Detroit Radiant Products LD3-15-40 User manual

WARNING
!
Improper installation, adjustment, alteration, service, or maintenance can cause
property damage, injury, or death. Read the installation, operation, and maintenance
instructions thoroughly before installing or servicing this equipment.
This heater must be installed and serviced by trained gas installation and service
personnel only. Failure to comply could result in personal injury, asphyxiation, death,
fire, or property damage.
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of
this or any other appliance.
In locations used for the storage of combustible materials, signs must be posted to
specify the maximum permissible stacking height to maintain the required clearances
from the heater to the combustibles. Signs must either be posted adjacent to the
heater thermostats or, in the absence of such thermostats, in a conspicuous location.
Do not use this heater in indoor living or sleeping quarters, etc.! Installation of
a tube heater system in residential indoor living spaces may result in property damage,
serious injury, asphyxiation, or death.
LD3 Series
Installation Manual
The LD3 Series Infrared Tube Heater is a positive pressure, two stage radiant tube heater system. This
manual provides specific information related to the LD3 series models. All persons involved with the
installation, operation, and maintenance of the heater system must read and understand the information
in this manual.
For Your Safety
If you smell gas:
• Do not try to light any appliance. • Immediately call your gas supplier from a neighbor’s phone.
• Do not touch any electrical switch. • Follow the gas supplier’s instructions.
• Do not use any phone in your building. • If you cannot reach your gas supplier, call the fire department.
LIOLD3-Rev. 31216
Print: 1c-09/18 (DRPC)
Replaces: LIOLD3-1M-12/15 (CDS)
INSTALLER: Present this manual to the end user.
Keep these instructions in a clean and dry place for future reference.
Model#: ___________________ Serial #: _________________________
(located on rating label)

2
LD3 Series
Contents
1.0 Introduction ......................................................................3
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Heater Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Specifications....................................................................... 3
Safety Signs and Labels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.0 Safety ...........................................................................6
Warning Symbols.................................................................... 6
Applications ........................................................................ 6
Standards, Certifications, and Government Regulations ..................................... 7
Clearances to Combustibles ........................................................... 8
3.0 Installation ......................................................................10
Design Considerations and Prechecks .................................................. 10
Recommended Mounting Heights and Coverages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Hanger Placement and Suspension ................................................... 12
Combustion / Radiant Tube Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Optional Elbow or U-Bend Accessory Configuration ....................................... 17
Burner Control Box Suspension ....................................................... 19
Reflector Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Final Heater Assembly............................................................... 22
Venting ........................................................................... 23
Combustion Air Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Separated Combustion Systems....................................................... 31
Combustion Air Supply - Room Air ..................................................... 32
Optional Unvented Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Gas Supply Installation Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Electrical Requirements and Wiring Diagrams ............................................ 39
Typical Field Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Thermostat Connection .............................................................. 40
Unit Start-up (Commissioning) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
High Altitude Operation .............................................................. 46
4.0 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Operating Instructions ............................................................... 47
Sequence of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Diagnostics ....................................................................... 48
5.0 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Heater Components and Parts List ..................................................... 54
Routine Inspection.................................................................. 56
Limited Warranty ................................................................... 58
Kit Contents ....................................................................... 60
1.0 Introduction •Table of Contents

1.0 Introduction
3
LD3 Series
Overview
The intent of this manual is to provide information regarding safety, design guidelines, installation,
operation, and maintenance of the tube heater. You must read and understand the instructions and all
safety warnings before installing the tube heater. This manual is property of the owner, and must stay
with the owner or unit after the installation is complete.
Heater Components
Prior to installation, verify that the heater’s gas type and voltage (as listed on the rating plate) match
that of your application. Also verify that you have received all heater contents included with your tube
heater. Reference page 60 for a list of the kit contents for your model heater. Materials not included in
the heater kit contents (e.g., screws, vent material, terminals, etc.) are the responsibility of the installer.
Notify your product representative or Detroit Radiant Products of any discrepancy or missing kit
contents prior to installing unit.
Specifications
Model Number Gas Type (select one) Maximum Input (BTU/h) Minimum Input (BTU/h) Straight Length U-Tube Length Standard Weight (lbs.) Recommended Mounting Height** Combustion Chamber (Black Coated) Radiant Emitter Tube(s) (Black Coated) Residential Certification^
LD3-15-40 Nat. or Prop. 40,000 28,000 16’-10” N/A 85 lbs. 8’ to 13’ Titan Alum Yes
LD3-15-50 Nat. or Prop. 50,000 35,000 16’-10” N/A 85 lbs. 10’ to 15’ Titan Alum No
LD3-20-40 Nat. or Prop. 40,000 28,000 21’-10” 13’-0” 100 lbs. 8’ to 13’ Titan Alum Yes
LD3-20-50 Nat. or Prop. 50,000 35,000 21’-10” 13’-0” 100 lbs. 9’ to 15’ Titan Alum No
LD3-30-50* Nat. or Prop. 50,000 35,000 31’-7” 17’-8” 120 lbs. 9’ to 14’ Titan Alum Yes
Chart 1.1 • LD3 Series Specifications
* Model requires LV3-5EA-SUB optional accessory package when installing in a ‘U’ configuration (P/N: DB-TF1B/TF1B).
** Recommended mounting heights are provided as a guideline. Actual conditions may dictate variations from this
data. Optional protective guard (P/N: PG) is required when mounting below 8 feet.
^ Certified models may be installed in attached residential garages/workshops.
Titan = Black coated titanium stabilized aluminized steel.
Alum = Black coated aluminized treated steel.
1.0 Introduction •Overview •Heater Components •Specifications

WARNING
!
4
LD3 Series
1.0 Introduction •Safety Signs and Labels
Safety Signs and Labels
Product safety signs or labels should be replaced by the product user when they no longer are legible.
Contact either your local distributor or the product manufacturer for obtaining replacement signs or labels.
Read and understand all safety information and warnings in this manual before
installation, operation, and maintenance of the radiant tube heater system.
SERVICE ACCESS PANEL
CONTROLS & GAS VALVECOMPARTMENT
1. Disconnect gas & electricity.
2. Remove four (4) thumbscrews.
3. Remove top cover.
4. Swing hinged panel downward.
KEEPCOVER IN PLACE. REMOVE FOR SERVICE ONLY.
SERVICE ACCESS PANEL
FAN COMPARTMENT
1. Disconnect gas & electricity.
2. Remove top cover (2 thumbscrews).
3. Remove tsix (6) 1/4” screws.
4. Lift and remove panel.
KEEPCOVER IN PLACE. REMOVE FOR SERVICE ONLY.
Top Panel
F/N: LLTCL006L/C/R
Clearance to Combustibles Label
Bottom Panel
F/N: LLLOGO32
Logo Label
!
WARNING
Improper installation, adjustment,
alteration, service or maintenance
can cause property damage, injury
or death.
Read and understand the installation, operating
and maintenance instructions thoroughly before
installing or servicing this equipment.
12”
This heater must be installed and serviced by trained
gas installation and service personnel only.
This is NOT an explosion-proof heater. DO NOT install
in explosive environments. Where there is the
possibility of exposure to flammable vapors or dusts,
consult the local fire marshall, your insurance carrier or
authorities for approval of the proposed installation.
VENTING. This heater must be properly vented
according to the manufacturer’s specifications.
WARNING: Operation of this heater, when
not properly vented with an approved
system, can result in carbon monoxide
(CO) poisoning and possible death.
This heater requires FRESH COMBUSTION AIR for
safe operation and must meet all provisions of the
specified combustion and ventilation requirements.
GAS CONNECTION. Allowances must be made for the
system to expand. A flexible gas connection of approved
type is required. Flexible stainless steel gas connectors
installed in one plane, without sharp bends, kinks or
twists is recommended. Consult manual for further
instructions .
WARNING: Connector must be installed in a “C”
configuration. Use only the connector that was
furnished with the heater.
Gas Pipe
Gas Flex
Hose
Gas Flex Hose
Heater
Movement
45°
45°
3
F/N: LLAC023
Combustion Air
Connector Label
F/N: LLTB018 (Natural Gas)
F/N: LLTB019 (Propane Gas)
NEUTRAL
EARTH
HOT
- 120V HEATER INPUT -
120V
F/ N : L LV3 EP1
120 V Input Label
F/ N : L LV3 EP14
Valve and PS Label Back Panel

5
LD3 Series
SERVICE ACCESS PANEL
1.0 Introduction •Safety Signs and Labels
Clearances to combustibles must be maintained at
all times in order to prevent the ignition of
combustible materials. In locations used for the
storage of combustible materials, signs must be
posted to specify the maximum permissible stacking height to
maintain the required clearances from the heater to the
combustibles. Signs must either be posted adjacent to the
heater’s thermostats or, in the absence of such thermostats, in a
conspicuous location. Clearances are provided on the heater’s
safety label and in the heater’s Installation, Operation, and
Maintenance manual. Product installation and operation must
comply with applicable standards, codes, and regulations. Post
this tag adjacent to the heater’s thermostat or controls before
operating the heater.
- INSTALLER: READ AND POST THIS NOTICE -
LL001-XM-07/18 (CDS)
This product can
expose you to
chemicals including
lead and carbon
monoxide, which are known to the
State of California to cause birth
defects or other reproductive harm.
For more information go to
www.P65Warnings.ca.gov.
WARNING
!
Avoid Serious Injury, Death, or Property Damage.
Maintain Clearances to Combustible to Prevent the Risk of Fire.
California Proposition 65
SERVICE ACCESS PANEL
IGNITER & FLAME SENSE COMPARTMENT
1. Disconnect gas & electricity.
2. Remove cover by lifting top
cover upward and outward.
CAUTION: HOT SURFACE.
KEEPCOVER IN PLACE. REMOVE FOR SERVICE ONLY.
DETROIT RADIANT PRODUCTS COMPANY
21400 HOOVER ROAD - WARREN, MI 48089
[phone] www.reverberray.com
LOW-INTENSITY INFRARED HEATER
MAX.HEAT INPUT
MAX.DEBIT CALORIFIQUE
MIN.HEAT INPUT
MIN.DEBIT CALORIFIQUE
VENTCATEGORY
ÉVENTCATÉGORIE
BTU/h
BTU/h
VOLTAGE
AMPS
PHASE
FREQUENCY
Hz
VAC
MANIFOLDPRESSURE
PRESSIONA LA TUBULURE D'ALIMENTATION
MAXIMUMINLET PRESSURE
PRESSIOND'ALIMENTATION MAXIMALE
MINIMUMINLET PRESSURE FOR PURPOSE OF ADJ.
PRESSIOND'ALIMENTATION EN GAS MIN. ADMISE
INCHESW.C.
INCHESW.C.
INCHESW.C.
RADIATEUR À INFRAROUGE À FAIBLEINTENSITÉ
ORIFICESIZE
DIMDE L'INJECTEUR
NATURALGAS PROPANEGAS
THISDESIGN COMPLIES WITH STANDARD(S):
COMPLESDE CETTE CONCEPTION AVEC LA NORME:
HEATERBUILD TYPE
TYPEOF GAS
TYPEDE GAZ
MIN.MOUNTING ANGLE
MIN.ANGLE DE SUPPORT
MAX.MOUNTING ANGLE
MAX.ANGLE DE SUPPORT
MODELNUMBER
NUMÉRODE MODÈLE
SERIALNUMBER
NUMÉRODE SÉRIE
VERSION
COMBUSTIONCHAMBER
®
FOR COMMERCIAL / INDUSTRIAL USE.
FOR INDOOR USE ONLY.
MADE IN U.S.A.
40,000
25,000
CATEGORY III
2.4
SINGLE
60
1203.5
14.0
5.0
49
D.M.S.
57
D.M.S.
ANSI Z83.20b-2011 • CSA2.34B-2011RADIANT TUBE HEATER
C1
NATURAL
AGA 7-89 RESIDENTIAL RADIANT TUBE HEATER
0°
45°
LD3-20-40N YYMMREPCSHIPPE#### 09/12
TP-26B; INCH BC ALUMINIZED
Controls Compartment
Burner Control Box
Component Label
(located inside the center
compartment lid)
LD3-20-40N
Data on this label is for the model shown on this label. If your heater has been converted,
this information is not accurate. Please contact the factory for assistance.
BURNER COMPONENTS:
For parts replacement information, contact factory at 586-756-0950 or visit www.drp-co.com/parts.
Serial No.: 1311XXXXXXXXXX 0001
Gas Valve:
Circuit Board:
Wire Harness:
N.O. Switch:
N.O. VL Orifice:
N.C. Switch:
N.C. VL Orifice:
Diff Switch:
Diff VL Orifice:
Igniter:
Burner:
16” Tube:
Ind. Lights:
Diag. Light:
Term. Block:
Transformer:
Fan:
Alt. Fan:
Alt. Fan Usage:
Relay:
Filter:
24 Volt In:
120 Volt In:
Gas In:
Extra VL Orifice:
Production Code:
Version:
Stock:
Add-On:
Internal Use Only:
HEATER
TYPE: Electric:
Tag:
Special 1:
Special 2:
Gas:
Air:
C1
C1 C2 C3
None
N/A
LD3-40
11.13
Two-Stage
Ignition Control
3 PCS Harness
None
None
None
None
IS22016051F5169
Grey (+ / -)
Norton
High
4” Gen.
Yellow - 120V
(Specify TP-#’s)
3140
851B
3252
N/A
N/A
264E
50
201B
1080
828
None
None
None
Fasco Lg.
50Hz - 120V
When Specified
None
None
None
120V Cord
7/8” FC Flare
None
N/A
N/A
55A
55B
N/A
N/A
334
333
83
3
1 1/2”
TP-204#
TP-44#
3
1 5/8”
LLWT038
None
1
1 5/8”
17
1 7/16”
Orifice Type:
SAMPLE
Fan
Compartment
Al-Ti Combustion
Chamber (see pg. 22)
16” Burner Tube
F/N: LL001 - Clearance Safety Tag
(Affix adjacent to heater’s thermostat)
Rating Plate
Aluminized
Radiant Tube(s)
(if applicable)
F/N: LLTCL015
Lighting Instructions
LOW-INTENSITY INFRARED HEATER
MAX. HEAT INPUT
MAX. DEBIT CALORIFIQUE
MIN. HEAT INPUT
MIN. DEBIT CALORIFIQUE
VENT CATEGORY
ÉVENT CATÉGORIE
BTU/h
BTU/h
VOLTAGE
AMPS
PHASE
FREQUENCY
Hz
VAC
MANIFOLD PRESSURE
PRESSION A LA TUBULURE D'ALIMENTATION
MAXIMUM INLET PRESSURE
PRESSION D'ALIMENTATION MAXIMALE
MINIMUM INLET PRESSURE FOR PURPOSE OF ADJ.
PRESSION D'ALIMENTATION EN GAS MIN. ADMISE
INCHES W.C.
INCHES W.C.
INCHES W.C.
RADIATEUR À INFRAROUGE À FAIBLE INTENSITÉ
ORIFICE SIZE
DIM DE L'INJECTEUR
NATURAL GAS PROPANE GAS
THIS DESIGN COMPLIES WITH STANDARD(S):
COMPLES DE CETTE CONCEPTION AVEC LANORME:
HEATER BUILD TYPE
TYPE OF GAS
TYPE DE GAZ
MIN. MOUNTING ANGLE
MIN. ANGLE DE SUPPORT
MAX. MOUNTING ANGLE
MAX. ANGLE DE SUPPORT
MODEL NUMBER
NUMÉRO DE MODÈLE
SERIAL NUMBER
NUMÉRO DE SÉRIE
VERSION
COMBUSTION CHAMBER
40,000
25,000
CAT. I AND III
2.4
SINGLE
60
1203.5
14.0
5.0
31 D.M.S. - D.M.S.
ANSI Z83.20b-2011 • CSA 2.34b-2011
C1
NATURAL
ANSI Z21.86-2016 • CSA 2.32-2016
0°
45°
LD3-20-40N YYMMREPCSHIPPE#### 09/12
TP-26B; INCH BC ALUMINIZED
DETROIT RADIANT PRODUCTS COMPANY
21400 HOOVER ROAD - WARREN, MI 48089
[phone] www.reverberray.com FOR COMMERCIAL / INDUSTRIAL USE. FOR INDOOR USE ONLY.
MADE IN U.S.A.
THIS HEATER REQUIRES A SPECIAL VENTING SYSTEM WHEN INSTALLED
AS A CATEGORY I OR III HEATER. REFER TO THE INSTALLATION
INSTRUCTIONS FOR PARTS LISTAND METHOD OF INSTALLATION.
SAMPLE
F/N: LLTB025R
Service Access
Panel - Fan
AVOID EQUIPMENT FAILURE
THIS 10 FT. TUBE IS THE
COMBUSTION CHAMBER.
THIS TUBE MUST BE THE FIRST TUBE
FOLLOWING THE BURNER CONTROL BOX.
!
INSTALLER
The combustion chamber utilizes either 409
stainless, titanium alloy or aluminized steel -
depending on the model number of your heater.
Rotate the tube’s welded seam to bottom.
Consult the manual(s) for further details.
F/N: LLTB004
Combustion Chamber (all heaters with 409
stainless steel tubes)
F/N: LLTB024L
Service Access
Panel - Controls
SERVICE ACCESS PANEL
F/N: LLTB026
Service Access
Panel - Igniter &
Flame Sense
SERVICE ACCESS PANEL
IGNITER & FLAME SENSE COMPARTMENT
1. Turn off gas & electricity.
2. Remove cover by lifting top
cover upward and outward.
CAUTION: HOT SURFACE.
KEEP COVER IN PLACE. REMOVE FOR SERVICE ONLY.
Bill of Material

6
LD3 Series
Warning Symbols
Safety is the most important consideration during installation, operation, and maintenance of the tube
heater. You will see the following symbols and signal words when there is a hazard related to safety or
property damage.
2.0 Safety •Warning Symbols •Applications
2.0 Safety
Warning indicates a potentially hazardous situation
which, if not avoided, could result in death or injury.
Caution indicates a potentially hazardous situation
which, if not avoided, could result in minor or
moderate injury.
Notice indicates a potentially hazardous situation
which, if not avoided, could result in property
damage.
NOTICE
WARNING
!
CAUTION
!
WARNING
!
Improper installation, adjustment, alteration, service, or maintenance can cause
property damage, serious injury, or death. Read and understand the installation,
operation, and maintenance instructions thoroughly before installing or servicing this
equipment. Only trained, qualified gas installation and service personnel may install or
service this equipment.
Applications
This is not an explosion proof heater. No tube heater may be used in a Class 1 or Class 2 Explosive
environment. Consult your local fire marshal, insurance carrier, and other authorities for approval if the
proposed installation is in question.
Read and understand all safety information and warnings in this manual prior to installation, operation,
and maintenance of this heater. Warnings indicate a potentially hazardous situation which, if not avoided,
could result in injury or death.

Standards, Certifications, and Government Regulations
Installation of this tube heater must conform with all applicable local, state, and national specifications,
regulations, and building codes. Contact the local building inspector and/or fire marshal for guidance.
In the absence of local codes, the installation must conform to the latest edition of:
United States: National Fuel Gas Code, ANSI Z223.1 (NFPA 54).
Canada: CAN/CGA B149.1 and .2, Canadian Electrical Code C22.1
Copies of the Standards can be viewed or purchased at www.nfpa.org or www.scc.ca.
Public Garages and Maintenance Facilities:
This heater must be installed in accordance with the latest edition of the Standard for Parking
Structures, ANSI/NFPA 88A or the Code for Motor Fuel Dispensing Facilities and Repair Garages ANSI/
NFPA 30A. In Canada, refer to CAN/CGA B149.1 and B149.2.
• Heaters must not be installed less than 8 ft. (2.4 m) above the floor. Minimum clearances to
combustibles must be maintained from vehicles parked below the heater.
• When installed over hoists, minimum clearances to combustibles must be maintained from the
upper most point of objects on the hoist.
Aircraft Hangars:
This heater must be installed in accordance with the latest edition of the Standard for Aircraft Hangars,
ANSI/NFPA 409. In Canada, refer to CAN/CGA B149.1 and B149.2.
• In aircraft storage and servicing areas, heaters shall be installed at least 10 ft. from above the upper
surface of wings or of the engine enclosures of the highest aircraft that may be housed in the hangar.
The measurement shall be made from the wing or engine enclosure, whichever is higher from the
floor, to the bottom of the heater.
• In areas adjoining the aircraft storage area (e.g., shops, offices) the bottom of heaters shall be
installed no less than 8 ft. (2.4 m) above the floor.
• Suspended or elevated heaters shall be located in spaces where they shall not be subject to damage
by aircraft, cranes, movable scaffolding or other objects.
Provisions shall be made to assure accessibility to suspended tube heaters for recurrent maintenance
purposes.
7
LD3 Series 2.0 Safety •Applications •Standards, Certifications and Regulations
Not For Use in Indoor Living Spaces. Installing this unit in residential indoor living spaces or
sleeping quarters, such as bedrooms or basements, may result in property damage, serious injury, or
death.
WARNING
!
Commercial / Industrial Applications
Unless otherwise indicated, tube heaters are designed and certified for use in industrial and commercial
buildings such as warehouses, manufacturing plants, aircraft hangars, and vehicle maintenance shops.
For maximum safety the building must be evaluated for potential problems before installing the heating
system. A critical safety factor to consider before installation is the clearances to combustibles.
Residential Applications
Only select LD3 series models are Design Certified under CSA Requirements for residential radiant tube
heaters. Not for use in the residential indoor living areas or sleeping quarters.

Children and adults should be alerted to the hazards of high surface temperatures and should stay
away to avoid burns or clothing ignition.
Young children should be carefully supervised when they are in the same space as the heater.
Clothing or other flammable materials should not be hung from the heater, or placed on or near the
heater.
Any guard or other protective device removed for servicing the heater must be replaced prior to
operating the heater.
Installation and repair should be done by a qualified service person. The heater should be inspected
before use and at least annually by a qualified service person. More frequent cleaning may be required
as necessary. It is imperative that the control compartment, air passageways and burner(s) of the
heater be kept clean.
CAUTION
!
8
LD3 Series
Hazards:
For maximum safety the building must be evaluated for hazards before installing the heating system.
Examples include, but are not limited to:
• Gas and electrical lines
• Combustible and explosive materials
• Chemical storage areas
• Areas of high chemical fume concentrations
• Provisions for accessibility to the heater
• Adequate clearances around air openings
• Combustion and ventilating air supply
2.0 Safety •Clearances to Combustibles
Clearances to Combustibles
A critical safety factor to consider before installation is the clearances to combustibles. Clearance to
combustibles
is defined as the minimum distance you must have between the tube surface, or reflector,
and the combustible item
. Considerations must also be made for moving objects around the tube heater.
The following is a partial list of items to maintain clearances from:
WARNING
!
Placement of explosive objects, flammable objects, liquids, and vapors
close to the heater may result in explosion, fire, property damage, serious
injury, or death. Do not store or use explosive objects, liquids, or vapor in
the vicinity of the heater.
When installing the tube heating system, the minimum clearances to combustibles for your series tube
heater and system configuration must be maintained. These distances are shown in Chart 2.1 on page 9
and on the burner control box. If you are unsure of the potential hazards, consult your local fire marshal,
fire insurance carrier, or other qualified authorities on the installation of gas fired tube heaters for approval
of the proposed installation.
• Vehicle parking areas
• Vehicles with lifts or cranes
• Storage areas with stacked materials
• Lights
• Sprinkler heads
• Overhead doors and tracks
• Dirty, contaminated environment
• Plastic
• Parked vehicles
• Gasoline
• Storage racks
Combustible items: Moving Objects:
• Wood • Overhead doors
• Paper • Vehicle lifts
• Fabric • Cranes
• Chemicals • Hoists
• Paint

Model Number
Mounting
Angle*
Sides
Front Behind Top Below
40,000 BTU/h MODELS
LD3 (15, 20) - 40 [N, P] 0° 15 15 645
45° 58 810 45
with 1 side shield 0° 42 8 6 45
with 2 side shields 0° 20 20 645
50,000 BTU/h MODELS
LD3 (15, 20, 30) - 50 [N, P] 0° 11 11 648
45° 39 810 48
with 1 side shield 0° 29 8 6 48
with 2 side shields 0° 16 16 648
20 ft. from burner 0° 77630
Chart 2.1 • Clearances to Combustibles in Inches (see Figure 2.1 for Mounting Angles)
*
Heaters mounted on an angle between 0° and 45° must maintain clearances posted for 0° or 45°, whichever is
greater.
NOTE: Use high BTU output when determining clearances. The minimum end clearance is 12 in.
Figure 2.1 •Mounting Angles
0° Mounting Angle 45° Mounting Angle
0° Mounting Angle
with 1 Side Shield
(P/N: SSE)
0° Mounting Angle
with 2 Side Shields
(P/N: SSE)
Side Side
Below
Top
Front Behind
Below
Top
Front Behind
Below
Top
Side Side
Below
Top
WARNING
!
Failure to comply with the stated clearances to combustibles may result in
personal injury, property damage, and/or death.
9
LD3 Series 2.0 Safety •Clearances to Combustibles
In locations used for the storage of combustible materials, signs must be posted to specify the maximum
permissible stacking height to maintain the required clearances from the heater to the combustibles.
Signs must either be posted adjacent to the heater’s thermostat or in a conspicuous location.
The stated clearances to combustibles represent a surface temperature of 90°F (50°C) above room
temperature. Building materials with a low heat tolerance (such as plastics, vinyl siding, canvas, tri-ply,
etc.) may be subject to degradation at lower temperatures. It is the installer’s responsibility to ensure that
adjacent materials are protected from degradation.

10
LD3 Series
3.0 Installation •Design Considerations and Prechecks
WARNING
!
Improper installation, adjustment, alteration, service, or maintenance can cause
property damage, serious injury, or death.
Read and understand the installation, operation, and maintenance instructions
thoroughly before installing or servicing this equipment.
Only trained, qualified gas installation and service personnel may install or service this
equipment.
Design Considerations and Prechecks
Placement of infrared heaters is influenced by many factors. Aside from safety factors, considerations
such as the number of heaters or vent elbows that are allowed, maximum vent lengths, ducting of
combustion air, and combining exhaust vents are a few examples. All installation manuals, along with
national, state, provincial, and local codes, address these issues. It is critical that you read, understand,
and follow all guidelines and instructions.
To ensure a properly designed heating system, a layout should be developed for the correct placement of
the burner control box, tubes, vents, and combustion air intake ducts. Inspect and evaluate the mounting
conditions, vent locations, gas supply, and wiring.
When designing an infrared radiant heating system, consider the following:
• Has the building’s heat loss been evaluated?
• Does the design meet the needs of the space?
• Have recommended mounting heights been observed?
• Have all clearance to combustible situations been observed?
• Is the supply (burner) end of the heater located where more heat is required?
• Is it best to offset the heaters and/or rotate the reflectors towards the heat zone?
• Are extra guards, side shields, ‘U’ or ‘L’ reflector covers required?
• Does the heater require outside fresh air for combustion?
• Is the environment harsh or contaminated (requiring outside air for combustion)?
• Are chemicals or vapors a concern (requiring outside air for combustion or additional ventilation)?
IMPORTANT: Fire sprinkler heads must be located at an appropriate distance from the heater to avoid an
inadvertant discharge. This distance may exceed the published clearances to combustibles as posted on
the heater. Certain applications may require the use of high temperature sprinkler heads or relocation of
the heaters.
The effective infrared surface temperature of a person or object may be diminished with wind velocities
above 5 mph. The use of adequate wind barrier(s) may be required.
3.0 Installation
Fire sprinkler systems containing propylene glycol, antifreeze, or other potentially flammable substances
shall not to be used in conjunction with this heater without careful consideration for and avoidance of
inadvertent discharge hazards. For further information consult NFPA 13. Always observe applicable
state and local codes.
CAUTION
!

11
LD3 Series
Chart 3.1 • Recommended Mounting Heights and Coverages
NOTE: This chart is provided as a guideline. Actual conditions may dictate variation from this data.
3.0 Installation •Recommended Mounting Heights
Model Maximum Input (BTU/h) Recommended Mounting Height (ft.)* Coverage Area Straight Config. (LxW) Coverage Area U-Tube Config. (LxW) Distance Between Heaters (ft.) Dimension A Distance Between Heater Rows (ft.) Dimension B Maximum Distance Between Heaters and Wall (ft.) Dimension C
15 ft. 40,000 8’ - 13’ 20’ x 12’ N/A 10’ - 20’ 20’ - 40’ 16’
50,000 10’ - 15’ 22’ x 15’ N/A 20’ - 30’ 30’ - 50’ 18’
20 ft. 40,000 8’ - 13’ 20’ x 13’ 12’ x 12’ 10’ - 20’ 20’ - 40’ 16’
50,000 9’ - 15’ 22’ x 15’ 12’ x 12’ 20’ - 30’ 30’ - 50’ 18’
30 ft. 50,000 9’ - 14’ 32’ x 15’ 15’ x 15’ 20’ - 30’ 30’ - 50’ 18’
* Optional protective guard (P/N: PG) is required when mounting below 8 feet.
Factory recommended mounting heights are listed as a guideline. If infrared heaters are mounted too low
or too high, they may result in discomfort or lack of heat. Detroit Radiant Products Company generally
recommends observing the recommended mounting heights to optimize comfort conditions. However,
certain applications such as spot heating, freeze protection, outdoor patio heating, or very high ceilings
may result in the heaters being mounted outside of the factory recommended mounting heights.
Figure 3.1 •Mounting Height Dimensions (See Chart 3.1 for dimensions)
Note: Dimensions A, B, & C are based upon heaters hung at the factory recommended mounting height.
Dim. C
Dim. A
Dim. B
Dim. C
Dim. A

WARNING
!
12
LD3 Series
Suspension of the heater must conform to applicable codes referenced in the Safety section and
these instructions.
1Lay all radiant tubing out in the following order. Position tubes in approximate location (see Figure 3.2).
• 10 ft. 4” O.D. or 4” to 3” O.D. titanium treated combustion chamber.
• 3” O.D. aluminized radiant emitter tube(s) if applicable.
2Connect the female end of the titanium combustion chamber to the 16” burner tube by
using the 4” stainless steel tube clamp (TP-220).
Important! The 10 ft. titanium alloy treated combustion chamber must be placed as the first tube
downstream of the burner control box. The combustion chamber has an orange identification
sticker located on the swaged end of the tube.
3Place a 4” tube hanger (TP-19B) on the tapered titanium combustion chamber’s 4” O.D. end. The
spacing between the burner control box mounting brackets and the 4” tube hanger should be 2’-4”.
4Mark locations for hanging points.
NOTE: If the available hanging points do not allow for the recommended spacing then additional
hangers (P/N: TP-19B(4”) or TP-1079(3”)) may be necessary.
• The spacing between the burner control box mounting brackets and the first hanger should be
approximately 2’-4”.
• The space between the first two hangers placed on the first tube, should be approximately 8’-10”.
• The space between hangers thereafter, one per tube, should be approximately 9’-8”.
Hanger Placement and Suspension
Improper suspension of the tube heater may result in collapse and being crushed. Always
suspend from a permanent part of the building structure that can evenly support the total
force and weight of the heater.
3.0 Installation •Hanger Placement and Suspension

2’ 4”
16” Burner
Tube
10 ft. 4” to 3” O.D. Tapered or 10 Ft. 4” O.D.
Titanium Treated Combustion Chamber
3” O.D. Aluminized
Steel Radiant Emitter
Tube(s) (if applicable)
8’ 10” 9’ 8” 9’ 8”
Burner
Control Box
Burner Control Box
Suspension Points
Suspension
Point
Igniter/
Sensor Box
3” or 4” Tube
Clamp (TP-1077
or TP-21B)
4” Stainless Steel
Tube Clamp (TP-220)
4” Tube Hanger (TP-19B)
3” or 4” Tube Hanger
(TP-1079 or TP-19B)
Suspension
Point
Suspension
Point
Figure 3.2 •Heater Mounting Layout
NOTE: A sticker identifying the combustion chamber(s) is located on the
swaged end of the tube(s).
3” or 4” Reflector Center Support (TP-1078 or TP-82)
13
LD3 Series
Chart 3.2 • Heater Mounting Requirements and Weights
*Refer to page 18 for U-Bend configuration dimensions.
Model Dimension* Straight Configuration Suspension Points Control Box Stabilizer Shipping Weight Chain Set Qty. Straight Chain Set Qty. w/TF1B Optional Brass Knuckle (P/N:BK) Optional Single Mount Bracket (P/N: SMB) U configurations only
15 ft. 16’-10” 3 2 85 lbs. 5N/A 3N/A
20 ft. 21’-10” 3 2 100 lbs. 5 6 3 2
30 ft. 31’-7” 4 2 120 lbs. 6 7 4 3
3.0 Installation •Hanger Placement and Suspension
The first 10 ft. tube will utilize 2
hangers spaced approximately
8’ - 10’ apart. Each subsequent
tube will utilize 1 hanger.
NOTICE

14
LD3 Series
7S-Hook and
#1 Double-Loop Chain
Figure 3.3 •Mounting the Hangers
5Wood Beam
5Concrete Beam
6Beam Clamp
6Screw Hook
7Threaded Rod
and Turnbuckle
8Chain
5
I-Beam
6Beam Clamp
8Chain 8Chain
5I-Beam
3.0 Installation •Hanger Placement and Suspension
6Screw hook
with Locknut
and Washer
5Prepare mounting surface and, if necessary, weld blocks and/or drill holes (see figure 3.3).
NOTE: The burner control box and radiant tubes should be in straight alignment and level.
6Fasten beam clamp, screw hook or other type of suspension anchor to hanging point.
7IF USING CHAINS: Attach and close S-hook (P/N: S-HOOK) and #1 double-loop chain (P/N: THCS)
to anchor. Check that it is securely attached. NOTE:Threaded rod and turnbuckles may be used.
8IF USING GRIPPLE: (P/N: THGHxx) Pass the loop end of the cable through the hook. Thread the
other end through the loop, the locking fastener, the hanger, and back up through the locking fastener.
Adjust to appropriate length. NOTE:Threaded rod and turnbuckles may be used.
9Attach hangers to chains. Adjust chain lengths until radiant tubing is level and equal weight distribution
is achieved. Chains must be straight up and down. Do not install chains at an angle as this can result
in tube warpage or separation.

15
LD3 Series
For 45° hanging angle, use two
S-hooks and two #1 double-loop chains.
For variety of hanging angles, use an optional
Brass Knuckle (P/N: BK) fitting with a #1 double-
loop chain and S-hook.
45°
30° 15°
U-Tubes can be mounted at a 15°, 30°, or 45° angle
with two suspension points using two optional Brass
Knuckle (P/N: BK) fittings, #1 double-loop chains,
and S-hooks.
U-Tubes can be mounted from a single suspension
point using an optional Single Mounting Bracket
(P/N: SMB) with five S-hooks and #1 double-loop
chains.
Figure 3.4 •U-Tube Hanger Mounting Options
Figure 3.5 •Angled Hanger Mounting Options
Exhaust
End
Single Mounting
Bracket
Brass Knuckle
3.0 Installation •Hanger Placement and Suspension

16
LD3 Series
Combustion / Radiant Tube Assembly
To install the combustion / radiant tubes:
1Place tubes in hangers with the welded seam facing downward and the swaged end of the tube
towards the exhaust end of the heater system (see Figure 3.6). NOTE: The first 10 ft. combustion tube
will utilize two (2) hangers and each subsequent tube will utilize one (1) hanger.
Refer to page 22 for tube installation sequence.
2Slide tube clamps onto radiant tubes (see figure 3.7).
Figure 3.6 •Attach Hangers
Figure 3.7 •Attach Tube Clamps
Hanger
Welded seam
faces down
Swaged End
Tube Clamp
NOTE: If the tube clamp comes apart, the spacer must be
re-assembled with the spacer’s concave surface facing against
the radiant tube surface.
Concave surface
3.0 Installation •Combustion / Radiant Tube Assembly
Combustion / Radiant Tube
(See NOTE above and pg. 22)

17
LD3 Series
Optional Elbow or U-Bend Accessory Configuration
A 90° elbow or 180° U-Bend accessory fitting may be installed on the radiant tube heating system. Refer
to Chart 3.3 for minimum distance requirements from the burner control box.
When installing an Elbow or U-Bend Accessory Fitting:
• The top clearance of an uncovered (no reflector) elbow or U-Bend accessory fitting to combustibles
is 18 inches.
• If operating the heater unvented, separate the intake air to the heater from its exhaust products a
minimum of 4 ft.; further separation may be necessary. Combustion air may also be supplied.
• A maximum of two 90° elbows or one 180° U-Bend can be installed on a heater.
Figure 3.9 •Optional Tube Connections
3Slip-fit the radiant tube sections together until tightly connected (install the swaged end of each tube
towards exhaust end). NOTE: If it is difficult to mate the tubes, they may be installed incorrectly.
4Center tube clamps over the seam where two radiant tube sections connect. If necessary, rotate tube
clamps so they will not interfere with the reflector end caps during expansion and contraction of
the heater.
5Tighten tube clamp bolts to secure. When proper compression is obtained (40-60 ft-lbs. torque) the
tube seam will create a visible mark on the tube clamp. NOTE: Excessive torque may damage the
tube clamp.
6Determine the location of the burner control box and note the placement of the mounting chains.
Figure 3.8 •Tube Connections
Tubes fit snuggly together and the
tube clamp is centered over the seam.
Tubes are not fit snuggly
together and the tube clamp is
not centered over the seam.
The tube clamp is tight when the
torque is achieved (normally
when seam becomes visible).
Correct Tube Connection Incorrect Tube Connection
3.0 Installation •Optional Elbow or U-Bend Accessory Configuration
90° 3” Elbow (P/N:
DB-E6) or
4” Elbow (P/N: E6)
180° 3” U-Bend
(P/N: DB-TF1B) or
4” U-Bend (P/N: TF1B)

* The LV3-5EA-SUB add-on may only be ordered at the time of
heater production.
12.5”
12.5”
90° 4” Elbow
P/N: E6
16”
16”
6”
20”
10”
20”
180° 4” U-Bend P/N:
TF1B
See Chart 3.6 on page 22 for tube diameters and locations.
18
LD3 Series
Chart 3.3 • Minimum Distance
From Burner Control Box to Elbow
or U-bend Accessory Fitting
Figure 3.11 •U-Bend and Elbow Dimensions
Chart 3.4 •
Overall Dimensions for Heaters Configured With
U-Bend
180° 3” U-Bend
P/N: DB-TF1B
90° 3” Elbow
P/N: DB-E6
Tube Length Dimension B Notes
15 ft. N/A N/A
20 ft. 13’-0” N/A
30 ft. 17’-8” Requires P/N: LV3-5EA-SUB *
Model BTU Range Dimension A
40,000 10 ft.
50,000 10 ft.
3.0 Installation •Optional Elbow or U-Bend Accessory Configuration
S.S. Tube Clamp Tube Clamp
Figure 3.10 •Elbow and U-Bend Clearances
Dimension A
U-Bend can be set in both directions
12”
Elbow can be set
in both directions
S.S. Tube Clamp Tube Clamp
Dimension A
Dimension B
8”
11.5”
15”
16”
6”
18”
10”
20”
11.5”

19
LD3 Series 3.0 Installation •Burner Control Box Suspension
Burner Control Box Suspension
Suspending the burner control box must be done in accordance with applicable codes listed in the Safety
section and these instructions.
The burner control box must be in straight alignment with radiant tubes and level. Contact your local
distributor or the factory to see if your application allows for the rotation of the burner control box.
1Determine the mounting chain locations for hanging the burner control box.
2Fasten beam clamp, screw hook, or other type of suspension anchor to hanging point.
3Attach S-hook and #1 double loop chain (P/N: THCS) to anchor. Check that it is securely connected.
4
Attach chain assemblies and S-hooks to mounting brackets on the burner control box. Adjust chain lengths
until level and in straight alignment with radiant tubes. Burner sight glass will be visible from the floor.
Figure 3.12 •Burner Control Box Assembly - Side View
Figure 3.13 •Burner Control Box showing U-Shaped Configuration - End View
Burner
Sight Glass
16 in. burner tube is in straight
alignment with combustion chamber
9.625”
16”
12.875”
TP-1077
3” Tube Clamp
TP-1079 3” Hanger
TP-19B
4” Hanger
TP- 220 4” Stainless
Steel Tube Clamp
12
3
4
31.5” or 32.5”
18.5”
4”
11. 2 5”
4.5”
8.625”
10.06”
5.31
Note: Special consideration must be given when U-Bend is
configured along the left side of the unit. Adequate spacing
must be provided for the service access panel.
Path of Access
Panel Door
15” or 16”

20
LD3 Series
Reflector Assembly
Reflectors and reflector accessories direct infrared energy to the floor level. The reflector assembly
depends on the heater configuration, proximity to combustibles, and space surrounding the heater.
Before you begin assembly, determine if the use of reflector accessories are necessary (see Chart 3.5).
To install the reflectors (see Figure 3.14):
1Attach the reflector center supports onto radiant tubes.
2Slide each reflector section through the hangers and adjust the reflector tension spring into the
V-groove on the top of the reflector. The reflectors should overlap approximately 4 inches.
3To prevent the reflectors from shifting, secure the reflector sections together using sheet metal
screws, except at the expansion joint (see p.22). NOTE: Installer to supply sheet metal screws.
4Attach reflector end caps with polished finish inward to each end of the reflector run. Secure with
clips.
Figure 3.14 •Reflector Assembly
Mid-point of
the tube
Burner Box
3.0 Installation •Reflector Assembly
SERVICE ACCESS PANEL
CONTROLS& GAS VA LVECOMPARTMENT
1.Disconnect gas & electricity.
2.Remove four (4) thumbscrews.
3.Remove top cover.
4.Swing hinged panel downward.
KEEPCOVER IN PLACE. REMOVE FOR SERVICE ONLY.
SERVICE ACCESS PANEL
FANCOMPARTMENT
1.Disconnect gas & electricity.
2.Remove top cover (2 thumbscrews).
3.Remove tsix (6) 1/4” screws.
4.Lift and remove panel.
KEEPCOVER IN PLACE. REMOVE FOR SERVICE ONLY.
Reflector
4” Overlap
Reflector Center
Support
Radiant
Tube
Hanger
and Chain
Reflector End Cap
Reflector Tension
Spring
Clips
13.75”
Figure 3.15 •Width of Installed Reflector - Top View
1”