Operating Temperature: –4° to 158°F (–20° to 70°C)
32° to 120°F (0° to 49°C) with module installed in the HFS-D
Storage Temperature: –22° to 158°F (–30° to 70°C)
Humidity: 0% to 93% Relative Humidity Non-condensing
Air Velocity: 100 to 4000 ft./min. (0.5 to 20.3 m/sec.)
Rectangular Footprint Dimensions: 14.38 in L×5 in W×2.5 in D (37 cm L×12.7 cm W×6.36 cm D)
Square Footprint Dimensions: 7.75 in L×9 in W×2.5 in D (19.7 cm L×22.9 cm W×6.35 cm D)
Weight: 1.8 pounds; 0.82 kg
Operating Voltage Range: 15 to 32 VDC
Standby Current: 300µA @ 24 VDC (one communication every 5 seconds with LED blink enabled)
Max. Alarm Current (LED on): 6.5 mA @ 24 VDC
NOTE: The HFS-D come with the sensor head factory installed, part number HFS-DPR.
Read the System Sensor Guide for Proper Use of Smoke Detectors in Duct Applications (A05-1004), which provides detailed information on detector spacing,
placement, zoning, wiring, and special applications. Copies of this manual
are available online at www.systemsensor.com. NFPA Standards 72 and 90A
should also be referenced for detailed information.
NOTICE: This manual shall be left with the owner/user of this equipment.
IMPORTANT: This detector must be tested and maintained regularly following
NFPA 72 requirements. The detector should be cleaned at least once a year.
[1]LIMITATIONS OF DUCT SMOKE DETECTORS
The National Fire Protection Association has established that DUCT DETECTORS MUST NOT BE USED AS A SUBSTITUTE FOR OPEN AREA DETECTOR
PROTECTION as a means of providing life safety. Nor are they a substitute for
early warning in a building’s regular fire detection system.
System Sensor supports this position and strongly recommends that the user
read NFPA Standards 90A, 72, and 101. The HFS-D Air Duct Smoke Detectors
are listed per UL 268A.
This device will not operate without electrical power. Fire situations may
cause an interruption of power. The system safeguards should be discussed
with your local fire protection specialist.
This device will not sense smoke unless the ventilation system is operating
and the cover is installed.
For this detector to function properly, it MUST be installed according to the instructions in this manual. Furthermore, the detector MUST be operated within
ALL electrical and environmental specifications listed in this manual and the
sensor head installation manual. Failure to comply with these requirements
may prevent the detector from activating when smoke is present in the air duct.
[2]GENERAL DESCRIPTION
Smoke introduced into this air duct system will be distributed throughout the
entire building. Smoke detectors designed for use in air duct systems are used
to sense the presence of smoke in the duct.
Model HFS-D Air Duct Smoke Detector utilizes photoelectric technology for
the detection of smoke. This detection method, when combined with an efficient housing design, samples air passing through the duct and allows detection of a developing hazardous condition. When sufficient smoke is sensed,
an alarm signal is initiated at the fire control panel monitoring the detector,
and appropriate action can be taken to shut off fans, blowers, change over air
handling systems, etc. These actions can facilitate the management of toxic
smoke and fire gases throughout the areas served by the duct system.
The HFS-D incorporates a sensor cover tamper feature that provides a trouble signal at the panel immediately if the cover is removed or improperly installed. Proper installation of the sensor cover removes the trouble condition.
If programmed with the system control panel, two LEDs on each duct smoke
detector light to provide local visible indication.
The HFS-D provides a remote alarm output for use with auxiliary devices, such
as the RA400Z/RA100Z remote LED annunciator, as well as remote test capability with the RTS451/151 or RTS451KEY/RTS151KEY Remote Test Stations.
[2.1] DETECTOR FEATURE SET
– Utilizes plug-in head, part number HFS-DPR
– Sampling tubes install from front and rear
– Compatible with existing accessories
– Able to address detector per code switches on sensor head.
[3]CONTENTS OF THE DUCT SMOKE DETECTOR KIT
1. Sensor/power board assembly and covers sensor head is factory installed
2. Three #10 sheet metal screws for mounting
3. One test magnet
4. Drilling template
5. One sampling tube end cap
6. One plastic exhaust tube
NOTE: A sampling tube must be ordered to complete the installation. It must
be the correct length for the width of the duct where it will be installed. See
Table 1 on page 3 to determine the inlet tube required for different duct widths.
[4]DETECTOR INSTALLATION
[4.1]VERIFY DUCT AIR FLOW DIRECTION AND VELOCITY
Model HFS-D detectors are designed to be used in air handling systems having air velocities of 100 to 4000 feet per minute. Duct widths from 6 inches to
12 feet can be accommodated. Be sure to check engineering specifications to
ensure that the air velocity in the duct falls within these parameters. If necessary, use a velocity meter (anemometer) to check the air velocity in the duct.
[4.2]DETERMINE MOUNTING LOCATION AND CONFIGURATION
On ducts wider than 18 inches it is recommended that the detector be
mounted downstream of a bend, obstruction in the duct, or the supply or
return air inlet.
ACCESSORY CURRENT LOADS AT 24 VDC
DEVICESTANDBYALARM
RA400Z/RA100Z0mA12mA Max.
RTS451/RTS1510mA12mA Max.
RTS451KEY/
RTS151KEY
I56-3488-001R
12 Clintonville Road
Northford, CT 06472-1653
Phone: 203.484.7161
12mA12mA Max.
HW-300-000 1 I56-3488-001R
FIGURE 1. EXPLODED VIEW OF DUCT SMOKE DETECTOR COMPONENTS:
EXHAUST TUBE
SAMPLING
TUBE
SOLD
SEPERATELY
WIRING COMPARTMENT
WIRING COMPARTMENT COVER
SENSOR MODULE
SENSOR HEAD
Exception: Installation of duct detectors can be on or within a commercial
packaged rooftop heating and air-conditioning system, fire/smoke dampers
and economizers. They may be mounted in either the supply and/or return air
section as determined by local code.
Once a suitable location is selected, determine if the detector is to be mounted
in a side-by-side “rectangular” configuration or a top-over-bottom “square”
configuration as shown in Figure 2. If mounting in the square configuration,
remove the rear attachment screw, rotate the unit at hinge, and replace the
screw into the new attachment hole as shown in Figure 2. Do NOT remove
the hinge screw during this process. Final installation approval shall be based
upon passing differential pressure and smoke entry tests described in the Measurement Tests section.
FIGURE 2:
REMOVE SCREW AND PIVOT
DETECTOR AS SHOWN BELOW.
REPLACE SCREW
TO SECURE DETECTOR
IN PLACE.
H0550-00
[4.3]DRILL THE MOUNTING HOLES
Remove the paper backing from the mounting template supplied. Affix the
template to the duct at the desired mounting location. Make sure the template
lies flat and smooth on the duct.
Center punch at (4) target centers: (2) “A” for sampling tubes and (2) “B” for
the rectangular configuration mounting tabs as shown on mounting template.
Drill pilot holes at target “A” centers and cut two 1.375 inch diameter holes
using a 13⁄8-inch hole saw or punch. Drill .156 inch diameter holes using a 5⁄32
inch drill at target “B” centers.
Center punch at (4) target centers: (2) “A” for sampling tubes and (2) “C” for
the square configuration mounting tabs as shown on mounting template. Drill
pilot holes at target “A” centers and cut two 1.375 inch diameter holes using
a 13⁄8-inch hole saw or punch. Drill .156 inch diameter holes using a 5⁄32 inch
drill at target “C” centers. If desired, drill an additional .156 inch hole at the
location of one of the mounting tabs on the lower housing.
SENSOR MODULE COVER
H0569-02
[4.4]SECURE THE DUCT DETECTOR TO THE DUCT
Use two (rectangular configuration) or three (square configuration) of the provided sheet metal screws to screw the duct detector to the duct.
The sampling tube must be purchased separately. Order the correct length,
as specified in Table 1, for width of the duct where it will be installed. The
sampling tube length must extend at least 2/3 across the duct width for optimal
performance.
The sampling tube is always installed with the air inlet holes facing into the
air flow. To assist proper installation, the tube’s connector is marked with an
arrow. Make sure the sampling tube is mounted so that the arrow points into
the airflow as shown in Figure 3. Mounting the detector housing in a vertical
orientation is acceptable provided that the air flows directly into the sampling tube holes as indicated in Figure 3. The sampling tube and exhaust tube
can be mounted in either housing connection as long as the exhaust tube is
mounted downstream from the sampling tube.
TABLE 1. SAMPLING TUBES RECOMMENDED FOR
DIFFERENT DUCT WIDTHS:
Outside Duct WidthSampling Tube Recommended*
Up to 1 ft.DST1
1 to 2 ft.DST1.5
2 to 4 ft.DST3
4 to 8 ft.DST5
8 to 12 ft.DST10 (2-piece)
2
*Must extend a minimum of
⁄3 the duct width
FIGURE 3. AIR DUCT DETECTOR SAMPLING TUBE:
SAMPLING TUBE ENDCAP
ARROW MUST FACE
INTO AIR FLOW
AIR FLOW
DIRECTION
H0551-00
HW-300-000 2 I56-3488-001R
Please refer to insert for the Limitations of Fire Alarm Systems
System Sensor warrants its enclosed product to be free from defects in materials and
workmanship under normal use and service for a period of three years from date of
manufacture. System Sensor makes no other express warranty for the enclosed product.
No agent, representative, dealer, or employee of the Company has the authority to increase or alter the obligations or limitations of this Warranty. The Company’s obligation
of this Warranty shall be limited to the replacement of any part of the product which
is found to be defective in materials or workmanship under normal use and service
during the three year period commencing with the date of manufacture. After phoning
System Sensor’s toll free number 800-SENSOR2 (736-7672) for a Return Authorization
number, send defective units postage prepaid to: System Sensor, Returns Department, RA
#__________, 3825 Ohio Avenue, St. Charles, IL 60174. Please include a note describing
the malfunction and suspected cause of failure. The Company shall not be obligated to
replace units which are found to be defective because of damage, unreasonable use,
modifications, or alterations occurring after the date of manufacture. In no case shall the
Company be liable for any consequential or incidental damages for breach of this or any
other Warranty, expressed or implied whatsoever, even if the loss or damage is caused by
the Company’s negligence or fault. Some states do not allow the exclusion or limitation of
incidental or consequential damages, so the above limitation or exclusion may not apply
to you. This Warranty gives you specific legal rights, and you may also have other rights
which vary from state to state.
CAUTION: The sampling tube end cap, included with the detector, is critical to proper operation of the duct smoke detector. The end cap is needed to
create the proper air flow to the sensor of the duct smoke detector. Once any
sampling tube length adjustments are made, plug the end of the sampling tube
with the provided end cap.
A plastic exhaust tube is included with the unit to be installed if needed. Install into the housing connection that is downstream from the sampling tube
connection. The exhaust tube can be installed from the front of the detector
or the back. A longer 1 foot exhaust tube, model ETX, is available as an accessory in cases where the molded exhaust tube does not extend at least 2 inches
into the duct.
[5.2]SAMPLING TUBE INSTALLATION
1. For tubes shorter than the width of the duct, slide the sampling tube,
with installed end cap, into the housing connection that meets the airflow first. Position the tube so that the arrow points into the airflow as
shown in Figure 3. Per NFPA sampling tubes over 3 feet long should be
supported at the end opposite of the duct detector. In ducts wider than 8
feet, work must be performed inside the duct to couple the other section
of the sampling tube to the section already installed using the ½-inch
conduit fitting supplied. Make sure that the holes on both sections of the
air inlet sampling tube are lined up and facing into the airflow.
2. For tubes longer than the width of the air duct, the tube should extend
out of the opposite side of the duct. Drill a ¾-inch hole in the duct opposite the hole already cut for the sampling tube. Ensure that the sampling tube is angled downward from the duct smoke detector to allow for
moisture drainage away from the detector. The sampling tube should be
[5.4]REMOTE SAMPLING TUBE INSTALLATION
The detector arrangement can also incorporate the remote mounting of the
sampling tube and/or exhaust tube. In this case both the detector, sampling
tube and exhaust tube (if included) should be rigidly mounted to withstand
the pressure and vibrations caused by the air velocity. The location of the
detector’s sampling tube should be such that there is uniform airflow in the
cross section area.
Pressure differential across the sampling and exhaust ports in the detector housing shall be verified to be between 0.01 and 1.11 inches of water. Do so by measuring the pressure difference between the inlet and outlet ports on the detector
housing using a manometer as described in the Measurement Tests sectiont of
this manual.
[6]MEASUREMENT TESTS
[6.1]AIR FLOW
The HFS-D is designed to operate over an extended air speed range of 100 to
4000 FPM. To verify sufficient sampling of ducted air, turn the air handler on
and use a manometer to measure the differential pressure between the two
sampling tubes. The differential pressure should measure at least 0.01 inches
of water and no more than 1.11 inches of water. Because most commercially
available manometers cannot accurately measure very low pressure differentials, applications with less than 500 FPM of duct air speed may require one
of the following: 1) the use of a current-sourcing pressure transmitter (Dwyer
Series 607) or 2) the use of aerosol smoke, see below for test descriptions.
FIGURE 5. PROCEDURE FOR VERIFYING AIR FLOW:
TO SAMPLING TUBE
TO EXHAUST TUBE
angled at least 1⁄4˝ downward for every 12˝ of duct width per Figure 4.
HIGH
There should be 10 to 12 holes spaced as evenly as possible across the
width of the duct. If there are more than 2 holes in the section of the tube
extending out of the duct, select a shorter tube using Table 1. Otherwise,
trim the tube to leave approximately 1 to 2 inches extending outside the
duct. Plug the end with the end cap and tape closed any holes in the
protruding section of the tube. Be sure to seal the duct where the tube
protrudes.
LOW
DIFFERENTIAL
PRESSURE
TRANSMITTER
MODEL #607-01
1000 OHM 5%
1 WATT RESISTOR
15 TO 36
VDC SUPPLY
9 VOLT
BATTERY
9 VOLT
BATTERY
9 VOLT
BATTERY
FIGURE 4.
VOLT METER FLUKE
MODEL 87 OR
EQUIVALENT
1
/4˝
12˝
+–
H0163-01
[6.2]LOW FLOW AIR FLOW TEST USING DWYER SERIES 607
DIFFERENTIAL PRESSURE TRANSMITTER
Verify the air speed of the duct using an anemometer. Air speed must be at
2˝
least 100 FPM. Wire the Dwyer transmitter as shown in Figure 5. Connect the
leads of the meter to either side of the 1000Ω resistor. Allow unit to warm up
for 15 seconds. With both HIGH and LOW pressure ports open to ambient air,
measure and record the voltage drop across the 1000Ω resistor (measurement
3
/4˝
HOLE
DETECTOR
H0215-00
NOTE: Air currents inside the duct may cause excessive vibration, especially
when the longer sampling tubes are used. In these cases, a 3-inch floor flange
(available at most plumbing supply stores) may be used to fasten the sampling tube to the other side of the duct. When using the flange/connector
mounting technique, drill a 1 to 1¼-inch hole where the flange will be used
[5.3]MODIFICATIONS OF SAMPLING TUBES
There may be applications where duct widths are not what is specified for the
installation. In such cases, it is permissible to modify a sampling tube that is
longer than necessary to span the duct width.
Use a 0.193-inch diameter (#10) drill and add the appropriate number of holes
so that the total number of holes exposed to the air flow in the duct is 10 to 12.
Space the additional holes as evenly as possible over the length of the tube.
CAUTION: This procedure should only be used as a temporary fix. It is not
intended as a permanent substitute for ordering the correct length tubes.
1), 4.00 volts is typical. Using flexible tubing and rubber stoppers, connect the
HIGH side of the transmitter to the sampling tube of the duct smoke detector housing, and the LOW side of the transmitter to the exhaust tube of the
duct smoke detector housing. Measure and record the voltage drop across the
1000Ω resistor (measurement 2). Subtract the voltage recorded in measurement 1 from the voltage recorded in measurement 2. If the difference is greater
than 0.15 volts, there is enough air flow through the duct smoke detector for
proper operation.
[7]FIELD WIRING; INSTALLATION GUIDELINES
All wiring must be installed in compliance with the National Electrical Code
and the local codes having jurisdiction. Proper wire gauges should be used.
The conductors used to connect smoke detectors to control panels and accessory devices should be color-coded to prevent wiring mistakes. Improper connections can prevent a system from responding properly in the event of a fire.
For signal wiring (the wiring between detectors or from detector to auxiliary
devices), it is usually recommended that single conductor wire be no smaller
than 18 gauge. The duct smoke detector terminals accommodate wire sizes up
to 12 gauge. Flexible conduit is recommended for the last foot of conduit; solid
conduit connections may be used if desired.
Duct smoke detectors and alarm system control panels have specifications for
Signaling Line Circuit (SLC) wiring. Consult the control panel manufacturer’s
specifications for wiring requirements before wiring the detector loop.
HW-300-000 3 I56-3488-001R
[7.1]WIRING INSTRUCTIONS
CAUTION
+ RA
Disconnect power from the communication line before installing the HFS-D
duct smoke detector.
The HFS-D detectors are designed for easy wiring. The housing provides a terminal strip with clamping plates. Wiring connections are made by sliding the
bare end under the plate, and tightening the clamping plate screw. See Figure 6 below for system wiring.
FIGURE 6. SYSTEM WIRING DIAGRAM FOR HFS-D:
COMM.
LINE (+)
COMM.
LINE
COMM.
LINE (–)
UL/FM LISTED
CONTROL
PANEL
[7.2] SET THE ADDRESS
Set the desired address on the sensor head code wheel switches. on the back
of the sensor head.
FIGURE 7. ROTARY ADDRESS SWITCHES
[8] VERIFICATION OF OPERATION
[8.1]INSTALL THE COVER
Install the covers making sure that the cover fits into the base groove. Tighten
the seven screws that are captured in the covers. Note that the cover must be
properly installed for proper operation of the sensor.
NOTE: Verify sensor cover gasket is properly seated on cover prior to cover
installation.
[8.2] POWER THE UNIT
Activate the communication line on terminals COM + and COM –.
[8.3] DETECTOR CHECK
Standby – If programmed by the system control panel, look for the presence of
the flashing LEDs through the transparent housing cover. The LED will flash
with each communication.
Trouble – If programmed by the system control panel and the detector LEDs
do not flash, then the detector lacks power (check wiring, missing or improperly placed cover, panel programming, or power supply), the sensor head is
missing (replace), or the unit is defective (return for repair).
[8.4]DUCT SMOKE DETECTOR TEST & MAINTENANCE PROCEDURES
Test and maintain duct smoke detectors as recommended in NFPA 72. The
tests contained in this manual were devised to assist maintenance personnel
in verification of proper detector operation.
Before conducting these tests, notify the proper authorities that the smoke
detection system will be temporarily out of service. Disable the zone or system
under test to prevent unwanted alarms.
1ST
DETECTOR
IN LOOP
2ND
DETECTOR
IN LOOP
HO572-00
HO112-00
[8.4.1]TEST THE UNIT
1. M02-04-00 Magnet Test – This sensor can be functionally tested with a
test magnet. The test magnet electronically simulates smoke in the sensing
chamber, testing the sensor electronics and connections to the control panel.
2. Remote Test Accessory – The use of a remote accessory for visible indication of power and alarm is recommended.
Verify system control panel alarm status and control panel execution of all
intended auxiliary functions (i.e. fan shutdown, damper control, etc.).
Two LEDs on the sensor are controlled by the panel to indicate sensor sta-
tus. Coded signals, transmitted from the panel, can cause the LEDs to blink,
latch on, or latch off. Refer to the control panel technical documentation for
sensor LED operation and expected delay to alarm.
[8.4.2] THE DETECTOR MUST BE RESET BY THE SYSTEM CONTROL PANEL
[8.4.3]SMOKE ENTRY TEST USING AEROSOL SMOKE
This test is intended for low-flow systems (100-500 FPM). If the air speed is
greater than 500 FPM, use a conventional manometer to measure differential
pressure between the sampling tubes, as described under Measurement Tests
on Page 3.
Drill a 1⁄4-inch hole 3 feet upstream from the duct smoke detector. With the air
handler on, measure the air velocity with an anemometer. Air speed must be
at least 100 FPM. Spray aerosol smoke* into the duct through the 1⁄4-inch hole
for five seconds. Wait two minutes for the duct smoke detector to alarm. If the
duct smoke detector alarms, air is flowing through the detector. Remove the
duct smoke detector cover and blow out the residual aerosol smoke from the
chamber and reset the duct smoke detector at the panel. Use duct tape to seal
the aerosol smoke entry hole. Remember to replace the cover after the test or
the detector will not function properly.
*Aerosol smoke can be purchased from Home Safeguard Industries at homesafeguard.com, model 25S Smoke Detector Tester, and Chekkit Smoke Detector
Tester model CHEK02 and CHEK06 available from SDi. When used properly,
the canned smoke agent will cause the smoke detector to go into alarm. Refer to the manufacturer’s published instructions for proper use of the canned
smoke agent.
Canned aerosol simulated smoke (canned smoke agent) formulas will vary by
manufacturer. Misuse or overuse to these products may have long term adverse
effects on the smoke detector. Consult the canned smoke agent manufacturer’s
published instructions for any further warnings or caution statements.
[9]DETECTOR CLEANING PROCEDURES
Notify the proper authorities that the smoke detector system is undergoing
maintenance, and that the system will temporarily be out of service. Disable
the zone or system undergoing maintenance to prevent unwanted alarms and
possible dispatch of the fire department.
[9.1]DETECTOR SENSOR
1. Remove the sensor to be cleaned from the system.
2. Remove the sensor cover by pressing firmly on each of the four removal
tabs that hold the cover in place.
3. Vacuum the screen carefully without removing it. If further cleaning is required continue with Step 4, otherwise skip to Step 7.
4. Remove the chamber cover/screen assembly by pulling it straight out.
5. Use a vacuum cleaner or compressed air to remove dust and debris from
the sensing chamber.
6. Reinstall the chamber cover/screen assembly by sliding the edge over the
sensing chamber. Turn until it is firmly in place.
7. Replace the cover using the LEDs to align the cover and then gently pushing
it until it locks into place.
8. Reinstall the detector.
[9.2]REINSTALLATION
1. Reinstall the detector in its housing.
2. Restore system power.
3. Perform Detector Check.
4. Notify the proper authorities testing has been completed and the smoke
detector system is back in operation.
[10]SENSOR REPLACEMENT
1. Remove the sensor head by rotating counterclockwise.
2. Pull gently to remove it.
3. To replace the sensor head, align the mounting features and rotate clockwise into place.
[11] OPTIONAL ACCESSORIES
Optional accessories include RA400Z/RA100Z, RTS451/RTS151 and
RTS451KEY/RTS151KEY.
NOTE: Ensure blue wire always remains connected to RA+ on the field
connector side of the terminal block.
FIGURE 8. WIRING DIAGRAM FOR HFS-D TO RA400Z/RA100Z:
(+)
RA400Z/RA100Z
– RA
(-)
REMOTE ALARM LED
OPTION 1 PER UNIT
H0570-03
Note: If using a RA400Z, the tab should be broken for use with the intelligent duct smoke detector. If using RA100Z, ensure that jumper is removed.
[11.1] REMOTE TEST USING HFS-DPR, SENSOR WITH
REMOTE TEST CAPABILITY:
The RTS451/RTS151/RTS451KEY/RTS151KEY Remote Test Station facilitates
test of the alarm capability of the duct smoke detector. These accessories
provide the stimulus to initiate an alarm condition at the detector. The HFS-D
duct smoke detector must be reset by the system control panel.
To install the RTS451/RTS151/RTS451KEY/RTS151KEY, using the HFS-DPR,
sensor with remote test capability, connect the device as shown in Figure 9;
wire runs must be limited to 25 ohms or less per interconnecting wire.
NOTE: Resistor assembly must be in place between RA+ and OUT+
inside the HFS-D for Remote Test function to operate.
FIGURE 9. RTS451/RTS451KEY/RTS151/RTS151KEY USING
HFS-DPR, SENSOR WITH REMOTE TEST CAPABILITY
TEST COIL +
TEST COIL –
COMM +
OUT (CONV ONLY) +
COMM –
RA/RTS –
RA +
RTS +
RTS451/RTS451KEY
RTS151/RTS151KEY
1
2
3
4
5
JUMPER
H0633-00
[11.2] ADDITIONAL MODULE OPTION
The HFS-D can also accommodate a relay or control module (sold separately)
within the power board side of the housing. The relay or control module must
be listed as compatible to the fire alarm control panel.
Physical Module Mounting
1) Remove the breakaway tabs at the four corners of the module
2) Locate the module at right most corner of the power board. The upper
left corner mounting hole of the module will align with a screw boss in
the housing.
3) Install a #8×3⁄8˝ Plastite screw at the screw boss location
Note: See the corresponding module Installation Instructions for general
description, control panel compatibility, wiring and ratings.