![Gas Valve Adjustment](/images/new-backgrounds/33765/33765185x1.webp)
Power Failure — The economizer damper motor is a spring return design. In event of power failure, dampers will re- turn to fully closed position until power is restored.
Refrigerant Charge — Amount of refrigerant charge is listed on unit nameplate and in Tables 1A and 1B. Refer to Carrier GTAC II; Module 5; Charging, Recovery, Recycling, and Reclamation section for charging methods and procedures.
Unit panels must be in place when unit is operating during charging procedure.
NOTE: Do not use recycled refrigerant as it may contain contaminants.
NO CHARGE — Use standard evacuating techniques. After evacuating system, weigh in the specified amount of refriger- ant (refer to Tables 1A and 1B).
LOW CHARGE COOLING — Using appropriate cooling charging chart (see Fig.
Using the above temperature and pressure readings, find the intersect point on the appropriate cooling charging chart. If in- tersection point on chart is above line, add refrigerant. If inter- section point on chart is below line, carefully reclaim some of the charge. Recheck suction pressure as charge is adjusted.
NOTE:
Thermostatic Expansion Valve (TXV) — Each circuit has a TXV. The TXV is nonadjustable and is factory set to main- tain 10 to 13° F superheat leaving the evaporator coil. The TXV controls flow of liquid refrigerant to the evaporator coils.
Gas Valve Adjustment
NATURAL GAS — The
When power is supplied to valve terminals 3 and 4, the pilot valve opens to the preset position. When power is supplied to terminals 1 and 2, the main valve opens to its preset position.
The regular factory setting is stamped on the valve body (3.5 in. wg).
To adjust regulator:
1.Set thermostat at setting for no call for heat.
2.Turn main gas valve to OFF position.
3.Remove
4.Set main gas valve to ON position.
5.Set thermostat at setting to call for heat (high fire).
6.Remove screw cap covering regulator adjustment screw (See Fig. 75).
7.Turn adjustment screw clockwise to increase pressure or counterclockwise to decrease pressure.
8.Once desired pressure is established, set unit to no call for heat
9.Turn main gas valve to OFF position.
10.Remove
11.Turn main gas valve to ON position and check heating operation.
Fig. 71 — Cooling Charging Chart,
48EJ,EK,EW,EY024-034
Fig. 72 — Cooling Charging Chart,
48EJ,EK,EW,EY038-048
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