OACS Central Chillers : with MG Series Control Instrument
Page: 74
ADVANTAGE ENGINEERING, INC.
525 East Stop 18 Road Greenwood, Indiana 46142
317-887-0729 Fax: 317-881-1277
Service Department Fax: 317-885-8683
Email: [email protected]
8.1 OPERATIONS BELOW 48°F FLUID OR 38°F AMBIENT
A.
The chiller is never to be operated below 48°F leaving water temperature without several
precautionary measures. All controls are factory adjusted for 48°F and above operations.
B.
Before readjusting the protective devices, a satisfactory antifreeze solution must be
substituted for the recirculating chilled water. This mixture will consist of inhibited
propylene glycol and water. Do not substitute an inhibited propylene glycol and water
solution with common automotive type antifreeze. The chart on the next page outlines the
glycol percentages at various water temperatures.
C.
Fluid must be tested with a refractometer to verify proper glycol percentages for freeze
protection. The ratio shall be according to the chart below. Too much glycol can cause
capacity and control problems.
D.
DO NOT USE AUTOMOTIVE TYPE ANTI-FREEZE.
E.
Once a satisfactory antifreeze solution is in place the protective devices may be
adjusted and the control instrument can be unlocked to allow operation below
48°F.
F.
If your unit is equipped with an adjustable low pressure switch, adjust the low pressure
switch according to the specifications in the chart on the next page.
Never lower the cut out setting on the adjustable low pressure
switch without adding glycol to the circulating system.
Evaporator damage will result and this damage is not covered by
the factory warranty.
G.
If your unit is equipped with a non-adjustable “fixed” pressure switch
with a factory low limit of 48°F this switch must be replaced with a
switch with a lower limit. The lower range low pressure switch can be
obtained from the factory by calling 317-887-0729 and asking for the
service department. The model and serial number of your unit is
required. A qualified refrigeration technician is required to change the
switch though no gas recovery is required. The switch attaches to a
threaded fitting on the refrigeration line.
H.
Once all limit switches are adjusted, the temperature control
instrument may be lowered to the desired operating temperature. Your
control instrument may require moving a jumper or DIP swith to allow the
temperature set points below 48°F. See the control instrument section of this manual or
call the Advantage service department for specific instructions.
I.
LE Instruments. The LE instrument requires an adjustment of the DIP switch to
accommodate the expanded temperature range. Please see section 5.6 in this manual
for more information.
J.
Multizone Instruments. The Multizone instrument requires an adjustment of the DIP
switch to accommodate the expanded temperature range. Please see section 5.7 in this
manual for more information.
Adjustable low
pressure switch
Fixed low
pressure switch
Содержание OACS Series
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