Lennox INNOVA DHADC Series User Manual

Fig. 9
28
32
18
C
C
Fig. 7
28
32
18
C
C
Fig. 8
% R 407C
T3
Oil T
T1
T2
Fig.10
Page 14 - Application Guide INNOV@-0907
25 40 43
Condenser water temperature
Indoor air temperature
Pressure
% Condenser water C in Oil
INNOV@ H units are designed for indoor installation in techno-
logical environments but have been tested also under extreme
conditions, typical for far East markets : the indoor temperature
limits are between 18°C and 32°C with a R.H. up to 75% on
the whole range. Practically indoor conditions don.t play any
role for a reliable operation. The application eld for DX units
-water or air condensed- is shown in the relative diagrams [Fig.
7 and Fig. 8]:
For water temperatures under 25°C a condensing control valve
is needed [option] :
• Using a 2 way modulating valve water side.
The valve is installed in the inlet piping to avoid that in case of
broken pipe refrigerant side, a lot of water could ow into the
system.
• Using the ooding technology.
In this case there are no inuence on water ow, but just a oo-
ding of heat exchanging surface by means of a constant back
pressure valve and a large liquid receiver.
If extended application ranges are needed, please contact the
R&D department or your local dealer.
application eld
For air temperatures below 20°C, a condensing control is ne-
cessary to ensure enough pressure drops across the expansion
device. For temperatures below -15°C and up to -30°C, a ooding
device has to be added in order to ood the condenser internal
surface allowing the right condensing temperature even in case
of strong and cold wind temperatures. This device is shipped
as a kit [Fig. 9] consisting of a back pressure valve, a receiver,
a safety valve and mounting instructions: the installation is very
simple and has to be done just close to the condensing unit at
bottom side.
Compressors Oil Heaters
The "Oil" [Fig. 10] illustrates a specic property [Charles' Law]
of gases, which are more soluble in liquids as the pressure
increases but less soluble as the temperature increases: if the
oil in the sump is held at a constant pressure, an increase in
temperature will signicantly reduce the amount of refrigerant
dissolved in it, thus ensuring that the lubricating function desired
is maintained. The problem of inadequate lubrication occurs if
the crankcase is not duly heated, above all after seasonal inter-
ruptions when, due to the suction effect of the compressor, there
is an abrupt drop in pressure inside the sump, which results in
considerable evaporation of the refrigerant previously dissolved
in the oil. If heating elements were not installed, this phenomenon
would cause two problems:
• Dilution of the oil, hence inadequate lubrication.
• Migration of the oil toward the cooling circuit due to the dragging
effect of the refrigerant.
Electrical heaters are necessary when units are put out of order
for longer periods and remain at a temperature below 15°C.
In case of crankcase heaters, please switch it on at least 12
hours before compressor start up.
Indoor air temperature
20 40 45
Condenser water temperature

Lennox INNOVA DHADC Series Specifications

General

Brand	Lennox
Model	INNOVA DHADC Series
Category	Chiller
Language	English