Guildline Autosal 8400B - 11.3.2. CHECKING THERMOELECTRIC COOLING UNIT; 11.3.3. CHECKING IMPELLER; 11.3.4. CHECKING HEATER LAMPS; 11.3.5. REMOVING TOP PANEL

Section 11
TM8400B-L-00
1 November 2004
11-3
11.3.2. CHECKING THERMOELECTRIC COOLING UNIT
The thermoelectric cooling unit is fairly inaccessible. Two simple checks are: open the
current leads to the unit (see Interconnections Schematic 18963.01.04) at TB1-11 and
measure the current, it should be several amps, and place your hand in front of the cutout
on the left hand side inside the front panel. The air expelled should be warm. If
thermoelectric cooling unit appears defective, we recommend returning the instrument to
the factory since changing it requires removing the tank from the instrument frame. If
removal is necessary see Section 11.3.6.
11.3.3. CHECKING IMPELLER
If the impeller is not stirring, do the following checks. Withdraw the chassis from
cabinet, and check impeller drive system. When power switch is on, the impeller motor
should be turning. The impeller pulley should turn easily by hand when the power is off.
The impeller drive belt should fit snugly over the impeller and motor pulleys without
slipping. The impeller assembly components and motor are shown in the Top Panel
figure 8.3 and drawing (18969.01.01).
11.3.4. CHECKING HEATER LAMPS
When the Temperature selector switch is turned to a temperature well above the bath
temperature, the heater lamps should both come on fully. When the selector switch is
turned to a temperature well below the bath temperature, the heater lamps should go dark.
If only one lamp lights the other one is almost certainly defective and should be replaced.
11.3.5. REMOVING TOP PANEL
(NOT NECESSARY TO REPLACE LIGHT BULBS)
Step 1. Turn off power, disconnect line cord, and remove instrument chassis from
cabinet.
Step 2. Disconnect cell connector, Lamp and thermistor wiring as required.
Step 3. Disconnect teflon Sample Tube from heat exchanger tube top (see Top
Panel and Top Panel Assembly and Plumbing drawings).
Step 4. Disconnect Cell Drain Tubing.
Step 5. Disconnect tubing from airline to flushing manifold.
Step 6. Remove 8 tank top securing screws from edges of tank top.
Step 7. Gently pry up one edge of the top panel. It is sealed by a greased gasket
which is fairly sticky.