Bryant 355CAV Altitude Derate Multiplier for U.S.A, Burner Flame, Unit Damage Hazard

!CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in component damage.

DO NOT redrill orifices. Improper drilling (burrs, out-of-round holes, etc.) can cause excessive burner noise and misdirection of burner flames. (See Fig. 61.)

h.Jumper R to W/W1.

i.Let furnace run for 3 minutes in medium-heat operation.

j.Measure time (in sec) for gas meter to complete 1 revolution. Note reading.

k.Refer to Table 12 for cubic ft of gas per hr.

l.Multiply gas rate cu ft/hr by heating value (Btu/cu ft).

m.Move setup switch SW4-2 to OFF position and jumper R and W/W1 and W2 thermostat connections. (See Fig. 33.) This keeps furnace locked in high-heat operation. Repeat items i through l for high-heat operation.

EXAMPLE: (High-heat operation at 0 - 2000 ft altitude) Furnace input from rating plate is 80,000 Btuh

Btuh heating input = Btuh/cu ft X cu ft/hr Heating value of gas = 975 Btuh/cu ft Time for 1 revolution of 2-cu ft dial = 88 sec Gas rate = 82 cu ft/hr (from Table 12)

Btuh heating input = 103 X 975 = 79,950 Btuh

In this example, the orifice size and manifold pressure adjustment is within +/- 2 percent of the furnace input rate.

n. Remove jumper across R, W/W1, and W2 thermostat connections to terminate call for heat.

ALTITUDE	% OF	DERATE MULTIPLIER
(FT)	DERATE	FACTOR FOR U.S.A.*
0—2000	0	1.00
2001—3000	4—6	0.95
3001—4000	6—8	0.93
4001—5000	8—10	0.91
5001—6000	10—12	0.89
6001—7000	12—14	0.87
7001—8000	14—16	0.85
8001—9000	16—18	0.83
9001—10,000	18—20	0.81

*Derate multiplier factor is based on midpoint altitude for altitude range.

Table 11 – Altitude Derate Multiplier for U.S.A.

o.Wait for blower off-delay to finish then reset 115-v power to furnace.

p.Jumper R and W/W1 thermostat connections on control to start furnace.

q.Wait for the blower to turn ON then repeat items i through l for low-heat operation. This setting should not require adjustment but if it does you will only have 15 minutes to make the adjustment. If you need more time then move setup switch SW1-2 on control center to ON position (See Fig. 33).

NOTE: Measured gas inputs (high heat, medium heat, and low heat) must be within +/-2 percent of that stated on furnace rating plate when installed at sea level or derated as stated above when installed at higher altitudes.

BURNER FLAME

BURNER

MANIFOLD

A89020

Fig. 62 - Burner Flame

355CAV

57