Carrier 48/50PM C16-28 manual Gas Valve Adjustment 48PG and PM, PuronR Refrigerant, 48PG08−14

Be sure unit is in normal cooling mode by checking that the RH2 solenoid coil(s) and the CRC relay are deenergized (control outputs off). Adjust charge per the charging charts as described in the To Use The Cooling Charging Charts, Standard Unit section. Switch system to run in the dehumidification mode for 5 minutes. Dehumidification mode is when the RH2 solenoid coil(s) and the CRC relay are energized. Switch back to cooling mode to recheck pressures and temperatures on the charging chart and adjust charge if necessary. If charge adjustment is necessary, then repeat the steps in this paragraph until no charge adjustment is necessary. When no more charge adjustment is necessary after switching from Dehumidification mode back to Cooling mode, then charge adjustment procedure is complete. Remove jumper from the outdoor motor speed controller.

PuronR Refrigerant

Puron refrigerant operates at 50 to 70 percent higher pressures than R-22. Be sure that servicing equipment and replacement components are designed to operate with Puron refrigerant. Do not mix with components that have been used with other refrigerants. Puron refrigerant, as with other HFCs, is only compatible with POE oils.

Recovery cylinder service pressure rating must be 400 psig. Puron systems should be charged with liquid refrigerant. Use a commercial-type metering device in the manifold hose. Manifold sets should be 750 psig high-side and 200 psig low-side with 520 psig low-side retard. Use hoses with 750 psig service pressure rating. Leak detectors should be designed to detect HFC refrigerant.

Table 28 – Altitude Compensation*

48PG03−07

ELEVATION	NATURAL GAS	PROPANE
(ft)	ORIFICE†	ORIFICE†
	45	52
	47	52
	47	53
	47	53
	48	53
	48	53
	48	53
	49	54
	49	54
	50	54
	51	54
	51	55
	52	55
	52	56

48PG08−14

ELEVATION	NATURAL GAS	PROPANE
(ft)	ORIFICE†	ORIFICE†
	43	50
	44	51
	44	51
	44	51
	45	51
	45	52
	47	52
	47	52
	47	53
	48	53
	49	53
	50	54
	50	54
	51	55

48PG08−14

ELEVATION	NATURAL GAS	PROPANE
(ft)	ORIFICE†	ORIFICE†
	30	38
	30	40
	31	40
	31	41
	31	41
	31	42
	32	42
	32	43
	32	43
	35	44
	36	44
	37	45
	38	46
	39	47

*As the height above sea level increases, there is less oxygen per cubic foot of air. Therefore, heat input rate should be reduced at higher altitudes. Includes a 4% input reduction per each 1000 ft.

†Orifices available through your Carrier dealer.

Gas Valve Adjustment (48PG and PM)

The gas valve opens and closes in response to the thermostat or limit control.

When power is supplied to valve terminals W2 (High Fire) and C1, the main valve opens to its preset position.

The regular factory setting is stamped on the valve body.

To adjust regulator:

1.Set unit at setting for no call for heat.

2.Turn main gas valve to OFF position.

3.Remove 1/8-in. pipe plug from manifold pressure tap connection. Install a suitable pressure-measuring device.

4.Set main gas valve to ON position.

5.Set thermostat at setting to call for heat.

6.Remove screw cap covering regulator adjustment screw. (See Fig. 69.)

7. Turn adjustment screw clockwise to increase pressure or counterclockwise to decrease pressure. The setting is 3.50 in. wg on sizes 03-14 and 3.00 on size 16−28.

8.Once desired pressure is established, set unit setting for no call for heat, turn off main gas valve, remove pressure-measuring device, and replace 1/8-in. pipe plug and screw cap.

2 LEADS, #18 WIRE 1/32 INSULATION,	REGULATOR
600V. MAX., 105°C	ADJUSTMENT SCREW
	(REMOVE COVER)

OUTLET PRESSURE TAP (PLUGGED) 1/8-27 N.P.T. THDS.

	D-1		D-2	RECEPTACLE AND
ON				TAB COMBINATION
	W-1		C1
				TERMINAL
OFF			C2
	PILOT ADJ.	W-2		PILOT CONNECTION
INLET PRESSURE TAP				FOR 1/4” O.D. TUBING
				(PLUGGED)
(PLUGGED)
1/8 - 27 N.P.T. THDS.	RECEPTACLE TERMINAL

C07262

Fig. 69 − Typical Gas Valve (20−28 Sizes Shown)

48/50PG and PM

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