Sea Frost ETT's User manual

148 OLD CONCORD TURNPIKE BARRINGTON, NH 03825 USA TEL [phone] FAX [phone]
E-Mail:[email protected] www.seafrost.com
ELECTRONIC THERMOSTAT AND THERMOMETER
• The Sea Frost ETT’s (Electronic Thermostat/Thermometer) accurate
operating settings and the programmable differential increases
efficiency. In comparison, mechanical controls tend to over run the
desired temperature range and must be set colder, running the
compressor longer, to maintain the proper average temperature.
• The ETT will operate any Sea Frost electrical compressor system, AC
or DC.
• The ETT always shows cabinet temperature, and will display in
Centigrade or Fahrenheit.
• Accurate numerical setting of operating temperatures and differential
makes set up and temperature adjustment easy.

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• Thermometer mode.
• Wire leads allow mounting any distance from cabinet.
• Black faceplate with red L.E.D. operation indicators.
• Non-volatile memory, control will not loose settings.
The ETT is pre-wired with plug in connectors for the two 10’ probes and
(custom length) data cable included.
The left hand rocker switch turns on the display. The right hand switch
activates the control relay. Red L.E.D.s indicate ON and RUN modes.
Faceplate size: 4 5/8” x 3 ½” (120 mm x 90 mm). Requires 2 ½” (64 mm)
behind mounting panel. Weight 1 lb (.4 kilo).
CLEANING
Do not use acetone or any solvent on the control panel, clean with a damp
cloth and mild detergent.
INSTALLATION AND OPERATION MANUAL
OPERATION
The Sea Frost Electronic Thermostat and Thermometer (ETT) is an
electronic device using two probes installed in the refrigerated space. One
probe is sensing the cabinet temperature, which is displayed. The other
probe controls the compressor operation by measuring the temperature of
a cold plate.
To operate the control, switch both rocker switches to the left position (off).
Make sure power is available then push the left rocker switch to the right
(on). The display will light and the temperature will be displayed. To switch
on the compressor controlled by the ETT, switch the right switch to the on
position. Both red indicators will light indicating the compressor switch is
on and the compressor is running. When the compressor cools to the pre-

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set cut out temperature the RUN indicator light will go off with the
compressor. The ON indicator light will remain lit indicating a standby or
ready to run mode.
To display temperature only turn off the right ON/RUN switch.
To turn off both the temperature readout and compressor the left switch
may be used however when turning it back on the compressor will start
immediately. All settings will always be saved.
CHECKING THE TEMPERATURE SETTING
Before adjusting the thermostat be sure the refrigeration system is working
properly.
The ETT can be adjusted and will maintain very stable temperatures. Care
must be taken to adjust the settings to maintain obtainable temperatures.
In initial testing do not set below -10 F. (–23 degrees C.) Excessive
compressor running will occur with no benefit if the setting is below the
temperature the compressor system can easily obtain.
To check the cut out setting (cold stopping point) push and hold the SEL
button until ST-1 appears. Release the button and a number will flash.
This is the cut out temperature. Push SEL again and the readout will return
to box temperature. The cut out temperature is associated with the second
probe (red banded). This probe read out temperature is hidden. (Press and
hold the down arrow button to view this read out temperature.)
CHECKING THE PLATE PROBE TEMPERATURE
To monitor the cooling progress, push in and hold the down arrow button.
The plate probe temperature will be displayed while this button is held.
RECOMMENDED SETTINGS
The air temperature in a refrigerator is always 10 to 15 degrees F. (6 to 9
C.) warmer than the cooling device. This difference in temperature must be
remembered when setting the control cut out temperature (stopping point).
A refrigerator might have to be set to run up to 20 degrees colder than the
desired box temperature.

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Make several small setting changes over a period of several days to
determine the proper setting.
CHANGING THE TEMPERATURE
To lower or raise the box temperature, hold the SEL button until the ST-1
appears. Release the button and the cut out temperature will flash. Use
the up and down arrows to change the temperature. Push SEL when
finished. The control setting has now been changed.
THE DIFFERENTIAL SETTING
The differential is the number of degrees the temperature must rise before
the compressor will come back on after cooling to the set point. The
factory test setting is 6 degrees F. (4.5 C.)
To change the differential setting press and hold PRG until P 1 is
displayed, then press SEL. Use the up and down arrows to change the
setting. Press PRG when finished.
READOUT CHANGES ~ Fahrenheit to Centigrade
To change the readout to centigrade hold down PRG and SEL for 5
seconds until 0 is displayed. Using the up and down arrows select #77,
which is the password. Press SEL. Using the up and down arrows scroll to
C-18. Press SEL. Using the arrows keys set 0 for centigrade or 1 for
Fahrenheit. Press PRG to store the change and return to the temperature
display. WARNING: When changing temperature measurement units the
cutoff setting and the differential setting must be changed to represent the
proper units.
INSTALLING THE ETT
The ETT can be located anywhere as long as it is protected from water and
spray. The leads to the probes may be extended to any length if the
connections are soldered and sealed with heat shrink.
The ETT requires a 3 5/8” x 2 ¾” (91 mm x 70 mm) panel cut out. The
minimum depth is 2 ½” (64 mm).

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WIRE ROUTING and CONNECTING
The blue cat-5 cable provides power and signal for the ETT. It connects at
the compressor. The RJ-45 connector on this cable plugs into the RJ-45
port on the Module PCB board. Make certain the plug is clean, and that the
plug has not been damaged when routing through the boat, before plugging
it in.
If shortening this cable make sure the color code is observed. Any pre-
made RJ-45 cable will work. Custom lengths are available.
FUSE
Install a 3 amp ATC fuse in the fuse holder on the Module PCB board. This
fuse is required only if using the RJ-45 jack.
The two black probe wires must enter the refrigerated space.
WIRING CONNECTIONS
The probes plug into the head unit cables. NOTE: One probe has a red
band and should connect to the plug with the red band attached to the back
of the ETT head. The probe with the red band must be routed to attach to
the cold plate, if fitted with two cold plates the probe will attach to the
second plate. The second plate is the one without an expansion valve. See
the special instructions for series plates.
If you need to disconnect the plugs, do not pull on the wires insert a small
screwdriver blade between the halves of the plug.
PROBE ATTACHMENT
The probe with red bands must be in excellent thermal
contact with the cold plate. Use the stainless steel clip
provided, and attach it to the edge of the plate as
shown in the drawing to the right.
The probe without a red band should be installed at
the mid point of the cabinet to get an accurate reading
of the average temperature. Avoid installing this probe

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near a front opening door or too close to a cold plate. Mount the probe
bulb with two nylon straps or self stick pads and tie wraps provided. Do not
drill and screw into a vacuum panel box!
Secure the wires neatly using cable ties, self-stick pads, and proper yacht
construction wiring practices.

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SEA FROST ELECTRONIC THERMOSTAT AND THERMOMETER
DRILL (4) HOLES 3/32" FOR #6 SCREWS.
(1) Control Panel Head
(2) Sensor Probes (1-with red band, 1-without red band)
(1) Cat 5 cable with RJ 45 Connector
INSTALLATION KIT
(4) #6 x 1/2" flat head screws for mounting panel
(6) #6 x 1/2" pan head screws
(5) 3/16" nylon clamps
(8) Adhesive mounting tabs
(10) 4" tie wraps
(1) Stainless steel bulb clip
(1) Fuse