Connections And Water Circuits - Carrier AQUASNAP JUNIOR 30RA015 User Manual

30RA015

Connections and water circuits

Available static pressure
300
250
200
150
100
50
0
0.3 0.4 0.5
Water flow rate l/s
°
Water temperature 20 C
Correction factors for ethylene glycol
Ethylene glycol 10%
Freezing
temperature –4°C
Capacity 0,996
Power input 0,990
Water flow rate 1,000
Pressure drop 1,003
Connections and water circuits
• The hydraulic circuit must be designed to ensure a steady water
flow through the evaporator at any time.
• The water pipes in the circuit must be well supported and firmly
fastened to ensure that they do not put a strain on the
connections to the unit.
• Water inlet and outlet are identified by a tag.
• Air purge and water drain are located at the inlet and outlet
connections and are closed by appropriate plugs.
• Pipes must have shut-off valves to permit emptying of the heat
exchanger without draining the whole system, as suggested in
the diagram.
Control of a boiler
With a PRO-Dialog configuration, the unit (if it is in heating mode)
can control the start-up of a boiler via the mother board output
signal (see Service Interface Manual).
If the boiler is operating, the unit water pump is stopped.
0.6 0.7 0.8 0.9 1
20% 30% 40%
–9°C –15°C –23°C
0,991 0,983 0,974
0,978 0,964 1,008
0,979 0,979 1,025
1,010 1,020 1,033
The boiler output is activated:
– in 30RA units, by selecting heating mode
Water circulating pump
A three-phase single speed water circulating pump, to be selected
at installation, is installed inside the unit.
The water circulating pump, can be fitted with a water system
resistor (pressure drop) as indicated in the diagrams, keeping water
flow at the correct values.
If the system pressure drop is higher then the pump available head,
water flow to the unit and unit performances are reduced.
To reduce to minimum system pressure drop it is necessary:
- to reduce number of bends;
- to avoid elbow bends;
- to reduce the system extension to a minimum;
- to use pipes of the correct diameter.
To avoid possible damage due to water freezing, it is
recommended to install the water refill system inside the
building.
It is recommend:
• to fit a replaceable filter of at least 10 mesh/cm
inlet, especially with welded joint iron pipes.
Water changes or additions should be reduced, if possible, as
they contribute to oxidation and to calcium deposit formation.
If the unit is not used for a long period, rotor shaft seizure can
occur; the user should unblock the rotor:
• switch off the system;
• unscrew the air purge cap on the pump;
• insert a screwdriver in the slot and turn the rotor shaft;
• reassemble the air purge cap;
• switch on the system.
The control can pilot an external pump with a current input of up to
8 Ampere.
It is recommended to disconnect the internal pump, replacing it with
a tube.
WARNING:
The minimum inlet pressure to the pump at maximum water flow
should be 13 kPa at the maximum supply water temperature
(50°C).
This precaution avoids cavitation noise and damage to the pump
bearings due to lack of water flow and poor lubrication of the
bearings.
Flow switch
The flowmeter installed on the pump backflow pipe prevents the
compressor from operating in the following cases :
• pump failure;
• water circulation cut-off;
• presence of air un the system.
E N G L I S H
2 in the water
GB- 7