BIRD ECONOLOAD 8730 Series User manual

INSTRUCTION BOOK
ECONOLOAD®LOAD RESISTOR
SERIES 8730
INCLUDING MODELS 8730A, 8731
8732A, 8738A, AND 8738A110
©Copyright 2009 by Bird Electronic Corporation
Instruction Book P/N 920-8730S Rev. D
Econoload and Termaline are Registered
Trademarks of Bird Electronic Corporation

This Page Intentionally Left Blank

i
Safety Precautions
The following are general safety precautions that are not necessarily related to any specific part or pro-
cedure, and do not necessarily appear elsewhere in this publication. These precautions must be thor-
oughly understood and apply to all phases of operation and maintenance.
Safety Symbols
WARNING
Keep Away From Live Circuits
Operating Personnel must at all times observe general safety precautions. Do not
replace components or make adjustments to the inside of the test equipment with
the high voltage supply turned on. To avoid casualties, always remove power.
WARNING
Shock Hazard
Do not attempt to remove the RF transmission line while RF power is present.
WARNING
Do Not Service Or Adjust Alone
Under no circumstances should any person reach into an enclosure for the
purpose of service or adjustment of equipment except in the presence of
someone who is capable of rendering aid.
WARNING
Safety Earth Ground
An uniterruptible earth safety ground must be supplied from the main power
source to test instruments. Grounding one conductor of a two conductor power
cable is not sufficient protection. Serious injury or death can occur if this
grounding is not properly supplied.
WARNING
Resuscitation
Personnel working with or near high voltages should be familiar with modern
methods of resuscitation.
WARNING
Remove Power
Observe general safety precautions. Do not open the instrument with the power on.
WARNING
Warning notes call attention to a procedure, which if not correctly performed,
could result in personal injury.

ii
Calls attention to supplemental information.
Warning Statements
The following safety warnings appear in the text where there is danger to operating and maintenance
personnel, and are repeated here for emphasis.
On pages 6, 13, 14 and 16.
On page 6.
On pages 8 and 14.
On page 17
CAUTION
Caution notes call attention to a procedure, which if not correctly performed,
could result in damage to the instrument.
This symbol indicates that a shock hazard exists if the precau-
tions in the instruction manual are not followed.
The caution symbol appears on the equipment indicating there
is important information in the instruction manual regarding
that particular area.
This symbol indicates that the unit radiates heat and should not
be touched while hot.
WARNING
Disconnect the unit from all power sources before servicing. The unit may be
energized from multiple sources. The potential for electric shock exists.
WARNING
Improper wiring could result in electric shock and death.
WARNING
Never attempt to connect or disconnect RF equipment from the transmission
line while RF power is being applied.
Leaking RF energy is a potential health hazard.
WARNING
If the resistor breaks, there may be splinters or sharp pieces inside the load
housing. Be careful when repairing to avoid being cut.

iii
Caution Statements
The following equipment cautions appear in the text and are repeated here for emphasis.
On page 5.
On page 6.
On pages 6, 7 and 11.
On page 7.
On page 11.
On page 17.
CAUTION
Incorrect hose connections will reverse coolant flow and could destroy the load.
CAUTION
Different control systems are used for 115 Vac and 230 Vac. Use the correct
interlock control for the specific voltage.
CAUTION
If installed, connect optional interlock before applying RF power.
CAUTION
Do not contaminate the coolant with pipe sealant.
CAUTION
Do not interrupt coolant supply. Even momentary application of RF power
while coolant is not circulating could cause immediate destruction of the load
CAUTION
Do not remove the resistor plug. Any attempt to do so will cause leakage and
resistor damage.

iv
Safety Statements
USAGE
ANY USE OF THIS INSTRUMENT IN A MANNER NOT SPECIFIED BY THE MANUFACTURER
MAY IMPAIR THE INSTRUMENT’S SAFETY PROTECTION.
USO
EL USO DE ESTE INSTRUMENTO DE MANERA NO ESPECIFICADA POR EL FABRICANTE,
PUEDE ANULAR LA PROTECCIÓN DE SEGURIDAD DEL INSTRUMENTO.
BENUTZUNG
WIRD DAS GERÄT AUF ANDERE WEISE VERWENDET ALS VOM HERSTELLER
BESCHRIEBEN, KANN DIE GERÄTESICHERHEIT BEEINTRÄCHTIGT WERDEN.
UTILISATION
TOUTE UTILISATION DE CET INSTRUMENT QUI N’EST PAS EXPLICITEMENT PRÉVUE PAR
LE FABRICANT PEUT ENDOMMAGER LE DISPOSITIF DE PROTECTION DE L’INSTRUMENT.
IMPIEGO
QUALORA QUESTO STRUMENTO VENISSE UTILIZZATO IN MODO DIVERSO DA COME
SPECIFICATO DAL PRODUTTORE LA PROZIONE DI SICUREZZA POTREBBE VENIRNE
COMPROMESSA.

v
SERVICE
SERVICING INSTRUCTIONS ARE FOR USE BY SERVICE - TRAINED PERSONNEL ONLY. TO
AVOID DANGEROUS ELECTRIC SHOCK, DO NOT PERFORM ANY SERVICING UNLESS
QUALIFIED TO DO SO.
SERVICIO
LAS INSTRUCCIONES DE SERVICIO SON PARA USO EXCLUSIVO DEL PERSONAL DE
SERVICIO CAPACITADO. PARA EVITAR EL PELIGRO DE DESCARGAS ELÉCTRICAS, NO
REALICE NINGÚN SERVICIO A MENOS QUE ESTÉ CAPACITADO PARA HACERIO.
WARTUNG
ANWEISUNGEN FÜR DIE WARTUNG DES GERÄTES GELTEN NUR FÜR GESCHULTES
FACHPERSONAL.
ZUR VERMEIDUNG GEFÄHRLICHE, ELEKTRISCHE SCHOCKS, SIND WARTUNGSARBEITEN
AUSSCHLIEßLICH VON QUALIFIZIERTEM SERVICEPERSONAL DURCHZUFÜHREN.
ENTRENTIEN
L’EMPLOI DES INSTRUCTIONS D’ENTRETIEN DOIT ÊTRE RÉSERVÉ AU PERSONNEL
FORMÉ AUX OPÉRATIONS D’ENTRETIEN. POUR PRÉVENIR UN CHOC ÉLECTRIQUE
DANGEREUX, NE PAS EFFECTUER D’ENTRETIEN SI L’ON N’A PAS ÉTÉ QUALIFIÉ POUR CE
FAIRE.
ASSISTENZA TECNICA
LE ISTRUZIONI RELATIVE ALL’ASSISTENZA SONO PREVISTE ESCLUSIVAMENTE PER IL
PERSONALE OPPORTUNAMENTE ADDESTRATO. PER EVITARE PERICOLOSE SCOSSE
ELETTRICHE NON EFFETTUARRE ALCUNA RIPARAZIONE A MENO CHE QUALIFICATI A
FARLA.

vi
CONNECT INTERLOCK TO TRANSMITTER BEFORE OPERATING.
BRANCHER LE VERROUILLAGE À L'ÉMETTEUR AVANT EMPLOI.
CONECTE EL INTERBLOQUEO AL TRANSMISOR ANTES DE LA OPERACION.
VOR INBETRIEBNAHME VERRIEGELUNG AM SENDER ANSCHLIESSEN.
PRIMA DI METTERE IN FUNZIONE L'APPARECCHIO, COLLEGARE IL DISPOSITIVO DI BLOCCO AL
TRASMETTITORE.

vii
About This Manual
This manual covers the operating and maintenance instructions for the following models:
Changes to this Manual
We have made every effort to ensure this manual is accurate. If you discover any errors, or if you
have suggestions for improving this manual, please send your comments to our Solon, Ohio factory.
This manual may be periodically updated. When inquiring about updates to this manual refer to the
part number and revision on the title page.
Terminology
The following terms will be used throughout this manual to refer to certain components of the Econo-
load:
Econoload or Load - The entire unit. It contains the RESISTOR.
Resistor - A subcomponent of the LOAD. This is the ceramic resistor which actually absorbs the RF
power.
Literature Contents
Chapter Layout
Introduction —Describes the features of the Econoload RF Load, lists equipment supplied and
optional equipment, and provides power-up instructions.
Theory of Operation —Describes how the load works on a fundamental level.
Installation —Describes how to install the load or Econoload and it’s components.
Operating Instructions - Describes the features of the Econoload RF Load and its process of operation.
Maintenance —Lists routine maintenance tasks as well as troubleshooting for common problems.
Specifications and parts information are also included.
8730A 8731 8738A
8732A 8738A110

viii

ix
Table of Contents
Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Safety Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i
Warning Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
Caution Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Safety Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .iv
About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Changes to this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Chapter Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Chapter 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Items Supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Optional Items . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Chapter 2 Theory Of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Optional Flow Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Optional Thermal Interlock (8732A Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Calorimetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Chapter 3 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Unpacking and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
DC Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Hoses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Interlock (Optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Thermoswitch (8732A Only) (Optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Installing the Thermoswitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Connecting the Thermoswitch to the Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Connecting the RF Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Using a Swivel Flanged Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Using an Unflanged Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Using a Slotted Connector Sleeve (for Model 8738A110) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Chapter 4 Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Shutting Down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Emergency Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Operation with the Optional Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Shutting Down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Emergency Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

x
Chapter 5 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
DC Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Replacing the Flow Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Replacing the Time Delay Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Replacing the Safety Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Servicing the Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Removing the Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Replacing the Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Replacing the Conductor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Storage and Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Storing the Load Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Shipping the Load Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Customer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Bird 8730A, 8732A, and 8738A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Bird 8731 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Bird 8738A110 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Interlock (Optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Limited Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

1
Chapter 1 Introduction
Bird 8730 Series Econoloads are compact, nonradiating, low reflection termi-
nations for medium power RF lines. They dissipate up to 10 kW with a VSWR
of less than 1.1:1 from 1 kHz to 1000 MHz.
Features
zUseable with CW, AM, FM, SSB, and TV modulation, and certain
pulse types. Contact Bird Electronic Corporation for information on
using Econoloads with pulsed signals.
zDesigned for easy field repair of all components.
Items Supplied
zLoad, Water-cooled
zInstruction Manual
Optional Items
zControl system with red pilot light that turns on when the load is
working properly. Also has flow switch and 12 second time delay inter-
lock to ensure steady coolant flow before RF power is applied.

Introduction
2
Figure 1 8730 Series Econoload Outline Drawing

3
Chapter 2 Theory Of Operation
Resistor
Bird 8730 Series Econoloads consist of a thin-film-on-ceramic resistor
immersed in externally-supplied coolant. The coolant flows directly over the
resistor instead of using an intermediate heat transfer system, reducing the
load size to a minimum. After passing over the entire length of the resistor,
the coolant leaves the load and can either be discarded or cooled in a heat
exchanger and reused.
Coolant
The load’s electrical and thermal performance is reduced by impurities or
chemical additives in the coolant, especially ones which are deposited as scale
on the resistor. This may cause the load to overheat and fail. Salt water will
have a similar effect and should not be used. For recommended coolant, refer
to "Coolant" on page 5 and to "Specifications" on page 20.
Optional Flow Interlock
A minimum coolant flow of four gallons per minute is required at all times to
dissipate the heat from RF power. When the flow rate drops below this point,
the flow switch opens causing immediate transmitter shutdown. The flow
switch is a “normally open” type, and is closed during normal operation.
After flow is restored, a time delay switch keeps the interlock open for an
additional 12 seconds. This ensures proper operation of the cooling system
before applying RF power, preventing resistor burnout.
Optional Thermal Interlock (8732A Only)
The 8732A can be supplied with an optional passive overtemperature thermo-
switch. Normally closed, it opens at a preset temperature, turning off trans-
mitter power. The temperature setting is preset at the factory for either 72 or
79 °C (162 or 175 °F). The interlock system will not permit use of the trans-
mitter until the load has reached a safe temperature.
Calorimetry
Almost all the RF power in the load is transferred to the coolant as heat.
There is no heat transfer to the outer housing of the load, leaving it at ambi-
ent temperature even at full power. The flow rate, and the difference between
the input and output coolant temperatures, can be used to calculate the power
dissipated in the load with the following formula:
where
P = Power in kilowatts
k = 0.263 for temperature in °C, 0.146 for temp. in °F
Tout = Water temperature at the output of the load
Tin = Water temperature at the input to the load.
F = Water flow rate in gallons per minute
PkT
out Tin
–()F××=

Theory Of Operation
4

5
Chapter 3 Installation
This chapter provides information on site requirements, unpacking, inspec-
tion, and preparing the Bird 8730 Series Econoload for use.
Unpacking and Inspection
1. Carefully inspect shipping container for signs of damage.
2. Do one of the following:
zIf the shipping container is damaged, do not unpack the unit. Immedi-
ately notify the shipping carrier and Bird Electronic Corporation.
zIf the shipping container is not damaged, unpack the unit. Save ship-
ping materials for repackaging.
3. Inspect unit for visual signs of damage.
Note: If there is damage, immediately notify the shipping carrier
and Bird Electronic Corporation.
DC Resistance
Before first using the load, get a resistance baseline for future maintenance.
Refer to "DC Resistance" on page 14 for instructions.
Placement
zDo not use outdoors or in areas of condensing humidity.
zVentilation or buffer space is not required. The Econoload may be
placed in very small spaces.
zThe load may be mounted in any position. Rotate the load so that the
warning label is visible and the water connections are easily accessible.
zAccess to a coolant supply or pump is required. Make sure the coolant
supply can meet the required flow rate.
zTo use the optional interlock, AC power is required.
Coolant
For operation at 1kHz or lower, use only distilled water as the coolant. For opera-
tion above 1kHz use distilled or potable water. Refer to the specifications for the
definition of potable water. If the water quality is doubtful, use distilled water.
Hoses
The Econoload is supplied with standard 3/4” hose fittings. For rigid piping,
replace the hose adapters with 1/2” male pipe fittings. If the optional flow
switch is installed, it is attached to the water INPUT.
Note: with the exception of Model 8738A110, which is equipped
with ½” barbed hose fittings
zThe Econoload’s water INPUT is located in the center of the back of
the load. Connect the coolant supply to the load’s INPUT. Secure with
hose clamps.
zThe Econoload’s water OUTPUT is on the rear side of the load, at a
90° angle to the INPUT. Connect the coolant drain to the load’s OUT-
PUT. Secure with hose clamps.
CAUTION
Incorrect hose connections will reverse coolant flow and could destroy the load.

Installation
6
Interlock (Optional)
The interlock control box has four 1/4” mounting holes in a 5” x 5” (127 x 127
mm) square. Mount it where the safety light will be clearly visible. Wire the
control box as follows (refer to Figure 2):
zConnect the flow switch leads to terminals 3 and 5.
zConnect the transmitter interlock to terminals 6 and 7.
zConnect the ac power source to terminals 2 and 3, making sure that ac
common is connected to terminal 2.
Figure 2 Interlock Connections
WARNING
Disconnect the unit from all power sources before servicing. The unit may
be energized from multiple sources. The potential for electric shock exists.
WARNING
Improper wiring could result in electric shock and death.
CAUTION
If installed, connect optional interlock before applying RF power.
CAUTION
Different control systems are used for 115 Vac and 230 Vac. Use the correct
interlock control for the specific voltage.
Flow Interlock Control
Trans.
Interlock
AC
Input
Common
WHITE
WHITE
BLACK
BLACK
YEL/WHT BLK/WHT
BLUE
ORANGE
VIOLET
GREY
Time Delay
Relay (NO)
12 sec.
Flow Switch (NO)
Red Lamp
1 2 3456 7

Installation
7
Thermoswitch (8732A Only) (Optional)
Installing the Thermoswitch
Note: The 8732A, only, can be equipped with an optional interlock
thermoswitch, P/N 2450-095-x.
1. Stand the unit with the water connectors up to prevent spills.
2. Remove the water outlet connector.
3. Replace the connector with the thermoswitch.
4. Sparingly apply pipe sealing compound to the external threads, only, of
the thermoswitch.
5. Check for coolant leaks upon completion.
Connecting the Thermoswitch to the Interlock
1. Unscrew the large knurled ring-nut [A] at the lower end of the coupling
jack assembly.
2. Pull it off the thermoswitch jack [B].
3. Unscrew the small knurled cover fitting from the base plug [D] of the con-
nector to release the base.
4. Thread the control switch wires through the clamp [E] with the washers
[F] inside and its threaded fitting in place.
5. Use short tips on the wires and put spaghetti sleeves over the ends if necessary.
6. Solder the switch leads to the lugs [G] of the connector base.
Note: The ring-nut [A] must be in place over the base plug [G] with
the knurled end facing out.
7. Screw on the cover ring, then fasten the cable clamp [E] in place and
tighten both yoke screws [H].
8. Put the plug back on the thermoswitch and tighten the nut [A].
Figure 3 Thermoswitch Assembly
CAUTION
If installed, connect optional interlock before applying RF power.
CAUTION
Do not contaminate the coolant with pipe sealant.

Installation
8
Connecting the RF Power
After installing the Econoload, the RF transmission line can be attached using
standard coaxial line coupling kits.
Using a Swivel Flanged Coupling
To couple the swivel flange with a flanged RF transmission line, use an appro-
priate coupling kit. Refer to Figure 4 while following the instructions below.
Figure 4 Swivel Flanged Coupling
1. Insert the center bullet and push it in until it is fully seated.
2. Connect the coaxial input in a straight line and push carefully on the cen-
ter conductor to close.
Note: The swivel flange on the load makes connection independent
of the orientation of the fixed flange on the coaxial input outer conductor.
3. Insert the bolt sets and tighten evenly all around to transmission line
manufacturer’s recommended torque.
Note: Use all of the bolts.
Using an Unflanged Coupling
To couple the unflanged connector with an unflanged RF line, use an appro-
priate coupling kit. Refer to Figure 5 while following the instructions below:
Figure 5 Unflanged Coupling
1. Insert the center bullet and bottom it on the midpoint nibs.
2. Position the outer sleeve, with clamping bands, over the input connector.
3. Set the transmission line snugly against the coupling stops.
4. Position the clamping bands evenly about 3/4” from the ends of the sleeve.
5. Tighten the clamping bands.
WARNING
Never attempt to connect or disconnect RF equipment from the
transmission line while RF power is being applied.
Leaking RF energy is a potential health hazard.
BOLT BULLET LOADRF COAXIAL LINE
RF COAXIAL
LINE
CLAMPING
BANDS
CONNECTOR
SLEEVE
BULLET
LOAD