Sterling ME User Manual
INSTALLATION AND SERVICE MANUAL
HVAC PRODUCTS
INDOOR MAKE-UP AIR UNIT ARRANGEMENTS
FOR HEATING, COOLING AND VENTILATING SYSTEMS
ATTENTION: READ THIS MANUAL, INDOOR DUCT FURNACE DISM MANUAL (STANDARD & POWER VENT TYPE)
(EVAPORATIVE OR COOLING COIL MANUALS IF APPLICABLE), UNIT SUBMITTAL DATA SHEETS AND ALL LABELS
ATTACHED TO THE UNIT CAREFULLY BEFORE ATTEMPTING TO INSTALL, OPERATE OR SERVICE THESE UNITS! CHECK
UNIT DATA PLATES FOR TYPE OF GAS AND ELECTRICAL SPECIFICATIONS AND MAKE CERTAIN THAT THESE AGREE
WITH THOSE AT THE POINT OF INSTALLATION. RECORD THE UNIT MODEL NUMBER AND SERIAL NO.(S) IN THE SPACE
PROVIDED. RETAIN THIS DOCUMENT FOR FUTURE REFERENCE.
Model No.______________________________________________ Serial No. ________________________
(S) MAIM-6
J30-05383A
FOR Y OUR SAFETY
The use or storage of gasoline or other
flammable vapors or liquids in open
containers in the vicinity of this appliance
is hazardous.
If you smell gas:
1. Open windows.
2. Don’t touch electrical switches.
3. Extinguish any open fl ames.
4. Immediately call your gas supplier.
FOR Y OUR SAFETY
Improper installation, adjustment, alteration, service or maintenance can
cause property damage, injury or death. This appliance must be installed by a licensed
contractor or qualifi ed service personnel. Read these installation, operating and
maintenance instructions thoroughly before installing or servicing this equipment.
APPROVED FOR USE IN CALIFORNIA
WHEN UNITS ARE EQUIPPED WITH INTERMITTENT (SPARK) IGNITION.
Install, operate and maintain unit in accordance with manufacturer’s
instructions to avoid exposure to fuel substances or substances from incomplete
combustion which can cause death or serious illness. The state of California has
determined that these substances may cause cancer , birth defects, or other reproductive
harm. Install and Service this product to avoid exposure to airborne particles of
glasswool fi bers and/or ceramic fi bers known to the State of Calif ornia to cause cancer
through inhalation.
01/11
INSTALLER’S RESPONSIBILITY
Installer Please Note: This equipment has been test fi red and inspected. It has been shipped
free from defects from our f actory. Ho w ever, during shipment and installation, problems such
as loose wires, leaks or loose fasteners may occur. It is the installer’s responsibility to
inspect and correct any problems that may be found.
RECEIVING INSTRUCTIONS
Inspect shipment immediately when
received to determine if any damage
has occurred to the unit during
shipment. After the unit has been
uncrated, check for any visible
damage to the unit. If any damage is
found, the consignee should sign
the bill of lading indicating such
damage and immediately file claim
for damage with the transportation
company.
IMPORTANT: Look in direction of unit air fl ow to determine
whether unit is right hand or left hand accessible.
260 NORTH ELM ST., WESTFIELD, MA 01085
TEL: (413) 564-5540 FAX: (413) 562-5311
http://www.mestek.com
Please utilize this toll free number to contact your local
representative 800-490-2290.
TABLE OF CONTENTS
I. RECEIVING & PRE-INSTALLATION
INSTRUCTIONS ......................................................... 2
II. GENERAL INSTALLATION SAFETY
REQUIREMENTS (throughout IOM) ..................3, 4
Rigging .......................................................................4
III. INSTALLATION
Location ........................................................................5
Combustion Air Considerations ....................................5
Mounting / Locations ...................................................5
Suspension ...................................................................5
Mounting on Field Furnished Supports ........................6
Installation Clearances .............................................6, 7
Access Panel Removal ................................................7
Venting ..........................................................................7
Air for Combustion .......................................................7
Duct Connections .....................................................7, 8
Gas Piping ....................................................................8
Modulating Gas Control ............................................8, 9
Electrical Connections ............................................9, 10
DX Coil Equipped Units ..............................................10
Chilled Water Coil Equipped Units ..............................10
Evaporative Cooling Equipped Units ..........................10
IV. OPERATION
General Information ....................................................11
Gas Control System ...................................................11
Optional Gas Controls ..........................................11, 12
Air Handling Requirements and Adjustments ...... 12, 13
Lighting .......................................................................13
Gas Input Adjustment ...........................................13, 14
Pilot Adjustment .......................................................... 14
Primary Air Shutter Adjustment .................................. 14
Controls ......................................................................14
V. START UP ......................................................14, 15
VI. MAINTENANCE .......................................15 thru 18
VII. TROUBLESHOO TING ............................19 thru 24
VIII. REPLACEMENT PARTS ...................................24
IX. SERVICE NOTE ................................................... 24
X. W ARRANTY ..........................................................24
Canadian Installations ...............................................25
XI. DIMENSIONAL DATA ..............................26 thru 29
XII. MOTOR ELECTRICAL DATA .............................30
XIII. UNIT/SHIP WEIGHTS ........................................31
XIV. COOLING COIL DIMENSIONAL DATA ............32
XV. CENTER OF GRAVITY .................................32, 33
XVI. UNIT NUMBER DESCRIPTION ..................34, 35
XVII. START UP SHEET ...........................................36
Unless otherwise specifi ed, the following conversions
may be used for calculating SI unit measurements:
1 foot = 0.305 m
1 inch = 25.4 mm
1 psig = 6.894 kPa
1 pound = 0.435 kg
1 gallon = 3.785 L
1 cubic foot = 0.028 m
1 inch water column =0.249 kPa
1000 Btu per hour = 0.293 kW
1000 Btu/Cu. Ft. = 37.5 MJ/m
3
liter/second = CFM x 0.472
meter/second = FPM ÷ 196.8
3
The following terms are used throughout this manual to bring
attention to the presence of potential hazards or to important
information concerning the product:
Indicates an imminently hazardous
situation which, if not av oided, will result in death,
serious injury or substantial property damage.
Indicates an imminently hazardous
situation which, if not avoided, could result in death,
serious injury or substantial property damage.
Indicates an imminently hazardous
situation which, if not avoided, may result in minor
injury or property damage.
NOTICE: Used to notify of special instructions on
installation, operation or maintenance which are
important to equipment but not related to personal
injury hazards.
I. RECEIVING INSTRUCTIONS
Inspect shipment immediately when received to
determine if any damage has occurred to the crate
during shipment.
After the unit has been uncrated, check for any visible damage
to the unit. Check motor position and turn blower wheel to
determine if damage has occurred to these critical parts.
If any damage is found, the consignee should sign the bill
of lading indicating such damage and immediately fi le
claim for damage with transportation company.
PRE-INSTALLATION INSTRUCTIONS
When the unit is received and uncrated, check the external
data plate and all labels on the unit for type of gas, electrical,
and operational specifi cations to confi rm that these agree
with those at point of installation. The unit is equipped with
an Indoor Duct Furnace; also check the data plate and
all labels located on each furnace.
Every Make-Up Air Unit will include an informational
packet which will include the following: This
make-up air manual, duct furnace, evaporative
cooler/cooling coil manuals (if applicable to the unit
order), wiring diagram(s), and special controls/data
sheets.
Failure to comply with the general
requirements may result in extensive property
damage, severe personal injury or death.
NOTICE: It is the equipment owner’s responsibility to
provide any scaffolding or other apparatus required
to perform emergency service or annual/periodic
maintenance to this equipment.
— 2 —
II. GENERAL SAFETY REQUIREMENTS
Open all disconnect switches
before installing the unit. If the po wer disconnect
is out of sight, lock it in the open position and ta g
it to prevent unexpected application of power.
Failure to do so may result in personal injury or
death from electrical shock.
Failure to comply with the general
requirements may result in extensive property
damage, severe personal injury or death.
Never service any component
without fi rst disconnecting all electrical and gas
supplies to the unit or severe personal injury or
death may occur.
1. Installation must be made in accordance with local
codes, or in absence of local codes, with ANSI
Standard Z223.1-1996 (N.F.P.A. No 54) “National
Fuel Gas Code”, or the latest edition of. All ANSI and
NFPA Standards referred to in these installation
instructions are the ones that were applicable at the
time the design of this appliance was certifi ed. The
ANSI Standards are available from the American
Gas Association, 1515 Wilson Boulevard, Arlington,
Virginia 22209. The NFPA Standards are available
from the National Fire Protection Association,
Batterymarch Park, Quincy, Massachusetts 02269.
The heaters are designed for use in airplane hangers
when installed in accordance with ANSI/NFPA No.
409 and in public garages when installed in
accordance with the NFPA No. 88A and NFPA No.
88B.
2. If installed in Canada, the installation must conform
with local building codes, or in the absence of local
building codes, with the current CGA-B149.1 or
B149.2 “Installation Codes for Gas Burning
Appliances and Equipment”. These indoor duct
furnaces have been designed for and certified to
comply with CGA 2.6.
3. No alterations are to be made on this equipment.
The duct furnace section of these make-up air units are
certifi ed by the American Gas Association for use with
natural and LP (propane) gases!
Do not alter the duct furnace in any
way or damage to the unit, se vere personal injury
or death will occur.
4. Make certain that the power sources conform to the
requirements of the heater.
5. Follow installation instructions CAREFULLY to
avoid creating unsafe conditions. All wir ing should
be done and checked by a qualifi ed electrician, using
copper wire only . All gas connections should be made
and leak-tested by a suitably qualifi ed individual, per
instructions in this manual.
6. Use only the fuel for which the heater is designed
(see nameplate). Using LP gas in a heater that
requires natural gas, or vice versa, will create the
risk of gas leaks, carbon monoxide poisoning and
explosion.
Do not attempt to convert the heater
for use with a fuel other than the one intended.
Such conversion is danger ous, as it could create
unsafe conditions that result in death, serious
injury or substantial property damage.
7. Make certain that power source conforms to
electrical requirements of heater. Disconnect
power before installing or servicing heater. If power
disconnect is out of sight, lock it in open position and
tag it to prevent unexpected application of power.
Failure to do so could result in fatal electric shock.
Do not depend upon a thermostat
or other switch as the sole means of disconnecting
power when installing or servicing heater. Always
disconnect power at main circuit breaker as
described above. Failure to do so could result in
fatal electric shock.
8. Special attention must be given to any grounding
information pertaining to this heater. To prevent
the risk of electrocution, the heater must be
securely and adequately grounded. This should be
accomplished by connecting a grounded conductor
from the service panel to the conduit box of the heater.
T o ensure proper ground, the g rounding means must
be tested by qualifi ed fi eld electrician.
9. Do not insert fingers or foreign objects into the
heater or its air moving device. Do not block or
tamper with the heater in any manner while in
operation or just after it has been turned off, as some
parts may be hot enough to cause injury.
10. This heater is intended for general heating
applications ONLY. It must NOT be used in
potentially dangerous locations such as fl ammable
explosive, chemical-laden or wet atmospheres.
In cases in which property damage may result from
malfunction of the heater, a backup system or a
temperature sensitive alarm should be used.
— 3 —
The open end of piping systems being
purged shall not discharge into areas where there are
sources of ignition or into confi ned spaces UNLESS
precautions are taken as follows: (1) By ventilation of
the space, (2) control of purging rate, (3) elimination
of all hazardous conditions. All precautions m ust be
taken to perform this operation in a safe manner!
LOCA TIONS TO A V OID
Unit heaters should not be installed within corrosive or
fl ammable atmospheres. Do not locate any gas fi red
heater where air for combustion contains chlorinated
vapors or acid fumes. Avoid locations where extreme
drafts can affect burner operation.
Presence of these air impurities can
cause premature failure of the heat exchanger and
void the warranty (See limited warranty on page 24).
The venting system must be installed in accordance with
heater manufacturer’s instr uctions. The venting system
is an integral part of the unit and must not be altered
in the fi eld!
RIGGING
Rig unit using either belt or cable slings. Use spreader bars
to protect the top of the unit when it is lifted. See Figures 1
and 2. Mak e sure all hardware used in the lifting/mounting
process is tightened and secured.
Figure 1 - Hoisting of Make-Up Air Unit
Without Lifting Brackets
Figure 2 - Hoisting of Make-Up Air Unit
With Lifting Brackets
On units with a total length of less than 104" (2642mm),
excluding evaporative cooler, two holes are provided in
the base rail on each side of the unit. Slide pipes beneath
the unit through these holes and attach rigging to pipes
for lifting the unit.
On units with a total length of a 104" (2642mm) or greater,
excluding evaporative cooler, lifting lugs/brack ets attached
to the base rail are provided. Once the unit is set in place
these lifting brackets may be removed if required.
Attach rigging to lugs/brackets for lifting the unit. F or distance
between lifting lugs/brackets and total unit lengths, refer
to the Dimensional Data section of this manual. Also see
Center of Gravity and W eights sections in this manual prior
to lifting and apply accordingly to the lifting process.
— 4 —
III. INSTALLATION
LOCATION
Before placing the Make-Up Air unit in its permanent
location, make certain that the structure is capable of
carrying the additional load of this equipment. Check the
unit weight given at the end of this manual.
Refer to Table for required clearances to combustible
material, and Figure 5 for manufacturer’s recommendations.
3. In parking structures, Gas Fired Indoor Make-Up Air
Handlers must be installed so that the burner fl ames
are located 18 in. (45mm) abo ve the fl oor or protected
by a partition not less than 18 in. (457mm) high as
specifi ed in NFPA 88A Parking Structures.
4. In public repair garages, Gas Fired Make-Up Air
Handlers must be installed in a detached building
or room separated from repair areas as specifi ed in
NFPA 88B Repair Garages.
Do not place unit in a location
where service personnel can not safely service this
equipment or personal injury could result.
NOTICE: When selecting a location for these MakeUp Air Units, both the size of the unit and the heating
requirements of the building must be considered.
COMBUSTION AIR CONSIDERATIONS
The presence of chlorine vapors or other corrosive vapors
in the combustion air supply for gas-fi red heating equipment
presents a potential corrosive hazard. Chlorine will, when
exposed to fl ame, precipitate from the compound (usually
freon or degreaser vapors) and go into solution with any
condensation that is present in the heat exchanger or
associated parts. The result is hydrochloric acid which
will readily attack all metals, including 300 grade stainless
steel. Care should be taken to separate these vapors
from the combustion process.
MOUNTING HEIGHT
1. When a Gas Fired Make-Up Air Handler is
discharging directly into the heated space, a
mounting height of eight feet (2.4m) above the fl oor
is recommended. Less effi cient air distribution results
at higher levels.
2. When Gas Fired Indoor Make-Up Air Handlers are
installed in airplane hangars, NFP A specifi es that the
units must be at least ten feet (3.0m) abov e the upper
surface of wings or engine enclosures of the highest
aircraft to be stored in the hangar. This measurement
should be made from the wing or engine enclosure
(whichever is higher from the fl oor) to the bottom of
the heater. Heaters must be installed at least eight
feet (2.4m) abov e the fl oor in shops, offi ces, and other
sections of the hangar where aircraft are not stored
or housed. Refer to NFPA 409 Aircraft Hangars.
SUSPENSION
The unit should never be lifted by
the fan housing, motor mounting, grille or fl ue
connection. These are not designed to support
the total weight and may break, causing per sonal
injury or unit damage.
Units can be set on supports or suspended by rod
hangers from the sub-frame (and lifting brackets).
Any unit that has a side base rail
longer than 104" (2.6m) requires additional field
furnished supports by a qualifi ed installer. Refer
to all dimensional data and center of gravity
information in this manual. If further information
is required, contact the manufacturer’s technical
service department.
The unit must be hung level from side to side and front to
back, using the four (9/16" diameter) hanging holes (see Figure
3) in the skid rail, and 3/8" or 1/2" threaded rod or pipe.
Make certain that the structure to
which the heater is to be mounted is capable of
supporting its weight. Under no circumstances
must the gas lines, the venting system or the
electrical conduit be used to support the heater;
or should any other objects (i.e. ladder, person)
lean against the heater , gas lines, venting system
or the electrical conduit for support.
Figure 3
— 5 —
D8769
MOUNTING ON FIELD FURNISHED SUPPORTS
Single, double, triple duct furnace models have base rails
which are suitable for mounting either directly on solid
planking or steel channels. (Refer to Figure 4).
Figure 4
Capacity
"C" Dim.
(CA)
30-5/8"
10/15
(778)
41-5/8"
20/25/50
"C"
Support Must Clear
Return Air Opening
And Fit Inside Base
Rail Flange
30/35
60/70
40/80/12
(1057)
52-5/8"
(1337)
58-1/8"
(1476)
INSTALLATION CLEARANCES
Minimum clearances to combustible material are shown
on the unit data plate. It is important that clearances
be maintained for servicing the unit, and that minimum
clearances are provided from the unit to combustible
material. Clearances around the fi eld installed optional
outside air hood (if unit is to be connected to one) must
be unobstructed. See Figure 5.
Every gas appliance should be located with respect
to building construction and other equipment so as to
permit access to the unit. Clearances between ver tical
walls and the vertical sides of the heater should be
no less than 6 inches (152mm). Minimum clearance
between the top of the heater and the ceiling is 6 inches
(152mm). The minimum clearance from combustibles
to the bottom of the furnace is 6 inches (the distance
between the unit skid rail bottom and the furnace bottom
is approximately 7 inches (178mm) which meets this
6 inch clearance requirement to combustible materials).
The minimum clearance from combustibles to the fl ue
collector is 6 inches (152mm). Adequate clear ance must
be maintained around all openings into the combustion
chamber. Adequate clearance should be planned for
the width of the unit to pull out the burner drawer. See
Figure 5 and Table #T4088-B, D.
A pilot burner plate is provided in the Duct Furnace
for easy access to the pilot burner and ignition
system without opening burner drawer compartment.
Accessibility is also provided for the safety switches
included with your unit without removal of jacketry. Refer
to the maintenance section and the Indoor Duct Furnace
manual for more information.
The unit should never be lifted by
furnace sections, blower housing/fi lter/sections,
motor mounts or fl ue connections. These are not
designed to support total weight of the unit, and
may break, causing personal injury or property
damage!
Figure 5 - Manufacturer’s Recommended Service Clearances
methods used to lift the Make-Up Air Unit are
capable of supporting the weight of the heater
during installation. Failure to heed this warning
may result in property damage or personal injury.
Clearance
For Drawer
Pull-Out
D8773
AIR FLOW
Indoor
Make-Up
Unit
A
AIR FLOW
A
Make certain that the lifting
Note: Recommended ceiling clearance 36"
(914mm) is to the top of the furnace venting
collar assembly.
— 6 —
Make certain that the structure
to which heater is to be mounted is capable
of safely supporting its weight. Under no
circumstances must the gas lines or the
electrical conduit be used to support the heater.
Failure to heed these warnings may result in
property damage, personal injury or death.
Open all disconnect switches
before installing the unit. Failure to do so may
result in personal injury or death from electrical
shock.
ACCESS PANEL REMOVAL
Unless your unit is equipped with optional hinged access
doors, the air handler sections are equipped with access
panels that are held in place with two “grip” latches.
To remove these access panels: use a slotted head
screw driver to turn the latch screwhead counterclockwise. Using the handle provided, push the panel
upwards. Pull the bottom of the panel out and lower the
panel to disengage it from the top lip.
To replace access door panels: guide the panel door
upwards on the tracks, and push up into the top lip,
swing and lower the panel in place until it engages with
the bottom panel. Turn the screwhead on each latch
clockwise. The screw must turn freely one quarter turn
before resistance is felt in order for the lock to engage. If
latch does not hold, turn screw counter-clockwise sev er al
turns and repeat the above procedure.
The furnace section service panel is easily accessible
- simply remove the mounting screws on the lower
jacket panel to disengage and remove the panel;
repeat procedure for installing back in place. See the
maintenance section and the duct furnace manual
for more information regarding burner drawer
removal/accessibility.
VENTING†
All venting installations shall be in accordance with the
latest edition of Part 7, “Venting of Equipment”, of the
National Fuel Gas Code, ANSI Z223.1-1996 (or the latest
edition), or applicable provisions of local building codes.
CARBON MONOXIDE! Your
venting system must not be blocked by any
snow, snow drifts or any foreign matter. Inspect
your venting system to ensure adequate
ventilation exists at all times! Failure to heed
these warnings could result in Carbon Monoxide
Poisoning (symptoms include grogginess,
lethargy, inappropriate tiredness, or flu-like
symptoms).
The venting is an integral part of
the unit and must not be altered in the fi eld.
The units are available in two types of venting processes
- Natural or Power Vented. Natural Vent units are
equipped with a draft diverter; air for combustion enters
in through an opening in the draft diverter, and products
of combustion are discharged through a fl ue vent (fi nal
connections fi eld installed). The High Effi ciency Power
Vented units feature a factory installed power venter and
sealed fl ue collector that controls combustion and excess
air during the on-cycle.
VENT SYSTEMS - TERMINATION CLEARANCE REQUIREMENTS
Minimum Clearances for
Structure Termination Locations
Door, window or 4 feet below
any gravity air inlet 4 feet horizontally
1 foot above
Forced air inlet within 10 feet 3 feet above
Adjoining building or parapet 6 feet
Adjacent public walkways 7 feet above grade
*If the vent terminal is to be installed near ground level, the vent
terminal must be positioned at least six inches (152mm) above the
maximum anticipated snow depth.
†Refer to the Indoor Duct Furnace Manual for more
venting requirements.
AIR FOR COMBUSTION
Appliances shall be installed in a location in which the
facilities for ventilation per mit satisfactory combustion of
gas, proper venting, and the maintenance of ambient
temperature at safe limits under normal conditions for use.
Appliances shall be located in such a manner as not to
interfere with proper circulation of air within the confi ned
space. When buildings are so tight that normal infi ltration
does not meet air requirements, outside air shall be
introduced per Sections 1.3.4.2 and 1.3.4.3 of ANSI
Z223.1 for combustion air requirements. A permanent
opening or openings having a total free area of not less
than one square inch per 5,000 Btu/Hr of total input
rating of all appliance within the space shall be provided.
Refer to the Indoor Duct Furnace Manual supplied with
your unit for more requirements.
DUCT CONNECTIONS
All ductwork must be properly supported so that no strain
is put on the unit. Do not alter or bend the discharge duct
fl anges supplied on your make-up air unit.
Duct connections must have a removable access panel
in the duct which is connected to a duct furnace. The
duct openings shall be accessible when the unit is
installed in service, and shall be of such size that smoke
or refl ected light may be observed inside the casing to
indicate the presence of leaks in the heating element.
The covers for the panels shall be attached in such a
manner as to prevent leaks . Ducts (or optional outside air
hoods) exposed to the outdoors must be insulated and
sealed to prevent water from entering either the unit or
building through the duct.
— 7 —
If a single, double or triple duct furnace only unit is
t
connected to a return air duct, or any other inlet air
restriction, the appliance shall be installed on the positive
pressure side of the air circulating blower.
The appliance and its individual shutoff 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 (3.5 kPa).
When connecting return air duct to Standard or High
CFM cabinets, attach duct to return air opening fl ange
when no dampers are used. Otherwise, if dampers are
used, attach return air duct around collar at bottom of
damper assembly. Also refer to the Dimensional Data
section of this manual, Submittal Data Sheets and Indoor
Duct Furnace Manual specifi ed for your unit.
GAS PIPING††
All gas piping must be installed in accordance with local
codes. It is required that a ground union be installed
adjacent to the gas valve of each duct furnace, and
a ground union be installed just external of each duct
furnace for unit servicing. On vertical runs, a drip leg
should be provided upstream of any control manifold. A
gas shutoff valve should be, or may be required by local
codes, installed upstream of the external ground union
for each duct furnace. A 1/8 inch N.P.T. plugged tapping,
accessible for test gauge connection, must be installed
immediately upstream of the unit gas supply connection.
†† For complete Gas Piping installation, see the
Indoor Gas-Fired Duct Furnace Installation and
Service Manual.
Gas piping must be installed to allow for removal of
burner drawer for unit maintenance. Refer to Figure 5,
and the maintenance section.
To avoid equipment damage or
possible personal injury, do not connect gas
piping to this unit until a supply line pressure/
leak test has been completed. Connecting the
unit before completing the pressure/leak test may
damage the unit gas valve and result in a fi re hazard.
The appliance must be isolated from the gas supply piping
system by closing the individual manual shutoff valve
during any pressure testing of the gas supply piping system
at test pressures equal to or less than 1/2 psig (3.5 kPa).
For additional gas piping information, including pipe sizing
and drip leg installation, refer to Indoor Gas-Fired Duct
Furnace Installation and Service Manual.
For additional piping information, refer to the National
Fuel Gas Code Z233.1 (latest edition).
NOTICE: If the gas duct furnace is to be fi red with LP gas,
consult local LP gas dealer for piping size information.
NOTICE: Unit installation for use with propane
(bottled) gas must be made by a qualified LP
gas dealer or installer. He will insure proper joint
compounds are used for making pipe connections;
that air is purged from lines; that a thorough test is
made for leaks before operating the unit; and that it is
properly connected to propane gas supply system.
Before any connection is made to an e xisting line supplying
other gas appliances, contact the local gas company to
make certain that the existing line is of adequate size to
handle the combined load.
Check all connections for leaks with soap solution.
MODULATING GAS CONTROL (OPTIONAL)*
Mechanical: On units equipped with mechanical modulating
gas control, the temperature sensing bulb for the gas v alv e
must be fi eld installed in the supply plenum. Carefully uncoil
the capillary tubing to prevent kinking or sharp bends.
Do not rely on a gas shutoff valve to
isolate the unit while conducting gas pressure/leak
tests. These valves may not be completely shutoff,
exposing the unit gas valve to excessive pressure,
resulting in damage.
Do not over-tighten the inlet gas piping
at unit gas valve or stresses that could crack the
valve may result.
Never use an open fl ame to detect
gas leaks. Explosive conditions may e xist which
would result in personal injury or death.
The gas line should be supported so that no strain
is placed on the unit. Pipe compounds which are not
soluble to liquid petroleum gases must be used on
threaded joints.
— 8 —
1
/2" (12.7mm) of the connection to the bulb or the valve.
Do not bend the capillary tubing within
Repeated bending may cause the tubing to leak or break.
Center and fasten the temperature sensing bulb in the
supply duct at least 6 inches beyond the last duct furnace
section. See Figure 7.
Figure 7
6"
(152)
Min.
Supply Duc
Temperature Sensing
Bulb Mounted To "L"
Bracket Centered In
Supply Duct.
D8772
D8772
Duct
Furnace
AIR FLOW
Electronic: On units equipped with electronic modulating
control, follow control manufacturer’s installation
instructions for sensing of outlet air temperature.
*Also refer to the Indoor Duct Furnace Installation
Manual supplied with your unit.
ELECTRICAL CONNECTIONS
All electrical connections, line voltage and thermostat,
are made in the Electrical Cabinet (See Figure 8). Line
voltage connections are made at the High Voltage
Terminal Block. Thermostat connections are made at the
Main Connection Board (See Figure 9).
Do not use any tools (i.e. screwdriver,
pliers, etc.) across terminals to check for po wer. Use
of a voltmeter is recommended.
HAZARDOUS VOL TAGE!
DISCONNECT ALL ELECTRIC
POWER INCLUDING REMOTE
DISCONNECTS BEFORE
SERVICING. Failure to
Locate the thermostat in accordance with the instructions
supplied with the thermostat. All fi eld wir ing must have
a minimum temperature rating of 85°C (185°F). Control
wiring shall be a minimum of 18 gauge wire size. Control
wiring must be sized for length of run.
disconnect power before
servicing can cause severe
personal injury or death.
All electrical connections must conform to: ANSI/NFPA
No. 70-1996 (or latest edition) National Electrical Code
and applicable local codes. In Canada, to the Canadian
Locate line voltage disconnect box per local codes. If
mounting the disconnect box to the unit, never mount
it to a unit access panel. Possible locations include
the front of the blower or fi lter section (See Figure 10).
Electrical conduit must be routed so as not to interfere
with removal of any access panel.
Electrical Code, Part I CSA Standard C22.1.
NOTICE: Should any original wire supplied with the
The Make-Up Air packaged unit is wired at the factory
and ready to be connected. Actual unit wiring will differ
according to the options chosen. Each unit is shipped
unit have to be replaced, it must be replaced with
wiring having a temperature rating of at least 105°C
(221°F).
with its own wiring diagram; refer to this wiring diagram
for all electrical connections to the unit.
Figure 8 - Make-Up Air Unit-Standard Blower Cabinet, Single Duct Furnace with Various Options Shown
[Power Vented ME Unit Shown]
1. Mixed Air Controller
2. Return Firestat
3. Economizer
4. Filters
5. Blower Motor
6. Reverse Air Flow Switch
7. Clogged Filter Switch
8. High Voltage Barrier, Lamp
and Circuit Breaker Mount
9. Main Connection Board
with Fan Time Delay
and Function Relays
10. Power Venter Motor Assembly
(includes Relay and
Air Pressure Switch)
11. Junction Box/Ignitor
12. Time Delay Freezestat
13. Supply Firestat
14. Duct Thermostat
15. Primary Safety Limit
16. Gas Valve
17. High Limit Safety Switch
18. Transformer
19. Electrical Wiring Inlet
20. High Voltage Terminal Block
21. Door Safety Switch
22. Contactor
23. Centrifugal Blower
24. Damper Motor
25. Outside and Return Dampers
26. Ambient Lockout
— 9 —
Figure 9 - Electrical Cabinet
Figure 10 - Disconnect Box Locations
Disconnect Box Located On Outside Air Application
Return Air Inlet
Return Air Inlet
DX COIL EQUIPPED UNITS (OPTIONAL)
See Coil Installation/Maintenance Manual for Refrigerant
Piping, Liquid and Suction Line Components, Refrigerant
Charging and Thermal Expansion Valve Adjustment.
Remove coil cabinet access door located next to blower
section. Cut holes in fi xed door to allow suction and liquid
line passage. Provide weatherproof seal around suction
and liquid lines at piping plate when installed.
The DX Coil has a 300 ft/min. (1.524 m/s) minimum and
a 600 ft/min. (3.048 m/s) maximum velocity through the
coil requirement. This is due to prevention of coil icing or
condensate blow-off. To calculate the velocity through the
coil, apply the following formula:
Velocity =
Cooling Air Flow in CFM (m3/s)
through the coil Coil Surface Area in ft2 (m2)
Condensate Drain piping must have a P-trap in line
immediately downstream of drain pan connection,
external to the unit, to prevent possible outside air
leakage into unit. The P-trap shall be of sufficient
differential to overcome negative pressure of the indoor
air blower. A minimum height difference of 2" (51mm) is
required (See Figure 11). Before unit operation begins,
the P-trap must be primed with either water (summer) or
glycol (winter).
CHILLED WATER COIL
EQUIPPED UNITS (OPTIONAL)
See Coil Installation/Maintenance Manual for General
Coil Piping Recommendations. Remove coil cabinet
access door, cut holes in door to allow chilled w ater piping
passage. Provide weatherproof seal around chilled water
pipes at piping plate when installed.
The Chilled Water Coil has a 600 ft/min (3.048 m/s)
maximum velocity through the coil requirement. This is
due to prevention of condensate blow-off. To calculate
the velocity through the coil apply the following formula:
Velocity =
Cooling Air Flow in CFM (m3/s)
through the coil Coil Surface Area in ft2 (m2)
Condensate Drain piping must have a P-trap in line
immediately downstream of drain pan connection,
external to the unit, to prevent possib le outside air leakage
into unit. The P-trap shall be of suffi cient differential to
overcome negative pressure of the indoor air blower. A
minimum height difference of 2" is required (See Figure
11). Bef ore unit operation begins, prime P-trap with either
water (summer) or glycol (winter).
EVAPORATIVE COOLER
EQUIPPED UNITS (OPTIONAL)
Refer to Evaporative Cooler Installation and Service
Manual for water and electrical connections.
— 10 —
Drain Pan Connection
H
Total
Height
of Trap
X = 1/2 “H”
H = At Least 1 Inch Plus
Casing Static Pressure
D3887
Total Height Of Trap = X+ H + (1-1/2 X Pipe Diameter)
Unit
Housekeeping
Pad
X
IV. OPERATION
GENERAL INFORMATION
Refer to Indoor Gas-Fired Duct Furnace Installation and
Service Manual for specifi c information regarding the
heating operation of this unit.
All units are equipped with an intermittent ignition pilot
system. The pilot is lit and e xtinguished each cycle of unit
heating operation.
The gas valve consists of two operators which provide
gas to the pilot and main burners. Both operators are
energized and de-energized by the ignition control
module each heating cycle.
The pilot burner includes an ignitor and fl ame sense
probe. The ignitor provides the spark, originating at the
ignition control module, to light the pilot. The ignition
control module proves and monitors the pilot fl ame
through the fl ame sensing probe.
On natural gas units, the ignitor will continue to spark and
pilot gas will continue to fl ow until the pilot fl ame is proven.
LP (propane) units are equipped with 100% lockout. The
lockout function shuts off the main and pilot gas valves if
the pilot gas fails to ignite within 90 seconds of the onset
of trial for ignition.
The gas control system operates at 24 VAC and is
supplied by a stepdown transf ormer found in the electrical
cabinet that will match the unit line voltage specifi ed. See
Figure 8 for unit controls location.
Figure 11 - Drain Pan Connection
SEQUENCE OF OPERATION
All units follow the same basic sequence of operation
and is as follows (additional power vented sequences
are also described):
1. Thermostat calls for heat. (Po wer vented units only:
Draftor relay energizes draftor with call for heat).
2. Ignition control module energizes pilot operator of gas
valve and initiates spark at ignitor of the pilot burner.
3. Pilot burner ignition is proven to the ignition control
by the fl ame sense probe and sparking of the ignitor
is discontinued.
4. Once pilot burner operation is proven, the ignition
control module energizes the main burner operator
of the gas valve, allowing gas flow to the main
burners. (Pow er vented units only: In addition, draftor
operation must be proven b y dr aftor pressure s witch
before ignition control module energizes main burner
operator of gas valve).
5. Approximately 60 seconds after the main burners
light, the fan time delay initiates fan operation.
Do not use a thermostatic fan control switch when either
two-stage fi ring or modulated gas controls are used.
GAS CONTROL SYSTEM
The standard unit comes equipped for single stage
operation. Unit heating operation is accomplished at
full input.
Each duct furnace is equipped with an individual ignition
control system which consists of the following components:
ignition control module, gas valve and pilot burner.
The ignition control module is the heart of the ignition
control system. This control initiates all gas fl ow, provides
means to light the pilot burner, proves and monitors the
pilot burner operation.
6. Ther mostat is satisfied and call for heat is
removed. (Power vented units only: Draftor relay
de-energizes draftor with removal of call f or heat).
7. Ignition control module de-energizes pilot and main
burner operators of the gas valve , ceasing all gas fl ow.
8. Approximately two minutes after satisfying the
thermostat, fan operation ceases.
OPTIONAL GAS CONTROLS
These units are available with optional gas controls
which will give either multi-stage or modulating operation.
The sequence of operation of those units equipped with
these optional gas controls differs only at what rate each
duct furnace’s main burners ignite and operate at, or the
order of duct furnace fi ring for those units equipped with
two or three duct furnaces.
Two Stage Units: Two stages of heating; fi rst stage is
50% of full rate, second stage is 100% of full rate. Main
burner ignition is at fi rst stage only.
— 11 —
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