Refrigerant Charging Procedure; Refrigerant Recovery Procedure; Commissioning Checklist - Carel Heosbox Mode D'emploi

4.6 Refrigerant charging procedure

Use only R448A or R449A certified refrigerant to charge the Heosbox
unit. The following points should be considered general indications
for correctly charging refrigerant into the unit, and are not technical
specifications. The expansion valves must be correctly sized in order to
complete the charging operation successfully. CAREL Industries S.p.A.
may in this case, based on specific agreements, act as a consultant for the
design/installation/commissioning/use of the unit, however in no case
does it accept liability for the correct operation of the unit and the overall
system if the warnings or suggestions provided in this manual or in other
product technical documents are not heeded. In order to charge the unit
(as described in the steps listed below), switch on and read the controller's
display, so as to monitor some operating variables that are useful in the
refrigerant charge process (such as superheat). To read and use the Carel
"Heos" controller, see the manual (+0300078EN).
The recommended sequence is as follows:
1. Electrically disconnect Heos Box using the on/off switch on the unit
and the disconnect device upstream of the unit's power supply line.
Then remove the refrigerant circuit cover panel.
2. Make sure that all of the valves (24), (26), (31), (32) in Fig. 2.e are
completely open.
3. Using a vacuum pump, bring the system to a pressure of less than 0.25
mbars (187 μmHG), medium vacuum. The time the circuit is kept in a
vacuum must be evaluated on site, according to the volume of the
circuit and in any case must not be less than 60 minutes.
4. Prepare a system to weight the amount of refrigerant charged into the
unit, and write the value on the rating label affixed in this document
and to the Heosbox structure.
5. Charge the unit with a refrigerant pre-charge (e.g. 2 kg (4.4 lbs)) in
order to activate the control system and switch on the compressor.
6. Check that the valve stators (24), (26) (see Fig. 2.e) are correctly installed.
7. Power on Heos Box using the on/off switch on the unit and the
disconnect device upstream of the unit's power supply line.
8. Set the Heosbox unit to OFF (screen Aa01 on the controller).
9. Adjust the condensing temperature to the lowest possible value
(lowest possible water inlet temperature with nominal flow) (screen
M04 on the controller).
10. Set the Heosbox unit to ON (screen AA01 on the controller) and make
sure that the compressor is close to maximum speed, at the same time
making sure that the unit works within the operating range stated
under "Transport and operating conditions" above (main screen M01,
and screens M04 and M08 on the controller).
11. Make sure that the compressor remains running at the maximum
allowed speed for a few minutes (air control temperature close to
the set point; for a Multi-Evaporator configuration, the air control
temperature must be close to the set point on each unit) (main screen
M01 on the controller)
12. If the superheat is greater than the set point (SH > SHset) and the
expansion valve/valves are fully open (EEV%=100%), add refrigerant
(e.g. 100/200 g) (for a Multi-Evaporator configuration, the superheat
on each evaporator must be monitored as described here) (screen
M08 on the controller. To check the superheat set point, see the Carel
Heos manual, as described previously)
13. Wait a few minutes to let the system stabilize.
14. Repeat steps 12 and 13 until SH=SHset and EEV%<90% (for multi
evaporator configurations this must be checked on each unit)
15. Check the refrigerant temperature in the section of piping leaving
the condenser and make sure that subcooling is between 0 and 5K
(0<SBC<5K) (screen M05 on the controller)
16. Carefully check for leaks using suitable instruments, after having
performed the refrigerant charge.
If the system is in good working order, no bubbles are evident in the flow
indicator (33) on the unit. Always make sure that the colour of the sensitive
ring inside the moisture indicator (33) is actually green (no moisture present).
Low condensing temperature and high compressor speed are set so as
to obtain the highest refrigerant flow and the lowest possible pressure
differential across the expansion valve/valves. The valve's capacity to
control superheat in these condition will guarantee correct control even in
other normal unit operating conditions.
Caution: the refrigerant charge must always be completed by
qualified personnel who have the qualifications and authorizations
required by local regulations, who are aware of the necessary precautions,
using appropriate personal protective equipment (PPE), and who are able
to correctly and safely complete all required operations.
Residual risk of pressurized parts yielding if the installer does not follow
the refrigerant gas charge instructions.

4.7 Refrigerant recovery procedure

The following points should be considered general indications for correctly
recovering refrigerant from the unit, and are not technical specifications.
The recommended sequence is as follows:
Switch Heos Box off.
1. Electrically disconnect Heos Box using the on/off switch on the unit
and the disconnect device upstream of the unit's power supply line.
Then remove the refrigerant circuit cover panel.
2. Maintain the flow of water and glycol at the condenser inlet.
3. Make sure the refrigerant inlet/outlet valves on the unit are closed.
4. Check the position of the stators on the electronic expansion valves (if
present in the box) and liquid injection valves respectively. Disconnect
the stators on the valves and open the valves using a suitable magnet
in the kit supplied by Carel (P/N E2VMAG0000).
5. Retrieve the refrigerant contained in the circuit through the ports
on in the liquid, suction and discharge lines. Weigh the amount of
refrigerant retrieved so to subsequently recharge the unit with the
same amount of refrigerant.
In the event of brazing or cutting operations on the refrigerant circuit (e.g.
to replace a component), it is recommended to completely discharge all of
the R448A or R449A refrigerant contained in the Heosbox unit.

4.8 Commissioning checklist

For correct installation and commissioning of the unit, the recommended
steps are as follows:
1. Make sure that the "Water Connections" have been carried out as
described in paragraph 4.1.
2. Make sure that the "Refrigerant Connections" have been carried out as
described in paragraph 4.3.
3. Make sure that the "Electrical Connections" have been carried out as
described in paragraph 4.4.
4. Make sure that there is at least one display kit available (PGD terminal,
P/N PGDEH00FZ0)
5. Make sure that the condenser cooling system (water loop) is correctly
installed and operational.
6. Make sure there is the correct water flow through the water
connections on the unit;
7. Connect the PGD terminal to position 13 in Fig. 2.h, or Fig. 2.g (for NAM
versions).
8. If connecting a PLD terminal, make sure that dipswitch 1 on the
controller is in the ON position (default), as described in the Carel Heos
manual (+0300078EN). For Multi-Evaporator systems, each controller
can have its own PLD terminal.
9. For Multi-Evaporator configurations only:
a.: Check correct connection of the stators on all expansion valves
(Main and Secondary), as shown in paragraph 6, on the Multi-
Evaporator units.
b.: Check correct connection of the RS485 serial line between the Main
and Secondary controllers.
10. Only when using a multi-evaporator system, make sure that:
a.: Each secondary unit has the correct address set in the pLAN network
(controller screen Ea03). This setting must be done with the pLAN RS485
serial between the units disconnected. When finished, reconnect it
b.: The number of evaporators is set on the Main unit (contr. screen Eb03)
c.: On each Main and Secondary unit in the same multi-evaporator
network, make sure to set the capacity of the evaporator that each
controller refers to (screen Eb04).
11. Make sure that the amount of refrigerant charge complies with the
specifications in paragraph 4.6.
12. Make sure the unit parameters have been set correctly, as shown in
the instructions in the Carel Heos manual (+0300078EN).
13. If installing a supervisory system, see Chap. 7.
19 Heos BOX - NAM version +0300097EF - rel. 1.0 - 17.06.2021
ENG