Master Catalog
Gas Flame Detection Controls and Devices Section
Product Bulletin
Issue Date
125
K
K15, K16
0996
K15, K16 Series
BASO Brand Thermocouples
®
Application
Johnson Controls thermocouples
are designed primarily for use
with Baso brand automatic pilot
controls and pilot burners;
however, many models are
completely interchangeable with
thermocouples made by other
manufacturers. Johnson Controls
thermocouples are built to provide
reliable performance and
designed to simplify installation.
General Description
Thermocouples are constructed of
two dissimilar metals as is shown
in the cross-section view of Fig. 1.
These metals are, in effect, the
“power plant” of the Baso brand
automatic pilot control. Heat
energy from the pilot flame is
converted by the thermocouple
into electrical energy, which is
conducted to the coil of an
electromagnet through copper
conductors. Thus, the magnet is
energized by the presence of a
pilot flame, but this energy flow
stops when the pilot flame is no
longer present. In Baso brand
automatic pilot controls, the
stopping of energy flow to the
electromagnet prevents the flow
of unburned gases to the burner.
The generation of electrical
current by the thermocouple
occurs because of the difference
in temperature between the
thermocouple’s “hot” and “cold”
junctions. This temperature
difference is accomplished by
placing the hot junction in direct
contact with the pilot flame.
Note: The pilot flame should
surround the end of the
thermocouple for approximately
1/2 in. and under no
circumstances should the pilot
flame come in contact with any
other part of the thermocouple
lead.
© 1996 Johnson Controls, Inc.
Code No. LIT-125355
All of Johnson Controls standard
thermocouples, except the K16R
model, are made of “dead-soft”
copper tubing and may be bent to
facilitate correct installation. Note:
Bends should NOT be made within
dimensions “A”. (See Fig. 1.)
Although a wide variety of
thermocouples have been
produced for special applications,
the thermocouples included in this
bulletin are the standard models
used with Johnson Controls Baso
brand pilot burners and automatic
pilot controls for general
application requirements. (See
the Selection Guides on Pages 2
and 3.)
Some applications may require
thermocouples longer than 72 in.
in length. Baso model K16B is
available in standard lengths over
72 in. Note: Leads in lengths
over 72 in. may be used only
with controls having a special
dropout range.
Repairs and Replacement
Field repairs must not be made.
For a replacement thermocouple,
contact the nearest Johnson
Controls wholesaler.
Packaging
The thermocouples are normally
bulk packed for shipment to
Original Equipment
Manufacturers. Individual pack is
available, if required.
Fig. 1-- Cut-away view of a
typical Thermocouple.
Ordering Information
To order, specify:
1.
Type of thermocouple.
2.
Thermocouple length.
3.
Quantity.
1
Selection Guides
General Purpose Thermocouples
Thermocouple Identification
K15D
Standard
Length in
Inches
Control No.
Approximate
Shipping
Weight*
12, 18, 20, 24,
30, 36, 40 and
48
Baso Valves and
switches, and
Basotrol Valves
with Automatic
Pilot
Carton of 300
Approx.
35 lbs. (16 kg)
Snap-In Thermocouples
Specifically designed thermocouple with snap-in spring clip for fast, easy assembly;
fits all standard Baso pilot burners.
K16C
12, 18, 24, 30,
36, 40, 48 and
60
Baso Valves and
switches, and
Basotrol Valves
with Automatic
Pilot and Ignition
controls
Carton of 300
Approx.
37 lbs.
(17 kg)
K15F
12, 18, 20, 22,
24, 27, 30, 36,
40 and 48
Baso Valves and
switches, and
Basotrol Valves
with Automatic
Pilot
Carton of 300
Approx.
35 lbs. (16 kg)
12, 18, 24, 30,
36, 40, 48, 60
and 72
Baso Valves and
switches, and
Basotrol Valves
with Automatic
Pilot and Ignition
controls
Carton of 300
Approx.
37 lbs. (17 kg)
24, 30, 48, 60
and 72
Baso Valves and
switches, and
Basotrol Valves
with Automatic
Pilot
Carton of 300
Approx.
37 lbs. (17 kg)
Miscellaneous Application Thermocouples
K16B
For Critical applications or multiple hookups.
K16N
Same as K16B but sealed and has spring washer at terminal end.
*Estimated Weights are for 24 in. lengths
2 K15, K16 Product Bulletin
Special Application
Thermocouples
Junction Block Thermocouples
Johnson Controls K16F and
K16J junction block
thermocouples have a built-in
junction block to which wires
from a high limit switch can be
connected. This type of
application places the power
unit of the pilot control in series
with the limit switch and the
thermocouple so that all gas to
the appliance will be shut off if
pilot flame failure occurs, or the
high limit switch opens.
The correct length of the wire for
connecting the limit switch to the
junction block is determined by
several factors; the size of the
wire, the wire temperature, the
thermocouple lead length, the
power unit type, and the distance
Thermocouple Identification
between the limit switch and the
junction block. The correct wire
length can be determined by
using Tables 1 and 2 of this
Bulletin, or for further information,
contact a Johnson Controls Sales
Engineer. The junction block of
the K16F model thermocouple is
3-35/64 in. from the terminal end
of the thermocouple, and
2-11/32 in. for the K16J model.
Standard
Length in
Inches
Control No.
Approximate
Shipping
Weight*
K16F(1)
18, 24, 30
and 36
Baso Valves and
switches, and
Basotrol Valves
with Automatic
Pilot
Carton of 125
Approx.
22 lbs. (10 kg)
K16J(1)
24
Baso Valves and
switches, and
Basotrol Valves
with Automatic
Pilot
Carton of 125
Approx.
22 lbs. (10 kg)
18,24
Baso Valves and
switches, and
Basotrol Valves
with Automatic
Pilot
Carton of 125
Approx.
22 lbs. (10 kg)
24, 30, 36, 40,
48, 60, 72, 96,
120, 144, 180
and 240
Baso Valves
and switches,
and Basotrol
Valves with
Automatic Pilot
K16K(1)
Same as K16J except screw-in type
(1) Cannot be bent within 1/2 in. of either side of junction block.
Corrosion Resistant Thermocouples
K16R
Carton of 300
Approx.
37 lbs. (17 kg)
Nickel plate, sealed. For high ambient or corrosive atmosphere.
Note:
Thermocouples may be used with any type pilot burner in a given application for which the
thermocouple is intended.
* Estimated weights are for 24 in. lengths.
K15, K16 Product Bulletin
3
Performance specifications appearing herein are nominal
and are subject to accepted manufacturing tolerances and
application variables.
Controls Group
507 E. Michigan Street
P.O. Box 423
Milwaukee, WI 53202
4 K15, K16 Product Bulletin
Printed in U.S.A.