Pvc Joint Cementing Procedure; Minimum Vent Pipe Lengths; Maximum Vent Pipe Lengths - Lennox G61MPV Service Manual

Use the following steps to correctly size vent pipe diameter.
1 − Determine the vent termination and its corresponding
equivalent feet value according to table 32.
2 − Determine the number of 90° elbows required for both
indoor and outdoor (e.g. snow riser) use. Calculate the
corresponding equivalent feet of vent pipe.
3 − Determine the number of 45° elbows required for both
indoor and outdoor use. Calculate the corresponding
equivalent feet of vent pipe.
4 − Determine the length of straight pipe required.
5 − Add the total equivalent feet calculated in steps 1
through 4 and compare that length to the maximum
values given in table 34 for the proposed vent pipe di-
ameter. If the total equivalent length required exceeds
the maximum equivalent length listed in the appropri-
ate table, evaluate the next larger size pipe.
IMPORTANT
Do not use screens or perforated metal in exhaust
terminations. Doing so will cause freeze−ups and
may block the terminations.
TABLE 33

MINIMUM VENT PIPE LENGTHS

G61MPV MIN. EQUIV.
MODEL VENT LENGTH
045, 070,
071, 090,
091
15 ft.*
110, 111**
135***
*Any approved termination may be added to the minimum equivalent length
listed.
**G61MPV−60C−110 must have 90° street ell (supplied) installed directly into
unit flue collar.
***G61MPV−60D−135 must have 3" to 2" reducing ell (supplied) installed direct-
ly into unit flue collar.
EXAMPLE
5 ft. plus 2 elbows of 2", 2−1/2", 3"
or 4" diameter pipe
5 ft. plus 2 elbows of 2−1/2" 3" or 4"
diameter pipe
5 ft. plus 2 elbows of 3" or 4"
diameter pipe

MAXIMUM VENT PIPE LENGTHS

ALTITUDE ALTITUDE
0 − 4500 0 − 4500
(0 − 1371 m)
4501−7500 4501−7500
(1372−2286 m) (1372 2286 m)
7501 10000 7501 − 10000
(2287 3048 (2287 − 3048
m) m)
n/a −− Not allowed.
*G61MPV−60C−110 must have 90° street ell (supplied) installed directly into
unit flue collar.
**G61MPV−60D−135 must have 3" to 2" reducing ell (supplied) installed directly
into unit flue collar.
†On G61MPV−071, −091 and −111 units, sweep elbows must be used for all
90° elbows in the venting system when 2", 2−1/2" or 3" vent pipe is used.
Sweep elbows are recommended for use in vent systems of other
G61MPV units.
‡ On G61MPV−60D−135 units, sweep elbows must be used for all 90°
elbows in the vent system when 3" pipe is used.
B−PVC Joint Cementing Procedure
All cementing of joints should be done according to the
specifications outlined in ASTM D 2855.
DANGER OF EXPLOSION!
Fumes from PVC glue may ignite during system
check. Allow fumes to dissipate for at least 5 minutes
before placing unit into operation.
1 − Measure and cut vent pipe to desired length.
2 − Debur and chamfer end of pipe, removing any ridges
or rough edges. If end is not chamfered, edge of pipe
may remove cement from fitting socket and result in a
leaking joint.
3 − Clean and dry surfaces to be joined.
4 − Test fit joint and mark depth of fitting on outside of pipe.
5 − Uniformly apply liberal coat of PVC primer for PVC or
ABS cleaner for ABS to inside socket surface of fitting
and male end of pipe to depth of fitting socket.
Page 49
TABLE 34
MAXIMUM EQUIVALENT VENT
G61MPV
LENGTH FEET
MODEL MODEL
2" dia. 2−1/2" dia.
045 59 65
070 59 65
†
071 59 65
090
26 42
†
091
26 42
110* n/a 32
†
111 n/a 32
‡
135** n/a n/a
045 59 65
070 59 65
†
0701 59 65
090 26 42
†
091 26 42
110* n/a 32
†
111 n/a 32
‡
135** n/a n/a
045 59 65
070 59 65
†
071 59 65
090 26 42
†
091 26 42
110* n/a 32
†
111 n/a 32
‡
135** n/a n/a
WARNING
3" dia. 4" dia.
77 234
78 214
78 214
72 204
72 204
72 179
72 179
61 160
77 234
78 214
78 214
72 204
72 204
72 179
72 179
46 160
77 234
78 214
78 214
72 204
72 204
72 179
72 179
46 160