Servicing Your Refrigeration System; Refrigerant; Uick Onnect Ittings; Echarging He Ystem - Dometic KRA Series Installation, Operation & Maintenance Manual

M A
ODBUS DDRESSES FOR
To implement remote monitoring and control of the KRA system(s) via the Dometic Smart Touch Integrated Intelligence Control
(STIIC), use the Modbus settings shown in the table below. There is a maximum of 3 controllers per KRA unit on STIIC.
Table 4: Modbus Device Addresses for KRA Units Using STIIC
Condensing Unit
KRA unit #1
KRA unit #2
KRA unit #3
KRA unit #4
KRA unit #5
KRA unit #6

SERVICING YOUR REFRIGERATION SYSTEM

R
EFRIGERANT
This refrigeration system uses R-404A refrigerant. With a properly designed system, R-404A will perform well for temperatures
down to 0°F/-32°C. R-404A is a blended-component refrigerant and should be charged in a liquid state. Never charge in the gas
(vapor) phase. Because R-404A is a blend of gases, the most volatile gas will boil off first, so if there is a leak, the system will
lose a portion of the blend first, creating an improper mixture and poor performance.
Q -C
UICK ONNECT
QCs may be used in a similar manner as base valves. To check compressor suction valve integrity, remove the liquid line QC
from the condensing unit. In 2-3 minutes or less, the unit should be pulling a vacuum. You may also use the QCs to troubleshoot
leaks by narrowing down the search to individual parts, such as the liquid line, suction line, box, and condensing unit.
Disconnect the QCs, and pressurize all parts separately.
R T
ECHARGING HE
You only need to recharge the system if it was improperly charged or after a repair, and only after checking for leaks and finding
none.
S S
YSTEM HUTDOWN
It is best if the system can be turned off for 8-12 hours prior to servicing to allow the refrigerant to reach ambient temperature.
This will expedite the recovery of the refrigerant, but is not necessary.
E R
VACUATE
1. Connect manifold gauges to both high and low side ports. Attach center line of gauge set to recovery apparatus.
2. Recover system per governing EPA regulations.
3. With the manifold gauges still connected to service ports, attach the center line of gauge set to vacuum pump.
4. Repeat vacuum process until a vacuum of 200-400 microns is achieved. If the system has been open to the
environment, allow a minimum evacuation time of 12 hours. Close manifold valves and turn off the pump. If no vacuum
is lost, proceed with charging.
C
HARGING THE
Refer to Figure 10: Refrigerant Pressure-Temperature Chart, page 21.
1. Remove line from vacuum pump and connect to a R-404A bottle. The charge must be weighed in.
2. Pressurize the charging lines with liquid R-404A refrigerant.
3. With system OFF, charge on high side and allow the correct amount of R-404A to flow into the system by weight
indicated on data label. Typical pressures are 20 PSI on the low side and 210 PSI on the high side (plus or minus 4
PSI) at typical entering temperatures of 73 to 75°F/23 to 24°C for air or water condenser. Since each installation is
unique, your readings may vary. If questionable, call Dometic Technical Support.
12
D
OMETIC
Modbus Address
40, 41, or 42
43, 44, or 45
46, 47, or 48
49, 50, or 51
52, 53, or 54
55, 56, or 57
F
ITTINGS
S
YSTEM
EFRIGERANT
S
YSTEM
STIIC I
NTERFACE
Extra Hardware KRA Parameter Code
IROPZ48500 Dongle h0
IROPZ48500 Dongle h0
IROPZ48500 Dongle h0
IROPZ48500 Dongle h0
IROPZ48500 Dongle h0
IROPZ48500 Dongle h0
STIIC Connection
J26-FB2
J26-FB2
J26-FB2
J26-FB2
J26-FB2
J26-FB2
L-3571 ENGLISH