355CAV
the
The thermostat and anticipator should NOT be in the circuit while measuring current. If thermostat has no subbase, the thermostat must be disconnected from R and W/W1 wires during current measurement.
Fig. 63 illustrates an easy method of obtaining thermostat amp draw measurements. The amp reading should be taken after blower motor has started and furnace is operating in low-heat.
1.To operate furnace in low-heat, turn setup switch SW1-2 to ON position (See Fig. 33) and connect ammeter leads across thermostat subbase R-W.
2.See thermostat manufacturer’s instructions for adjusting the heat anticipator and for varying heating cycle length.
NOTE: When using an electronic thermostat, set cycle rate for 3 cycles per hr.
3.Return setup switch SW1-2 to OFF position and replace thermostat on subbase.
Check Safety Controls
This section covers the safety controls that must be checked before the installation is complete. The flame sensor, gas valve, and pressure switches were all checked in the
Check Primary Limit Control
This control shuts off the gas control system and energizes the
1.The recommended method of checking this limit control is to gradually block off return air after furnace has been op- erating for a period of at least 5 minutes.
2.As soon as limit control has shut off burners, a status code 33 will appear on furnace control.
3.The
By using this method to check the limit control, it can be established that the limit is functioning properly and the furnace
will operate safely if there is a restricted
Check Pressure Switches
This control proves operation of the draft inducer. Check switch operation as follows:
1.Turn off
2.Remove control access door and disconnect inducer motor
3.Turn on
4.Set thermostat to “call for heat.” When pressure switches are functioning properly, status code 42 will flash on fur- nace control approximately 20 sec after thermostat switch is closed. If either a status code 31 or 32 is flashed when inducer motor is disconnected, the furnace will shut itself down immediately. Determine the reason pressure switches did not function properly and correct the condi- tion.
5.Turn off
6.Reconnect inducer motor wire harness. Reinstall furnace access door.
7.Turn on
8.Reset thermostat to desired temperature.
CHECKLIST
1.Put away tools and instruments. Clean up debris.
2.Verify flame rollout manual reset switch has continuity.
3.Verify that blower and main access doors are properly in- stalled.
4.Cycle test furnace with room thermostat.
5.Check operation of accessories per manufacturer’s instruc- tions.
6.Review User’s Manual with owner.
7.Leave literature packet near furnace.
THERMOSTAT SUBBASE TERMINALS WITH THERMOSTAT REMOVED (ANITICIPATOR, CLOCK, ETC.,
MUST BE OUT OF CIRCUIT.)
R Y W G
10 TURNS
FROM UNIT
CONTROL TERMINALS
EXAMPLE: | 5.0 AMPS ON AMMETER | = | 0.5 AMPS FOR THERMOSTAT | |
10 TURNS AROUND JAWS | ANTICIPATOR SETTING | |||
|
|
A96316
Fig. 63 - Amp Draw with Ammeter
60