Kees INDIRECT FIRED GAS MAKE-UP AIR UNITS Maintenance Manual

INSTALLATION AND SERVICE MANUAL

(S) RISM-9

J30-05380A

OUTDOOR ROOFTOP GAS-FIRED DUCT FURNACE

(NATURAL OR POWER VENTED)

ATTENTION: READ THIS MANUAL AND ALL LABELS ATTACHED TO THE UNIT CAREFULLY
BEFORE ATTEMPTING TO INSTALL, OPERATE OR SERVICE THESE UNITS! CHECK UNIT DATA
PLATE FOR TYPE OF GAS AND ELECTRICAL SPECIFICATIONS AND MAKE CERTAIN THAT THESE
AGREE WITH THOSE AT POINT OF INSTALLATION. RECORD THE UNIT MODEL AND SERIAL No.(s)
IN THE SPACE PROVIDED. RETAIN FOR FUTURE REFERENCE.

Model No. Serial No.

SAVE THIS MANUAL

FOR YOUR SAFETY
The use and storage of gasoline or other flammable vapors and liquids in open
containers in the vicinity of this appliance is hazardous.

FOR YOUR SAFETY

If you smell gas:

1. Don’t touch electrical switches.

2. Extinguish any open flame.

3. Immediately call your gas supplier.

Improper installation, adjustment, alteration, service or maintenance can
cause property damage, injury or death. Read the installation, operating and
maintenance instructions thoroughly before installing or servicing this equipment.

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.

INSTALLER'S RESPONSIBILITY

Installer Please Note: This equipment has been test fired and inspected. It has been shipped

free from defects from our factory. However, 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.

These units are certified by CSA International for operation on either natural or propane gas.

Read this manual and all labels attached to the unit carefully before attempting to install, operate or

service the following unit models:*

Outdoor Rooftop Duct Furnaces: QV(RT/PV)- (100, 150, 200, 250, 300, 350, 400) (H)(M)

(RT = Natural Vent; PV = Power Vent)

*L

ook in the direction of the unit air flow to determine whether the unit is right or left-hand accessible.

HVAC PRODUCTS

260 NORTH ELM ST., WESTFIELD, MA 01085

TEL: [phone] FAX: [phone]

http://www.mestek.com

TABLE OF CONTENTS

RECEIVING/PRE-INSTALLATION

INSTRUCTIONS .................................................... 2

GENERAL SAFETY INFORMATION .................. 2, 3

SPECIFICATIONS

Dimensional Data ........................................ 4, 5

Performance and Specification Data ............... 5

Performance Data Curves ........................... 6, 7

INSTALLATION

Location/Mounting ................................... 2, 3, 8

Clearances ............................................... 4, 5, 8

Venting ............................................................. 9

Duct and Drain Specifications ........................ 10

Gas Connections ............................... 10, 11, 12

Electrical Connections ................................... 12

OPERATION

General Information ................................. 13, 14

Auto Spark Parts ............................................ 13

Controls ......................................................... 14

Gas Controls ...................................... 14, 15, 16

Air Distribution/Throughput ............................ 17

Lighting .................................................... 17, 18

Primary air Shutter/Pilot Adjustment .............. 18

Gas Input Adjustment .................................... 19

START-UP ...................................................... 19, 20

MAINTENANCE .............................................. 20, 21

TROUBLE SHOOTING GUIDE........................ 22-25

REPLACEMENT PARTS ...................................... 26

WARRANTY.......................................................... 26

GAS EQUIPMENT CHECK SHEET...................... 27

The following terms are used throughout this manual to
bring attention to the presence of potential hazards or to
important information concerning the product:

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 the latch does not hold,
turn the screw counter-clockwise several turns and
repeat the above procedure. Also refer to Figures 8Aa,
8b and 8c. for more specifications.

RECEIVING INSTRUCTIONS

Inspect shipment immediately when received to
determine if any damage has occurred to the
carton/crate during shipment.

After the unit has been uncrated, check for any visible
damage to the unit. On power vented units, check
motor position and turn blower wheel by hand 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
file claim for damage with the transportation company.

PRE-INSTALLATION INSTRUCTIONS

When unit is received and uncrated check data plate
on unit for type of gas and electrical specifications and
make certain that these agree with those at point of
installation.

Open all disconnect switches
and secure in that position before installing the
unit. Failure to do so may result in personal
injury or death from electrical shock.

Indicates an imminently hazard­ous situation which, if not avoided, 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.

SERVICE ACCESS PANEL REMOVAL

To remove an access panel door, use the following
procedure: remove the two screws and two washers
from the louvered flue discharge area of the service
panel (power vent doors only). Each panel is held in
place with two “Grip” Latches. Using a slotted head
screw driver, turn the latch screwhead counter
clockwise. Using the handle provided, pull the panel
upwards. Pull the bottom of the panel out and lower the
panel to disengage it from the top lip. To replace an
access door panel, guide the panel door upwards on the

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.

RIGGING

Rig the unit using either belt or cable slings. Use
spreader to protect the top of the unit when it is lifted.

The furnace units are provided with two holes in the
base rail on each side of the unit. Slide pipes beneath
the unit through these holes and attach rigging to the
pipes for lifting the unit.

LOCATION

Before placing the rooftop unit in its permanent
location, make certain that the roof is capable of
carrying the additional load of this equipment. Check
the shipping weights given in Chart 2.

Refer to Figures 1, 2 and 6 and charts 1 and 2 for
adequate unit dimensions and required clearances.

MOUNTING

The units are mounted on skids and are suitable for
use on combustible flooring. It is recommended that the
skids be mounted either on level solid planking or steel
channels, but never on a soft tar roof where the skids
could sink and reduce the clearance between the
bottom panel and the roof.

– 2 –

GENERAL SAFETY INFORMATION

Roofcurb kits for rooftop gas heating units are shipped
knocked down. A curb kit contains (insulated) curb
rails, hardware, sealant, self-adhering rubber
gasketing, and installation instructions. Roof insulation,
cant strips, flashing, roof felts, caulking and nails must
be furnished by the installer. See separate curb
specifications from manufacturer.

Failure to comply with the
general safety information may result in
extensive property damage, severe personal
injury or death!

Do not alter the unit heater in
any way or damage to the unit and/or severe
personal injury or death may occur!

Never service any component
without first disconnecting all electrical and
gas supplies to the unit or severe personal
injury or death may occur!

Ensure that all power sources
conform to the requirements of the unit heater or
damage to the unit will result!

vent through a protective grille, and the design of the
vent cap is such that the products of combustion are
discharged at the upper section of the cap. This cap is
shipped in a separate carton. It should be fastened in
position as shown in Figure 7 and should not be

altered in any way.

The Power Vented unit has a power venting system
with the inlet and discharge grille located in the upper
section of the side access panel. This balanced flue
design also performs well under all wind conditions.

All internal parts of the standard unit are fabricated
from aluminized steel. Standard burners are pressed
aluminized steel and have a stainless steel burner port
protector and air shutters. All internal and external
jacket parts are fabricated from galvanized steel.
Stainless steel heat exchangers, burners and flue
collectors are optional. An optional 321 or 409 stainless
steel heat exchanger is highly recommended for the
following applications:

1) When the entering air temperature is below
40°F (4.4°C).

2) When the furnace is installed downstream of a
cooling coil section.

Installation must be made in accordance with local
codes, or in absence of local codes, with ANSI
Standard Z223.1-1999 (N.F.P.A. No. 54) National Fuel
Gas Code, or the latest edition. All of the ANSI and
NFPA Standards referred to in these installation
instructions are those that were applicable at the time
the design of the appliance was certified. 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, MA 02269.

If installed in Canada, the installation must conform
with local building codes, or in absence of local building
codes, with current CGA-B149.1 “Installation Codes for
Natural Gas Burning Appliances and Equipment” or
CGA-B149.2 “Installation Codes for Propane Gas
Burning Appliances and Equipment”. These outdoor
duct furnaces have been designed for and certified to
comply with CGA 2.8.

These units have been designed and certified for
outdoor use only, and may be located on the roof of the
building or at any convenient location external of the
building to be heated. The input range is 100,000 BTU/
HR. (29.3 kW) to 400,000 BTU/HR. (117.1 kW) in 50,000
BTU/HR. (14.6 kW) increments.

A pilot burner plate is provided for access to the pilot
burner and ignition systems without removing the
burner drawer. Clearances between the external unit
and obstruction must be sufficient for proper servicing
of pull-out drawer. See Figures 1 and 2 for this
clearance.

The outdoor units are certified for operation on either
natural or propane gas. If a unit is to be installed at an
altitude exceeding 2000 ft. (610 m) above sea level,
derate the input by 4% for each 1000 foot rise (305 m
rise) above sea level. Check all local codes.

Special orifices are required for installations above
2000 ft. (610 m). Check all local codes.

In Canada, if a unit is to be installed at altitudes of
2000 ft. (610 m) to 4500 ft. (1372 m), the unit must be
orificed to 90% of the normal altitude rating.

Unless otherwise specified, the following conversions
may be used for calculating SI unit measurements:
1 inch = 25.4 mm
1 foot = 0.305 m
1 gallon = 3.785 L
1 pound = 0.435 kg
1 psig = 6.894 kPa
1 cubic foot = 0.028 m

1000 Btu/Cu. Ft. = 37.5 MJ/m
1000 Btu per hour = 0.293 kW
1 inch water column = 0.249 kPa
liter/second = CFM x 0.472
meter/second = FPM ÷ 196.8

3

3

The venting is an integral part of the unit and must not
be altered in the field. The Natural Vented units are
equipped with a vent cap which is designed for gravity
venting. Air for combustion enters at the base of the

– 3 –

SPECIFICATIONS

Figure 1 - Standard Natural Vented Outdoor Duct Furnace

1" (25)

Typ.

26"

(660)

Vent Cap
Is Shipped
In Separate
Carton

A

C (Typ.)

C

L

D

19"

(483)

Opening

10-1/8"

13/16" (21) Typ.
Anchor Hole
Location

(991)

(257)

4" (102)

39"

Electrical
Connections

5/8" (16) Typ.
Anchor Hole
Location

DFR3538A
TFR3779A

31-1/4"

(794)

Gas
Connection

5-1/16"

(129)

8-3/4"

(222)

1-1/8" (29)

Typ. Duct

Flange

*

F

B

Opening Typ.

K

Chart 1 - Dimensional/Data

CAPACITY US CANADA GAS INLET

(CA) ABCDD*FKNATLP

10 32-7/8 15-9/16 12 11 20-11/16 19-3/8 30-3/16 1/2 1/2

15 32-7/8 18-5/16 21-1/2 16 25-3/16 23-1/2 30-3/16 1/2 1/2

20 43-7/8 23-13/16 23-1/2 16 25-3/16 26-1/4 41-3/16 1/2 1/2

25 43-7/8 29-5/16 23-1/2 16 25-3/16 34-1/2 41-3/16 3/4 1/2 OR 3/4

30 54-7/8 34-13/16 26 17-1/2 26-11/16 37-1/4 52-3/16 3/4 1/2 OR 3/4

35 54-7/8 40-5/16 26 17-1/2 26-11/16 45-1/2 52-3/16 3/4 1/2 OR 3/4

40 60-3/8 45-13/16 26 17-1/2 26-11/16 51 57-11/16 3/4 1/2 OR 3/4

NOTE:
DIMENSIONS ARE IN INCHES, DIMENSIONS IN PARENTHESIS ARE IN MILLIMETERS.
* “F” DIMENSION IS THE RECOMMENDED CLEARANCE TO SERVICE THE BURNER DRAWER(S).

REFER TO FIGURE 6 FOR ADDITIONAL CLEARANCE REQUIREMENTS.

(835) (395) (305) (279) (525) (492) (767)

(835) (465) (546) (406) (640) (597) (767)

(1114) (605) (597) (406) (640) (667) (1046)

(1114) (745) (597) (406) (640) (876) (1046)

(1394) (884) (660) (445) (678) (946) (1326)

(1394) (1024) (660) (445) (678) (1156) (1326)

(1534) (1164) (660) (445) (678) (1295) (1465)

Figure 2 - Standard Power Vented Outdoor Duct Furnace

1" (25)

Typ.

Flue
Product
Outlet

Combustion
Air Inlet

Electrical
Connections

5/8" (16) Typ.
Anchor Hole
Location

DFR3541A
TFR3779 A

26"

(660)

31-1/4"

(794)

Gas
Connection

5-1/16"

(129)

8-3/4"

(222)

1-1/8" (29)

Typ. Duct

Flange

*

F

– 4 –

A

C

L

B

Opening Typ.

K

19"

(483)

Opening

(991)

10-1/8"

(257)

4" (102)

13/16" (21) Typ.
Anchor Hole
Location

39"

Chart 2 - Performance and Specification Data

F* Nat. L.P.

INPUT OUTPUT Temp. Rise Min. Gas Gas Net Shipping

CAPACITY RATING RATING EFF. MIN. MAX. F Deg. Static Clearance Inlet Inlet Weight Weight

MBH BTU/Hr BTU/Hr % CFM CFM (C Deg.) in. of Water in. in. in. lb. lb.

(kW) (kW) (cu. m/s) (cu. m/s) Min. - Max. (KPa) (mm) (kg) (kg)

100 100,000 80,000 80 823 2,469 30 - 90 2 7-1/8 1/2 1/2 202 221

150 150,000 118,500 79 1,219 3,657 30 - 90 2 11-1/4 1/2 1/2 228 247

200 200,000 158,000 79 1,626 4,876 30 - 90 2 14 1/2 1/2 283 304

250 250,000 197,500 79 2,032 6,096 30 - 90 2 22-1/4 3/4 1/2 OR 3/4 309 330

300 300,000 237,000 79 2,438 7,315 30 - 90 2 34 3/4 1/2 OR 3/4 365 387

NATURAL VENT

350 350,000 276,500 79 2,845 8,534 30 - 90 2 33-1/4 3/4 1/2 OR 3/4 391 413

400 400,000 316,000 79 3,251 9,753 30 - 90 2 38 3/4 3/4 1/2 OR 3/4 427 459

100 100,000 79,000 79 813 2,438 30 - 90 2 7-1/8 1/2 1/2 200 219

150 150,000 118,500 79 1,219 3,657 30 - 90 2 11-1/4 1/2 1/2 223 242

200 200,000 158,000 79 1,626 4,876 30 - 90 2 14 1/2 1/2 270 291

250 250,000 197,500 79 2,032 6,096 30 - 90 2 22-1/4 3/4 1/2 OR 3/4 296 317

300 300,000 237,000 79 2,438 7,315 30 - 90 2 34 3/4 1/2 OR 3/4 343 365

POWER VENT

350 350,000 276,500 79 2,845 8,534 30 - 90 2 33-1/4 3/4 1/2 OR 3/4 369 391

400 400,000 316,000 79 3,251 9,753 30 - 90 2 38-3/4 3/4 1/2 OR 3/4 405 437

(29.3) (23.4) (0.388) (1.165) (17) - (50) (0.50) (181) (92) (100)

(43.9) (34.7) (0.575) (1.726) (17) - (50) (0.50) (286) (103) (112)

(58.6) (46.3) (0.767) (2.301) (17) - (50) (0.50) (356) (128) (138)

(73.2) (57.8) (0.959) (2.877) (17) - (50) (0.50) (565) (140) (150)

(87.8) (69.4) (1.151) (3.453) (17) - (50) (0.50) (864) (166) (176)

(102.5) (81.0) (1.343) (4.028) (17) - (50) (0.50) (845) (177) (187)

(117.1) (92.5) (1.534) (4.603) (17) - (50) (0.50) (984) (194) (208)

(29.3) (23.1) (0.384) (1.151) (17) - (50) (0.50) (181) (91) (99)

(43.9) (34.7) (0.575) (1.726) (17) - (50) (0.50) (286) (101) (110)

(58.6) (46.3) (0.767) (2.301) (17) - (50) (0.50) (356) (123) (132)

(73.2) (57.8) (0.959) (2.877) (17) - (50) (0.50) (565) (134) (144)

(87.8) (69.4) (1.151) (3.453) (17) - (50) (0.50) (864) (156) (166)

(102.5) (81.0) (1.343) (4.028) (17) - (50) (0.50) (845) (167) (177)

(117.1) (92.5) (1.534) (4.603) (17) - (50) (0.50) (984) (184) (198)

100H 100,000 80,000 80 1,235 3,704 20 - 60 2 7 1/8 1/2 1/2 199 218

**

150H 150,000 120,000 80 1,852 5,556 20 - 60 2 11-1/4 1/2 1/2 226 245

200H 200,000 160,000 80 2,469 7,407 20 - 60 2 14 1/2 1/2 281 302

250H 250,000 200,000 80 3,086 9,259 20 - 60 2 22-1/4 3/4 1/2 OR 3/4 306 327

300H 300,000 240,000 80 3,704 11,111 20 - 60 2 34 3/4 1/2 OR 3/4 362 384

NATURAL VENT

350H 350,000 280,000 80 4,321 12,963 20 - 60 2 33-1/4 3/4 1/2 OR 3/4 387 409

400H 400,000 320,000 80 4,938 14,815 20 - 60 2 38-3/4 3/4 1/2 OR 3/4 423 455

100H 100,000 80,000 80 1,235 3,704 20 - 60 2 7-1/8 1/2 1/2 197 216

**

150H 150,000 120,000 80 1,852 5,556 20 - 60 2 11-1/4 1/2 1/2 221 240

200H 200,000 160,000 80 2,469 7,407 20 - 60 2 14 1/2 1/2 268 289

250H 250,000 200,000 80 3,086 9,269 20 - 60 2 22-1/4 3/4 1/2 OR 3/4 293 314

300H 300,000 240,000 80 3,704 11,111 20 - 60 2 34 3/4 1/2 OR 3/4 340 362

POWER VENT

350H 350,000 280,000 80 4,321 12,963 20 - 60 2 33-1/4 3/4 1/2 OR 3/4 365 387

400H 400,000 320,000 80 4,938 14,815 20 - 60 2 38-3/4 3/4 1/2 OR 3/4 401 433

(29.3) (23.4) (0.583) (1.748) (11) - (33) (0.50) (181) (90) (99)

(43.9) (35.1) (0.874) (2.622) (11) - (33) (0.50) (286) (103) (111)

(58.6) (46.9) (1.165) (3.496) (11) - (33) (0.50) (356) (127) (137)

(73.2) (58.6) (1.457) (4.370) (11) - (33) (0.50) (565) (139) (148)

(87.8) (70.3) (1.748) (5.244) (11) - (33) (0.50) (864) (164) (174)

(102.5) (82.0) (2.040) (6.119) (11) - (33) (0.50) (845) (176) (186)

(117.1) (93.7) (2.331) (6.993) (11) - (33) (0.50) (984) (192) (206)

(29.3) (23.4) (0.583) (1.748) (11) - (33) (0.50) (181) (89) (98)

(43.9) (35.1) (0.874) (2.622) (11) - (33) (0.50) (286) (100) (109)

(58.6) (46.9) (1.165) (3.496) (11) - (33) (0.50) (356) (122) (131)

(73.2) (58.6) (1.457) (4.375) (11) - (33) (0.50) (565) (133) (142)

(87.8) (70.3) (1.748) (5.244) (11) - (33) (0.50) (864) (154) (164)

(102.5) (82.0) (2.040) (6.119) (11) - (33) (0.50) (845) (166) (176)

(117.1) (93.7) (2.331) (6.993) (11) - (33) (0.50) (984) (182) (196)

* See figures 1 and 2. ** “H” indicates low temperature rise furnace.

The clearances dimensions shown in chart #2 are the absolute minimum clearances for servicing the burner drawer. However, the clearances
shown in chart #1 are the

recommended

clearances for ease of servicing the unit.

– 5 –

PERFORMANCE DATA CURVES

Figure 3 - High Temperature Rise Duct Furnaces — 30-90 F° (17-50 C°)

Pressure drop through the heat exchanger is based on
the CFM throughput. The desired data is obtained in
the following manner:

1. Select heater size based on heat loss of the building
to be heated.

2. Select temperature rise desired.

3. Based on temperature rise, the horizontal line inter­sects heater temperature vs. CFM curve.

Figure 4 - Low Temperature Rise Duct Furnaces — 20-60 F° (11-33 C°)

4. Follow vertical line down to select CFM.

5. For pressure drop selection, follow vertical CFM line
until it intersects the selected heater performance
curve vs. pressure drop.

6. Follow the horizontal pressure drop line to the left,
and read pressure drop of the selected heater.

– 6 –

BYPASS SIZING INFORMATION

(BUILT ON THE JOB – NOT FURNISHED BY
FACTORY)

On occassion when a duct furnace is incorporated in
an air handling system, it may be desirable to handle a
total of more CFM than the duct furnace will pass at a
given static pressure drop and temperature rise. There­fore, it is necessary to arrange to bypass the additional
CFM required. The size of the bypass duct can be
determined by referring to the chart. This permits the
static pressure drop through the bypass to balance off
the drop through the heat exchanger. The bypass duct
is not factory furnished and must be built on the job by
the installer and a damper placed therin if required.

Figure 5 - By-Pass Curve

USE OF BYPASS CURVES

The width of the by-pass for CFM in excess of that
provided through the heater may be found in the
following manner:

1. Determine the CFM and pressure drop through the
heater based on the heating requirement
specifications.

2. Determine the additional CFM desired, over and
above the CFM for the heating requirements.

3. Using the pressure drop which was determined from
performance curves above, for the heating load,
locate this pressure drop on the by-pass curves.
Follow this curve until it intersects thevertical CFM
line for the excess CFM desired.

4. Follow horizontal line to left to obtain width of by-pass
duct.

– 7 –

INSTALLATION

5

Open all disconnect switches and
secure in that position before installing unit.
Failure to do so may result in personal injury or
death from electrical shock.

Installation must conform with local building codes,
or in the absence of local codes, with the National
Fuel Gas Code ANSI Z223.1-1999, or the latest
edition.

A heat loss study and a complete layout of the system
should be made first.

When locating the unit in its permanent location, make
certain that the roof is capable of carrying the additional
load of the equipment. Check the net weights from the

engineering data.

Make certain that clearances are provided for service,
minimum clearance to combustible material and to
venting cap. See below for this information. Service
clearance information is given in the engineering data in
Figures 1, 2 and 6. Clearances around secondary air
must be unobstructed.

If the unit is installed downstream of refrigeration coils,
condensate will form and collect in the bottom of the
heater. Drain connections are provided to dispose of this
condensate from the unit. Connect drain pipes to
dispose of this condensate where necessary. Ducts

which are outdoors must be insulated and sealed to
prevent water from entering either furnace or
building through duct (see section on duct and drain
specifications).

Ducts connected to duct furnaces shall have removable
access panels on both upstream and downstream sides
of the unit. These openings shall be accessible when the
unit is installed in service, and shall be of such size that
smoke or reflected light may be observed inside the
casing to indicate the presence of leaks in the heating
element. The covers for the openings shall be attached
in such a manner as to prevent leaks.

If a duct furnace is connected to a return air duct or
any other inlet air restriction, the appliance shall be
installed on the positive pressure side of the air­circulating blower.

Atmospheres containing solvents or chlorinated
hydrocarbons will produce corrosive acids when coming
in contact with the flames. This will greatly reduce the life
of the gas duct furnace and may void the warranty. Avoid
such areas.

CLEARANCES

Minimum clearances are shown in Figures 1, 2 & 6 and
charts 1 & 2. It is important that clearances be main­tained for servicing the unit (refer to Figures 1 & 2 for
clearances necessary to pull out the burner drawer for
servicing), and that minimum clearances are provided
from combustible material and from the venting cap/top
of unit. Clearances around the outside air hood must be
unobstructed.

Provide adequate clearance from
combustibles to prevent injury or death from
fire.

Figure 6 - Minimum Clearances to Combustible Material or Obstructions

18"

(457)

18"

(457)

/16"
(8)

Natural

Ductwork

D3589A

(or Power)

Vent

Furnace

D3589

18"

(457)

Air Flow

*See figures 1 & 2 and charts 1 & 2.

5/16"

(8)

5/16" (8) Typ.

Clearance

For Drawer

Pul-out

36"

(914)

Power Vent Units required 36"
clearance above top of unit.

36"

(914)

18"

(457)

– 8 –

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 Z223.1-1999, or
applicable provisions of local building codes”.

Natural venting models are equipped with a vent cap
designed for natural venting. Air for combustion enters
at the base of the vent through a protective grille, and the
design of the vent cap is such that the products of
combustion are discharged at the upper section of the
cap. The cap is shipped in a separate carton. It should
be fastened in position as shown in Figure 7 and should
not be altered in any way.

The venting is an integral part of
the unit and must not be altered in the field. If
altered, excessive carbon monoxide could be
produced.

Figure 7 - Vent Cap Assembly
(Natural Vented Furnaces Only)

1

2

4

Power vented models are designed with combustion
air inlet and flue products outlet located in the louvered
side access panel. Never locate these units in an area
where the flue products outlet may be directed at any
fresh air vents.See Figures 8a 8b, and 8c for
installation and servicing requirements.

Figure 8a - Power Venter Discharge Location

TOP VIEW

Neoprene Washers

*These Surfaces (indicated with an asterisk in figures 8a & 8b)
MUST be flush and sealed at all times to ensure the proper
discharge of flue products from the unit.

These discharge flanges are equipped with special gasketing,
which must create an air tight seal connection around the louvers
of the access panel.

Secure in place the access door to the discharge adaptor using the
two screws and neoprene washers, then tighten the grip
latches (see service access panel removal section).

Screws

D3505

3

3591

LEFT

REAR

FRONT

RIGHT

D3591

FIELD INSTALLATION INSTRUCTIONS

1. Remove “Side Access Panel”.

2. Insert Vent Sleeve of “Vent Cap Assembly” (Item 1)
thru “Top Panel Assembly” (Item 2), and over Vent
Collar of “Flue Collector Assembly” (Item 3).

3. Align “Vent Cap Assembly” so it is square to “Top
Panel Assembly”.

4. Fasten with “Drill Screw” or “Sheet Metal Screw”
(Item 4) by reaching between “Flue Collector
Assembly” (Item 3) & “Top Panel Assembly” (Item

2), and drilling through vent sleeve of “Vent Cap
Assembly” into vent collar of “Flue Collector
Assembly”.

5. Replace “Side Access Panel”.

Figure 8b

D3725

Figure 8c

NOTICE: If your unit is to be equipped with the
optional extended vent cap assembly, see the special
instructions supplied with the vent cap.

D4596

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