Enerco HSU 75, HSU 45 User Manual
Starting Serial Numbers - Page 2
OPERATING INSTRUCTIONS AND OWNER’S MANUAL
READ INSTRUCTIONS CAREFULLY: Read and
MR. HEATER
MODEL
MHU 45
MHU 75
COMPACT UNIT HEATER
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.
HEATSTAR
MODEL
HSU 45
HSU 75
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.
10/09 #60016ENERCO GROUP, INC., 4560 W. 160TH ST., CLEVELAND, OHIO 44135 • 216-916-3000
Starting Serial Numbers
MHU45NG -- 260045-09001001
MHU45LP -- 260145-09001001
MHU75NG -- 260775-09001001
MHU75LP -- 260875-09001001
HSU45NG -- 160245-09001001
HSU45LP -- 160345-09001001
HSU75NG -- 160775-09001001
HSU75LP -- 160975-09001001
Enerco | Compact Unit Heater Operating Instructions and Owner’s Manual
2
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.
CONTENTS
UNIT DIMENSIONS .................................................................. 4
SHIPPING ................................................................................. 5
REQUIREMENTS ....................................................................... 5
UNIT HEATER INSTALLATION.................................................... 6
COMBUSTION & VENTILATION AIR .......................................... 6
VENTING .............................................................................6-10
ELECTRICAL CONNECTIONS ....................................................10
GAS CONNECTION ................................................................. 11
LEAK CHECK ........................................................................... 11
START-UP OPERATION ............................................................. 11
HEATING SEQUENCE OF OPERATION ......................................12
IGNITION CONTROL LED ......................................................... 12
ADJUSTMENTS........................................................................ 12
SERVICE ..................................................................................13
WIRING DIAGRAM ..................................................................14
PARTS LIST ..............................................................................16
WARRANTY ............................................................................18
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:
The State of California requires the following 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).
Operating Instructions and Owner’s ManualEnerco | Compact Unit Heater
3
AIR
FLOW
HEAT EXCHANGER
(ALUMINIZED STEEL)
MHU45/MHU75 AND HSU45/HSU75 UNIT DIMENSIONS
(N-NATURAL GAS, P-PROPANE)
HANGING
BRACKETS
MOUNTING SLOTS (Typical)
5/16 x 3 Inches (8 x 76 mm)
DIMENSION 45 75
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
ELECTRICAL
INLETS
DIRECT
DRIVE FAN
FLUE
OUTLET
GAS
INLET
BACK 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? _________________________________________________________________
Enerco | Compact Unit Heater Operating Instructions and Owner’s Manual
4
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 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 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 unit heaters are CSA International certified for the
clearances to combustible material listed on the rating plate
and table 1. 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 oor 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 oor 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.
Operating Instructions and Owner’s ManualEnerco | Compact Unit Heater
5
These units are approved 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 180o depending on desired location
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 180o. Secure with
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 HEATER
MOUNTING
BRACKETS (2)
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 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.
FIGURE 1
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
Enerco | Compact Unit Heater Operating Instructions and Owner’s Manual
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).
6
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 WA LL VENT
AND “B”VENT AND THE ANNULAR SPACE OF THE “B” VENT
PIPE – COMMERCIAL AND RESIDENTIAL
INSTALLATIONS
MHU/HSU compact unit heaters are listed as Category I
appliances for vertical vent installations.
1. MHU/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 45 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
berglass 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-red 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.
C – HORIZONTAL VENTING – GENERAL
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.
FIGURE 2
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.
Operating Instructions and Owner’s ManualEnerco | Compact Unit Heater
7
5. Vent termination must be a minimum of 4’ (1.2m) below or
4’ (1.2m) horizontally from any soft 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. Where local authorities permit, a single section
of type B-1 vent pipe may be used as an alternative to the
thimble. When using a type B-1 vent termination use the
clearances specified by the vent manufacturer. Seal the
connection between the single wall and double wall pipes
and the annular space of the double wall pipe as shown in
gure 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 4V” (76mm) on 45 units. In all cases, a ue 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. The vent
may be single wall material minimum 26 GSG (0.46mm)
galvanized steel or equivalent grade stainless steel. Seal
single wall vent material according to the section A - General
Recommendations and Requirements.
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 I appliances. The vent may be single
wall material minimum 25 GSG (0.46mm) galvanized steel
or equivalent grade stainless steel. 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 45 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
MAY BE SINGLE WALL (26 GSG) GALV. OR EQUIV. STAINLESS STEEL SEALED 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 HEATER
Enerco | Compact Unit Heater Operating Instructions and Owner’s Manual
FLUE TRANSITION
(PROVIDED)
LISTED THIMBLE
THROUGH COMBUSTIBLE
WALL
DRAIN LOOP WITH WATER
TRAP (TO CONDENSATE DRAIN)
FIGURE 3
8
12 INCHES MIN.
(30.5 CM)
VENT TERMINATION
CAP
12” (30.5 CM)
MINIMUM ABOVE ALL
HIGHEST SNOWFALL
INDUCED DRAFT BLOWER
MAY BE SINGLE WALL (26 GSG) GALV. OR EQUIV. STAINLESS
STEEL SEALED ACCORDING TO THESE INSTALLATION
INSTRUCTIONS OR A SINGLE SECTION OF TYPE B-1 VENT.
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.
HORIZONTAL VENTING - RESIDENTIAL INSTALLATION
FLUE TRANSITION
(PROVIDED)
LISTED THIMBLE THROUGH
COMMON VENTING NOT ALLOWED WHEN HORIZONTALLY VENTING THE UNIT HEATER.
UPWARD SLOPE
12 INCHES
MIN. (30.5CM)
VENT TERMINATION CAP
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 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 rst 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 ue 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 exible 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.
Operating Instructions and Owner’s ManualEnerco | Compact Unit Heater
9
L1
N
EQUIPMENT
GROUND
LINE VOLTAGE FIELD WIRING
UNIT
BLACK
BLACK
WHITE
WHITE
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, replace 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.
BLACK WIRE WITH WHITE TAPE OR
WHITE WIRE WITHOUT TAPE
FIGURE 7
GAS SUPPLY CONNECTION
GROUNDED
JOINT UNION
1/8 NPT
PLUGGED TAP
DRIP LEG
FIGURE 8
MANUAL
MAIN SHUT-OFF VALVE
(FURNISHED BY INSTALLER)
GAS FLOW
ELECTRICAL CONNECTIONS
NOTE The MHU/HSU series unit heaters use a direct spark
ignition system. There is no pilot necessary as the spark lights
the main burner as the gas valve is turned on. The direct spark
WARNING
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.
WARNING
Danger of explosion. Can cause injury or
product or property damage. If overheating occurs or if gas supply fails to
shut off, shut off the manual gas valve
to the appliance before shutting off
electrical supply.
GAS SUPPLY TO UNIT HEATER
MANUAL MAIN SHUT-OFF VALVE
WILL NOT HOLD NORMAL TEST
PRESSURE
CAP
UNIT HEATER
FIGURE 9
WARNING
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
ISOLATE
GAS VALVE
switch(es). Unit may have multiple power
supplies.
WARNING
Danger of explosion and fire. Can
cause injury or product or property
damage. You must follow these
instructions exactly.
Enerco | Compact Unit Heater Operating Instructions and Owner’s Manual
10
ignition control board emits radio noise as the sparking process
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
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
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.
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.
GAS CONNECTION
When connecting gas supply, the length of the run from the
meter must be considered in determining the pipe size to avoid
excessive pressure drop. A line pressure of 7” w.c. (178mm w.c.)
for natural gas should be maintained when sizing piping. A line
pressure of 13” w.c. (330mm w.c.) should be maintained for
liquefied petroleum (LP) gas. For correct sizing of piping, refer to
the (American) National Fuel Gas Code ANSI Z223.1 or (Canada)
CSA B149.1, Natural Gas and Propane Installation Code or consult
the utility having jurisdiction.
A drip leg should be installed in the vertical pipe run to the unit.
In some localities, codes may require that a manual main shutoff
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
readily accessible to permit cleaning and emptying. See figure 8.
NOTE If a switch box is mounted over electrical knockouts on
back of unit, leave a minimum of 4” (102mm) clearance between
switch 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 of gas piping must be
resistant to the actions of liquefied petroleum gases.
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 push in or turn the gas control knob. Never
use tools. If the knob will not push in or turn by hand, do not try
to repair it, call a qualified service technician. Force or attempted
repair may result in a fire or explosion.
MHU45/75 and HSU45/75 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 ROBERTSHAW
2000DER 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. Depress knob on gas valve; knob will snap to OFF.
(See Figure 10)
6. Wait five minutes to clear out any gas. If you then smell gas,
STOP! Immediately call your gas supplier form a neighbor’s
phone. Follow the gas supplier’s instructions. If you do not
smell gas go to next step.
7. Turn knob on gas valve 90o counterclockwise 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.
11. If unit does not light first time (gas line not fully purged) it
will attempt up to two more ignitions before locking out.
11
Operating Instructions and Owner’s ManualEnerco | Compact Unit Heater
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