APPENDIX I. FURNACE FAN CURVES

TABLE OF CONTENTS

1.1 Furnace Fan Curves .............................................. I-1

LIST OF TABLES

Table I.1 Coefficients for CFM equation for PSC motors ........................ I-1

Table 1.2 Coefficients for CFM equation for Two-Stage and Continuous Modulating

furnaces with ECM motors ........................................ 1-4

LIST OF FIGURES

Figure I.1 Example Fit of CFM for 3-ton Non-Condensing Single-Stage Furnace ...... 1-2

Figure 1.2 Fan Curves for Non-Condensing Single-Stage Virtual Model Furnaces ..... 1-3

Figure 1.3 Fan Curves for Condensing Single-Stage Virtual Model Furnaces .......... 1-3

Figure 1.4 Fan Curves for Non-Condensing Two-Stage Virtual Model Furnaces

- High Fire ..................................................... 1-6

Figure 1.5 Fan Curves for Non-Condensing Two-Stage Virtual Model Furnaces

- Low Fire ..................................................... 1-6

Figure 1.6 Fan Curves for Condensing Two-Stage Virtual Model Furnaces

- High Fire ..................................................... 1-7

Figure 1.7 Fan Curves for Condensing Two-Stage Virtual Model Furnaces

- Low Fire ..................................................... 1-7

 EE-RM/STD-01-350 COMMENT 164

1.1 

Table 1.1 

Table 1.2 

Figure 1.1 

Figure 1.2 

Figure 1.3 

Figure 1.4 

Figure 1.5 

Figure 1.6 

Figure 1.7 

APPENDIX I. FURNACE FAN CURVES 

TABLE OF CONTENTS 

Furnace Fan Curves .......... . ................................... I-I 

LIST OF TABLES 

Coefficients for CFM equation for PSC motors . .. .. . ... . .............. I-I 

Coefficients for CFM equation for Two-Stage and Continuous Modulating 

furnaces with ECM motors ........ . .............. . .. . ............. 1-4 

LIST OF FIGURES 

Example Fit ofCFM for 3-ton Non-Condensing Single-Stage Furnace ...... 1-2 

Fan Curves for Non-Condensing Single-Stage Virtual Model Furnaces .. .. . 1-3 

Fan Curves for Condensing Single-Stage Virtual Model Furnaces .. ... ..... 1-3 

Fan Curves for Non-Condensing Two-Stage Virtual Model Furnaces 

- High Fire . . . ................................... . ...... . ....... 1-6 

Fan Curves for Non-Condensing Two-Stage Virtual Model Furnaces 

- Low Fire ..................................................... 1-6 

Fan Curves for Condensing Two-Stage Virtual Model Furnaces 

- High Fire ............ .. ... ... ............... . ... . ............. 1-7 

Fan Curves for Condensing Two-Stage Virtual Model Furnaces 

- Low Fire .............. ... .. . . .. . .............. . ...... . . ... .. . 1-7 

I-i 
APPENDIX I. FURNACE FAN CURVES

1.1 Furnace Fan Curves

Depending on the resistance (measured as static pressure) of the supply and return air ducts,

a furnace will move more or less air. When these airflow values are plotted graphically against

pressure, they are referred to as fan curves.

The Department developed fan curves for the single-stage virtual furnace models by fitting

the manufacturer airflow and pressure data points from the basic model furnaces',', 3, 4, 5, 6, 7 to a

fourth-order polynomial. The Department did this separately for each of the four nominal air

handlers sizes for both non-condensing and condensing furnaces. The CFM for PSC blower motors

is given by the following equation:

CFM= mo+m'x(P)+m2x(P2)+m3X(P3)+ m4X(P4) Eq.I

where,

CFM

m0,1,2, 3,and4

P

airflow in CFM reported by manufacturer,

coefficients derived from 4t' degree polynomial approximation (see Table

I.1 for actual coefficient values), and

external static pressure (in. w.g.).

'fable 1.1 Coefficients for CFM equation for PSC motors

MO m, m2 m3 m4

2-ton 891.0 -590.8 564.6 -552.2 0.0

3-ton 1280.6 -279.8 194.4 -456.3 0 0.

4-ton 1585.1 32.8 -575.7 -78.4 12.3

5-ton 1998.1 260.9 -93.2 -359.8 115.9

2-ton 840.4 70.0 -908.4 294.3 56.4

3-ton 1169.5 -226.1 -272 . 6 -95 . 7 137. 0

4-ton 1541.2 -110.3 -777.3 419.0 0.0

5-ton 1915.1 -198.0 -594.5 -277.8 8.3

Figure 1.1 shows an example of a CFM curve for a 3-ton Non-Condensing Single-Stage

Furnace fitted with the manufacturers' raw data.

I-1

 EE-RM/STD-01-350 COMMENT 164

APPENDIX I. FURNACE FAN CURVES 

1.1 Furnace Fan Curves 

Depending on the resistance (measured as static pressure) of the supply and return air ducts, 

a furnace will move more or less air. When these airflow values are plotted graphically against 

pressure, they are referred to as fan curves. 

The Department developed fan curves for the single-stage virtual furnace models by fitting 

the manufacturer airflow and pressure data points from the basic model furnacesl

, 2,3, 4,5,6, 7 to a 

fourth-order polynomial. The Department did this separately for each of the four nominal air 

handlers sizes for both non-condensing and condensing furnaces. The CFM for PSC blower motors 

is given by the following equation: 

where, 

CFM 

mO,!,2,3, and4 

p 

airflow in CFM reported by manufacturer, 

coefficients derived from 4 th degree polynomial approximation (see Table 

1.1 for actual coefficient values), and 

external static pressure (in. w.g.). 

T a e bi 11 . C oe ffi· IClen t s ~ or CFM equa f Ion ~ or PSC mo t ors 

mo mI m2 m3 m4 ell 2-ton 891.0 -590,8 564.6 -552.2 0.0 .S 

til 

= 3-ton 1280.6 -279.8 194.4 -456.3 0.0 Q,) 

'0 

= = 4-ton 1585.1 32.8 -575.7 -78.4 12.3 U I 

= = 5-ton 1998.l 260.9 -93.2 -359.8 115.9 

Z 

ell 2-ton 840.4 70.0 -908.4 294.3 56.4 

.S 3-ton 1169.5 -226.1 -272.6 -95.7 137.0 til 

= Q,) 

'0 4-ton 1541.2 -110.3 -777.3 419.0 0.0 = = U 5-ton 1915.1 -198.0 -594.5 -277.8 8.3 

Figure I.1 shows an example of a CFM curve for a 3-ton Non-Condensing Single-Stage 

Furnace fitted with the manufacturers' raw data. 

I-I 
2500

2000

•

1 500 n -- ♦

U

---._..--

®

00

Yak

00

0

0.00 0.10 0.20

Figure 1.1

0.30 0.40 0.50 0.60

Pressure (in.w.g.)

0.70 0.80 0.90 1.00

M1GH

MG

M1 MB

P4UA

i A Utiti+:!lVIaH

Example Fit of CFM for 3-ton Non-Condensing Single-Stage

Furnace

Figures 1.2 and 1.3 show the fan curves for non-condensing and condensing furnaces.

Appendix H, Determination of Basic Furnace and Boiler Models, contains the data on the basic

models that were used to develop these fan curves.

 EE-RM/STD-01-350 COMMENT 164

2500,---------------- --------------, 

2000 1------- ~- ~. ---- ... -

_ 1500 -- :IE 

... 

!:!. 

~ ii: 

'" • 

• a '" 1--- ------- -- l • 

:;;: 1000 T---""---"" --"----

500 1------ ----------.-- --~.----

O~-~--~ ~--~-~-~--~-~--~-~ 

0.00 0.10 

Figure 1.1 

0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 

Pressure (In.w.g.) 

Example Fit of CFM for 3-ton Non-Condensing Single-Stage 

Furnace 

Figures 1.2 and 1.3 show the fan curves for non-condensing and condensing furnaces. 

Appendix H, Determination of Basic Furnace and Boiler Models, contains the data on the basic 

models that were used to develop these fan curves. 

1-2 
2500

-0,-2000 CFM

-1600 CFM

x-1200 CFM

2000

-800 CFM

9 1500

U.

0

9

0

t

1000 Q

0.- O

0 _IC

500

0 -+-

0.00 0.25 0.50 0.75

External Static Pressure (in. w.g.)

1.00

Figure 1.2 Fan Curves for Non-Condensing Single-Stage Virtual Model

Furnaces

Figure 1.3 Fan Curves for Condensing Single-Stage Virtual Model Furnaces

I-3

 EE-RM/STD-01-350 COMMENT 164

~ IL 

~ 

~ IE 

« 

2500 ,-----------,------------,-----------,-----------, 

2000 o--o.iiii7"'=-;::::-= 

1500 

1000 

500 

.. _--- -~----+-I 

~2000CFM 

~1600CFM 

~1200CFM 

0+-----------~----------_+----------_4~--------~ 

0.00 0.25 0.50 0.75 1.00 

External Static Pressure (in. w.g.) 

Figure 1.2 Fan Curves for Non-Condensing Single-Stage Virtual Model 

Furnaces 

~ IL 

~ 

:= 

0 

IE 

« 

2500~---------r--------~~------~~======~~ 

2000 

1500 

1000 

500 

~2000CFM 

~1600CFM 

~1200CFM 

( ~ tr-Oo-c:I-o(-"")"',,-, .... SOO CFM 

'-' ~(-o-.o. ~. 

- '-'-~~ 

J'. 

- - -....... 

----I 

0+-----------~-----------+----------_1----------~ 

0.00 0.25 0.50 0.75 1.00 

External Static Pressure (in. w.g.) 

FigureI.3 Fan Curves for Condensing Single-Stage Virtual Model Furnaces 

1-3 
The two-stage and continuous modulating design options in this analysis use brushless

permanent magnet motors (or sometimes referred as Electronically Commutated Motors (ECM)).

Unlike PSC motors, these motors are electronically commutated and the speed they operate at

can be varied across a wide range. These motors are controlled to operate the blower fans at a

wide variety of air flows and static pressures. In the furnaces with these motors currently on the

market, the controls are designed to provide a nearly constant air flow across the entire range of

pressures at which they operate.

Because of the versatility of the motors, manufacturers only offer furnaces with blowers

nominally designed for operation with five-ton and three-ton air conditioners. The

manufacturers provide control options to decrease the airflow for installations that use smaller

air conditioners.

To develop fan curves for furnaces with ECM motors, the Department fit quadratic

curves through the air flow and pressure data points reported by manufacturers.8°9, 10, 11, 12, 13, 14

DOE did this separately for high-fire and low-fire operation for both non-condensing and

condensing furnaces. See Figures 1.4 through 1.7 for charts showing the fit lines. Table 1.2

shows the coefficients for two-stage and continuous modulating furnaces with ECM motors

using Eq. 2. Data from the basic models that were used to develop these fan curves is shown in

Appendix H, Determination of Basic Furnace and Boiler Models.

CFM = mo + m1 x (P) + m2 x (P2) Eq. 2

where,

CFM = airflow in CFM reported by manufacturer,

mo,1, anal = coefficients derived from 2°d degree polynomial approximation (see

Table 1.2 for actual coefficient values), and

P = external static pressure (in. w.g.).

 EE-RM/STD-01-350 COMMENT 164

The two-stage and continuous modulating design options in this analysis use brushless 

permanent magnet motors (or sometimes referred as Electronically Commutated Motors (ECM)). 

Unlike PSC motors, these motors are electronically commutated and the speed they operate at 

can be varied across a wide range. These motors are controlled to operate the blower fans at a 

wide variety of air flows and static pressures. In the furnaces with these motors currently on the 

market, the controls are designed to provide a nearly constant air flow across the entire range of 

pressures at which they operate. 

Because of the versatility of the motors, manufacturers only offer furnaces with blowers 

nominally designed for operation with five-ton and three-ton air conditioners. The 

manufacturers provide control options to decrease the airflow for installations that use smaller 

air conditioners. 

To develop fan curves for furnaces with ECM motors, the Department fit quadratic 

curves through the air flow and pressure data points reported by manufacturers. 8, 9, 10, II, 12, 13, 14 

DOE did this separately for high-fire and low-fire operation for both non-condensing and 

condensing furnaces. See Figures 1.4 through 1.7 for charts showing the fit lines. Table 1.2 

shows the coefficients for two-stage and continuous modulating furnaces with ECM motors 

using Eq. 2. Data from the basic models that were used to develop these fan curves is shown in 

Appendix H, Determination of Basic Furnace and Boiler Models. 

where, 

CFM 

mO,], and 2 

p 

Eq.2 

airflow in CFM reported by manufacturer, 

= coefficients derived from 2nd degree polynomial approximation (see 

Table 1.2 for actual coefficient values), and 

= external static pressure (in. w.g.). 

1-4 
Table 1.2

EL High Fire Low Fire

m0 m1 m1 m0 m' m2

2-ton 857.5 62.0 0.0 634.7 37.5 0.0

3-ton 1091.1 37.4 0.0 831.7 6.4 0.0

4-ton 1324.8 12.9 0.0 1028.7 -24.7 0.0

5-ton 1558.5 -11.7 0.0 1225.7 -55.8 0 0.

2-ton 714.0 -16.4 -13.8 489.4 -50.2 0 0.

3-ton 1003.0 -27.4 0.0 680.2 -31 . 5 0 0.

4-ton 1291.9 -38.4 13.8 870.9 -12.9 0.0

5-ton 1580.9 -49.5 27.6 1061.6 5.8 0.0

To be consistent with the analysis it did for the single-stage furnaces with PSC blower

motors, the Department created virtual models for furnaces intended to act as air handlers for

four and two ton air conditioners even though these are not currently offered by manufacturers.

To generate the fan curves for the virtual furnaces intended to be used with 4 ton air

conditioners, DOE calculated the average of the slopes and intercepts of the virtual furnaces with

air handler for 5 ton and 3 ton air conditioners. This was done separately for high and low fire

operations for non-condensing and condensing furnaces.

For the virtual furnace models intended to operate with two-ton air conditioners, the fan

curves were created by extrapolating the values for the slopes and intercepts of the virtual

furnace models with air handlers intended to operate with three-ton and five- ton air

conditioners. This was also done separately for high fire and low fire operation for both noncondensing and condensing furnaces. See Figures 1.4 through 1.7 for charts showing the fan

curves for these air handlers.

Coefficients for CFM equation for Two-Stage and Continuous Modulating

furnaces with ECM motors

 EE-RM/STD-01-350 COMMENT 164

Table 1.2 

~ 2-ton .S 

'" = ~ 3-ton 't:l 

= Q 

u 4-ton I 

= 5-ton Q 

Z 

~ 2-ton 

.S 

'" 3-ton ~ = 

Coefficients for CFM equation for Two-Stage and Continuous Modulating 

furnaces with ECM motors 

High Fire Low Fire 

mo mJ m2 mo mJ m2 

857.5 I 62.0 0.0 634.7 I 37.5 0.0 

1091.1 37.4 0.0 831.7 I 6.4 0.0 

I 1324.8 12.9 0.0 1028.7 -24.7 0.0 

1558.5 -11.7 0.0 1225.7 -55.8 I 0.0 

714.0 I -16.4 I -13.8 489.4 -50.2 0.0 

1003.0 -27.4 0.0 680.2 -31.5 0.0 

I 

I 

I 

't:l 4-ton 129l.9 -38.4 13.8 870.9 -12.9 I 0.0 

= Q - I 

U 5-ton I 1580.9 -49.5 27.6 1061.6 I 5.8 I 0.0 I 

To be consistent with the analysis it did for the single-stage furnaces with PSC blower 

motors, the Department created virtual models for furnaces intended to act as air handlers for 

four and two ton air conditioners even though these are not currently offered by manufacturers. 

To generate the fan curves for the virtual furnaces intended to be used with 4 ton air 

conditioners, DOE calculated the average of the slopes and intercepts of the virtual furnaces with 

air handler for 5 ton and 3 ton air conditioners. This was done separately for high and low fire 

operations for non-condensing and condensing furnaces. 

For the virtual furnace models intended to operate with two-ton air conditioners, the fan 

curves were created by extrapolating the values for the slopes and intercepts of the virtual 

furnace models with air handlers intended to operate with three-ton and five- ton air 

conditioners. This was also done separately for high fire and low fire operation for both noncondensing and condensing furnaces. See Figures 1.4 through 1. 7 for charts showing the fan 

curves for these air handlers. 

1-5 
2500

-0-2000 CFM

11600 CFM

4-1200 CFM

2000 f

4-800 CFM

g 1500

LL

0

1000

500

0 4 -

0.00 0.25 0.50 0.75

External Static Pressure (in. w.g.)

1.00

Figure 1.4

2500

Fan Curves for Non-Condensing Two-Stage Virtual Model

Furnaces - High Fire

4-2000 CFM

X1600 CFM

2000

9 1500

LLt)

500

04-

0.00

4-1200 CFM

4-800 CFM

0.25 0.50 0.75

External Static Pressure (in. w.g.)

1.00

Figure 1.5 Fan Curves for Non-Condensing Two-Stage Virtual Model

Furnaces - Low Fire

I-6

 EE-RM/STD-01-350 COMMENT 164

~ II.. 

~ 

~ 0 

'E 

~ 

2500 

2000 ----_ .. _--

1500 

--

1000 .- - .----

500 

o 

0.00 

-

~ 

--

---- - --

0.25 

~OOCF" I 

-+-1600CFM 

~1200CFM ---

---aoo CFM 

...... 

--- - --------1--

-

- ---------

0.50 0.75 

External Static Pressure (in. w.g.) 

... _" 

...... ...... 

-

-- -

--

1.00 

Figure 1.4 Fan Curves for Non-Condensing Two-Stage Virtual Model 

Furnaces - High Fire 

2500 

~2000CFM 

-+-1600CFM 

2000 ~1200CFM 

___ aOOCFM 

~ 1500 - - -- II.. 

~ 

~ 0 

'E 

~ 1000 

500 - -

o 

0.00 

Figure 1.5 

~ ~ ~ -~ ~ 

~ -"" ~ 

...... ...... -

- -- - - --

0.25 0.50 0.75 1.00 

External Static Pressure (in. w.g.) 

Fan Curves for Non-Condensing Two-Stage Virtual Model 

Furnaces - Low Fire 

1-6 
2500

2000 t9 1500

LL

V

--2000 CFM

--1600 CFM

-4-1200 CFM

-M-800 CFM

1000

500

Figure 1.6

2500

04-

0.00 0.25 0.50 0.75

External Static Pressure (in. w.g.)

1.00

Fan Curves for Condensing Two-Stage Virtual Model Furnaces

- High Fire

-0-2000 CFM

--1600 CFM

2000

9 1500

U.

U

500

--1200 CFM

f800 CFM

0.00

0

0.25 0.50 0.75

External Static Pressure (in. w.g.)

1.00

Figure 1.7 Fan Curves for Condensing Two-Stage Virtual Model Furnaces

- Low Fire

I-7

 EE-RM/STD-01-350 COMMENT 164

i' 

u.. 

~ 

~ 1: 

C( 

2500 

2000 

1500 

1000 

500 _ .. 

o 

0.00 

Figure 1.6 

i' 

u.. 

~ 

~ 0 

1: 

C( 

2500 

2000 

1500 

1000 

500 

o 

0.00 

Figure 1.7 

~2000CFM 

~1600CFM 

-<>-1200 CFM . - .. . ... 

..... SOOCFM 

~ ~ ~ ~ ~ ~ 

~ 

- - - - - ... 

- - - - - - --- --- ---

0.25 0.50 0.75 1.00 

External Static Pressure (in. w.g.) 

Fan Curves for Condensing Two-Stage Virtual Model Furnaces 

- High Fire 

~2000CFM 

~1600CFM 

-<>-1200 CFM 1---. 

..... SOOCFM 

~ ~ 

- - -

-

. -- _ . 

- .- - - - --- --

0.25 0.50 0.75 1.00 

External Static Pressure (in. w.g.) 

Fan Curves for Condensing Two-Stage Virtual Model Furnaces 

- Low Fire 

1-7 
REFERENCES

1. Lennox Industries Inc. Lennox Engineering Data: G40DF (Merit Series

Upflow/Horizontal Gas Furnace). 2003. Lennox Industries, Inc. 2003.)

<http://pirl.lennox.com/C03 e7ol4l/76EOZC21u/ehb_g4Odf 03 07.pdf>

2. Lennox Industries Inc. Lennox Engineering Data: G40UH (Merit Series

Upflow/Horizontal Gas Furnace). 2004. Lennox Industries, Inc.

<http ://pirl.lennox . com/C03e7o141/76EOZC2lu/ehb_g4Ouh0407.pdf>

3. Lennox Industries Inc. Lennox Engineering Data.. G41 UF (Merit Series Downflow Gas

Furnace). 2004. Lennox Industries, Inc.

<http ://pirl.lennox. com/C03e7ol4l/76EOZC21u/ehb_g4luf 0402.pdf>

4. Lennox Industries Inc. Lennox Engineering Data: G43 OF (Merit Series Upflow Gas

Furnace). 2004. Lennox Industries, Inc.

<http://pirl.lennox.com/C03e7ol4l/76EOZC21u/ehb_g43uf 0412.pdf>

5. Lennox Industries Inc. Lennox Engineering Data: G50DF (Elite Series Downflow Gas

Furnace). 2003. Lennox Industries, Inc.

<http://pirl.lennox.com/C03e7ol41/76EOZC21u/ehb_g5Odf 0307.pdf>

6. Lennox Industries Inc. Lennox Engineering Data: G50UH (Elite Series

Upflow/Horizontal Gas Furnace). 2003. Lennox Industries, Inc.

<http://pirl.lennox.com/C03e7o141/76EOZC2lu/ehb_g5Ouh-0307.pdf>

7. Lennox Industries Inc. Lennox Engineering Data: G51 MP (Elite Series Multi-Position

Gas Furnace). 2004. Lennox Industries, Inc.

<http ://pirl.lennox . com/C03e7ol4l/76EOZC2 lu/ehb-95 Imp_0412.pdf>

8. Carrier Corporation. Carrier Product Data: 58CVA/CVX(Infinity 80 Series MultiPoise

Furnace). 2004. Carrier Co.

<http ://www.xpedio. carrier. com/idc/groups/public/documents/techlit/5 8cv-3pd.pdf>

9. Carrier Co. Carrier Product Data: 58MVP (Infinity 96 Deluxe 4-Way Multipoise

Furnace). 2004. Carrier Co.

<http://www.xpedio. carrier. com/idc/groups/public/documents/techlit/5 8mvp-11 pd.pdf>

10. Lennox Industries Inc. Lennox Engineering Data: G61 WV (Multi-Position - Variable

Speed Blower - Two-Stage Heat - Direct Vent/Non-Direct Vent). 2004. Lennox

Industries, Inc.

11. Lennox Industries Inc. Lennox Engineering Data: G60UHV (Up-Flow/Horizontal - Two

Stage Heat - Variable Speed Blower). 2003. Lennox Industries, Inc.

1-8

 EE-RM/STD-01-350 COMMENT 164

REFERENCES 

1. Lennox Industries Inc. Lennox Engineering Data: G40DF (Merit Series 

Upjlow/Horizontal Gas Furnace). 2003. Lennox Industries, Inc. 2003.) 

<http://pirl.lennox.comlC03e7014l176EOZC21u/ehb_g40dC0307.pdf> 

2. Lennox Industries Inc. Lennox Engineering Data: G40UH (Merit Series 

Upjlow/Horizontal Gas Furnace). 2004. Lennox Industries, Inc. 

<http://pirl.lennox.comlC03 e70 14117 6EOZC21 ul ehb _g40uh _0407. pdf> 

3. Lennox Industries Inc. Lennox Engineering Data: G41UF (Merit Series Downjlow Gas 

Furnace). 2004. Lennox Industries, Inc. 

<http://pirl.lennox.comlC03e7014l176EOZC21u/ehb_g41uC0402.pdf> 

4. Lennox Industries Inc. Lennox Engineering Data: G43 UF (Merit Series Upjlow Gas 

Furnace). 2004. Lennox Industries, Inc. 

<http://pirl.lennox.comlC03e7014l176EOZC21u/ehb_g43uC0412.pdf> 

5. Lennox Industries Inc. Lennox Engineering Data: G50DF (Elite Series Downjlow Gas 

Furnace). 2003. Lennox Industries, Inc. 

<http://pirl.lennox.comlC03e7014l176EOZC21u1ehb_g50dC0307.pdf> 

6. Lennox Industries Inc. Lennox Engineering Data: G50UH (Elite Series 

Upjlow/Horizontal Gas Furnace). 2003. Lennox Industries, Inc. 

<http://pirl.lennox.comlC03e70141176EOZC21u1ehb_g50uh_0307.pdf> 

7. Lennox Industries Inc. Lennox Engineering Data: G51MP (Elite Series Multi-Position 

Gas Furnace). 2004. Lennox Industries, Inc. 

<http://pirl.lennox.comlC03e7014l176EOZC21u/ehb_g51mp_0412.pdf> 

s. Carrier Corporation. Carrier Product Data: 58CVA/CVX(Injinity 80 Series MultiPoise 

Furnace}. 2004. Carrier Co. 

<http://www.xpedio.carrier.comlidc/ groups/publicl documents/techlitl5 Scv-3pd.pdf> 

9. Carrier Co. Carrier Product Data: 58MVP (Infinity 96 Deluxe 4-Way Multipoise 

Furnace). 2004. Carrier Co. 

<http://www.xpedio.carrier.comlidc/ groups/publicl documents/techlitl 5 Smvp-l1 pd. pdf> 

. 10. Lennox Industries Inc. Lennox Engineering Data: G61MPV (Multi-Position - Variable 

Speed Blower - Two-Stage Heat - Direct Vent/Non-Direct Vent). 2004. Lennox 

Industries, Inc. 

11. Lennox Industries Inc. Lennox Engineering Data: G60UHV (Up-Flow/Horizontal - Two 

Stage Heat - Variable Speed Blower). 2003. Lennox Industries, Inc. 

1-8 
12. Lennox Industries Inc. Lennox Engineering Data: G60DFV (Down flow - Variable Speed

Blower - Two-Stage Heat). 2004. Lennox Industries, Inc.

13. Trane Co. Trane Product Data: XV 80. 2004. Trane Co.

14. Trane Co. Trane Product Data: XV 90. 2004. Trane Co.

 EE-RM/STD-01-350 COMMENT 164

12. Lennox Industries Inc. Lennox Engineering Data: G60DFV (Down-jlow - Variable Speed 

Blower - Two-Stage Heat). 2004. Lennox Industries, Inc. 

13. Trane Co. Trane Product Data: XV 80. 2004. Trane Co. 

14. Trane Co. Trane Product Data: XV 90. 2004. Trane Co. 

1-9