JOHNSON CONTROLS
23
FORM 160.00-O10
ISSUE DATE: 8/24/2020
3
SECTION 3 - CYCLING SHUTDOWNS
VSD FREQUENTLY ASKED QUESTIONS
Is a Condenser Water Strainer used with the shell
and tube heat exchanger?
Since the shell and tube heat exchanger can be cleaned
with a rifle brush, no extra precautions are needed to
keep the heat exchanger cleaned. No strainer is pro-
vided with this OSCD. The intent is to have the heat
exchanger cleaned annually. Gaskets are available (re-
fer to the service parts list).
What is the timing of the Anti-Recycle when an
OSCD is applied?
The anti-recycle time is much quicker with an OSCD
than with a starter. The reason is the elimination of
inrush current on start-up. The OptiSpeed compres-
sor drive slowly accelerates the compressor motor so
that the motor does not consume more than 100% of
the motor’s nameplate full load amps. The anti-recy-
cle time is five (5) starts in succession, followed by a
ten minute wait. After ten minutes, the OSCD can be
started five more successive starts. This is permitted
on OSCD units only, due to the low current draw and
reduced motor heating during startup.
Should the customer install isolation between the
Power Conduits and the OptiSpeed Compressor
Drive?
We no longer require a section of non-metallic conduit
at the entrance and exit of the OSCD as we did on pre-
vious products. If any customer or installer wishes to
continue to follow this practice, we have no objections
as long as the OSCD is properly grounded.
Can I apply an OptiSpeed Compressor Drive to a
generator?
Yes, the OSCD can be applied to a generator. No modi-
fications are required for a generator application. We
have several OSCD installations running on generator
power without difficulty. It is necessary that the gen-
erator’s output voltage and frequency be maintained
within the specified range for that particular OSCD.
This is usually not a problem for most generators, since
motor current at startup is limited to less than 1X the
Full Load Amps (FLA). Although no changes are re-
quired for the generator, the generator will need to sup-
port a level of harmonic current. Also, a time delay is
required between the switching of power supplies of 10
seconds. This delay applies to switch between utility
power to generator power and generator power back to
utility power.
Do I have a problem with my coolant? The pink
color is no longer visible?
The coolant normally has a pink or rose color when
new. After several months of operation, this color may
dissipate, and the coolant may appear almost colorless.
The lack of the color in the coolant does not necessarily
indicate a problem. Most colorless samples test above
1000 PPM nitrite, which is normal. There is no need to
flush the system unless you find the coolant becoming
opaque or cloudy. In this case we suggest you obtain a
sample for analysis, then flush the system with coolant
and install fresh coolant. The coolant must be changed
every year regardless of color or test results. The cool-
ant is required to be changed every year.
