Application Note
Y99AB-4
Issue Date
May 15, 2002
© 2002 Johnson Controls, Inc.
1
Part No. 24-8711-838, Rev. —
www.johnsoncontrols.com
A
PPLICATION
N
OTE
Y99AB-4 BASO® Test Kit
MILLIAMPS
MILLIVOLTS
20
0
10
10
0
300
DC MILLIVOLTS
PENN-BASO CONTROLS
500
700
900
30
40
50
MILLIAMPS
0-500
0-1000 0-50
MILLIVOLTS
JOHNSON CONTROLS, INC
WATERTOWN, WI., U.S.A
ADJUST
TCN10-4
Thermocouple Nut
31543-3
Thermocouple
Terminal Nut
40073-4
Lead Nut
64119-1D
Adapter Assembly
44549-4
Lead Assembly
44549-7
Lead Assembly
Figure 1: Y99AB-4 Test Kit
Description
The Y99AB-4 Test Kit combines four test functions
to enable service contractors to test BASO® controls
and thermocouples in the field. These four functions
are:
•
Millivoltmeter
with 0 to 50 and 0 to 1000 ranges
for checking the open and closed circuit
millivoltage of thermocouple leads.
•
Performance Tester
with a source of power for
holding open BASO power units while taking
open circuit millivolt readings of the
thermocouple when the main burner is in
operation.
•
Milliammeter
with a 0 to 500 (50 on scale)
range for checking the current dropout range of
BASO power unit assemblies. (There are
10 milliamperes for each division on the dial.)
•
Continuity Tester
for detecting a broken or
open circuit.
Definitions
Automatic Pilot
- A device employed with gas burning
equipment, which automatically shuts off the gas supply
to the burner being served by either direct or indirect
means when the pilot flame is extinguished. The pilot
burner may or may not be constructed integrally with the
device.
Closed Circuit
- Millivoltage measured with the BASO
control attached to the thermocouple.
Couple Lead
- The thermocouple, current carrying
conductors, and attaching nut.
Dropout
- The point, defined by a millivolt or milliampere
reading, at which the electromagnet releases the
armature.
Milliampere
- One thousandth of an ampere.
Abbreviation mA used to check BASO control dropout.
Millivolt
- One thousandth of a volt. Abbreviation mV
used to measure thermocouple output.
Open Circuit
- Millivoltage measured without the BASO
control attached to the thermocouple.
Power Unit
- Electromagnet unit that is internally
connected to the seat of the gas valve and cuts off the
gas when pilot flame fails. Also called a power unit
assembly or hood.
Reset Button
- The button that is manually depressed to
place the BASO control in operation.
Thermocouple
- The pair of dissimilar metallic elements
joined to produce a millivoltage when the junctions are at
different temperatures.
