Forma Series II 3110 Water-Jacketed co2 Incubators User Manual

3. Carefully slide out electronics drawer and locate the Analog Output
board (Figure 6-4).
4. Each system monitored ( Temp, CO
2
, O
2
, RH) requires two
conductors. Feed the wire through the analog wiring inlet on the back
of the drawer. See Figure 6-5.
5. Strip the ends of each conductor and wire to the appropriate terminals
of connectors J2 and J3 on the analog board.
6. When wiring is completed, slide the electronics drawer back in being
very careful to place the door heater cable back into the provided slot
so that the drawer does not pinch the cable.  See Figure 6-3. 
7. Replace the two screws removed earlier and return the unit to service.
The Model 3100 Series incubators can be equipped with a built-in gas
guard system that will operate with either a CO
2
or a N
2
gas supply. Only
one gas guard can be installed on each unit. The gas guard uses two
pressure switches to continuously monitor the pressures of two
independent CO
2
or N
2
supplies and automatically switches from one
supply to the other when the supply pressure drops below 10 psig (0.690
bar). The gas guard is not designed to be used with multiple incubators.
Both of the CO
2
or the N
2
gas supplies must be equipped with two-stage
pressure regulators. The high pressure gauge at the tank should have a 0-
2000 psig range and the low pressure gauge should have a 0-30 psig range.
The gas supply to the incubator must  be maintained at 15 psig (1.034
bar), ±5 psig. Gas pressures below 15 psig (1.034 bar) will cause nuisance
alarms to occur on incubators equipped with the built-in Gas Guard.
6-4
Water Jacketed CO2 Incubator
Thermo Scientific
Section 6
Factory Installed Options
Gas Guard for CO
2
or
N
2
(190640/190642)
Figure 6-4. Analog Output Board    Figure 6-5. Analog Wiring Inlet
Analog Wiring
Inlet

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De-activating Built-in
Gas Guard
Connecting N
2
Gas
Supplies
Figure 6-6. Unit Back with All Connections
The CO
2
inlets for a built-in gas guard are located on the rear of the
electronics drawer (see Figure 6-6).  Using 1/4” ID tubing, connect one of
the CO
2
supply tanks to the fitting labeled CO2 Inlet #1 Tank.  Connect
the second CO
2
supply tank to the fitting labeled CO2 Inlet #2 Tank.
Install 3/8” hose clamps to secure the 1/4” ID tubing to the fittings on the
rear of the drawer.
The N
2
inlets for a built-in gas guard are located on the rear of the
electronics drawer (see Figure 6-6). Using 1/4” ID tubing, connect one of
the N
2
supply tanks to the fitting labeled N2 Inlet #1 Tank. Connect the
second N
2
supply tank to the fitting labeled N2 Inlet #2 Tank.  Install
3/8” hose clamps to secure the 1/4” ID tubing to the fittings on the rear of
the drawer.
The built-in Gas Guard is turned ON when shipped from the factory. In
addition, the Tank Select for the gas guard is specified as Tank 1 when
shipped. Refer to Section 3, Configuration, to de-activate the Gas Guard
or change the Tank Select from 1 to 2. If the operator does not want to use
the Gas Guard, the incubator functions normally by supplying CO
2
(or
N
2
) through the CO2 Inlet #1 Tank (or the N2 Inlet #1 Tank).
Water Jacketed CO2 Incubator        6-5
Thermo Scientific
Section 6
Factory Installed Options
Connecting CO
2
Gas
Supplies

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With the Gas Guard in operation, the incubator will use the gas supplied
through CO2 (or N2) Inlet #1 Tank until the pressure drops below
approximately 10 psig. At this time, the Gas Guard automatically switches
to the gas supplied through CO2 (or N2) Inlet #2 Tank. 
In addition, the incubator automatically changes the Tank Sel in Configure
mode from 1 to 2 to indicate that the incubator is now using gas supplied
through CO2 (or N2) Inlet # 2 Tank. If the gas supply to CO2 (or N2)
Inlet #1 Tank is replenished, the incubator will continue to operate using
the gas supplied through CO2 (or N2) Inlet #2 Tank unless the operator
changes the Tank Select from 2 to 1 through the Configuration mode.
Refer to Section 3, Configuration.
An audible alarm and two visual alarms occur on the control panel when
the gas guard switches from one supply to the other. The audible alarm will
sound until the operator presses the Silence key on the control panel. A
visual alarm in the Message Center will read Tank 1 Low while the audible
alarm is sounding, but will be removed after the operator presses the
Silence key.
Caution Both the audible and visual alarms described above do not ring
back once the Silence key is pressed. 
▲
However, there is a second visual alarm, Tank Low, that illuminates in red
below the Silence key on the control panel when either of the two gas
supplies fall below 10 psig (0.690 bars). The Tank Low remains
illuminated as long as the gas guard detects a low pressure on either of the
gas supply lines. This message is a reminder for the operator to replace or
check for insufficient gas supply to the incubator.
If the gas guard does not detect an adequate gas supply at the CO2 (or
N2) Inlet #1 Tank or CO2 (or N2) Inlet #2 Tank, a visual and audible
alarm will again occur on the control panel.  The visual alarm in the
Message Center will read Tank 1&2 Low.  The audible alarm will continue
to ring until the Silence key is pressed.  The audible alarm will ring back
every 15 minutes after the alarm is silenced, if the Gas Guard continues to
detect that both gas supply pressures are below 10 psig (0.690 bars).
6-6
Water Jacketed CO2 Incubator
Thermo Scientific
Section 6
Factory Installed Options
Operation of CO
2
or N
2
Gas Guard

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