Dectron, Inc. March 2012
DSH/DSV/RSH/DBH/RBH Series Dehumidifier Owner’s Manual
Startup Prepare to Adjust Expansion Valve(s)
Data subject to change without notice.
224
The expansion valve(s) must be adjusted at startup, since airflow affects the evaporator loading.
To obtain proper operation and long life, it is important to adjust the expansion valve(s) as described here.
Do not attempt to adjust the expansion valve based on evaporator superheat.
1. For units with air-cooled air conditioning, be sure that the specified additional refrigerant has been added. See
Product Description - Unit Nameplate, Installation - Piping - Refrigerant, and Startup - Add Refrigerant.
2. Be sure that the airflows have been adjusted as described previously in this section.
3. Be sure that the room temperature and relative humidity are near the values shown on the unit nameplate.
(See Product Description - Unit Nameplate).
4. If the evaporator-bypass damper is manually operated, be sure that it is fully open.
If the unit model number ends in “2”, e.g. DS042, RB282, there will be two refrigeration circuits. Identify the
compressor(s), CLP switches (see unit wiring diagram), and expansion valve(s) associated with each circuit. Such
components may ship already marked with circuit numbers.
The methods of expansion-valve adjustment apply to all circuits present.
DECTRON
Probe
Cable must be able
to reach outside the
unit cabinet.
Probe should be 6
inches (15 cm) from
the compressor.
Foil Wrapped
Around
Insulation
Insulation
Sample
Compressors and
layout may vary.
5. Locate the compressor for the circuit being
adjusted.
6. Attach the probe of a remote-reading
electronic thermometer (by others) to the
compressor-discharge tube approximately
6 inches from the compressor shell. The
thermometer should have a range including
100 to 250°F (38 - 120°C).
7. Wrap 1/2 inch (1cm) thick insulation
around the tube-probe assembly. The
insulation should go all the way around the
tube, and extend at least 3 inches (8 cm)
along the tube on both sides of the
probe end.
8. Wrap the insulation with foil or foil-
backed tape. Close the foil tightly
(especially the ends) against the
turbulent airflow that will form inside
the cabinet.
GO TO NEXT PAGE.
Outdoor-Air
Damper
Evaporator-
Bypass
Damper
Risk of contact with moving parts. Can cause injury or death.
This product contains rotating parts and V-belt drives. Do not approach any moving
parts while electric power is applied to unit. Use only approved devices (e.g. locking
safety switch), to disconnect, lockout, and tagout all sources of electrical energy before
working inside the unit cabinet. Allow adequate time for rotating parts to stop. Follow
all applicable safety regulations.
WARNING
STARTUP
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