these units must be installed so that the bottom of the heater is located no less than 8 feet (2.438m) above floor. Heater must be located or protected to avoid physical damage by vehicles. Refer to the National Fuel Gas Code, ANSI Z223.1, current edition.

Authorities having jurisdiction should be consulted before NFPA installation. Air for combustion and ventilation must conform to the methods outlined in ANSI Z223.1, section 5.3, Air for Combustion and Ventilation, or applicable provisions of local building codes. The National Fuel Gas Code is available from:

American National Standard Institute Inc. 11 West 42nd Street New York, NY 10036

These units are CSA International design certified. These unit heaters are certified for installation to combustible material as listed in table 1 and on unit rating plate. Accessibility and service clearances must be observed in addition to fire protection clearances.

All electrical wiring and ground for unit must be in accordance with the regulations of the current National Electric Code ANSI/ No. 70.

The National Electric Code is available from:

National Fire Protection Association 1 Batterymarch Park PO Box 9101 Quincy, MA 02269-9101

TABLE 1

UNIT CLEARANCES

Top Sides Access Panel

in mm in mm in mm

1 25 1 25 18 457

Bottom Rear Single Wall Vent* in mm in mm in mm

0 0 18 456 6 152

*Except for listed clearance thimbles.

REQUIREMENTS – CSA IN CANADA

The instructions are intended only as a general guide and do not supersede local codes in any way. Authorities having jurisdiction should be consulted before installation. The installation must conform with local building codes or in the absence of local codes, with the current CSA B149.1, Natural Gas and Propane Installation Code. All electrical wiring and grounding for the unit must also comply with the Canadian Electrical Code CSA C22.1, current edition.

These heaters are CSA International certified for the clearances to combustible material listed on the rating plate and table1. Provide adequate clearance around air openings into the combustion chamber, clearances from combustible material, and provisions for accessibility and for combustion and ventilation air supply. Provision shall be made for service accessibility to the heater. Note that fire protection clearances may be exceeded to provide additional space for service and accessibility.

GARAGE INSTALLATIONS:

Installation in parking structures must be in accordance with the current Standard for Parking Structures ANSI/NFPA No. 88A.

Installation in repair garages must be in accordance with the current Standard for Repair Garages ANSI/NFPA No. 88B.

1. In a storage area, clearance from heaters to combustible materials must be such that the material shall not attain a temperature above 160°F by continuous operation of the unit.

2. Eight foot minimum clearance from the floor to the bottom of the heater must be maintained. Refer to the CSA B149.1, Natural Gas and Propane Installation Code

AIRCRAFT HANGER:

Installation of gas unit heaters must conform with local building codes or, in the absence of local codes, with the current National Fuel Gas Code ANSI Z223.1.

1. In an area where aircraft are housed or serviced, 10’ minimum clearance from highest surface of aircraft to bottom of the heater must be maintained.

2. In other areas, 8’ minimum clearance from the floor to bottom of heater must be maintained.

3. Heaters should be located so as to be protected from damage from aircraft or other appliances needed for servicing of aircraft. Refer to requirements of the enforcing authorities.

Compact Unit / Utility Heater Operating Instructions and Owner’s Manual

E-4

These units are certified for residential applications. For installation in a residential garage, these units must be installed so that burners and ignition source are located no less than 18” (457mm) above floor. Heater must be located or protected to avoid physical damage by vehicles. Refer to CSA B149.1, Natural Gas and Propane Installation Code current edition.

In a confined area, the heater must be installed in accordance with the CSA B149.1, Natural Gas and Propane Installation Code. Be sure to check with local codes and ordinances for additional requirements.

UNIT HEATER INSTALLATION

Unit is shipped ready for installation. Unit may be installed as shown in figure 1 or inverted 180 as governed by clearances, vent connection, air direction, gas supply, electrical supply and service accessibility.

1. If installing unit in an inverted position: Remove and retain screws securing door and rotate door 180 retained screws. Rotate louvers directing airflow as desired.

2. Choose location for mounting brackets.

3. Remove and retain three screws along top edge (bottom edge when inverted) of front of unit.

4. Align screw holes on mounting bracket with holes along top edge (either upright or inverted) of unit. Secure one mounting bracket to front of unit with retained screws. Secure other mounting bracket to back of unit with screws provided in bag assembly containing flue transition.

5. To support unit, secure mounting bracket to ceiling joist or truss. Unit may also hang on rods as shown in figure 1.

INSTALL UNIT / UTILITY HEATER

MOUNTING

BRACKETS (2)

depending on desired location

. Secure with

FIGURE 1

SUPPORT

RODS

Gas Code, ANSI Z223.1, in the U.S.A., CSA B149.1 Natural Gas and Propane Installation Code, or applicable provisions of local building codes.

All gas fired appliances require air to be used for the combustion process. In many buildings today, there is a negative indoor air pressure caused by exhaust fans, etc. If sufficient quantities of combustion air are not available, the heater or another appliance will operate in an inefficient manner, resulting in incomplete combustion which can result in the production of excessive carbon monoxide.

CAUTION Insufficient combustion air can cause headaches, nausea, dizziness, asphyxiation or death.

If indoor air is to be used for combustion, it must be free of the following substances or the life of the heat exchanger will be adversely affected: chlorine, carbon tetrachloride, cleaning solvent, halogen refrigerants, acids, cements and glues, printing inks, fluorides, paint removers, varnishes, or any other corrosives.

VENTING

A – GENERAL RECOMMENDATIONS AND REQUIREMENTS

NOTE: The vent is a passageway, vertical or nearly so, used to

convey flue gases from an appliance, or its vent connector, to the outside atmosphere. The vent connector is the pipe or duct that connects a fuel-gas burning appliance to a vent or chimney.

Unit heaters must be vented in compliance with all local codes or requirements of the local utility, the current standards of the (American) National Fuel Gas Code, ANSI Z223.1 or (Canada) CSA B149.1 Natural Gas and Propane Installation Code, and the following instructions.

A metal stamped/extruded transition is supplied with this certified unit. It must not be modified or altered and must be installed on the outlet of the induced draft blower assembly prior to the installation of the vent or vent connector. Failure to comply with this requirement will void the certification of the unit by the approval agencies. All joints shall be secured with at least two corrosion resistant screws. All joints must be checked for gas tightness after installation.

COMBUSTION AND VENTILATION AIR

Adequate facilities for supplying air for combustion and ventilation must be provided in accordance with the latest edition of section

5.3, Air for Combustion and Ventilation, of the National Fuel

TABLE 2

MAXIMUM VENT LENGTHS

HORIZONTAL VENTS

No. of ft m Elbows

1 25 7.6

2 20 6.1

3 15 4.6

4 10 3.0

5 5 1.5

Maximum length of vent connector not to exceed 30 ft. (9.1m).

Operating Instructions and Owner’s ManualCompact Unit / Utility Heater

E-5

B – VERTICAL VENTS USING METAL VENT

VENT TERMINATION ON SINGLE WALL VENT

SINGLE WALL TERMINATION

DOUBLE WALL (TYPE B-1) TERMINATION

ROOF FLASHING

ROOF PITCHED

FROM 0” TO 45”

SHALL NOT BE A

CONCEALED SPACE

2” CLEARANCE

THIMBLE

ROOF FLASHING

ROOF PITCHED

FROM 0” TO 45”

12” MAX

CLEARANCE TO BE AS

SPECIFIED ON TYPE “B”

VENT PIPE

SEAL JOINT BETWEEN SINGLE WALL VENT

AND “B”VENT AND THE ANNUL AR SPACE OF THE “B” VENT

PIPE – COMMERCIAL AND RESIDENTIAL INSTALLATIONS

HSU compact unit heaters are listed as Category I appliances for vertical vent installations.

1. HSU unit heaters are to be used with NFPA- or ANSI-approved chimneys, U.L. listed type B-1 gas vents, single wall metal pipe, or listed chimney lining system for gas venting where applicable, as well as the modifications and limitations listed in figure 2. Seal single wall vent material according to the section A - General Recommendations and Requirements.

2. The vent connector shall be 3” (76mm) diameter on 50 units. In all cases, a flue transition piece (supplied) is required to fit over the outlet of the induced draft assembly on the appliance.

3. Keep the vent connector runs as short as possible with a minimum number of elbows. Refer to the (American) National Fuel Gas Code ANSI Z223.1 or (Canada) CSA B149.1 Natural Gas and Propane Installation Code for maximum vent and vent connector lengths. Horizontal run of the vent connector from the induced draft blower to the chimney/vent cannot exceed the values in table 2.

4. When the length of a single wall vent, including elbows, exceeds 5 feet (1.5m), the vent shall be insulated along its entire length with a minimum of 1/2” thick foil faced fiberglass 1-1/2# density insulation. If a single wall vent is used in an unheated area it shall be insulated. Failure to do so will result in condensation of flue gases.

5. The unit may be vented vertically as a single appliance or as a common vent with other gas-fired appliances. In common venting situations, vent connectors for other appliances must maintain a 4” (100mm) vertical separation between the vent connectors. Refer to common venting tables in the (American) National Fuel Gas Code ANSI Z223.1 or (Canada) CSA B149.1 Natural Gas and Propane Installation Code for proper vent size.

6. Clearance to combustible material is 6” (152mm) for single wall vent material except where a listed clearance thimble is used. Clearance to combustible material for type B-1 vent or factory-built chimney is per manufacturer’s instructions.

7. The vent connector shall be supported without any dips or sags. Vertical vents shall be supported in accordance with their listing and manufacturers’ instructions. All horizontal vent connector runs shall have a slope up to the vertical vent of at least 1/4” per foot (1mm per 50mm).

8. All vertical type B-1 vents, single wall vents, or listed chimney lining system must be terminated with a listed vent cap or listed roof assembly.

9. The vent must extend at least 3’ (1m) above the highest point where it passes through a roof of a building and at least 2’ (0.6m) higher than any part of a building within a horizontal distance of 10’ (3.05m) unless otherwise specified by the (American) National Fuel Gas Code, ANSI Z223.1 or (Canada) CAN/CGA-B149 Installation Code. The vent must extend at least 5’ (1.6m) above the highest connected equipment flue collar.

Compact Unit / Utility Heater Operating Instructions and Owner’s Manual

FIGURE 2

C – HORIZONTAL VENTING – GENERAL

Due to changes to Z83-8 2009 CSA2.6-2009, the use of single wall B-Vent is no longer permitted as an acceptable material when venting horizontally, this change covers both residential and commercial installations. All horizontally vented units manufactured after July of 2011 must be vented as a Caterory III Unit/Utility Heater in compliance with UL 1738 & ULS636. Common venting is not allowed when horizontally venting the unit heater.

The minimum horizontal vent length is three feet (914mm).

1. If possible, do not terminate the horizontal vent through a wall that is exposed to prevailing wind. Exposure to excessive winds can affect unit performance.

2. Vent termination must be free from obstructions and at least 12” (306mm) above grade level and maximum snow height.

3. Do not terminate vent directly below roof eaves or above a walkway, or any other area where condensate dripping may be troublesome and may cause some staining. Avoid windows where steam may cause fogging or ice buildup.

4. When horizontally vented, minimum clearance for termination from any door, window, gravity air inlet, gas or electric meter, regulators, and relief equipment is 4 ft. (1.2m) for U.S. installations. Refer to NFPA 54/ANSI Z223.1 in the U.S.A. and CSA B149.1 Natural Gas and Propane Installation Code and .2 in Canada or with authorities having local jurisdiction. In Canada, vent termination must have a minimum 6 ft. (1.8 m) horizontal clearance from gas and electric meters and relief devices as specified in the Canadian B149.1, Natural Gas Installation Code.

E-6

5. Vent termination must be a minimum of 4’ (1.2m) below or 4’ (1.2m) horizontally from any soffit vent or under-eave vent.

6. Vent must be a minimum of 6’ from an inside corner formed by two exterior walls. If possible, leave a 10’ clearance.

7. Vent termination must be a minimum of 10’ (3m) from any forced air inlet (includes fresh air inlet for other appliances, such as a dryer).

8. When termination is routed through an exterior combustible wall the vent must be supported using a listed clearance thimble. Seal the connection between the single wall and double wall pipes and the annular space of the double wall pipe as shown in figure 2. Inside edge of vent termination tee must be at least 12 inches from outside wall as shown in

figure 3.

9. For horizontal venting, the vent pipe shall be supported with hangers no more than 3ft. (1m) apart to prevent movement after installation.

D – HORIZONTAL VENTING – COMMERCIAL

1. Horizontal commercial installations are for buildings which are not attached to living spaces. The vent may be single wall vent material installed according to the sections

Venting A - General Recommendations and

Requirements and C - Horizontal Venting General and D - Horizontal Venting - Commercial. Refer to figure 3.

2. The vent pipe diameter for horizontal commercial installations shall be 4” (76mm) on 50 units. In all cases, a flue transition piece (supplied) is required to fit over the outlet of the induced draft assembly on the appliance.

3. Refer to table 2 for maximum vent connector lengths.

4. Select a wall termination point that will maintain ¼” rise per foot slope of horizontal run of vent pipe.

5. For upward sloped vent a condensate tee and drain must be installed within the first 5’ (1.5m) from the unit heater to protect the appliance. If a flexible condensate drain line is used, the drain line must include a loop entering the structure. If the unit is shut down for an extended period of time and will be exposed to sub-freezing temperatures, the condensate may freeze.

E – HORIZONTAL VENTING – RESIDENTIAL

1. For horizontal residential installations these units are certified as Category III appliances. Venting A - General

Recommendations and Requirements and C - Horizontal Venting General and E - Horizontal Venting - Residential.

Refer to figure 6.

2. The vent pipe diameter for horizontal residential installations shall be 4” (100mm) on 50 and 80 units. A standard vent transition is required at unit in addition to the transition supplied with the unit.

3. The maximum vent length is 5’ (1.5m) plus one 90-degree elbow. The minimum length is 3’(.91m).

4. The vent must maintain a ¼” rise per foot of slope upwards toward the termination.

CONDENSATE DRAIN THROUGH TEE PIPE AND DRAIN LOOP

UPWARD SLOPE ON HORIZONTAL VENT-COMMERCIAL INSTALLATION

CATEGORY III VENT ACCORDING TO THESE INSTALLATION INSTRUCTIONS.

SLOPE: + 1/4 INCH FOR 1 FOOT RUN MINIMUM.

INDUCED DRAFT BLOWER

NOTE - MINIMUM HORIZONTAL LENGTH 3 FT. (914MM), NOT INCLUDING CAP FOR TERMINATION. REFER TO TABLE 2 FOR MAXIMUM LENGTH AND NUMBER OF ELBOWS.

COMMON VENTING NOT ALLOWED WHEN HORIZONTALLY VENTING THE UNIT / UTILITY HEATER

FLUE TRANSITION

(PROVIDED)

LISTED THIMBLE

THROUGH COMBUSTIBLE

WALL

DRAIN LOOP WITH WATER

TRAP (TO CONDENSATE DRAIN)

FIGURE 3

12 INCHES MIN.

(30.5 CM)

EXHAUST VENT

TERMINATION TEE

12” (30.5 CM)

MINIMUM ABOVE ALL

HIGHEST SNOWFALL

E-7

Operating Instructions and Owner’s ManualCompact Unit / Utility Heater

INDUCED DRAFT BLOWER

CATEGORY III VENT ACCORDING TO THESE INSTALLATION INSTRUCTIONS. SLOPED: + 1/4 INCH FOR 1 FOOT RUN MINIMUM.

NOTE - MINIMUM HORIZONTAL LENGTH 3FT. (914MM), NOT INCLUDING CAP FOR TERMINATION.

MAXIMUM HORIZONTAL LENGTH 5FT. (1.5M) PLUS ONE 90-DEGREE ELBOW.

COMMON VENTING NOT ALLOWED WHEN HORIZONTALLY VENTING THE UNIT / UTILITY HEATER.

HORIZONTAL VENTING - RESIDENTIAL INSTALLATION

FLUE TRANSITION

(PROVIDED)

UPWARD SLOPE

12 INCHES

MIN. (30.5CM)

VENT TERMINATION CAP

LISTED THIMBLE THROUGH

COMBUSTION WALL

FIGURE 6

F – VENTING USING A MASONRY CHIMNEY

The following additional requirements apply when a lined masonry chimney is being used to vent the compact unit / utility heater.

1. Masonry chimneys used to vent Category I units heaters must be either tile-lined or lined with a listed metal lining system or dedicated gas vent. Unlined masonry chimneys are prohibited. A category I appliance must never be connected to a chimney that is servicing a solid fuel appliance. If a fireplace chimney flue is used to vent this appliance, the fireplace opening must be permanently sealed.

2. A fan assisted unit heater may be commonly vented into an existing lined masonry chimney provided:

• The chimney is currently serving at least one draft-hood

equipped appliance.

• The vent connector and chimney are sized in accordance

with venting tables in the (American) National Fuel Gas Code ANSI Z223.1 or (Canada) CSA B149.1 Natural Gas and Propane Installation Code.

IMPORTANT Single appliance venting of a fan assisted unit heater into a tile lined masonry chimney (interior or outside wall) is prohibited. The chimney must first be lined with either type B-1 vent or an insulated single wall flexible vent lining system, sized in accordance with venting tables in the (American) National Fuel Gas Code ANSI Z223.1 or (Canada) CSA B149.1 Natural Gas and Propane Installation Code.

3. A type B-1 vent or masonry chimney liner shall terminate above the roof surface with a listed cap or a listed roof assembly in accordance with the terms of their respective listings and the vent manufacturer’s instructions.

4. Do not install a manual damper, barometric draft regulator, or flue restrictor between the unit heater and the chimney.

5. If type B-1 double-wall vent is used inside a chimney, no other appliance can be vented into the chimney. Outer wall of type B-1 vent pipe must not be exposed to flue products.

6. Insulation for the flexible vent pipe must be an encapsulated fiberglass sleeve recommended by the flexible vent pipe manufacturer.

7. The space between liner and chimney wall should NOT be insulated with puffed mica or any other loose granular insulating material.

8. If type B-1 vent or an insulated flexible vent pipe cannot be used as liners, the chimney must be rebuilt to accommodate one of these methods or some alternate approved method must be found to vent the appliance. When inspection reveals that an existing chimney is not safe for the intended purpose, it shall be rebuilt to conform to nationally recognized standards, lined or relined with suitable materials or replaced with a gas vent or chimney suitable for venting unit heaters. The chimney passageway must be checked periodically to ensure that it is clear and free of obstructions.

G – REMOVAL OF UNIT FROM COMMON VENT

In the event that an existing unit heater is removed from a venting system commonly run with separate gas appliances, the venting system is likely to be too large to properly vent the remaining attached appliances. The following test should be conducted while each appliance is in operation and the other appliances are not in operation, yet remain connected to the common venting system. If the venting system has been installed improperly, the system must be corrected.

1. Seal any unused openings in the common venting system.

2. Visually inspect the venting system for proper size and horizontal pitch. Determine there is no blockage or restriction, leakage, corrosion, or other deficiencies which could cause an unsafe condition.

3. If practical close all building doors and windows and all doors between the space in which the appliances remaining connected to the common venting system are located and other spaces of the building. Turn on clothes dryers and any appliances not connected to the common venting system. Turn on any exhaust fans, such as range hoods and bathroom exhausts, so they will operate at maximum speed. Do not operate a summer exhaust fan. Close fireplace dampers.

4. Follow the lighting instructions. Place the appliance being inspected in operation. Adjust thermostat so appliance will operate continuously.

Compact Unit / Utility Heater Operating Instructions and Owner’s Manual

E-8

LINE VOLTAGE FIELD WIRING

EQUIPMENT GROUND

BLACK WIRE WITH WHITE TAPE OR

WHITE WIRE WITHOUT TAPE

FIGURE 7

GAS SUPPLY CONNECTION

GROUNDED

JOINT UNION

DRIP LEG

FIGURE 8

GAS SUPPLY TO UNIT HEATER

MANUAL MAIN SHUT-OFF VALVE

WILL NOT HOLD NORMAL TEST

PRESSURE

UNIT

BLACK

WHITE

MANUAL

MAIN SHUT-OFF VALVE

(FURNISHED BY INSTALLER)

GAS FLOW

ISOLATE

GAS VALVE

5. Test for spillage at the draft hood relief opening after five

minutes of main burner operation. Use the flame of a match or candle, or smoke from a cigarette, cigar, or pipe.

6. After it has been determined that each appliance remaining

connected to the common venting system properly vents when tested as outlined above, return doors, windows, exhaust fans, fireplace dampers and any other gas-burning appliance to their previous condition of use.

7. If improper venting is observed during any of the above

tests, the common venting system must be corrected. The common venting system should be resized to approach the minimum size as determined by using the appropriate tables in Appendix G in the current standards of the National Fuel Gas Code, ANSI Z223-1 in the U.S.A. and the appropriate Category I Natural Gas and Propane appliances venting sizing tables in the current standards of the CSA B149.1 Natural Gas and Propane Installation Code in Canada.

NOTE Local codes may supersede any of the above provisions.

ELECTRICAL CONNECTIONS

NOTE The MHU series unit heaters use a direct spark ignition

NOTE: The MHU/HSU series unit/utility heaters use a direct spark

system. There is no pilot necessary as the spark lights the

ignition system. There is no pilot necessary as the spark lights main burner as the gas valve is turned on. The direct spark

the main burner as the gas valve is turned on. The direct spark ignition control board emits radio noise during burner ignition. The level of energy may be enough to disturb a logic circuit in a microprocessor controlled thermostat. It is recommended that an isolation relay be used when connecting the unit heater to a microprocessor controlled thermostat. Select circuit protection and wire size according to the unit rating plate. Install a separate disconnect switch (protected by either fuse or circuit breaker) near the unit so that power can be turned off for servicing. Remove electrical junction box cover and connect wiring through knockout on the junction box located on the side of the heater. Refer to heater wiring diagram for connection information. Use 18 gauge wire or larger for line power connections. Make sure to connect line power to wires located in the external electrical junction box behind junction box cover. DO NOT CONNECT LINE POWER TO

THERMOSTAT TERMINAL STRIP ON OUTSIDE OF HEATER.

Electrically ground the unit in accordance with local codes or in the absence of local codes, in accordance with the current National Electrical Code (ANSI/NFPA No. 70) in the USA, and in Canada with the current Canadian Electrical Code, Part 1 CSA C22.1

NOTE: Un-insulated ground wire must be warped in electrical tape to avoid damage to the electrical system.

Make line voltage connections as shown in figure 7. Connect field wiring as shown on wiring diagram on unit. Also, refer to typical diagram in this manual.

An additional thermostat wire must be run to terminal g on heater when continuous blower is desired. Thermostat (optional). See wiring schematic on pager E-13.

CAP

UNIT HEATER

FIGURE 9

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Operating Instructions and Owner’s ManualCompact Unit / Utility Heater

ignition control board emits radio noise as the sparking process

WARNING

is underway. The level of energy may be sufficient to disturb a logic circuit in a microprocessor controlled thermostat. It is recommended that an isolation relay be used when connecting the unit heaters to a microprocessor controlled thermostat. Install the thermostat according to instructions provided. Select circuit protection and wire size according to the unit rating plate. Install a separate disconnect switch (protected by either fuse or

WARNING

circuit breaker) near the unit so that power can be turned off for servicing. Connect wiring through knockout on the junction box located on the side of the unit heater. Refer to heater wiring diagram for connection information. Use 18 gauge wire or larger for thermostat connections.

Electrically ground unit in accordance with local codes or, in the

WARNING

absence of local codes, in accordance with the current National Electrical Code (ANSI/NFPA No. 70) in the U.S.A., and in Canada with the current Canadian Electrical Code, Part 1 CSA C22.1.

NOTE Un-insulated ground wires must be wrapped in electrical tape to avoid damage to the electrical system.

WARNING

Make line voltage connections as shown in figure 7. Connect field wiring as shown on wiring diagram on unit. Also refer to typical diagram in this manual. An additional thermostat wire must be run to terminal “G” on heater when continuous blower is desired.

Electric shock hazard. Can cause injury or death. Do not use this heater if any part has been under water. Immediately call a qualified service technician to inspect the furnace and to replace any part of the control system and any gas control which has been under water.

Danger of explosion. Can cause injury or product or property damage. If over-heating occurs or if gas supply fails to shut off, shut off the manual gas valve to the appliance before shutting off electrical supply.

Electric shock hazard. Can cause injury or death. Before attempting to perform any service or maintenance, turn the electrical power to unit OFF at disconnect switch(es). Unit may have multiple power supplies.

Danger of explosion and fire. Can cause injury or product or property damage. You must follow these instructions exactly.

GAS CONNECTION

When connecting gas supply lines, the length of the piping run from the meter to must be considered in determining the pipe size

When connecting gas supply, the length of the run from the to avoid excessive pressure drop. A line pressure of 7” WC (178mm

meter must be considered in determining the pipe size to avoid WC) for natural gas should be maintained when sizing the piping. excessive pressure drop. A line pressure of 7” w.c. (178mm w.c.) A line pressure of 13” WC (330mm WC) should be maintained for natural gas should be maintained when sizing piping. A line

for propane (LP) gas. For correct sizing of piping, refer to the pressure of 13” w.c. (330mm w.c.) should be maintained for

(American) National Fuel Gas Code ANSI Z223.1, or (Canada) CSA liquefied petroleum (LP) gas. For correct sizing of piping, refer to

B149.1, National Gas and Propane Installation Code or consult the the (American) National Fuel Gas Code ANSI Z223.1 or (Canada)

utility having jurisdiction. CSA B149.1, Natural Gas and Propane Installation Code or consult

WARNING: TO PREVENT HEATER DAMAGE.

the utility having jurisdiction.

WHEN USING A PROPANE TANK TO SUPPLY

A drip leg should be installed in the vertical pipe run to the unit.

HEATER, A MINIMUM 11”W.C. LOW PRESSURE

In some localities, codes may require that a manual main shutoff

REGULATOR TO A MAXIMUM 14”W.C. LOW PRESSURE

valve and union (furnished by installer) be installed external to the

REGULATOR IS REQUIRED. THIS REGULATOR MUST BE

unit. Union must be of the ground joint type. A drip leg should be

INSTALLED BETWEEN THE TANK AND THE HEATER. readily accessible to permit cleaning and emptying. See figure 8.

Regulator not supplied with heater. NOTE If a switch box is mounted over electrical knockouts on

A drip leg should be installed in the vertical pipe run to the unit. back of unit, leave a minimum of 4” (102mm) clearance between

In some localities, codes may require that a manual main shutoff switch box and drip leg.

valve and union (furnished by installer) be installed external to the unit. Union must be of the ground joint type. A drip leg should be

A 1/8” NPT plugged tap shall be installed immediately upstream readily accessible to permit cleaning and empting. See figure 8.

of the gas supply connection to the heater. NOTE If a switch box is mounted over electrical knockouts on back

NOTE Compounds used on threaded joints of gas piping must be of unit, leave a minimum of 4” (102mm) clearance between switch

resistant to the actions of liquefied petroleum gases. box and drip leg.

A 1/8” NPT plugged tap shall be installed immediately upstream of the gas supply connection to the heater.

NOTE Compounds used on threaded joints or gas piping must be resistant to the actions of Liquefied petroleum gasses.

LEAK CHECK

After gas piping is completed, carefully check all piping connections, (field and factory), for gas leaks. Use a soap solution or other preferred means.

Due to the natural heating cycles and vibration of this unit it is recommended, as part of its annual maintenance, to check these

connections for proper tightness and leak-check with a soap solution or other preferred means prior to putting into service.

CAUTION DO NOT use matches, candles, flame or other sources of ignition to check for gas leaks.

IMPORTANT The heater and its individual shut off valve must be disconnected from the gas supply piping system during any pressure testing of that system at test pressures in excess of 1/2 psig (3.45kPa).

The appliance must be isolated from the gas supply piping system by closing its individual manual gas shutoff valve during any pressure testing of the gas supply system at test pressures equal to or less than 1/2 psig (3.45kPa). See figure 9.

NOTE In case emergency shutdown is required, shut down main gas valve and disconnect main power to unit. These devices should be properly labeled by the installer.

START – UP AND OPERATION

UNIT START–UP

FOR YOUR SAFETY READ BEFORE LIGHTING

BEFORE LIGHTING smell all around the appliance area for gas. Be sure to smell next to the floor because some gas is heavier than air and will settle on the floor.

Use only your hand to move the gas control switch to the on position. Never use tools. Do not use excessive force to switch valve from off to on position. Force or attempted repair may result in a fire or explosion.

MHU 50/80 unit heaters are equipped with an automatic spark ignition system. There is no pilot. In case of a safety shutdown, move thermostat switch to OFF, then return the thermostat switch to HEAT position.

Should overheating occur, or the gas supply fail to shut off, shut off the manual gas valve to the appliance before shutting off the electrical supply.

GAS VALVE OPERATION FOR HONEYWELL VR8205M SERIES VALVE (FIGURE 10)

1. STOP! Read the safety information at the beginning of this section.

2. Set the thermostat to lowest setting.

3. Turn off all electrical power to appliance.

4. This appliance is equipped with an ignition device which automatically lights burner. DO NOT attempt to light the burners manually.

5. There is a black rotary switch knob that can be moved between the on and off position. Rotate the switch knob to the off position. (See Figure 10)

6. Wait five minutes to clear out any gas. If you then smell gas, STOP! Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s instructions. If you do not smell gas go to next step.

7. Rotate the black switch knob to ON.

8. Turn on electrical power to unit.

9. Set the thermostat to desired setting.

10. The combustion air blower will start. The burners will light within 40 seconds.

Compact Unit / Utility Heater Operating Instructions and Owner’s Manual

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11. If unit does not light first time (gas line not fully purged) it will attempt up to two more ignitions before locking out.

12. If lockout occurs, repeat steps 1 through 9.

13. If appliance still will not operate, follow the instructions “TO TURN OFF GAS TO UNIT” and call your service technician or gas supplier.

HONEYWELL VR8205M GAS VALVE

GAS VALVE KNOB SHOWN

IN OFF POSITION

MANIFOLD

PRESSURE TAP

flashback or burning within the burner. The flames shall be predominantly blue in color and shall be approximately centered in the tubes with no apparent impingement taking place.

7. The ignition control will energize the fan approximately 45 seconds after ignition is established.

8. After the thermostat demand is satisfied the gas valve is closed; 5 seconds after the demand is satisfied the combustion air blower is shut off.

9. The control center shall shut off the system fan approximately 150 seconds after the gas valve is de-energized.

IGNITION CONTROL LED

The ignition control board contains a green LED which indicates the following:

LED UNIT OPERATION

Slow Flash* Normal Operation - No call for heat

Fast Flash Normal Operation - Call for heat

Current signal at FLAME terminal 0.6 to 1.0 microamps

INLET PRESSURE TAP

MANIFOLD PRESSURE ADJUSTMENT

SCREW UNDER CAP

GAS VALVE

ROTARY SWITCH

FIGURE 10

TO TURN OFF GAS TO UNIT

1. Set thermostat to lowest level.

2. Turn off all electrical power to unit if service is to be performed.

3. Rotate black knob

to OFF position.

HEATING SEQUENCE OF OPERATION

1. When the thermostat calls for heat, the combustion air blower starts immediately.

2. Combustion air pressure switch proves blower operation before allowing power to the ignition controller. This switch is factory set and no adjustment is necessary.

3. After pre-purge of approximately 30 seconds, the spark ignition is energized and the solenoid valves open in the gas valve.

4. The spark then ignites the gas, the ignition sensor proves the flame and the combustion process continues.

5. In the event that the flame is not detected after the first 10-second trial for ignition, the controller will repeat steps 3 and 4 an additional two times before locking out the gas valve. Ignition control will then automatically repeat steps 3, 4, and 5 after 60 minutes.

To interrupt the 60-minute lockout period, move thermostat from “Heat” to “OFF” then back to “HEAT.” Heating sequence then restarts at step 1.

6. The burners shall light without noticeable crossover delay. There shall be no flame lifting from the burner heads,

2 Flashes System lockout - failed to detect or sustain flame

Current signal at FLAME terminal <0.6 microamps

3 Flashes Pressure switch failed closed before CAB is energized

or failed open after CAB is energized

4 Flashes High limit or rollout switch open

5 Flashes Flame sensed and gas valve not energized

Steady Off Loss of power

Steady On Ignition control failure

*When thermostat is placed in continuous fan mode LED will slowly flash.

TABLE 3

IGNITION CONTROL LED

ADJUSTMENTS

HIGH ALTITUDE

Units may be fired at full input up to 2000 ft. (610m) above sea level. Above 2000 ft. (610m), manifold pressure must be adjusted on some units. Adjust pressure regulator to pressure shown in

table 4 for natural gas and table 5 for LP/propane gas.

GAS FLOW

To check for proper gas flow to the combustion chamber, determine the Btu input from the appliance rating plate. Divide this input rating by the Btu per cubic feet of available gas. Result is the required number of cubic feet per hour. Determine the flow of gas through the gas meter for two minutes and multiply by 30 to get the hourly flow of gas.

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Operating Instructions and Owner’s ManualCompact Unit / Utility Heater

GAS PRESSURE

1. Check gas line pressure with unit firing at maximum rate. A

minimum of 5.0” w.c. for natural gas or 10.9” w.c. for LP/

propane gas should be maintained for proper unit operation.

2. After line pressure has been checked and adjusted, check manifold pressure. Correct manifold pressure is shown on the unit rating plate. See figure 10 for gas pressure adjustment

screw location. A natural gas to LP/propane gas changeover kit is required to convert unit. Refer to installation instructions

provided with changeover kit for conversion procedure.

TABLE 4

NATURAL GAS MANIFOLD PRESSURES - IN.WG. (KPA)

ALTITUDE FT. (M)

MHU 50/80 0-2000 2000-4500

(0-610) (610-1370)

50/80 4.0”WC (0.99 kPa)*

3.6”WC (0.89 kPa)

*No adjustment required.

TABLE 5

LP/PROPANE GAS MANIFOLD PRESSURES - IN.WG. (KPA)

ALTITUDE FT. (M)

MHU 50/80 0-2000 2000-4500 (0-610) (610-1370)

50/80 10.5”WC (2.62 kPa)*

8.5”WC (2.12 kPa)

*No adjustment required.

LIMIT CONTROL

The limit control switch is factory set and not field adjustable.

LOUVER VANE ADJUSTMENTS

Rotate louver vanes to direct airflow upward, downward, straight,

or any combination of these directions. When unit is installed

in an inverted position, louvers may be positioned in the same

manner.

COMBUSTION AIR PRESSURE SWITCH

This pressure switch checks for proper combustion air blower operation before allowing an ignition trial. The switch is factory set

and no field adjustment is necessary.

FLAME ROLLOUT SWITCH

The flame rollout switch(es) are located on the burner box top, behind the ignition control board. This normally closed switch opens on a temperature rise. Check for adequate combustion air

before manually resetting switch.

SERVICE

CAUTION Turn off gas and electrical power to unit before

performing any maintenance or service operations on this unit. Remember to follow lighting instructions when putting unit back

into operation after service or maintenance.

If any of the original wire as supplied with the appliance must

be replaced, it must be replaced with wiring material having a temperature rating of at least 105°C.

Do not use this appliance if any part has been under water.

Immediately call a qualified service technician to inspect the

appliance and replace any gas control which has been under water.

BURNERS

1. Periodically examine burner flames for proper appearance

during the heating season.

2. Before each heating season examine the burners for any

deposits or blockage that may have occurred.

3. Clean burners as follows:

• Turn off both electrical and gas supplies to unit.

• Disconnect gas supply piping, high tension and sensor

leads. Remove gas manifold. Remove burner tray.

• Clean burners as necessary. Make sure that burner heads line up properly to ensure flame crossover. Check

spark gap on electrode and adjust if required. The gap

should be between 0.110 inch and 0.140 inch (2.79mm

to 3.56mm). The gap may be checked with appropriately sized twist drills or feeler gauges.

• Reinstall burner tray, gas manifold, high tension and sensor leads. Reconnect gas supply piping.

• Restore electrical power and gas supply. Follow lighting

instructions to light unit. Check burner flame.

4. Clean burner filter screen as follows:

• Turn off both electrical and gas supply to unit.

• Remove the filter screen from the inlet to the burner

housing by squeezing and pulling out.

• With screen out of the heater, clean with light soap and

water or blow out with compressed air (blowing away from you).

• Dry screen thoroughly with air and make sure all air

passages in the screen are fully opened.

• Replace screen into burner housing opening.

• Restore electrical and gas supply.

• Follow lighting instructions to light the heater. Check

burner flame.

FLUE PASSAGEWAY AND FLUE BOX

The flue passages and flue box should be inspected and cleaned prior to each heating season. The sequence of operation should be as follows:

1. Turn off both electrical and gas supply to unit.

2. Disconnect combustion air blower wiring.

3. Remove screws securing flue box to unit. Remove flue box. If necessary, remove blower assembly from flue box. Clean flue

box with wire brush.

4. Remove turbulator retention bracket and turbulators. Clean

turbulators with wire brush.

5. Remove burners as described in section “BURNERS” section.

6. Clean tubes with a wire brush.

7. Reassemble unit. The combustion air and flue box gaskets

should also be replaced during reassembly.

8. Restore electrical power and gas supply. Follow lighting

instructions to light unit. Check operation of unit.

COMBUSTION AIR BLOWER

Under normal operating conditions, the combustion air blower should be checked and cleaned prior to the heating season with the power supply disconnected. Use a small brush to clean blower wheel.

Compact Unit / Utility Heater Operating Instructions and Owner’s Manual

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LADDER DIAGRAM

Red

White

OPTIONAL THERMOSTAT INSTALLATION

IT IS RECOMMENDED TO USE 18AWG WIRE WHEN INSTALLING THE THERMOSTAT. CONNECT THERMOSTAT WIRING TO TERMINALS ‘R’ AND ‘W’ AS ILLUSTRATED ON THE SCHEMATIC DIAGRAM.

NOTE: THERMOSTAT TERMINAL CONNECTIONS ARE MOUNTED ON THE BACK PANEL OF THE HEATER.

EXTERNAL THERMOSTAT TERMINAL STRIP WARNING: DO NOT CONNECT LINE POWER TO THE THERMOSTAT TERMINAL STRIP.

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Operating Instructions and Owner’s ManualCompact Unit / Utility Heater

ELECTRICAL

1. Check all wiring for loose connections.

2. Check for correct voltage at unit (unit operating).

3. Check amperage draw.

FLUE AND CHIMNEY

Check all vent and vent connector joints for tightness. Ensure that connections are sealed and that there are no blockages.

2. Is main disconnect closed?

3. Is there a breaker tripped or a fuse blown?

4. Is gas turned on at meter?

5. Is manual shutoff valve open?

6. Is unit ignition system in lock out? If unit locks out again, call service technician to inspect unit.

7. Is pressure switch closed? Obstructed flue will cause unit to shut off at pressure switch. Check flue passage and outlet.

FAILURE TO OPERATE

If unit fails to operate check the following:

1. Is thermostat calling for heat?

HeatStar • Compact Unit / Utility Heater • Model # MHU 50/80

REPAIR PARTS

When ordering repair parts include the complete unit model number listed on the unit rating plate. For example: HSU50/80.

Compact Unit / Utility Heater Operating Instructions and Owner’s Manual

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PARTS LIST:

SEE BACK PAGE FOR PARTS ORDERING INFORMATION

REF #. DESCRIPTION 50 ITEM # QUANTITY 80 ITEM # QUANTITY

1.................CIRCUIT BOARD .................................................... 60105 .......................1 ....................................S/A .......................1

2.................LIMIT SENSOR ....................................................... 60022 ......................1 ....................................60021 ...................2

3.................ELECTRODE IGNITER .............................................. 60139 .......................1 ....................................S/A .......................1

4.................ELECTRODE SENSOR .............................................. 60141 .......................1 ....................................S/A ....................... 1

5.................BURNER ................................................................60155 .......................3 ....................................60191 ....................5

6.................IGNITION LEAD ..................................................... 60045 ......................1 ....................................S/A .......................1

7.................SENSOR LEAD .......................................................60046 ......................1 ....................................S/A .......................1

8.................ORIFICE (NAT) ....................................................... 60049 ......................3 ....................................S/A ....................... 5

9.................ORIFICE (LP) .......................................................... 60156 .......................3 ....................................S/A .......................5

10 ...............GAS VALVE (NAT) .................................................. 60128 .......................1 ....................................S/A .......................1

11 ...............GAS VALVE (LP) ..................................................... 60129 .......................1 ....................................S/A .......................1

12 ...............TRANSFORMER .....................................................60025 ......................1 ....................................S/A .......................1

13 ...............PRESSURE SWITCH ................................................ 60147 .......................1 ....................................60146 ...................1

14 ...............HI LIMIT SENSOR HEAT EXCH. ...............................60015 .......................1 ....................................S/A .......................1

15 ...............PRESSURE SWITCH TUBE ....................................... 60031 .......................1 ....................................S/A .......................1

16 ...............INDUCED DRAFT MOTOR ...................................... 60020 ......................1 ....................................S/A .......................1

17 ...............VENT ADAPTER ..................................................... 60130 .......................1 ....................................60140 ...................1

18 ...............INDUCED DRAFT MOTOR GASKET .........................60157 .......................1 ....................................S/A .......................1

19 ...............BACK BRACKET ....................................................60075 ......................1 ....................................S/A .......................1

20 ............... FRONT BRACKET ..................................................60080 ......................1 ....................................S/A .......................1

21 ...............LOUVERS .............................................................. 60100 .......................5 ....................................S/A ....................... 7

22 ............... LOUVER SPRING ................................................... 60103 .......................5 ....................................S/A ....................... 7

23 ............... FLUE BOX ..............................................................60189 .......................1 ....................................60190 ...................1

24 ...............FLUE BOX GASKET ................................................. 60090 ......................1 ....................................60092 ................... 1

25 ............... HEAT EXCHANGER ................................................60065 ......................1 ....................................60068 ...................1

26 ............... ACCESS DOOR ..................................................... 60070.......................1 ....................................60072 ...................1

27 ...............FRONT ..................................................................60095 ......................1 ....................................60097 ................... 1

28 ............... SIDE DOOR ..........................................................60110 .......................1 ....................................60112 ....................1

29 ............... WRAPPER .............................................................60115 ........................3 ....................................60117 ....................3

30 ............... FAN MOTOR .......................................................... 60055 ......................1 ....................................60054 ................... 1

31 ...............FAN GUARD .........................................................60120 .......................1 ....................................60122 ....................1

32 ............... FAN ASSEMBLY ..................................................... 60125 .......................1 ....................................60127 ....................1

33* ............. CAPACITOR STARTER .....................................................................................................................28788 ...................1

34 ............... MANIFOLD ............................................................60062 ......................1 ....................................60064 ...................1

35 ............... INLET PIPE ............................................................. 60132 .......................1 ....................................S/A .......................1

36 ............... INLET FITTING ....................................................... 60131 .......................1 ....................................S/A .......................1

37 ...............BURNER SCREEN ...................................................60142 .......................1 ....................................S/A .......................1

38 ............... THERMOSTAT TERMINAL .......................................60144 .......................1 ....................................S/A ....................... 1

39 ............... WIRING JUNCTION BOX ........................................ 60159 .......................1 ....................................S/A ....................... 1

40...............COVER, WIRING JUNCTION BOX ........................... 60160 .......................1 ....................................S/A .......................1

Not Shown . GAS VALVE BRACKET ............................................. 60158 .......................1 ....................................S/A .......................1

*Not Shown

Optional Installation Components

24V THERMOSTAT ..................................................................................F210359

4” VERTICAL VENT KIT (80) ....................................................................F102848

3” VERTICAL VENT KIT (50) ....................................................................F102840

4” HORIZONTAL STAINLESS STEEL VENT KIT (80) ...................................F102860

Gas Conversion Kits Natural Gas to Liquid Propane

MHU 50/80 50,000 and 80,000 BTU ....................................F260163

Liquid Propane to Natural Gas

MHU 50/80 50,000 and 80,000 BTU ....................................F260164

Operating Instructions and Owner’s ManualCompact Unit / Utility Heater

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