Set Temperature Rise. Bryant 345MAV, Series F

CANADA

At installation altitudes from 2000 to 4500 ft, this furnace must be derated 5% by an authorized Gas

Conversion Station. To determine correct input rate for altitude, see example above and use 0.95 as derate multiplier factor.

b. Reinstall burner box cover.

NOTE: Burner box cover MUST be isntalled while clocking gas input rate.

c. Gas valve regulator seal cap MUST be installed.

d. Turn off all other gas appliances and pilots.

e. Start furnace and let operate for 3 minutes.

f. Measure time (in sec) for gas meter test dial to complete

1 revolution.

g. Refer to Table 11 for cu ft of gas per hr.

ON/OFF SWITCH

INLET

PRESSURE TAP h. Multiply gas rate (cu ft/hr) X heating value (Btu/cu ft) using natural gas heating value from local gas utility/supplier.

EXAMPLE:

Btu heating input = Btu/cu ft X cu ft/hr Heating value of gas = 975 Btu/cu ft

Time for 1 revolution of 2-cu ft dial = 70 sec

Gas rate = 103 cu ft/hr (from Table 11)

Btu heating input = 103 X 975 = 100,425 Btuh

In this example, the orifice size and manifold pressure adjustment is within

±

2 percent of the furnace input rate.

REGULATOR

SEAL CAP

REGULATOR

ADJUSTMENT

SCREW

B.

Set Temperature Rise

CAUTION: Temperature rise must be within limits specified on unit rating plate. Recommended operation is at midpoint of rise or slightly above. Failure to follow this caution may result in primary and secondary heat exchangers failure.

REGULATOR SPRING

(PROPANE - WHITE, 6 TURNS

NATURAL - SILVER, 10 TURNS)

GAS PRESSURE

REGULATOR

ADJUSTMENT

MANIFOLD

PRESSURE TAP

Determine and adjust air temperature rise as follows:

1. Place thermometers in return and supply ducts as close to furnace as possible. Be sure thermometers do not see heat exchanger so that radiant heat does not affect readings. This practice is particularly important with straight-run ducts.

2. When thermometer readings stabilize, subtract return-air temperature from supply-air temperature to determine air temperature rise.

3. Adjust temperature rise by adjusting blower speed. Increase blower speed to reduce temperature rise. Decrease blower speed to increase temperature rise.

BURNER FLAME

BURNER

Fig. 46—Redundant Automatic Gas Valve

A03142

BURNER

ORIFICE

A93059

Fig. 47—Orifice Holes

CAUTION: DO NOT redrill orifices. Improper drilling

(burrs, out-of-round holes, etc.) can cause excessive burner noise and misdirection of burner flames. This can result in flame impingement of burners and heat exchangers causing failures.

—40—

MANIFOLD

A89020

Fig. 48—Burner Flame

TABLE 10—ALTITUDE DERATE MULTIPLIER FOR U.S.A.

ALTITUDE

(FT)

0—2000

2001—3000

3001—4000

4001—5000

5001—6000

6001—7000

7001—8000

8001—9000

9001—10,000

% OF

DERATE

0

4—6

6—8

8—10

10—12

12—14

14—16

16—18

18—20

DERATE MULTIPLIER

FACTOR FOR U.S.A*

1.00

0.95

0.93

0.91

0.89

0.87

0.85

0.83

0.81

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