Carrier 58ZAV operating instructions START-UP Procedures, Adjustments

until the end of the ignition warm up and trial for ignition periods (a total of 24 sec). The blower then comes back on at heating speed.

When the W input signal disappears, the control begins the normal inducer post-purge period and the blower changes to cooling speed after a 1-sec delay. If the W-Y-G signals disappear at the same time, the blower remains on for the selected heating blower off delay period and the inducer goes through its normal post-purge period. If the W-Y inputs should disappear, leaving the G signal input, the control goes into continuous blower and the inducer remains on for the normal post-purge period.

Anytime the control senses false flame, the control locks out of the heating mode. This occurs because the control cannot sense the W input due to the false flame signal and, as a result, sees only the Y input and goes into cooling mode blower off delay. All other control functions remain in standard format.

NOTE: EAC-1 terminal is energized whenever blower operates. HUM terminal is only energized when gas valve is energized.

START-UP PROCEDURES

1.Purge gas linesÐAfter all connections have been made, purge the lines and check for leaks.

Never purge a line into a combustion chamber. Never use matches, candles, flame, or other sources of ignition to check for gas leakage. Use a soap-and-water solution to check for gas leaks. Failure to follow this warning could result in fire, explosion, personal injury, or death.

2.Component testÐThe furnace control allows all components, except gas valve, to be run for a short period of time.

→This feature helps diagnose a system problem in case of a component failure. To initiate component test procedure, short (jumper) the TEST 3/16-in. quick connect terminal on control (adjacent to diagnostic light) and the COM-24V terminal on furnace thermostat connection block for approximately 2 sec. (See Fig. 14.)

NOTE: Component test feature will not operate if any thermostat signal is present at control.

Component test sequence is as follows.

a. Momentarily jumper TEST and COM-24V terminals until LED goes off.

b.LED will display previous status 4 times.

c.Inducer motor starts and continues to run for entire com- ponent test.

d.Hot surface igniter is energized for 15 sec, then de- energized.

e.Blower motor operates on cooling speed for 10 sec, then stops.

f.Blower motor operates on heating speed for 10 sec, then stops.

g.Inducer motor stops.

3.To operate furnace, follow procedures on operating instruction label attached to furnace.

4.With furnace operating, set thermostat below room tempera- ture and observe that furnace goes off. Set thermostat above room temperature and observe that furnace restarts.

ADJUSTMENTS

1.Set gas input rate

Furnace gas input rate on rating plate is for installations at altitudes up to 2000 ft. Furnace input rate must be within ±2

percent of input on furnace rating plate.

a.Determine natural gas orifice size and manifold pressure for correct input.

→(1.) Obtain average yearly gas heat value (at installed altitude) from local gas supplier.

→(2.) Obtain average yearly gas specific gravity from local gas supplier.

(3.) Verify furnace model. Table 7 can only be used for model 58ZAV Furnaces.

(4.) Find installation altitude in Table 7.

NOTE: For Canada altitudes of 2000 to 4500 ft, use U.S.A. altitudes of 2001 to 3000 ft in Table 7.

(5.) Find closest natural gas heat value and specific gravity in Table 7.

(6.) Follow heat value and specific gravity lines to point of intersection to find orifice size and manifold pressure settings for proper operation .

EXAMPLE: (0Ð2000 ft altitude)

Heating value = 1050 Btu/cu ft

Specific gravity = 0.62

Therefore: Orifice No. 43*

Manifold pressure 3.6-in. wc

*Furnace is shipped with No. 43 orifices. In this example all main burner orifices are the correct size and do not need to be changed to obtain proper input rate.

(7.) Check and verify burner orifice size in furnace.

NEVER ASSUME ORIFICE SIZE. ALWAYS CHECK AND VERIFY.

b.Adjust manifold pressure to obtain input rate.

(1.) Remove regulator adjustment seal cap. (See Fig. 18.)

(2.) Turn adjusting screw, counterclockwise (out) to de- crease manifold pressure or clockwise (in) to increase manifold pressure.

NOTE: This furnace has been approved for a manifold pressure of 3.2-in. wc to 3.8-in. wc when installed at altitudes up to 2000 ft. For altitudes above 2000 ft, the manifold pressure can be adjusted from 2.0-in. wc to 3.8-in. wc.

DO NOT bottom out gas valve regulator adjusting screw. This can result in unregulated manifold pressure and result in excess overfire and heat exchanger failures.

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