ETS 5506-00 User manual

CONTROLLED ENVIRONMENT
CHAMBER
Model 5506-00 & 5506-11
Plus
Packages D & E
Operating Manual
3/07
www.electrotechsystems.com

TABLE OF CONTENTS
Page
1.0GENERAL 1
1.1 Basic Chambers 1
1.2 Standard Packages 1
1.2.1 Chamber Specifications: 2
1.2.2Pkg.D: 2
1.2.3Pkg.E 3
1.3 Unpacking 3
2.0CHAMBER 5
2.1 Description 5
2.2Installation 6
3.0 PACKAGE SYSTEMS 6
3.1 Package D 6
3.1.1 Description 7
3.1.2 System Function 8
3.1.3 Installation 8
3.1.4 Operation 10
3.1.5Calibration 10
3.1.6 Troubleshooting 11
3.1.6 Specifications 11
3.2 Package E 12
3.2.1 Description 12
3.2.2 System Function 16
3.2.3 Installation 17
3.2.4 Operation 19
3.2.5Calibration 20
3.2.6 Troubleshooting 21
3.2.7 Specifications 23
3.2.8 Model 5465 Dry Gas Dehumidification System (Optional) 24
3.3 Replacement Parts 25
4.0WARRANTY 26

1
1.0 GENERAL
Many applications, such as electronics, medical, pharmaceutical and research
require a controlled environment for testing, assembly or storage. The Model 5506 is
designed to meet these requirements. The Model 5506 is available in standard or
custom configurations to meet specific customer requirements.
1.1 Basic Chambers
Model 5506-00: Enclosure only without glove ports
Model 5506-11: Enclosure only with 8” (203mm) glove ports (Fig. 1.1-1)
Figure 1.1-1: Model 5506-11
1.2 Standard Packages
The ability of the chamber to reach and then hold a given humidity level along
with humidity gradients is a function of the chamber (size, configuration etc.),
temperature, operating systems and controllers used. The following packages
provide solutions to most dehumidification applications. Chambers can also
be custom configured to meet special user requirements.
The following charts show the time typically required to decrease and
increase humidity (Blue = RH, Red = T °C) plus humidity gradients using
an ETS Controller in conjunction with the Model 5461 Desiccant/Pump
Dehumidification System.

2
Rate of humidity decrease Low humidity gradient
1.2.1 Chamber Specifications
1.2.2 Package D:
This configuration incorporates a single point controlled valve
(factory set to 5% RH; other values available) to regulate the flow of
nitrogen, dry air or other dry gas to provide controlled
dehumidification in the chamber at a single point. This system,
utilizing the ETS Model 5311 Controlled Gas Dehumidification
System, shown in Figure 1.2-1, is primarily used for storage or
single use applications.
Material: Fan: 32 cfm (900 l/min)
¼” (6mm) clear acrylic front, top (Specify 115 or 230VAC)
¼” (6mm) white, rear, side, bottom Access Ports (left side):
3/8” (9mm) white left side 2x¼” (6mm) hose barbs
1x1” (25.4mm) Hose barb
Construction: 1x½” (12mm) compression fitting
6-panel, PS30 welded seams 1x1½” (31.4mm) cable pass through
Door (left side): Dimensions: 24”Wx18”Dx15”H
½” (12mm) clear acrylic with ½-turn latch (61x46x38cm)
Seal: ¼” (6mm) Poron, non-setting gasket Weight: 41 lbs (19kg)
Gloves (when configured):
.018” (0.5mm), replaceable hands
natural rubber, accordion sleeves,
8” (203mm) ports
Operating Range:
Humidity: <1 – 100%
Temperature: <32 – 135 °F (0-55 °C)

3
Figure 1.2-1: Package D Controlled Valve System 5506 None
1.2.3 Package E:
This configuration incorporates an adjustable dehumidification
control system, shown in Figure 1.2-2, utilizing the ETS Model 5112
Dehumidifier Controller and the Model 5461 Desiccant/Pump
Dehumidification System. The controller can measure and display
humidity over the entire range, but controls humidity only from 0 to
55% RH. Optionally, the Model 5465 Dry Gas Dehumidification
System can be used. (Ordered separately, not part of Pkg. E.)
Figure 1.2-2: Package E Dehumidification System
1.3 Unpacking
Figure 1.3-3 shows the chamber in its shipping carton. Unpack the
chamber and accessories from the shipping cartons and inspect for any
damage. When handling the chamber DO NOT use any of the fittings or
the door handle as a grip or for leverage. Lift the chamber by placing your
hand all the way into the glove port and grabbing hold of the chamber wall
or gripping around the outside of the chamber. If an item is missing or
broken please contact ETS immediately at 215-887-2196 x226 and
photograph the damage to both chamber and shipping carton. Save all
boxes and shipping material until the system is operational!

4
Figure 1.3-3: Chamber in shipping carton
Chambers only and with standard Package D or E configurations
operating instructions are contained in this Operating Manual. Each
chamber system includes the following:
Model 5506-00
1. Chamber without glove ports with 12”x12” (30x30cm) door
with gasket seal and inlet/outlet ports for accessories.
2. Pliable sealer
3. Operating Manual
Model 5506-11
1. Chamber with glove ports, 8” (203mm) gloves, 12”x12”
(30x30cm) door with gasket seal, inlet/outlet ports for
accessories.
2. Pliable sealer
3. Operating Manual
Model 5506-00, Package D
1. Chamber
2. Model 5311 Controlled Valve assembly
3. Pliable sealer
4. Operating Manual
Model 5506-00, Package E
1. Chamber
2. Model 5461 Desiccant/Pump Dehumidification System.
Includes pump (110 or 220 VAC), desiccator and 12’ (3.7m)
of clear plastic tubing.
3. Model 5112 Automatic Humidity Controller. Includes
humidity sensor, IEC power cord (North American plug).
4. Operating Manual

5
2.0 CHAMBER
2.1 Description
The Model 5506 is a 9.0 cubic foot (0.26 cu. m), sealed chamber
fabricated from 0.25” (6mm) and 0.375” (9.5mm) clear and white acrylic
and measures 36”Wx24”Dx18”H (92x61x46 cm). Access to the chamber is
through a 12” (30.5cm) square opening. A heavy-duty, 0.5” (13mm) clear
acrylic door, secured by a single ½-turn latch, along with a compression
resistant gasket ensures an airtight seal when the door is locked. A 1.25”
(32mm) diameter pass-through is provided for passing cables and/or
tubing through the chamber wall. A pliable reusable sealer seals the
opening. The access door and all fittings are located on the left-hand side
of the chamber as shown in Figure 2.0-1. Additional holes may be
positioned elsewhere as an option.
Figure 2.0-1: Chamber access door and fittings
The humidity level within the chamber is reduced using either dry gas
(usually dry nitrogen or dry air) injected into the chamber or a
desiccant/pump drying system. The desiccator contains a self-indicating,
renewable drying agent (Anhydrous CaSO4) and is mounted externally to
the chamber. A small pump draws air from the chamber and forces it
through the desiccator back into the chamber. This circulating system is
capable of producing humidity levels below 10% RH within the chamber
(Actual lower humidity limit may be determined by the object placed in the
chamber).
Humidifier In
p
u
t
Dr
y
Air In
Sensor Fittin
g
Air Ou
t
Fan Power
Cord
Access Hole

6
2.2 Installation
Place the chamber on an appropriate support surface such as a bench or
desk. Open the latch by turning the handle counterclockwise until the cam
turns away from the chamber wall and then open the access door. Place
the object(s)to be stored or tested inside the chamber and feed any cables
through the cable pass-through located at the rear of the left panel. Seal
the opening using the supplied pliable sealer.
3.0 PACKAGE SYSTEMS
Model 5506 Chambers configured as Package D or Package E feature automatic
dehumidification control.
The Model 5311 and 5112 Dehumidification Controllers used in these packages
operate in a similar manner. When the measured humidity exceeds the set point
by more than 0.5% RH (Model 5112), a solid-state control circuit turns on a
solenoid valve or pump. When the valve is activated, dry gas is injected into the
chamber, or the pump is turned on to circulate chamber air through the
desiccator, absorbing moisture and lowering the humidity level and then back
into the chamber. When the humidity level set point is reached, the controller
turns off the valve or pump. The valve or pump then cycles on and off
automatically as required by the controller to maintain the humidity level at the
desired set point.
3.1 Package D
Many applications require the accurate control of relative humidity at a
specific point below ambient for long-term storage or test applications.
Package D incorporates the Model 5311 Controlled Dry Gas System to
meet these requirements. The controlled solenoid activated valve
regulates the amount of dry gas required to both maintain a dry
environment and conserve the amount of dry gas used in the Model 5506
Chamber.
The Model 5311 is self-contained and comes complete with a controlled
solenoid valve, adjustable flow control valve, universal input voltage 12
VDC power module (90-260 VAC, 50/60 Hz), 5% RH sensor with ½” NPT
compression fitting plus a ¼” NPT quick disconnect fitting for ¼” polyflo
tubing.
The standard sensor supplied with the Dry Gas System has a fixed set
point of 5%. Sensors with other humidity set points are available as an
option. Supplied sensors cannot be reprogrammed to other set points. The
Model 5311 is capable of maintaining the humidity level to better than ±3%
of the fixed controller set point with a measurement accuracy of ±2% R.H.

7
3.1.1 Description
The Model 5311 Controlled Dry Gas System consists of two (2)
basic components: a humidity sensor and a controlled solenoid
valve with adjustable flow regulator.
The standard humidity sensor is an integrated unit measuring
approximately 1”Lx.44”Wx.375”D (25x12x10mm) that plugs into a
24” (61cm) multi-conductor cable that is hard-wired to the control
module. Longer cable lengths are available as an option. A
temperature compensated capacitive sensing element where
capacitance is proportional to humidity is used to detect the relative
humidity level. This sensor is programmed at the factory to produce
a digital output around a pre-selected set point. The standard
factory setting is 5% RH. Other fixed RH set points are available as
an option. Contact ETS to order.
The sensor is mounted to the wall of the chamber using the ½” NPT
compression fitting, shown in Figure 3.1-1. Other mounting
configurations can also be used to meet the user’s specific
requirement.
Figure 3.1-1: Sensor mounted in compression fitting No 5506 Ph
The 36” (91cm) hard wired cable provides the input/output
interconnect between the Control unit and the Humidity Sensor.
The sensor end is fitted with a flat, 4-pin female receptacle with the
following pin-out configuration:
The Control/Solenoid/Flow Regulator unit is shown in Figure 3.1-2.
It will be referred to as just the Control Unit.

8
Figure 3.1-2: Control/Solenoid/Flow Regulator unit
The Control Unit is designed as a complete assembly. There are no
user controls except the flow regulator adjust knob. The only
indicator is a Green LED that indicates the solenoid is on and
supplying gas to the chamber.
3.1.2 System Function
The Humidity Sensor measures the relative humidity inside the
chamber. If the humidity measured in the chamber exceeds 7% RH
the solenoid valve is powered and dry gas is injected. When the
humidity inside the chamber drops to 4% RH the solenoid valve is
deactivated, shutting off the flow of dry gas. The valve will then
cycle on and off automatically as required by the Controller to
maintain the specified humidity level.
A 12V DC universal power module is used to power the Model
5311. It operates from 90-260 VAC, 50/60 Hz. For international
applications the user will have to provide the appropriate adapter
plug to convert the standard North American 2-prong plug to mate
with the available power (MAINS) outlet.
3.1.3 Installation
3.1.3.1 Initial Check Out
Inspect the Control unit and Sensor and inspect for any
visible damage. If no damage is observed then check out the
system as follows:
1. The Humidity Sensor is pre-wired to the control unit when
shipped.
2. Plug the low voltage connector from the power module
into the power jack located on the bottom of the Control

9
unit. Then plug the power module into the appropriate
power outlet (MAINS). This will automatically power up
the Control unit. There is no power ON/OFF switch.
3. Wait 3 minutes and check the Green LED mounted on
top of the unit. If the ambient humidity is above the fixed
set point the solenoid will be activated and the LED
should light.
3.1.3.2 Installation
The sensor mounts in the ½” NPT compression fitting
installed on the left chamber wall.
CAUTION:
The sensing element is sealed within the sensor
assembly, protected against mechanical damage by a
slotted housing cover. Under no circumstances should
the sensing element be touched. The sensor should
never be cleaned using compressed air. Dust and dirt
particles can be removed by blowing gently. There are
no user serviceable parts in the Model 5311 sensor.
The Control Unit may be installed either directly onto the
chamber wall using the fitted 2” (5cm) long, ¼” NPT
threaded tube with ¼” NPT nylon adapter or located
remotely and connected to the chamber using the ¼” polyflo
tubing and the quick disconnect fitting supplied. A small relief
hole is required to prevent pressure build-up in the chamber.
The extra quick disconnect is used for this application.
3.1.3.3 Dry Gas Requirements
Typical dry gases are nitrogen, CO2and dry air. Usually
these gases are under high pressure at the source. An
appropriate pressure reducer should be installed between
the source and the Dry Gas Control System.

10
Gas flow to the chamber is controlled by the Flow Regulator.
It is connected to the solenoid valve gas input. It should be
adjusted for a flow rate between 10 and 50 cfm. If the
chamber door is to be opened frequently then a higher flow
rate will reduce the humidity quicker. If the door is to be
opened occasionally then a lower flow rate will better
conserve the dry gas. If the flow rate is to be monitored then
a flow gauge can be installed between the valve output and
the chamber inlet. Ultimately, it is up to the user to determine
the optimum flow rate for the particular application.
3.1.4 Operation
The Model 5311 Dry Gas Control System is self-sustaining and
does not need any operator function to maintain the required
humidity level. Once the unit is operating and the proper flow rate
established no further user action is required.
Frequent on/off cycling of the solenoid valve may be indicative of a
poor chamber seal. The chamber should be thoroughly inspected to
determine where the leak(s) are occurring and the problem
corrected.
3.1.5 Calibration
The Model 5311 Controller is calibrated prior to leaving the factory.
There are no user adjustable controls. Calibration can be checked
by placing a calibrated humidity indicator in the chamber next to the
sensor to observe that the Controller is maintaining the humidity
within the specified range. If significantly out of tolerance or it just
does not work then the unit will have to be returned to the factory
for service.
NOTE:
If returning to the factory for repair or replacement, first obtain
a RMA number from ETS by calling 215-887-2196 Ext. 220.
3.1.6 Troubleshooting
The Model 5311 should provide trouble-free service. If a problem
with the system is suspected, it is recommended the fault be initially
isolated to either the Sensor, Control Unit or solenoid.
The following troubleshooting guide will assist the user in identifying
various possible problems:
1. No Power - Check power at the wall outlet.

11
2. Green LED does not come on even though the humidity level
inside the chamber is known to be at least several percent
above the fixed set point of the Model 5311. Return unit to
factory.
3. Obviously incorrect humidity control – If sensor was removed
from its connector, check to see that it has been replaced
properly. The arrow (5) should line up with the left hand side of
the sensor with the sensing grill facing up. If it was reversed,
reinstall properly. The sensor will not be damaged if plugged in
backwards.
Next, if the ambient humidity is near the fixed set point, check
sensor operation by blowing gently onto sensor for several
seconds and observe the Green LED. If the LED turns on, the
humidity sensor and control electronics are working.
4. No dry gas flow, Green LED remains on constantly – Check to
see if there is dry gas at the source. If so, the valve may be
contaminated preventing it from opening or closing. Return the
unit to the factory for replacement.
5. Difficulty maintaining low humidity within the chamber – The
chamber may either be leaking, ambient humidity may be very
high or the flow rate is too low. Generally, with a dry gas system
the humidity within the chamber should recover and stabilize
within a few minutes. If this is not happening, try increasing the
flow rate. Also, check to ensure that dry gas is being injected. If
dry air is being used, there may be condensation in the line.
3.1.7 Specifications
Sensor type: Temp compensated, capacitive film
Range: Fixed point, 5%RH, standard
Accuracy: ±3% RH
Lo/Hi band: 4% RH off / 7% RH on
Set pt adjust: None
Manual control: None
Control Out: 12VDC, Solenoid Valve
Power req.: 90-260 VAC, 50/60Hz, 30W max
Gas In/Out: ¼” Quick Disconnect
3.2 Package E
Package E is for those applications that require the accurate
measurement and control of relative humidity at various set points below
ambient for long-term applications in a seal environment. The Model 5112
Dehumidifier Controller is used to control dehumidification in the Model
5506 Chamber to any user selectable set point up to 55% RH. The

12
standard Package E utilizes the ETS Model 5461 Desiccant/Pump
Dehumidification System to dry the chamber.
As an option, the ETS Model 5465 Dry Gas Dehumidification System may
be substituted for the Model 5461. This system uses a solenoid valve to
control the flow of dry gas
The Model 5112 can measure relative humidity over the entire 0 to 100%
range, but only controls levels below 55% RH. The standard sensor
supplied with the Controller has a response time satisfactory for
maintaining long-term humidity stability. For applications requiring a fast
recovery time the optional ETS Model 554 Humidity Sensor should be
used.
3.2.1 Description
3.2.1.1 Model 5112 Dehumidifier Controller
The Model 5112 Dehumidifier Controller shown in Figure
3.2-1 consists of two (2) basic components: a Humidity
Sensor and a Control Unit.
Figure 3.2-1: Model 5112 Dehumidifier Controller
The standard Humidity Sensor is an integrated unit
measuring approximately1”Lx.44”Wx.375”D (25x11x10mm)
that plugs into a 24” (61cm) multi-conductor cable that is
hard-wired to the Control unit. Longer cable lengths are
available as an option. A temperature compensated
capacitive sensing element where capacitance is
proportional to humidity is used to detect the relative
humidity level. This type of sensor can measure over the
entire range of 0 to 100% R.H. with accuracy better than
±2% R.H at a temperature of 20-40°C. The sensor has a
slew rate (response time) of 0.35% R.H./sec.

13
The sensor is mounted to the wall of the chamber using a ½”
NPT compression fitting installed in the chamber wall. Other
mounting configurations can also be used to meet the user’s
specific requirement. The Control Unit provides the
necessary indicators and controls to set the desired humidity
level and to measure the actual humidity level in the
chamber.
The front panel of the Control Unit shown in Figure 3.2-2
contains a 0.375”, 3½-digit LCD readout for both setting the
desired set point and for reading the relative humidity with a
resolution of ±0.1% R.H. A black, momentary RH LEVEL,
SET PT/READ switch selects the information to be
displayed. In the normal (Button out) position the readout
displays the measured relative humidity level. In the
depressed position, the readout displays the desired
humidity set point. When released, it automatically returns to
the READ position. A 10-turn screwdriver adjustable
potentiometer is used to adjust the set point from 0 to 100%
R.H.
Figure 3.2-2: Control Unit front panel
The Green DEHUMIDIFIER switch, when in the ON position
(in), places the system in the DEHUMIDIFY mode. When the
measured humidity is above the set point level, a control
signal activates the DEHUMIDIFY relay circuit and 115/230
VAC is applied to the DEHUMIDIFY AC outlet on the rear
panel. This turns on the Dehumidification System. When this
switch is in the OFF position (out) the Dehumidification
System will remain off irrespective of the RH level measured.
When this switch is in the OFF position, the Model 5112
operates as a precision electronic hygrometer.

14
The system Power switch and the controlled North American
3-prong grounded outlet are located on the rear panel as
shown in Figure 3.2-3.
Figure 3.2-3: Control Unit rear panel
The Power switch, Fuse and AC line cord are separate
components that control the power input to the Model 5112
Controller. The AC line cord is a standard North American 3-
prong grounded type, 8” (2.5m). The Model 5112 contains a
universal power supply that operates from 90-260VAC,
50/60Hz. Optional line cords are available to conform to the
requirements of other countries when ordered with the
Controller. Otherwise, the user must use either an adapter or
cut off the plug and install the appropriate type.
The ON/OFF switch located on the rear panel, controls the
ON/OFF status of the Controller. The AC line fuse is located
internally on the PC board and protects both the controller
electronics, and the solid-state relay. It is a 3AG Slo Blo type
rated at 250 Volts, 2 Amps. The solid-state relay is not
voltage dependent and is capable of switching a maximum
of 3 Amps at either voltage, however, for extra protection a 2
Amp fuse is installed.
This AC output receptacle accepts the standard 3-prong
North American grounded plug. When the measured
humidity exceeds the humidity level set point by about 1%
R.H., 115/230 VAC power is applied to the receptacle.

15
NOTE:
A 115 VAC pump or solenoid must be used when
operating at 115 VAC and a 230 VAC pump or solenoid
must be used when operating at 230 VAC.
This 18” (46cm) hard wired cable provides the input/output
interconnect between the Controller and the Humidity
Sensor. The sensor end is fitted with a flat, 4-pin female
receptacle with the following pin-out configuration:
Pin-1 Temp Signal In (0-5V)
Pin-2 Power (2-5.5VDC)
Pin-3 RH Out (0-5V)
Pin-4 Ground
The Control unit is housed in a flame resistant Noryl, SE1
GFN1 housing that conforms to the dimensional standard
DIN 43700. The case measures 3.78”Wx3.78”Hx3.35”D
(96x96x85mm). To install the control module into a panel a
3.62”x3.62” (92x92mm) cutout and the optional panel mount
kit are required.
3.2.1.2 Model 5461 Dehumidification System
The Model 5461 Dehumidification System can reduce the
relative humidity level in the Model 5503 Chamber to less
than 10% RH. Calcium Sulfate; however, is capable of
reducing the humidity to <5%RH, but mechanical
considerations of the chamber, load and operating system
limit the specified lower limit to <10% RH.
This Dehumidification System utilizes a pump to draw air
from the chamber and circulate it through a plastic cylinder
that contains Calcium Sulfate. The desiccant absorbs any
moisture that is in the air. This dried air is then forced back
into the chamber. The Calcium Sulfate contains an indicator
that turns the normally blue colored desiccant pink as it
absorbs moisture. When the entire cylinder turns pink, the
desiccant must either be replaced or renewed by removing it
from the column and placing in an oven at 400°F (200°C) for
one (1) hour.
The complete Model 5461 Dehumidification System consists
of a desiccant column containing 1 lb (.45kg) of renewable,
calcium sulfate (CaSO4) desiccant, a 0.6cfm pump, and 12’
(4m) of 5/16” (8mm) ID of flexible plastic tubing for
connecting the pump, desiccator and chamber together.
The desiccant can be renewed approximately ten (10) times
before having to be replaced. The granules should be

16
removed from the drying column and spread evenly, one
granule deep on a tray. The desiccant should then be heated
for approximately one (1) hour at about 400ºF (200º C). It
should be allowed to cool in an airtight container before
refilling the acrylic drying column. The felt filters should also
be pre-dried at 200º F (100º C) for about 30 minutes before
assembly.
3.2.2 System Function
Figure 3.2-4 is a block diagram illustrating the Dehumidifier
Controller and Dehumidification System connected to the Model
5506 Chamber.
Figure 3.2-4 Controlled humidity chamber block diagram
The Humidity Sensor measures the relative humidity inside the
chamber. The Sensor output signal is then compared to the set
point. When the humidity measured in the chamber exceeds the set
point the Controller turns on the pump circulating the test chamber
air through the desiccator or injecting dry gas through a solenoid
valve. For the desiccator system the desiccant absorbs moisture,
thereby lowering the humidity level inside the chamber. For the dry
gas system the dry gas replaces the wet air that is ejected into the
atmosphere or through a vent. When the humidity level drops below
the set point, the Controller turns off the pump. The pump will then
cycle on and off automatically as required by the Controller to
maintain the desired humidity level.
Power to operate the Dehumidification System is controlled by a 3
amp solid-state relay. When the measured humidity deviates from
the R.H. set point the Controller turns on the relay which then
supplies the necessary 115/230 VAC power to the system.

17
3.2.3 Installation
3.2.3.1 Initial Check Out
Unpack the Control Unit and Sensor and inspect for visible
damage. If no damage is observed then proceed to check
out the system as follows:
1. The Humidity Sensor is already connected to the Control
Unit when shipped.
2. Connect the line cord into the appropriate power outlet
(MAINS). Be sure the POWER switch is in the OFF
position and the DEHUMIDIFIER switch is in the OFF
(out) position. Plug the Dehumidification System into the
AC outlet.
NOTE:
All ETS operating systems utilize the standard 3-prong
North American plug. A 230V/50Hz system will be
marked as 230V, but will still have the same 3-prong
plug.
3. Turn on the Controller (the POWER switch is located on
the rear panel). The LCD readout will initially read a
humidity level much lower than ambient and the Green
DEHUMIDIFIER indicator should be OFF.
4. The LCD reading will slowly start to increase until it
reaches the ambient RH level. This may take as long as
5 minutes if the ambient humidity is very high.
5. Depress the READ RH/SET RH Switch to the SET PT
position. The Display will read some level. While holding
the switch down in the SET PT position, rotate the
ADJUST Control to the desired RH level set point using a
small (1/8”/3mm) screwdriver.
6. Release the switch so that it returns to the READ RH
(out) position and note the humidity level reading on the
display. Turn on the DEHUMIDIFIER switch (Green
button out). If the set point is below ambient, the Green
DEHUMIDIFIER ON light will turn on and power will be
applied to the Dehumidifier outlet, activating the
dehumidification system. If the SET PT is above the
ambient RH reading, the Green LED indicator light will be
off.
7. The dehumidification process will start. The
Dehumidification System will remain on until the set point

18
is reached. It will continue to cycle to maintain the set
point level.
3.2.3.2 Installation
The Humidity Sensor is normally mounted in the bulkhead
using the compression fitting. However, other mounting
locations may be used to meet user requirements.
CAUTION:
The sensing element is sealed within the sensor
assembly protected against mechanical damage by a
slotted housing cover. Under no circumstances should
the sensing element be touched. The sensor should
never be cleaned using compressed air. Dust and dirt
particles can be removed by blowing gently. There are
no user serviceable parts in the Model 5112 sensor.
The Control Unit may be placed on any surface near the test
chamber or installed into a panel 3.62”x3.6” (92x92mm
cutout) using the optional mounting clips.
Installation of the Dehumidification System is as follows:
1. Locate the desiccator at a convenient location near the
left-hand side of the chamber. Place the pump at a
convenient location near the desiccator or on the floor as
shown in Figure 3.2-5.
Figure 3.2-5: Model 5503 Package E installation No 5506
2. Insert one end of the length of supplied plastic tube into
the lower hose barb on the chamber.
3. Cut the tube and insert the other end into the INLET or
vacuum side of the pump.