SYSTEM OPERATION
7
A copy of the National Fuel Gas Code (NFPA 54/ANSI Z223.1)
can be obtained from any of the following:
American National Standards Institute
25 West 43
rd
Street, 4
th
Floor
New York, NY 10036
National Fire Protection Association
1 Batterymarch Park
Quincy, MA 02169-7471
CSA International
8501 East Pleasant Valley
Cleveland, OH 44131
A copy of the CAN/CGA B149 Installation Codes can be
obtained from:
CSA International
178 Rexdale Boulevard
Etobicoke, Ontario, Canada M9W, 1R3
The rated heating capacity of the furnace should be greater
than or equal to the total heat loss of the area to be heated.
The total heat loss should be calculated by an approved
method or in accordance with “ASHRAE Guide” or “Manual
J-Load Calculations” published by the Air Conditioning
Contractors of America.
Maximum Allowable Vent Length of Vent/Flue
Pipe & Combustion Air Pipe (Ft)
1
2
3
4
5
6
7
8
2
90 85 80 75 70 65 60 55
3
158 151 144 137 130 123 116 109
2
55 50 45 40 35 30 25 20
3
151 144 137 130 123 116 109 102
MODEL
Pipe Size (in)
Number of Elbows
*MVS960603BUU
*MVS960805CU
1) Maximum allowable limits listed on individual lengths for inlet and flue and NOT
a combination.
2) Minimum requirement for each vent pipe is five (5) feet in length and one elbow/
tee.
3) Tee used in the vent/flue termination must be included when determining the
number of elbows in the piping system.
4) 2 1/2” or 3” diameter pipe can be used in place of 2” diameter pipe.
5) Increased Clearance Configurations using (2) 45 deg. Long Sweep elbows should
be considered equivalent to one 90 deg. elbow.
6) One 90° elbow should be secured to the combustion air intake connection.
WARNING
D
O NOT OP
ER
AT
E
TH
E
F
UR
NAC
E
WI
TH TH
E
R
A
I
N CAP
REM
O
VE
D A
S
RE
C
IRU
CLAT
I
ON OF TH
E
FL
UE
GA
SES
M
AY OCC
UR
.
W
AT
ER
M
AY AL
S
O
COLL
E
CT
I
N
SI
D
E
TH
E
LA
R
G
ER
CO
M
B
US
T
I
N A
IR
P
I
P
E
AND FLO
W
TO TH
E
B
UR
N
ER
E
NCLO
SURE
.
F
A
I
L
URE
TO FOLLO
W
TH
IS
W
A
R
N
I
NG CAN
RESU
LT
I
N
P
R
OP
ER
TY DA
M
AG
E
,
EQUI
P
ME
NT DA
M
AG
E
, P
ERS
ONAL
I
N
JUR
Y O
R
D
E
ATH.
Condensate Drain Lines and Drain Trap
A condensing gas furnace achieves its high level of efficiency
by extracting almost all of the heat from the products of
combustion and cooling them to the point where condensation
takes place. The condensate which is generated must be
piped to an appropriate drain location.
WARNING
I
N
U
P
RI
GHT
U
PFLO
W
I
N
S
TALLAT
I
ON
S
, TH
E
D
R
A
I
N T
R
AP
MUS
T B
E
M
O
U
NT
E
D ON
TH
E
OPPO
SI
T
E
SI
D
E
OF TH
E
U
N
I
T F
R
O
M
TH
E
JU
NCT
I
ON BO
X
.
T
H
IS
WI
LL
RE
D
U
C
E
TH
E
RISK
OF
W
AT
ER
RE
ACH
I
NG TH
E
JU
NCT
I
ON BO
X
I
N TH
E
EVE
NT OF
A BLOC
KE
D D
R
A
I
N COND
I
T
I
ON.
F
A
I
L
URE
TO FOLLO
W
TH
ESE
I
N
S
T
RU
CT
I
ON
S
CAN
RESU
LT
I
N PO
SSI
BL
E
P
R
OP
ER
TY DA
M
AG
E
, P
ERS
ONAL
I
N
JUR
Y, O
R
D
E
ATH
D
UE
TO
E
L
E
CT
RI
CAL
S
HOC
K
.
•
If the drain line is routed through an area which may
see temperatures near or below freezing, precautions
must be taken to prevent condensate from freezing
within the drain line.
•
If an air conditioning coil is installed with the furnace,
a common drain may be used. An open tee must
be installed in the drain line, near the cooling coil, to
relieve positive air pressure from the coil’s plenum.
This is necessary to prohibit any interference with the
function of the furnace’s drain trap.
Drain Information for Horizontal Installations
NOTE:
Horizontal installations require 5.5” under the furnace
to accommodate the drain trap. The horizontal furnace
must be installed with ¾” slope from back to front to permit
condensate flow towards the front of the furnace.
When installing a *MVS9* horizontally with the left side
down, there are two options for connecting the vent pipe to
the furnace.
Option 1
Venting may be connected to the furnace vent pipe fitting on
the original top (now the end) of the furnace.
Option 2
The internal vent pipe and elbow may be removed from the
furnace to permit the vent to exit the top (original side) of
the furnace. If this option is used, an RF000142 Vent-Drain
coupling must be used to keep condensate from collecting
in the inducer assembly.
To install the drain, refer to the following instructions and
illustration.
