15
Installation, operation and maintenance instructions - VMGFE102
IMPORTANT: Before connection of the main power cables (L1
- L2 - L3) on the terminal block, it is impera-tive to check the
correct order of the 3 phases before pro-ceeding to the
connection on the main disconnect/isolator switch.
Power cable entry
The power cables can enter the control box from below or
from the side of the unit, at the bottom of the angle iron.
Pre-punched holes facilitate the entry. Refer to the certifi ed
dimensional drawing for the unit. A removable aluminium
plate below the control box allows introduction of the cables.
10.5 - Field control wiring
Refer to the AR05 017-160 Controls IOM and the certifi ed
wiring diagram supplied with the unit for the fi eld control
wiring of the following features:
•
Water heat exchanger pump interlock (mandatory)
• Remote
on/off switch
•
Demand limit external switch
•
Remote dual set point
•
Alarm, alert and operation report
• Heating/cooling
selection
10.6 - Power supply
ATTENTION: After the unit has been commissioned, the power
supply must only be disconnected for quick main-tenance
operations (one day maximum). For longer main-tenance
operations or when the unit is taken out of service and stored
(e.g. during the winter or if the unit does not need to generate
cooling) the power supply must be main-tained to ensure
supply to the heaters (compressor oil crankcase heaters, unit
frost protection).
After all possible options have been connected, the trans-
former ensures the availability of a usable 24 VA or 1 A power
reserve for the control circuit on site.
11 WATER CONNECTIONS
For size and position of the unit water inlet and outlet
con-nections refer to the certifi ed dimensional drawings
supplied with the unit. The water pipes must not transmit any
radial or axial force to the heat exchangers nor any vibration.
The water supply must be analysed and appropriate fi lter-
ing, treatment, control devices, shut-off and bleed valves and
circuits built in, to prevent corrosion (example: damage to the
protection of the tube surface if the fl uid is polluted), fouling
and deterioration of the pump fi ttings.
Before any start-up verify that the heat exchange fl uid is
compatible with the materials and the water circuit coating.
In case additives or other fl uids than those recommended by
Danfoss are used, ensure that the fl uids are not considered as
a gas, and that they belong to class 2, as defi ned in direc-tive
97/23/EC.
The pumps in the hydronic module are compatible with 40%
propylene glycol and 40% ethylene glycol. But if these fl uids
are used, the pump fi ttings need to be replaced more
frequently (every 15000 operating hours instead of 25000
hours for an appliacation using water).
Recommendations on heat exchange fl uids:
• No
NH
4+
ammonium ions in the water, they are very
detrimental for copper. This is one of the most impor-
tant factors for the operating life of copper piping. A
content of several tenths of mg/l will badly corrode the
copper over time.
• Cl
-
Chloride ions are detrimental for copper with a risk of
perforations by corrosion by puncture. If possible keep
below 10 mg/l.
• SO
4
2-
sulphate ions can cause perforating corrosion, if
their content is above 30 mg/l.
• No
fl uoride ions (<0.1 mg/l).
• No
Fe
2+
and Fe
3+
ions with non negligible levels of dis-
solved oxygen must be present. Dissolved iron < 5 mg/l
with dissolved oxygen < 5 mg/l.
•
Dissolved silicon: silicon is an acid element of water and
can also lead to corrosion risks. Content < 1mg/l.
•
Water hardness: >0.5 mmol/l. Values between 1 and 2.5
mmol/l can be recommended. This will facilitate scale
deposit that can limit corrosion of copper. Values that are
too high can cause piping blockage over time. A total
alkalimetric titre (TAC) below 100 is desirable.
•
Dissolved oxygen: Any sudden change in water oxyge-
nation conditions must be avoided. It is as detrimental
to deoxygenate the water by mixing it with inert gas as it
is to over-oxygenate it by mixing it with pure oxygen. The
disturbance of the oxygenation conditions encou-rages
destabilisation of copper hydroxides and enlarge-ment of
particles.
• Specifi c resistance - electric conductivity: the higher the
specifi c resistance, the slower the corrosion tendency.
Values above 30 Ohm·m are desirable. A neutral
environment favours maximum specifi c resistance
values. For electric conductivity values in the order of
20-60 mS/m can be recommended.
•
pH: Ideal case pH neutral at 20-25°C (7 < pH < 8).
ATTENTION: Charging, adding or draining fl uid from the water
circuit must be done by qualifi ed personnel, using air vents and
materials suitable for the products. Water circuit charging
devices are fi eld-supplied. Charging and removing heat
exchange fl uids should be done with devices that must be
included on the water circuit by the installer. Never use the
unit heat exchangers to add heat exchange fl uid.
11.1 - Operating precautions and recommendations
The water circuit should be designed to have the least number of
elbows and horizontal pipe runs at diff erent levels. Below the
main points to be checked for the connection:
•
Comply with the water inlet and outlet connections
shown on the unit.
•
Install manual or automatic air purge valves at all high
points in the circuit.
•
Use an expansion device to maintain pressure in the
system and install a safety valve and an expansion tank.
•
Units with a hydronic module include the safety valve
and the expansion tank.
