Carrier 48/50PM C16-28 - Manual (Page 91)

91
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.
Puron
R 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
(ft)
NATURAL GAS
ORIFICE†
PROPANE
ORIFICE†
0‐1,999 45 52
2,000 47 52
3,000 47 53
4,000 47 53
5,000 48 53
6,000 48 53
7,000 48 53
8,000 49 54
9,000 49 54
10,000 50 54
11,000 51 54
12,000 51 55
13,000 52 55
14,000 52 56
48PG08−14
ELEVATION
(ft)
NATURAL GAS
ORIFICE†
PROPANE
ORIFICE†
0‐1,999 43 50
2,000 44 51
3,000 44 51
4,000 44 51
5,000 45 51
6,000 45 52
7,000 47 52
8,000 47 52
9,000 47 53
10,000 48 53
11,000 49 53
12,000 50 54
13,000 50 54
14,000 51 55
48PG08−14
ELEVATION
(ft)
NATURAL GAS
ORIFICE†
PROPANE
ORIFICE†
0‐1,999 30 38
2,000 30 40
3,000 31 40
4,000 31 41
5,000 31 41
6,000 31 42
7,000 32 42
8,000 32 43
9,000 32 43
10,000 35 44
11,000 36 44
12,000 37 45
13,000 38 46
14,000 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.
OFF
ON
W-1
W-2
D-1 D-2
C1
C2
PILOT ADJ.
INLET PRESSURE TAP
(PLUGGED)
1/8 - 27 N.P.T. THDS.
2 LEADS, #18 WIRE 1/32 INSULATION,
600V. MAX., 105
° C
REGULATOR
ADJUSTMENT SCREW
(REMOVE COVER)
OUTLET PRESSURE
TAP (PLUGGED)
1/8-27 N.P.T. THDS.
PILOT CONNECTION
FOR 1/4” O.D. TUBING
(PLUGGED)
RECEPTACLE AND
TAB COMBINATION
TERMINAL
RECEPTACLE TERMINAL
C07262
Fig. 69 − Typical Gas Valve (20−28 Sizes Shown)
48/50PG and PM