PILOT CHECKOUT
The pilot flame should envelope 3/8 inches of the end of the flame sensor. Refer to Figure 12. To adjust pilot flame, (1) remove pilot adjustment cover screw, (2) adjust the screw for the proper pilot flame, (3) be sure to replace cover screw after adjustment to prevent possible gas leakage.
FIG. 12 - PROPER FLAME ADJUSTMENT
Put the system into operation and observe through complete cycle to be sure all controls function properly.
BURNER INSTRUCTIONS
To check or change burners, pilot or orifices, CLOSE MAIN MANUAL
1.Remove the two screws holding either end of the manifold to the burner supports.
2.Open the union fitting in the gas supply line just upstream of the unit gas valve and downstream from the main manual
3.Remove the gas piping patch plate.
4.Disconnect wiring to the gas valve and spark ignitor. Remove the
Burners are now accessible for service.
Reverse the above procedure to replace the assembly. Make sure that burners are level and seat at the rear of the heat exchanger.
BURNER AIR SHUTTER ADJUSTMENT
Adjust burner shutters so that a distinct, sharp, blue flame is obtained. Refer to Figure 13.
FIG. 13 - TYPICAL FLAME APPEARANCE
SUPPLY AIR AIR BLOWER AND TEMPERATURE RISE ADJUSTMENTS
The speed of the supply air blower will depend on the required CFM, the unit accessories and the static resistances of both the supply and the return air duct systems. With this information, the speed for the supply air blower can be determined from the blower performance and accessory static resistance data in Table 5 through 8.
Knowing the required blower RPM and the blower motor HP, the speed setting for the supply air motor can be determined.
The setting (turns open) for the optional
TABLE 13 - BELT-DRIVE SUPPLY AIR
MOTOR PULLEY ADJUSTMENT
TURNS | BLOWER DRIVE RANGE (RPM) | ||
OPEN* | 3 TON | 4 TON | 5 TON |
5 | 780 | 790 | 850 |
4 | 842 | 856 | 924 |
3 | 904 | 922 | 998 |
2 | 966 | 988 | 1072 |
1 | 1028 | 1054 | 1246 |
0 | 1090 | 1120 | 1220 |
*Pulley can be adjusted in
OPTIONAL BELT-DRIVE BLOWER
All units with | ||||||
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variable pitch pulley on the blower motor can be adjusted to | ||||||
Procedure foradjustingblttension: |
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obtain the desired supply air CFM. Refer to Table 9 for blower | ||||||
1Loosennut(D)fromthemotormount. |
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mot and drive data. The tension on the belts | ||||||
2Never |
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adjust | as shown in Figu 14. | frcetoonebetensioningatthe | ||||
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3 | di | thetsionbyturningbolt(B). |
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| isasfollows: |
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deflectionsTnsion.Checknewbeltstheatbeltthetemaxnsionshould.(Ade)atfectias
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FIG. 14 - BELT ADJUSTMENT
Start the supply air blower motor. Adjust the resistances in both the supply and the return air duct systems to balance the air distribution throughout the conditioned space. The job specifications may require that this balancing be done by someone other than the equipment installer.
To check the supply air CFM after the initial balancing has been completed:
1.Remove the (two) 
" dot plugs from the holes located on the filter access panel side of the unit.
2.Insert at least 8" of 1/4 inch tubing into each of these holes for sufficient penetration into the air flow on both sides of
the evaporator coil.
Unitary Products Group | 15 |