Humidi−Mizerr Dehumidification System - Carrier 48TC 17 Series Service And Maintenance Instructions

3. Thoroughly wet finned surfaces with clean water and
a low velocity garden hose, being careful not to bend
fins.
4. Mix TotalineR environmentally sound coil cleaner in
a 2−1/2 gallon (9.6 L) garden sprayer according to the
instructions included with the cleaner. The optimum
solution temperature is 100_F (38_C).
NOTE: Do NOT USE water in excess of 130_F (54_C),
as the enzymatic activity will be destroyed.
5. Thoroughly apply TotalineR environmentally sound
coil cleaner solution to all coil surfaces, including
finned area, tube sheets and coil headers.
6. Hold the garden sprayer nozzle close to finned areas
and apply cleaner with a vertical, up−and−down mo-
tion.
7. Avoid spraying in a horizontal pattern to minimize
potential for fin damage.
8. Make sure the cleaner thoroughly penetrates deep into
the finned areas.
9. Interior and exterior finned areas must be thoroughly
cleaned.
10. Finned surfaces should remain wet with cleaning so-
lution for 10 minutes.
11. Make sure surfaces are not allowed to dry before rins-
ing. Reapply cleaner as needed to ensure 10−minute
saturation is achieved.
12. Thoroughly rinse all surfaces with low−velocity clean
water using a downward rinsing motion of the spray
nozzle. Protect fins from damage from the spray noz-
zle.
Evaporator Coil Metering Devices
The metering devices are multiple fixed−bore devices
(Acutrolt) swedged into the horizontal outlet tubes from
HUMIDI−MIZERR ADAPTIVE
DEHUMIDIFICATION SYSTEM
Units with the factory−equipped Humidi−MiZerR option
are capable of providing multiple modes of improved
dehumidification as a variation of the normal cooling
cycle. The design of the Humidi−MiZerR system allows
for two humidity control modes of operation of the
the liquid header, located at the entrance to each
evaporator coil circuit path. These are non−adjustable.
Service requires replacing the entire liquid header
assembly.
To check for possible blockage of one or more of these
metering devices, disconnect the supply fan contactor
(IFC) coil, then start the compressor and observe the
frosting pattern on the face of the evaporator coil. A frost
pattern should develop uniformly across the face of the
coil starting at each horizontal header tube. Failure to
develop frost at an outlet tube can indicate a plugged or a
missing orifice.
Refrigerant System Pressure Access Ports
There are two access ports in the system − on the suction
tube near the compressor and on the discharge tube near
the compressor. These are brass fittings with black plastic
caps. The hose connection fittings are standard 1/4 SAE
male flare couplings.
The brass fittings are two−piece High Flow valves, with a
receptacle base brazed to the tubing and an integral
spring−closed check valve core screwed into the base (See
Fig. 15). This schrader valve is permanently assembled
into this core body and cannot be serviced separately;
replace the entire core body if necessary. Service tools are
available from RCD (p/n P920−0010) that allow the
replacement of the schrader valve core without having to
recover the entire system refrigerant charge. Apply
compressor refrigerant oil to the schrader valve core's
bottom o−ring. Install the fitting body with 96 ± 10 in−lbs
(10.85 ± 1.13 Nm) of torque; do not overtighten.
NOTE: The High−Flow valve has a black plastic cap
with a rubber o−ring located inside the cap. This rubber
o−ring must be in place in the cap to prevent refrigerant
leaks.
o
Fig. 15 − CoreMax Access Port Assembly
rooftop unit, utilizing a common subcooling/reheat
dehumidification coil located downstream of the standard
evaporator coil. This allows the rooftop unit to operate in
both a dehumidification (Subcooling) mode and a hot gas
Reheat Mode for maximum system flexibility. The
Humidi−MiZerR package is factory−installed and will
operate whenever there is a dehumidification requirement
present.
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C08453