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Remove the screws retaining the wiring box cover. Route the
power wiring through the unit top panel with a conduit connec-
tor or other proper connection. Make wiring connections as
shown in Figure 9 or 10. Replace the wiring box cover and
screws.

An alternate wiring method is to use a field provided 2 x 4  box
and cover on the outside of the furnace. Route the furnace
leads into the box using a protective bushing where the wires
pass through the furnace panel.

ELECTRICAL CONTROL CONNECTIONS

Install the field-supplied thermostat. The thermostat instruc-
tions for wiring are packed with the thermostat. With the thermo-
stat set in the OFF position and the main electrical source
disconnected, complete the low-voltage wiring from the
thermostat to the terminal board on the ignition module. Con-
nect Class 2 control wiring as shown in Figures 11 & 12.
Electronic thermostats may require a "C" common connection
as shown dashed in Figure 12.

NOTE: Some electronic thermostats do not have adjustable

heat anticipators. They may have other type cycle rate
adjustments. Follow the thermostat manufacturer’s in-
structions.

The 24-volt, 40 VA transformer is sized for the furnace compo-
nents only, and should not be connected to power auxiliary
devices such as humidifiers, air cleaners, etc. The transformer
may provide power for an air conditioning unit contactor.

COMBUSTION AIR AND VENT SYSTEM

1. Two-pipe with a sealed combustion intake/vent system

using outdoor combustion air.

2.  Single pipe vent system using combustion air from the area

surrounding the furnace.

3.  Two-pipe intake/vent system using combustion air from a

ventilated attic space and a vent pipe to the outside.

 

Be sure to follow the appropriate venting section details, related

information and limitations for your type of installation.

COMBUSTION AIR INTAKE/VENT CONNECTIONS

This type installation requires outdoor combustion air. Two
separate, properly-sized pipes must be used. One bringing  air
from the outdoors to the furnace combustion air intake collar
on the burner box, and a second pipe from the furnace vent
connection (top right of unit) back to the outdoors. See Figure
13 or 14.

The intake/vent should be located either through the wall
(horizontal or side vent) or through the roof (vertical vent). Care
should be taken to locate side vented systems where trees or
shrubs will not block or restrict supply air from entering or
combustion products from leaving the terminal. 

Also, the terminal assembly should be located as far as possi-
ble from a swimming pool or a location where swimming pool
chemicals might be stored. Be sure the terminal assembly
follows the outdoor clearances listed in Table 3 for U.S. instal-
lations: In Canada, refer to CAN/CGA-B149.1 or .2 Installation
Code (latest edition -Venting Systems and Air Supply).

COMBUSTION AIR/VENT PIPE SIZING

Refer to Tables 4 or 5 to select the proper size piping for
combustion air intake and venting. The size will be determined
by a combination of furnace model, total length of run, and the
number of elbows required. The following rules must also be
observed.

ROOM

THERMOSTAT

FURNACE

CONTROL

CONDENSING

UNIT

TO AIR CONDITIONER

CONTROLS

R

W

G

Y

C

R
W

G

Y

C

FIGURE 11 - POWER WIRING CONNECTIONS

FIGURE 12 - TYPICAL HEATING AND COOLING

Set the heat anticipator in the room thermostat to .45
amps. Setting it lower will cause short cycles. Setting it
higher will cause the room temperature to exceed the
setpoints.

     

METHOD ONE: TWO

 

PIPE

 

SEALED

   

COMBUSTION

 

AIR

 

AND

 

VENT

 

SYSTEM

This furnace is certified to be installed with one of three
possible intake/vent configurations.

Furnace Intake / Vent Connection Size

40 - 100 MBH

120-140 MBH

Intake

2"

3"

Vent

2"

2" (See Note 1)

NOTE: 1

Vent must be increased to 3" on these model.

     

2. Any vent pipe size change must be made outside 

          furnace casing in a vertical pipe section to allow 
     proper drainage of condensate.

     

3

.

 An offset using two 45 degree elbows will be required for    

     plenum 

clearance 

when 

the 

vent 

is 

increased 

to 

3".

TABLE 4 - UPFLOW UNITS - INTAKE/VENT PIPING
     2-PIPE 

SYSTEM

Model

Pipe

Size

Max. Elbows vs.

One Way Vent Length (Ft.)

5  - 40

45

50

75

40 / 37 / 800 / A

2"

6

5

4

N/A

60 / 55 / 1000 / B
80 / 75 / 1200 / C
80 / 75 / 1600 / C

100 / 95 / 1400 / C
100 / 95 / 2000 / C

40 / 37 / 800 / A

3"

8

7

6

5

60 / 55 / 1000 / B
80 / 75 / 1200 / C
80 / 75 / 1600 / C

100 / 95 / 1400 / C
100 / 95 / 2000 / C

120 / 112 / 2000 / D

 3" Only

6

5

4

N/A

140 / 130 / 2000 / D

650.75-N4U

Unitary Products Group

11

Summary of Contents for 65075-N4U

Page 1: ...r other flammable vapors and liquids in the vicinity of this or any other appliance WARNING IMPROPER INSTALLATION ADJUSTMENT AL TERATION SERVICE OR MAINTENANCE CAN CAUSE INJURY OR PROPERTY DAMAGE RE F...

Page 2: ...ce since it requires separate properly sized air intake and vent lines The furnace shall not be connected to any type of B BW or L vent or vent connector and not connected to any portion of a factory...

Page 3: ...e access is required for passage to the front when servicing or for inspection or replacement of flue vent connections NOTE In all cases accessibility clearances shall take prece dence over clearances...

Page 4: ...95 2000 C 21 19 3 4 16 5 8 2 2 120 112 2000 D 24 1 2 23 1 4 20 1 8 3 2 3 140 130 2000 D 24 1 2 23 1 4 20 1 8 3 2 3 Vent pipe must be increased to 3 on this model INPUT MBH OUTPUT MBH NOM CFM CAB WIDTH...

Page 5: ...75 1200 17 1 2 91 0 35 65 1370 165 11 8 1 2 9 0 20 14 80 75 1600 21 91 0 30 60 1563 160 11 8 3 4 12 0 20 14 100 95 2000 21 91 0 40 70 1582 170 11 10 1 12 0 20 14 120 112 2000 24 1 2 91 0 40 70 1885 1...

Page 6: ...ambient temperature may drop below 32 F a UL listed self regulated heat tape must be installed It is recommended that self regulating heat tape rated at 3 watts per foot be used This must be installe...

Page 7: ...r sides of the cabinet wall NOTE Air velocity through throw away type filters may not exceed 300 feet per minute All velocities over this require the use of high velocity filters Side Return External...

Page 8: ...n sions Install the plenum following instructions under Ductwork in this instruction SUPPLY AIR DUCTS Installations on combustible material or floors must usea combus tible floor base shown in Figure...

Page 9: ...ezing are possible refer to Page 6 Below Freezing Locations GAS PIPING The gas supply must be installed in accordance with the current National Fuel Gas Code ANSI Z223 1 in the U S or CAN CGA B149 1 o...

Page 10: ...switch should be close to the unit for convenience in servicing With the disconnect switch in the OFF position check all wiring against the unit wiring label Also see the wiring diagram in this instru...

Page 11: ...nnection top right of unit back to the outdoors See Figure 13 or 14 The intake vent should be located either through the wall horizontal or side vent or through the roof vertical vent Care should be t...

Page 12: ...roofor sidewall NOTE Accessory concentric intake vent terminations models 1CT0302 and 1CT0303 are available and approved for use with these furnaces Refer to Form 650 75 N2 4V for installation details...

Page 13: ...ning at the furnace 2 Deburr the piping inside and outside 3 Chamfer the outer edges of the piping 4 Dry fit the entire vent combustion air piping assembly 5 Disassemble the piping and apply cement pr...

Page 14: ...the furnace This may be from within the space in a non confined location or it may be brought into the furnace area from outdoors It is not directly ducted into the furnace A single properly sized pi...

Page 15: ...m dimension of rectangular ducts shall be three inches 2 One permanent opening commencing within 12 inches of the top of the enclosure shall be permitted where the equipment has clearances of at least...

Page 16: ...t connections NOTE An offset using two 45 degree elbows may be required for plenum clearance when the vent is increased to 3 1 Long radius elbows are required for all units 2 Elbows are assumed to be...

Page 17: ...on may require seal ing or shielding of building surfaces with a corrosive resistant material due to vent system corrosive combus tion products PIPING ASSEMBLY The final assembly procedure for the ven...

Page 18: ...e allowable locations shown in Figure 24 and Section 7 8 in the National Fuel Gas Code ANSI Z223 1 current edition Follow all local agency and utility requirements if more restrictive than those shown...

Page 19: ...w the instructions with the coil for trapping the drain SAFETY CONTROLS Control Circuit Fuse A 3 amp fuse is provided to protect the 24 volt transformer from overload caused by control circuit wiring...

Page 20: ...blower motor failure START UP AND ADJUSTMENTS The initial start up of the furnace requires the following addi tional procedures 1 When the gas supply is initially connected to the furnace the gas pip...

Page 21: ...MPLE CHECKING GAS INPUT It is found by measurement that it takes 26 seconds for the hand on the 1 cubic foot dial to make a revolution with only a 120 000 Btuh furnace running Using this information l...

Page 22: ...and electrical supplies ON Start furnace and observe manifold pressure on manometer 5 Adjust manifold pressure by adjusting gas valve regulator screw for natural gas set at 3 5 W C If gas valve regula...

Page 23: ...or lead Place all unused motor leads on Park terminals Two Park terminals are provided CAUTION Do not energize more than one motor speed at a time or damage to the motor will result ADJUSTMENT OF FAN...

Page 24: ...the thermostat circuit opens the ignition control is deener gized Withtheignitioncontroldeenergized thegasflowstopsand the burner flames are extinguished The venter continues to operate for 15 seconds...

Page 25: ...me Lift filter slightly to dislodge and remove for service 3 Remove the filter and follow the cleaning instructions above DO NOT remove the filter stiffener rods if provided When reinstalling the filt...

Page 26: ...blower and the condensate pan The turbulators can then be gently re moved from the secondary heat exchanger 3 With a stiff wire brush brush out loose scale or soot 4 Vacuum the secondary heat exchang...

Page 27: ...e is lost 5 times during the heating cycle This could be caused by low gas pressure or faulty gas valve 9 FLASH TI61F 2 CONTROL ONLY Indicates reversed line voltage polarity Check incoming power wirin...

Page 28: ...985 835 757 665 450 MED 900 887 851 810 752 693 609 403 LOW 581 577 569 542 468 60 55 1000 B HI 1220 1200 1190 1152 1115 1065 1012 950 872 771 MED 920 915 900 880 842 803 740 650 LOW 725 729 715 700...

Page 29: ...UNIT WIRING DIAGRAM UPFLOW 650 75 N4U Unitary Products Group 29...

Page 30: ...UNIT WIRING DIAGRAM DOWNFLOW HORIZONTAL...

Page 31: ...NOTES 650 75 N4U Unitary Products Group 31...

Page 32: ...ect to change without notice Printed in U S A Copyright by Unitary Products Group 1998 All rights reserved 650 75 N4U Supercedes 650 75 N4U 498 5005 York Drive Norman OK 73069 Unitary Products Group 6...

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