Advantage Maximum MG Series - Checking the Refrigerant Charge; Proper Cleaning Procedure for Brazed Plate Evaporators

update 08/02/2021
Maximum Series Portable Chiller : Air & Water-Cooled : MG Series Instrument
Page: 61
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: service@AdvantageEngineering.com
5.6 CHECKING THE REFRIGERANT CHARGE
A. All standard chillers are manufactured with thermostatic
expansion valves as the metering device to the evaporator.
B. All standard chillers have a refrigerant sight glass with a
moisture indicator. To check the refrigerant charge under
normal operating conditions:
1. Remove the plastic cap covering the sight glass.
2. Start the chiller and allow system pressures and
temperatures to stabilize.
3. With the unit operating at 100% capacity (not in the “capacity control” mode)
the sight glass should appear clear with no foam or bubbles evident. If foam or
bubbles are evident, the chiller has suffered from a loss of refrigerant and should
becheckedbyaqualiedrefrigerationtechnician.
4. The “dot” in the middle of the sight glass is the moisture indicator. It should
appear green at all times. A white or yellow color indicates moisture has invaded
the refrigeration system, which is detrimental to the life of the compressor. The
lter-driershouldbereplacedbyaqualiedrefrigerationtechnician.
5.7 PROPER CLEANING PROCEDURE FOR BRAZED PLATE EVAPORATORS
A. The brazed plate evaporator is made of stamped stainless
steel plates, furnace brazed together with copper based
joints.Thecomplexgeometryoftheowpassages
promotesturbulentowwhichgiveshighefciencyand
reduces fouling by mineral deposits. Large solids such as
plastic pellets or chunks of mineral deposits will collect
atthewaterinletportattheevaporatorandrestrictow
through some of the passages. If this possibility exists, the
Manufacturer recommendsltersorstrainersbeaddedto
the “from process” line. If the evaporator becomes fouled
there are a couple of methods for cleaning.
B. To begin, remove the piping to the “water in” port at the evaporator. Remove any solids
thathavecollectedatthispoint.Thenbackushtheevaporatortoremoveanysolidsthat
maybetrappedbetweentheplates(seebackushprocedurebelow).Iftherearemineral
depositsadheredtotheplates,theevaporatormustbebackushedwithamildacid
solution (5% phosphoric or 5% oxalic acid is recommended.) After cleaning rinse with
clear water before returning to service. Continue with step C on the next page.
C. Back ushing procedure:
1. Turn off all power to the machine. For chillers with a reservoir tank, drain the tank
to below the evaporator outlet. For chillers without a reservoir tank, drain total
unit.
Sight Glass
Evaporator