Reznor HRPD, Installation, Operation And Maintenance Manual

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RP-HRPD-IOM (07-22) 132210-B
Figure 11. Bypass Duct Dimensions
1 . Refer to Table 9 or Table 10 to determine pressure drop and allowable CFM for furnace being installed . For
example: model RP unit size
150
@ 5
0°F
temperature rise = pressure drop of
0.38
and CFM of
2,210
.
2 . Subtract allowable CFM from blower CFM to determine how much air must be diverted through bypass duct . For
example: blower CFM of 3,000 − allowable CFM of 2,210 = bypass CFM of 790 .
3 . Refer to
Table 11
to determine bypass duct size as follows:
a . Go to column closest to pressure drop through heater .
b . Move down to CFM closest (round up) to CFM determined in step 2 .
c . Move to left column to determine required bypass duct size . For example: in pressure drop column
0.40 , move
down to bypass CFM row
900
and move left to dimension A column
3 inches
.
Table 11. Bypass Duct Size
Dimension A
(Inches (mm))
*
Pressure Drop Through Furnace
0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50
Bypass CFM
3 (76) 490 530 610
700 780 830 900 960 1010
4 (102) 630 750 870 980 1090 1160 1250 1310 1400
5 (127) 850 1010 1190 1300 1410 1520 1640 1730 1810
6 (152) 1050 1290 1480 1650 1800 1940 2090 2200 2320
7 (178) 1250 1510 1760 1960 2180 2320 2500 2650 2800
8 (203) 1490 1810 2100 2350 2560 2760 2940 3110 3290
9 (229) 1700 2100 2400 2700 2970 3200 3400 3600 3800
10 (254) 1920 2350 2760 3090 3650 4020 4300 4550 4800
*
See
Figure 11
.
NOTE: Not all capacities are covered above . If your installation is not covered, consult your distributor or the factory representative to
determine the appropriate size of the bypass duct .
Venting Connections
• Locate power-vented furnaces so that flue discharge is not directed at fresh air inlets . The flue discharge openings
are located on the side of the furnace just above the control access panel . The position of this opening discourages
recirculation of combustion products and provides for furnace operation in all normal weather conditions .
• Optional vertical flue discharge (option CC3): These power vented furnaces are certified with 4 feet of vertical
pipe connected as shown in
Figure 12
, DETAIL A . The distance is measured from the top of the unit to the bottom
of the vent cap . The vent pipe and supports are field-supplied . Optional vertical vent piping provides compliance
with local codes that require either 10-foot horizontal or 4-foot vertical clearance between the flue outlet and the
fresh air intake of the heating system and/or building . The option package (PN 45021) includes the 5-inch vent
cap, the adapter assembly, and the seal plate as shown in
Figure 12
, DETAIL B . Attach venter seal plate and
oval adapter assembly with sheet metal screws . Use venter seal plate as drill template .