32
HYDRAULIC CONNECTIONS
General rules
A mesh filter (hole Ø £ 500 µm) must be installed on the unit's water inlet otherwise warranty is immediately forfeited
for units with either the standard or the complete pipe kit and MP-PS. The filter performs the function of blocking any
foreign matter in the system's plumbing circuit (shavings, machining debris, etc.). This prevents the plate exchanger
water pipes from clogging then possibly freezing (and therefore bursting). This filter is included in the unit equipped
with the hydronic kit accessory.
Comply with the local laws governing safety matters in order to correctly design the hydraulic circuit. The following information
gives suggestions on how to correctly install the unit.
1) Standard supply.
• The unit comes as standard with a differential pressure switch located between the entrance and exit of water exchanger to
prevent freezing problems in case of lack of water flow.
The intervention is calibrated to a
Δ
P of 80 ± 5 mbar, while the reset occurs with a
Δ
P of 105 ± 5 mbar.
The differential pressure switch contact opens and stop the unit when you reduce the water flow and so
Δ
P ≤ 80 mbar ± 5.
The differential pressure switch closes and then the unit can restart when the water flow increases and so
Δ
p ≥ 105 mbar ± 5.
• The unit comes standard with an antifreeze heater placed between the evaporator and its insulation controlled by the electro-
nic controller unit.
2) With hydronic kit accessory.
•
Besides the standard accessories, the unit is equipped with all the hydraulic components, as specified in the
"
Options and accessories
" section.
Hydraulic layout of the system
General suggestions
•
The pipes must have the least possible number of bends to minimize load losses and must be adequately supported in order
to prevent the connections of the unit from being excessively stressed.
•
Install on-off valves near components that need to be serviced to isolate them when maintenance work needs to be done
and to allow them to be replaced without having to discharge the system.
•
Before isolating the pipes and charging the system, carry out preliminary inspections to make sure that there are no leaks.
•
Isolate all the chilled water pipes to prevent condensation from forming along the pipes themselves. Make sure that the mate-
rial used is the steam barrier type, failing this, cover the insulation with an appropriate protection. Also make sure that the air
venting valves can be accessed through the insulation.
•
Do not forget to install or at least allow for the installation of pressure and temperature reading instruments on the inlet and
outlet parts of the hydraulic circuit. These instruments will allow you to monitor the operation of the system.
•
The circuit can be kept under pressure by means of an expansion tank (with which the unit is equipped if the hydronic kit
accessory is installed) and a pressure reducer. A plant filling unit can also be used in order to automatically charge the system
and keep it at the desired pressure if it drops below a certain pressure value. Install manual or automatic values in the highest
point of the system to eliminate air from the circuit.
Fit manual or automatic valves at the highest point in the circuit in order to vent air from the circuit.
• Depending on the chosen accessory, there may be male threaded connections or Victaulic-type joints for hooking up to the
unit. The joints allow the pipes to expand due to changes in temperature and in addition the elastomer gasket and the speci-
fied play help insulate and absorb noise and vibration.
• If anti-vibration mounts are installed under the unit, it is recommended to use flexible couplings before and after the water cir-
culation pump and near the unit.
•
Install a tap on the outlet of the unit in order to regulate the water flow.
Precautions for the Winter
The water could freeze and damage the exchanger of the unit and other parts of the system during the winter period, if the system
was to remain at a standstill. This problem can be obviated in 3 different ways:
1.
Drain the system completely, taking care to drain the plate exchanger (in ord
er to drain the unit's plumbing system comple-
tely, open the water drain ball valves and the air vent valves) and centrifugal pumps.
2.
Operate with glycol water taking account, depending on the % of glycol, of the factor of correction of the refrigerating capa-
city, power input, water flow rate and losses of head (see table on following page)
3.
If it is certain that the unit will always be powered throughout the winter, the unit is able to protect itself from freezing, down
to a temperature of -20°C: this is possible thanks to an antifreeze electric heating element installed on the plate exchanger and
intelligent control of the water pump that must be governed by the microprocessor board (see the “Electric Connections” sec-
tion). If the unit is fitted with a Storage tank, solution no. 3 requires installing the tank antifreeze heating element accessor