Carrier 25VNA8 User Manual

12
Charging Non--Communicating Systems
Charging Procedure: Force system to operate in high stage
cooling by creating a lar ge differential between room temperature
and set point on thermostat. Use multi--meter to verify that 24
VAC is present between C, Y1 /Y2 terminals at outdoor unit.
Factory charge amount is shown on unit rating plate for high stage.
Target subcooling chart is provided on back of control box door
see Fig. 21 -- 26 for example. To properly check or adjust charge,
condition must be favorable for subcooling charging. Favorable
conditions exists when outdoor temperature is between 65_F
(18_C) and 100_F(38_C), and the indoor temperature is between
70_F(21_C) and 80_F(27_C). Follow the procedure b elow:
Unit is factory charged for 15ft (4.57 m) of lineset. Adjust charge
by adding or removing 0.6 oz/ft (17.7 g/m) of 3/8 liquid line above
or below 15ft (4.57 m) respectively.
For standard refrigerant line lengths (80ft/24.4 m or less), allow
system to operate in cooling mode at least 25 minutes. If conditions
are favorable, check system charge by subcooling method. If any
adjustment is necessary, adjust charge slowly and allow system to
operate for 25 minutes to stabilize before declaring a properly
charged system.
If the indoor temperature is below 70°F (21.11°C), or the outdoor
temperature is not in the favorable range, adjust charge for line set
length above or below 15ft (4.57 m) and indoor fan coil /furnace
coil per Table 4. Charge level should then be appropriate for the
system to achieve rated capacity. The charge level should then be
checked at another time when the both indoor and outdoor
temperatures are in a more favorable range.
NOTE: If the line length is beyond 80ft (24.38 m) or greater than
20ft (6.10 m) vertical separation see Long line guideline for special
charging requirement.
Fig. 20 -- Charging in Cooling Mode 25VNA813
(53ºC) (56ºC)(47ºC) (50ºC)(42ºC) (44ºC)(36ºC) (39ºC) (58ºC)
Liquid Service Valve Subcooling - For all AHRI listed indoor combinations
CHARGING IN COOLING MODE - 24A, 25
13
9
9.5
10
10.5
11
11.5
12
12.5
14
13.5
Outdoor Ambient Temperature ºF (ºC)
SUBCOOLING TEMPERATURE º F
7.2
5.0
5.3
5.6
5.8
6.1
6.4
6.7
7.0
7.8
7.5
SUBCOOLING TEMPERATURE º C
65 70 75 80 85 90 10595 100
Fig. 21 -- Charging in Cooling Mode 25VNA824A/25
CHARGING IN COOLING MODE - 24B
Fig. 22 -- Charging in Cooling Mode 25VNA824B
Fig. 23 -- Charging in Cooling Mode 25VNA836
Fig. 24 -- Charging in Cooling Mode 25VNA837
Fig. 25 -- Charging in Cooling Mode 25VNA848
Fig. 26 -- Charging in Cooling Mode 25VNA860
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations .
Catalog No: 25
V
N
A
8 --- 5 S I
Replaces: 25VNA8---4SI

Carrier 25VNA8 Specifications

General

Brand	Carrier
Model	25VNA8
Category	Heat Pump
Language	English