Start Up; Temperature Adjustment - Neslab System I Liquid to Liquid Instruction And Operation Manual

Section IV Operation

Start Up

Before starting the unit, check all electrical and plumbing connections and
make sure the circulating system has been properly filled with cooling fluid.
To start the unit, place the POWER ON/OFF switch in the ON position and
momentarily press and hold the PUSH TO START button. The recirculation
pump will start.
If the unit does not continue to run when the PUSH TO START button is
released, check the fluid level in the reservoir. The float switch in the reservoir
prevents the unit from operating if the fluid level in the reservoir is below the
operating level. If the fluid level is low, "top off" the reservoir and restart the unit.
Once the System I continues to circulate cooling fluid through the instrument
being cooled, replace the reservoir plug. Tighten the plug "hand tight";
excessive pressure can damage the PVC reservoir.
Temperature
Adjustment
A control valve, located in the COOLING WATER INLET line, regulates the
flow rate of the cooling water supply as it enters the unit. The valve regulates
the flow rate based on the heat load. Flow through the unit is discontinued
when the unit is shut off.
To adjust the temperature of the cooling fluid, turn the calibrated
TEMPERATURE dial and position the desired temperature as close as
possible to the reference line.
The RECIRCULATING TEMPERATURE gauge on the front of the unit
indicates the temperature of the fluid in the reservoir.
The temperature controller opens and closes the control valve in the COOL-
ING WATER INLET to maintain the desired temperature. The green and
amber lights on the control panel indicate the status of the valve. When the
green light is on, the valve is open and heat is being removed from the
cooling fluid. When the amber light in on, no cooling is occurring.
When selecting an operating temperature, remember that the lowest achiev-
able temperature is a function of the available flow rate, the temperature of
the cooling water supply and the heat load.
When tap water is used as a cooling water source, a slight "bucking" may occur as
the valve opens and closes. The amount of "bucking" depends on the pressure
differential between the COOLING WATER INLET and the COOLING WATER
OUTLET/DRAIN. By lowering the pressure differential to 12 psi, the amount of
"bucking" can be minimized. The "bucking" is not harmful to the System I.
- 10 -