Portions of the text and tables are reprinted from NFPA 54 /ANSI Z223.1−2012©, with permission of National Fire Protection Association, Quincy, MA 02269 and American Gas Association, Washington,

DC 20001. This reprinted material is not the complete and official position of the NFPA or ANSI, on the referenced subject, which is represented only by the standard in its entirety.

Printed in U.S.A.

80% Two−Stage, PSC Motor

Category I, Gas Furnace

F8MTL & G8MTL

Safety Labeling and Signal Words

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Signal Words in Manuals

The signal word WARNING is used throughout this manual in the

following manner:

The signal word CAUTION is used throughout this manual in the

following manner:

Signal Words on Product Labeling

Signal words are used in combination with colors and/or pictures

or product labels.

Safety−alert symbol

When you see this symbol on the unit and in instructions or manu-

als, be alert to the potential for personal injury.

Use of the AHRI Certified TM Mark indicates a

manufacturer's participation in the program. For

verification of certification for individual products,

go to www.ahridirectory.org .

WARNING

PERSONAL INJURY, AND/OR PROPERTY

DAMAGE HAZARD

Failure to carefully read and follow this warning could

result in equipment malfunction, property damage,

personal injury and/or death.

Installation or repairs made by unqualified persons

could result in equipment malfunction, property

damage, personal injury and/or death.

The information contained in this manual is intended for

use by a qualified service technician familiar with safety

procedures and equipped with proper tools and test

instruments.

Installation must conform with local building codes and

with the Natural Fuel Gas Code (NFCG) NFPA

54/ANSI Z223.1, and National standards of Canada

CAN/CSA−B149.1 and .2 Natural Gas and Propane

Installation Codes.

INSTALLER: Affix these instructions on or adjacent to the furnace.

CONSUMER: Retain these instructions for future reference.

WARNING

CAUTION

441 01 2101 05

5/2/2016

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Summary of Contents for Tempstar F8MTL

Page 1: Table Of Contents
INSTALLATION INSTRUCTIONS 80% Two−Stage, PSC Motor Category I, Gas Furnace F8MTL & G8MTL These instructions must be read and understood completely before attempting installation. Safety Labeling and Signal Words DANGER, WARNING, CAUTION, and NOTE Signal Words in Manuals The signal words DANGER, WARNING, CAUTION, and NOTE...
Page 2 Figure 1 − Dimensional Drawing NOTES: 1. Two additional 7/8-in. (22 mm) diameter holes are located in the top plate. 2. Minimum return-air openings at furnace, based on metal duct. If flex duct is used, see flex duct manufacturer's recommendations for equivalent diameters. a.
Page 3: Safety Considerations
SAFETY CONSIDERATIONS damage. NOTE is used to highlight suggestions which will result in enhanced installation, reliability, or operation. WARNING product and property damage. NOTE is used to highlight suggestions which will result in enhanced installation, reliability, or operation. FIRE, EXPLOSION, ELECTRICAL SHOCK, AND 1.
Page 4: Introduction
END4X, ENW4X, or when the manufacturer’s coil casing F8MTL & G8MTL 4−way multipoise Category I fan−assisted model number NAEA is used. See Figure 2 for clearance to furnace is CSA (formerly A.G.A. and C.G.A.) design−certified.
Page 5: Step 3 - Combustion And Ventilation Air
Step 3 — Combustion and Ventilation Air 3. After touching the chassis, you may proceed to service the control or connecting wires as long as you do Section 9.3 of the NFGC, NFPA 54/ ANSI Z223.1−2012 Air nothing to recharge your body with static electricity (for for Combustion and Ventilation example;...
Page 6: Location
LOCATION S Water softening chemicals S De−icing salts or chemicals GENERAL S Carbon tetrachloride This multipoise furnace is shipped in packaged configuration. S Halogen type refrigerants Some assembly and modifications are required when used in S Cleaning solvents (such as perchloroethylene) any of the four applications shown in Figure 4.
Page 7: Air For Combustion Andventilation
AIR FOR COMBUSTION AND Figure 6 − Prohibit Installation on Back VENTILATION Provisions for adequate combustion, ventilation, and dilution air must be provided in accordance with: U.S. installations: Section 9.3 of the NFPA 54 /A ANSI Z223.1−2012, Air for Combustion and Ventilation, and applicable provisions of the local building codes.
Page 8: Minimum Free Area Required
d. TWO OPENINGS OR VERTICAL DUCTS require 1 b. Not less than the sum of the areas of all vent −in of free area per 4,000 Btuh (550 mm /kW) for connectors in the space. combined input of all gas appliances in the space per Figure 7 and Table 2 3.
Page 9 2. The air infiltration rate is not known to be less than 0.40 WARNING air changes per hour (ACH). The Known Air Infiltration Rate Method shall be used, if the CARBON MONOXIDE POISONING HAZARD infiltration rate is known to be: 1.
Page 10: Installation
Combination of Indoor and Outdoor Air closure panel, see item 1 in Bottom Return Air Inlet section in Step 1 above. 1. Indoor openings shall comply with the Indoor Combustion Air Method below and, To install leveling legs: 2. Outdoor openings shall be located as required in the 1.
Page 11 Figure 11 − Furnace, Plenum, and Subbase installed on HORIZONTAL INSTALLATION a Combustible Floor The furnace can be installed horizontally in an attic or crawl space on either the left−hand (LH) or right−hand (RH) side. The furnace can be hung from floor joists, rafters or trusses or FURNACE installed on a non−combustible platform, blocks, bricks or (OR COIL CASING...
Page 12 combustible deck or suspended furnaces closer than 12 1. Tilt or raise furnace and remove two (2) screws holding inches (305 mm) to joists. The sheet metal MUST extend bottom filler panel. (See Figure 9) underneath the furnace casing by 1 in. (25 mm) with the door 2.
Page 13 Figure 15 − Horizontal Unit Suspension " (6mm) THREADED ROD 4 REQ. OUTER DOOR A S SEMBLY SECURE ANGLE IRON TO BOTTOM OF FURNACE WITH 3 #8 x " (19mm) SCREWS TYPICAL FOR 2 SUPPORTS 8" (203mm) MIN FOR DOOR REMOVAL 1”...
Page 14 Figure 17 − Typical Attic Installation LINE CONT A CT ONL Y PERMISSIBLE BETWEEN LINES FORMED BY INTERSECTIONS OF THE T OP AND TW O SIDES OF THE FURNA CE JA CKET AND BUILDING JOISTS , STUDS , OR FRAMING. ″...
Page 15 Table 5 – Air Delivery − CFM (With Filter)* FURNACE RETURN-AIR EXTERNAL STATIC PRESSURE (IN. W.C.) SPEED SIZE INLET High 1465 1400 1325 1250 1175 1085 Med-High 1295 1260 1210 1155 1090 1015 Bottom or 0451412 Medium 1150 1120 1085 1040 Side(s) Med-Low...
Page 16 WARNING FIRE OR EXPLOSION HAZARD Failure to protect gas valve inlet from water and debris could result in death, personal injury and/or property damage. Gas valve inlet and/or inlet pipe must remain capped until gas supply line is permanently installed to protect the valve from moisture and debris.
Page 17: Table 6 – Maximum Capacity Of Pipe
Figure 20 − Horizontal Return Air Configurations and Restrictions 5 TONS AND GREATER * * 2000 CFM AND GREATER AT .6 ESP HI COOLING SPEED Gas piping must be installed in accordance with national and WARNING local codes. Refer to current edition of NFGC in the U.S. Table 6 –...
Page 18 Figure 21 − Burner and Manifold Figure 22 − Typical Gas Pipe Arrangement SUPPLY MANUAL SHUTOFF VALVE (REQUIRED) SEDIMENT TRAP UNION 2” (51mm) Street Elbow A08551 Install a sediment trap in riser leading to furnace as shown in Figure 22. Connect a capped nipple into lower end of tee. A02035 Capped nipple should extend below level of furnace gas controls.
Page 19 CAUTION WARNING ELECTRICAL SHOCK HAZARD FURNACE MAY NOT OPERATE HAZARD Failure to follow this warning could result in personal Failure to follow this caution may result in intermittent injury or death. furnace operation. Blower access panel door switch opens 115−v power Furnace control must be grounded for proper to control.
Page 20 Figure 24 − Relocating J−Box NOTE: Check that duct on side of furnace will not interfere with installed electrical box. 2. Remove the desired electrical box hole knockout and position the hole in the electrical box over the hole in FACTORY the furnace casing.
Page 21 Figure 26 − Two−Stage Furnace with Single−Speed Air Figure 28 − Two−Stage Furnace with Single−Stage Heat Conditioner Pump (Dual Fuel) Figure 27 − Two−Stage Furnace with Two−Stage Air Conditioner Figure 29 − Two−Stage Furnace with Two−Stage Heat Pump (Dual Fuel) 441 01 2101 05 Specifications are subject to change without notice.
Page 22 Figure 30 − Two−Stage Furnace and Humidifier Only For Figure 26 − Figure 32 1. Refer to outdoor equipment Installation Instructions for additional information and setup procedure. 2. Outdoor Air Temperature Sensor must be attached in all dual fuel application. 3.
Page 23 Figure 33 − Furnace Control−PSC Blower Motor SETUP SWITCHES THER- TWINNING AND/OR MOSTAT TYPE AND HEAT COMPONENT TEST OFF−DELAY TERMINAL 24−V THERMOSTAT TERMINALS 24VAC HUMIDIFIER TERMINAL (24−VAC 0.5 AMP MAX) TRANSFORMER 24VAC CONNECTIONS 3−AMP FUSE P1 − LOW VOLTAGE MAIN COM/BLUE 24VAC/RED HARNESS CONNECTOR...
Page 24 The following information and warning must be considered in WARNING addition to the requirements defined in the NFGC. WARNING CARBON MONOXIDE POISONING HAZARD Failure to follow this warning could result in personal injury or death. CARBON MONOXIDE POISONING HAZARD Failure to follow the steps outlined below for each Failure to follow this warning could result in personal appliance connected to the venting system being placed injury or death.
Page 25 Figure 34 − Chimney Inspection Chart A10133 441 01 2101 05 Specifications are subject to change without notice.
Page 26 The Chimney Adapter Kit is a listed alternative venting Exterior Masonry Chimney FAN + NAT system for these furnaces. See the kit instructions for Installations with Type−B Double−Wall Vent complete details. Connectors ENFPA & AGA This furnace is permitted to be vented into a clay tile−lined masonry chimney that is exposed to the outdoors below the Table 8 –...
Page 27 APPLIANCE APPLICATION REQUIREMENTS be required for some model furnaces. A field−supplied 4 in. to 5 in. (102 to 127 mm) or 4 in. to 6 in. (102 mm to 152 mm) Appliance operation has a significant impact on the sheet metal increaser fitting is required when 5 in. or 6 in. performance of the venting system.
Page 28 Figure 37 − Downflow Application−Vent Elbow Up then Figure 39 − Downflow Application−Vent Elbow Left then Left SEE NOTES:1,2,3,4,5,7,8,9 SEE NOTES: 1,2,4,5,6,7,8,9,10 on the page following on the page following these figures these figures A03210 A03207 Figure 38 − Downflow Application−Vent Elbow Up Figure 40 −...
Page 29 Figure 41 − Horizontal Left Application − Vent Elbow Left Figure 45 − Horizontal Left Application − Vent Elbow Right SEE NOTES: 1,2,4,7,8,9 on the page following these figures SEE NOTES: 1,2,4,5,7,8,9 on the page following these figures A03213 Figure 42 − Horizontal Left Application − Vent Elbow Right then Up A03216 Figure 46 −...
Page 30 4. Type−B vent where required, refer to Note 1 above. 8. Secure vent connector to furnace elbow with (2) corrosion−resistant sheet metal screws, spaced 5. Four−in. (102 mm) single−wall (26 ga. min.) vent must approximately 180_ apart. be used inside furnace casing and when the Downflow Vent Guard Kit is used external to the furnace.
Page 31: Start−Up, Adjustment, And Safety Check
START−UP, ADJUSTMENT, AND SAFETY 3. Gas supply pressure to the furnace must be greater than 4.5−In. W.C. (0.16 psig ) but not exceed 14−In. CHECK W.C. (0.5 psig). Step 1 — General CAUTION WARNING CUT HAZARD FIRE HAZARD Failure to follow this caution may result in personal Failure to follow this warning could result in personal injury.
Page 32: Step 3 - Adjustments
a. LED will display previous status code 4 times. Low NOx models in downflow or horizontal positions MUST use Table 16 (21,000 BTUH per burner). See input listed on NOTE: If no previous code is present, go directly to b. rating plate.
Page 33 c. Connect a water column manometer or similar device b. Run for 3 minutes in low−heat operation. to manifold pressure tap. c. Measure time (in sec) for gas meter to complete 1 d. Turn gas valve ON/OFF switch to ON. revolution and note reading.
Page 34 Table 13 – Gas Rate (cu ft. /hr) SECONDS SECONDS SIZE OF TEST DIAL SIZE OF TEST DIAL U FT. U FT. U FT. U FT. U FT. U FT. REVOLUTION REVOLUTION 1800 1636 1500 1385 1286 1200 1125 1059 1000 c.
Page 35 NOTE: Using the 2 cu. ft. or 5 cu. ft. gas meter dial provides WARNING greater accuracy in verifying gas input rate. If clocked rate does not match required input from Step 1, FIRE HAZARD increase manifold pressure to increase input or decrease Failure to reinstall manifold pressure tap plug in gas manifold pressure to decrease input.
Page 36: Step 4 - Check Safety Controls
Table 14 – Speed Selection c. Restore power to furnace and set room thermostat above room temperature. COLOR SPEED AS SHIPPED d. After normal start−up, allow furnace to operate for 2 White Common minutes, then block vent elbow in furnace 80% of vent Black High COOL...
Page 37 Table 15 – Orifice Size* and Manifold Pressures (in. w.c.) for Gas Input Rate A10184 441 01 2101 05 Specifications are subject to change without notice.
Page 38 Table 15 − Orifice Size and Manifold Pressures (in. w.c.) for Gas Input Rate (cont.) A10184A 441 01 2101 05 Specifications are subject to change without notice.
Page 39 Table 16 – Orifice Size* and Manifold Pressures (in. w.c.) for Gas Input Rate A10185 441 01 2101 05 Specifications are subject to change without notice.
Page 40: Service And Maintenance Procedures
Table 16 − Orifice Size* and Manifold Pressures (in. w.c.) for Gas Input Rate (cont.) A10185A SERVICE AND MAINTENANCE WARNING PROCEDURES ELECTRICAL SHOCK, FIRE EXPLOSION Untrained personnel can perform basic maintenance functions HAZARD such as cleaning and replacing air filters. All other operations must be performed by trained service personnel.
Page 41: Step 2 - Care And Maintenance
ELECTRICAL CONTROLS AND WIRING WARNING WARNING FIRE OR EXPLOSION HAZARD ELECTRICAL SHOCK HAZARD Failure to follow this warning could result in personal injury, death and/or property damage. Failure to follow this warning could result in personal Never store anything on, near, or in contact with the injury or death.
Page 42 Figure 51 − Service Label 441 01 2101 05 Specifications are subject to change without notice.
Page 43: Filter Size Information
5. Inspect the vent pipe/vent system before each heating 3. For downflow or horizontal furnaces having vent pipes season for rust, corrosion, water leakage, sagging within the furnace that pass in front of the blower pipes or broken fittings. Have vent pipes/vent system access door: serviced by a qualified service agency.
Page 44 15. Refer to furnace wiring diagram, and connect disconnecting wires from switches because damage thermostat leads if previously disconnected. may occur): 16. To check blower for proper rotation: a. Draft safeguard switch. a. Turn on electrical supply. b. Inducer motor. b.
Page 45: Step 3 - Sequence Of Operation
(4.) Insert brush end of cable in burner inlet opening Figure 54 − Cleaning Heat Exchanger Cell of cell, and proceed to clean 2 lower passes of cell in same manner as upper pass. (5.) Repeat foregoing procedures until each cell in furnace has been cleaned.
Page 46 a. Inducer Prepurge Period (see Figure 55 schematic furnace control CPU will switch the inducer motor IDM diagram) speed from low to high. The high−heat pressure switch relay HPSR is de−energized to close the NC contact. (1.) Low heat (W/W1) the inducer motor IDM comes When sufficient pressure is available the high−heat up to high−speed, the low−heat pressure switch pressure switch HPS closes, and the high−heat gas...
Page 47: Step 4 - Wiring Diagrams
furnace blower motor BLWM on cool speed. quickly, then restarts at the end of the blower−ON delay period at LO HEAT or HI HEAT speed respectively. The The electronic air cleaner terminal EAC 1 AMP is blower motor BLWM will revert to continuous−blower energized with 115 vac when the blower motor BLWM speed after the heating cycle is completed.
Page 48 Figure 55 − Wiring Diagram 337797−201 Rev. B 441 01 2101 05 Specifications are subject to change without notice.
Page 49 Figure 56 − Troubleshooting Guide − Two−Speed 441 01 2101 05 Specifications are subject to change without notice.
Page 50 441 01 2101 05 Specifications are subject to change without notice.
Page 51: Parts Replacement Information Guide
PARTS REPLACEMENT INFORMATION GUIDE CASING GROUP BLOWER GROUP HEAT EXCHANGER GROUP Blower housing Heat exchanger cell Outer door Blower cutoff Cell panel Blower door Blower motor Lox NOx baffle (California models Top filler plate Blower wheel only) Bottom filler plate Capacitor (where used) Capacitor strap (where used) Bottom enclosure...
Page 52 Copyright 2016 International Comfort Products Lewisburg, TN 37091 USA Specifications are subject to change without notice 441 01 2101 01...

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