Universal-Ray RHT-65 SERIES 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.
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.
Not for residential use! Do not use this heater in the home, sleeping quarters,
attached garages, etc. Installation of a commercial tube heater system in
residential indoor spaces may result in property damage, serious injury,
asphyxiation or death.
RHT Series
Insert Manual
For complete installation instructions, see the Tube Heater General Manual
that accompanies this Series Insert 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.
LIORHTa-Rev. 24414
Draft: 1M-9/14(DRP)
The RHT Series Infrared Tube Heater is a positive pressure, two-stage radiant heater system. This insert
manual is a supplement to the Tube Heater General Manual and provides specific information related to
the RHT Series model. All persons involved with the installation, operation and maintenance of the heater
system must read and understand the information in this insert manual and the accompanying Tube
Heater General Manual.
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
RHT Series
Contents
1.0 Safety...................................................................3
Safety Labels and Locations ............................................3
Clearances to Combustibles ............................................4
2.0 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Gas Requirements ...................................................6
Electrical Requirements................................................6
Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Specifications ......................................................10
Tube Installation Sequence ............................................11
3.0 Operation ..............................................................12
Sequence of Operation ...............................................12
Thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.0 Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.0 Parts ..................................................................18
Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Parts List ..........................................................18
Kit Contents Check List ...............................................20
Approvals..........................................................20
Limited Warranty ....................................................20
NOTE: See page 10 for a list of available models and specifications.

1.0 Safety
3
RHT Series
Safety Labels and Their Locations
1.0 Safety • Safety Labels and Locations
Read and understand all safety information and warnings in this insert manual and the
Tube Heater General Manual before installation, operation and maintenance of the
radiant tube heater system.
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.
SAMPLE
RHT-125N
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 store.reverberray.com.
Serial No.: 1014XXXXXXXXXX 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
RHT-125
10.14
36E96-224-N
MICRO 50X-117
3 PCS Harness
None
None
None
None
IS22010051F5166
Grey (+ / -)
Norton
Mid
4” Gen.
Yellow - 24V
(Specify TP-#’s)
240
551
552
N/A
N/A
264E
555
201B
580
328
On Circuit Board
None
40 VA
Fasco Lg.
50Hz - 120V
When Specified
None
None
3 T-plug
2 x 4 Box
7/8” FC Flare
None
N/A
826
55A
55B
N/A
N/A
832
66
83
19
1 5/16”
TP-204#
TP-44#
19
1 7/16”
LLWT000
None
19
1 5/16”
17
1 7/16”
Orifice Type:
SAMPLE
®
DETROIT RADIANT PRODUCTS COMPANY
21400 HOOVER ROAD - WARREN, MI
UNIVERSAL-RAY INFRARED RADIANT TUBE HEATER
FOR OUTDOOR USE AND INDOOR (Non-Residential)
INSTALLATION ONLY. Class IIIA Permanent Label
[phone] - www.universal-ray.com
Volts AC:
AMPS - Starting:
AMPS - Running:
Combustion Chamber:
120V - 60Hz
4.8
1.1
4” Black Coated Aluminized
DESIGN COMPLIES WITH:
ANSI Z83.20-2008-GAS FIRED LOW INTENSITY INFRARED HTR.
Manifold Pressure:
Maximum Inlet Pressure:
Minimum Inlet Pressure:
Serial No.: 1014XXXXXXXXXX 0001
MODEL NO.
RHT- 40 - 75N
Heater Type
Minimum Mounting Angle:
Maximum Mounting Angle:
C1
0
45
DEGREES
DEGREES
INPUT BTU/H
75,000/50,000
FOR USE WITH
Natural Gas
3.5 Inches
14 Inches
5.0 Inches
W.C.
W.C.
W.C.
Air Metering Orifice
DO NOT REMOVE
TP-114
TP-3014 3”
Back Panel
Top Panel
Bottom Panel
Rating
Plate
F/N: LLTB018 (Natural Gas)
F/N: LLTB019 (LP Gas)
F/N: LLTCL001 Clearance to
Combustibles Label.
F/N: LLLOGO3
Burner Control Box
Component Label
(located under the top
panel)
F/N: LLAC
Air Metering Orifice
SAMPLE

!
CAUTION
Provide 24
Volts Only
This heater has a 24 Volt
control system. Do not
connect 120 Volt power
supply, as it will damage
the controls.
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.
This heater is equipped with an
HLRB Relay(s) required for grouping
multiple heaters on the same
thermostat. This heater must be wired with a
field supplied transformer in accordance with
the installation, operation manual.
4
RHT Series
HIGH
FIRE
HL
LOW
FIRE
1.0 Safety • Safety Labels and Locations • Clearance to Combustibles
F/N: LLTB031
Clearance to combustibles is defined as the minimum distance that must exist between the tube surface,
or reflector, and any combustible items (see Figure 1.1). It also pertains to the distance that must be
maintained from moving objects around the tube heater.
When installing the tube heater system, clearances to combustibles for the model tube heater and
configuration must be maintained. Refer to Chart 1.1 below to determine the required distances for your model.
Clearance to Combustibles
F/N: LLDR003
F/ N : LLV3EP2
Orange Crescent
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.
SERVICE ACCESS PA NEL
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.
F/N: LLTB026
Right Panel
(Valve Compartment)
Radiant Tube(s)Combustion Chamber
16” Burner Tube
Left Panel
(Fan Compartment)
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 (orange)
F/N: LL01 - Clearance Safety Tag
(Affix adjacent to heater’s thermostat)
F/N: LLV2EP9

5
RHT Series 1.0 Safety • Clearance to Combustibles
Chart 1.1 • Clearance to Combustibles in Inches (see Figure 1.1 for Mounting Angles)
The stated clearance to combustibles represents a surface temperature of 90°F (32°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
assure that adjacent materials are protected from degradation.
Figure 1.1 •Mounting Angles
*
Heaters mounted on an angle between 0° to 45° must maintain clearances posted for 0° or 45°; whichever is greater.
45° Mounting Angle
0° Mounting Angle
with 1 Side Shield
(P/N: SSE)
0° Mounting Angle
with 2 Side Shields
(P/N: SSE)
Front Behind
Below
Top
Front Behind
Below
Top
Side Side
Below
Top
0° Mounting Angle
Side Side
Below
Top
Model Number
Mounting
Angle*
Side
Top BelowFront Behind
RHT-(65, 75)[N, P]-(20, 30, 40) 0° 99660
45° 39 810 60
with 1 side shield 0° 29 8 6 60
with 2 side shields 0° 99660
20 ft. from burner 0° 77630
RHT-100[N, P]-(30, 40) 0° 14 14 666
45° 39 810 66
with 1 side shield 0° 29 8 6 66
with 2 side shields 0° 16 16 666
20 ft. from burner 0° 77630
RHT-125[N, P]-(40, 50) 0° 20 20 676
45° 58 8 10 76
with 1 side shield 0° 42 8 6 76
with 2 side shields 0° 20 20 676
20 ft. from burner 0° 77630
RHT-150[N, P]-(40, 50, 60) 0° 24 24 681
45° 58 8 10 81
with 1 side shield 0° 42 8 6 81
with 2 side shields 0° 23 23 681
20 ft. from burner 0° 11 11 644
RHT-175[N, P]-(50, 60) 0° 34 34 692
45° 63 810 92
with 1 side shield 0° 50 8 6 92
with 2 side shields 0° 30 30 692
20 ft. from burner 0° 11 11 644
RHT-200[N, P]-(50, 60) 0° 41 41 694
45° 63 810 94
with 1 side shield 0° 54 8 6 94
with 2 side shields 0° 30 30 694
20 ft. from burner 0° 11 11 644

6
RHT Series
2.0 Installation
2.0 Installation • Electrical Requirements
WARNING
!
!
Improper installation, adjustment, alteration, service or maintenance can cause property
damage, serious injury or death. Read and understand, the installation, operating and
maintenance instructions thoroughly before installing or servicing this equipment. Only
trained, qualified gas installation and service personnel may install or service this equipment.
Not for residential use! Do not use this heater in the home, sleeping quarters, attached
garages, etc. Installation of a commercial tube heater system in residential indoor
spaces may result in property damage, serious injury or death.
NOTICE
• 120 Volt - 60 Hz., single phase, 3-wire.
• 24V thermostat connection.
• Starting current 1.7 amps
• Running current 1.1 amps
Electrical Requirements
Connecting the thermostat with a voltage other than 24V may damage the heater. The RHT Series
requires a 24V connection to the thermostat. The RHT Series is equipped with an internal relay board. A
field supplied external transformer must be installed. See wiring diagram (Figures 2.1A-B).
Instructions for the following are detailed in the Tube Heater General Manual:
• Design considerations
• Hanger suspension and placement
• Tube layout and assembly
• Burner control box suspension
• Reflectors (and accessories)
• Venting and combustion air intake
• Gas requirements
• Baffle assembly
Note: Electronic versions of all manuals are available at www.universalray.com
Gas Requirements
Type of Gas Required Manifold
Pressure
Minimum Inlet
Pressure
Maximum Inlet
Pressure
Natural 3.5 Inches W.C. 5.0 Inches W.C. 14.0 Inches W.C.
Propane 10.0 Inches W.C. 11.0 Inches W.C. 14.0 Inches W.C.
IMPORTANT: Consult the Tube Heater General Manual for gas connection requirements.

WARNING
!
7
RHT Series 2.0 Installation • Wiring
Electric Shock
Field wiring to the tube heater must be connected and grounded in accordance with national,
state, provincial, local codes and to the guidelines in the Tube Heater General Manual and
Series Insert Manual. In the United States refer to the most current revisions to the ANSI/NFPA
70 Standard and in Canada refer to the most current revisions to the CSA C22.1 Part I Standard.
Wiring
THERMOSTAT
BURNER BOX
(observe polarity)
120 Volt Power
L1 N
PANEL GROUND
Additional wire needed on
thermostats requiring
constant power.
24VAC High
LowN
NOTE: If optional black
power cord is installed,
then L1 is brown or
black and Neutral is blue
or white.
12
LO HI
1/4” spade
terminals required
(as supplied)
120VAC
24VAC
EXTERNAL
TRANSFORMER
(Field Supplied)
L1
N(observe polarity)
120 Volt Power
Figure 2.1 •Field Wiring Diagrams
A. Single Heater, Single Thermostat.
B. Multiple Heaters, Single Thermostat.
12
LO HI
12
LO HI
BURNER CONTROL BOX
1 2
LO HI
BURNER CONTROL BOX
BURNER CONTROL BOX
L1
N
PANEL GROUND
120 VAC
(Observe polarity)
PANEL GROUND
PANEL GROUND
NOTE: If optional yellow control cord is
installed, then the following wire colors apply:
Neutral = Green
Low = White
High = Black
NOTE: If optional black power
cord is installed, then:
L1 is brown or black
Neutral is blue or white.
Three 1/4” spade
terminals required
(as supplied)
Additional wire needed on thermostats
that require constant power.
EXTERNAL TRANSFORMER
(Field Supplied)
120VAC
24VAC
Orange
Label
Orange
Label
Orange
Label
24V High
LowN
THERMOSTAT
120 VAC
(Observe polarity)
120 VAC
(Observe polarity)
N
N
N
120VAC Power (observe polarity)

8
RHT Series
2.0 Installation • Wiring
Before field wiring this appliance - Check existing wiring; replace if necessary.
Note: If any of the original wire supplied with the appliance must be replaced, it must be replaced with
wiring material having a temperature rating of at least 105° C.
Figure 2.2 • Internal Wiring Diagrams
A. RHT-Ladder Diagram
B. RHT Block Diagram
NEUTRAL THERMOSTAT NEUTRAL VALVE GROUND
HIGH VOLTAGE
BLOWER
MOTOR
L1 120VAC
N
LIGHT
T- STAT TERMINAL
GAS VALVE
PRESSURE
SWITCH
P
M
H
ELECTRODE
ASSEMBLY
24V
120V
BKBK
RBK BK
BL
BK BK
R
W
BL
O
R
W
G
Y
BL
BK
W
Y
R
HIGH
RELAY
LOW
RELAY
HI M
C C
HI M
C C
NEUTRAL THERMOSTAT NEUTRAL VALVE GROUND
HIGH VOLTAGE
COM
NO NC
+
120V-24V TRANSFORMER
GAS VALVE
N.O. PRESSURE
SWITCH
120VAC
BURNER
Y
O
R
LIGHT
N
BK
BL
Y
W
W
R
BK
BK
BL
RO
G
Y
BK
BK
BK
W
BK
BK
ELECTRODE
Y
LOW
RELAY
HIGH
RELAY
COM
NO NC

9
RHT Series 2.0 Installation
This page intentionally left blank.
There are no alternative wiring diagrams for the RHT Series

10
RHT Series
2.0 Installation • Product Specifications
Model
Number
Gas Type
(Select One)
BTU/h
High Fire
BTU/h
Low Fire
Tube
Length
36”
Baffle
Sections
Weight
(lbs.)
Typical
Mounting
Heights
Tube Package Options
(see Chart 2.2)
Hot-Rolled Aluminized
RHT-65-20
Nat or Prop 65,000 50,000 20' 5 120 9' to 14' TPK-B TPK-H
RHT-65-30
Nat or Prop 65,000 50,000 30' 4 160 10' to 15' TPK-D TPK-I
RHT-65-40
Nat or Prop 65,000 50,000 40' 2 190 11' to 18' TPK-F TPK-K
RHT-75-20
Nat or Prop 75,000 50,000 20' 5 120 10' to 15' TPK-B TPK-H
RHT-75-30
Nat or Prop 75,000 50,000 30' 4 160 11' to 18' TPK-D TPK-I
RHT-75-40
Nat or Prop 75,000 50,000 40' 2 190 11' to 18' TPK-F TPK-K
RHT-100-30
Nat or Prop 100,000 65,000 30' 5 160 12' to 20' TPK-D TPK-I
RHT-100-40
Nat or Prop 100,000 65,000 40' 4 190 12' to 20' TPK-F TPK-K
RHT-125-40
Nat or Prop 125,000 82,000 40' 4 190 13' to 23' TPK-F TPK-K
RHT-125-50
Nat or Prop 125,000 82,000 50' 4 235 15' to 27' T PK- F, A TPK-K,G
RHT-150-40
Nat or Prop 150,000 100,000 40' 4 190 14' to 25' TPK-F TPK-K
RHT-150-50
Nat or Prop 150,000 100,000 50' 4 235 15' to 27' T PK- F, A TPK-K,G
RHT-150-60
Nat or Prop 150,000 100,000 60' 2 265 16' to 30' TPK-F,C TPK-K,H
RHT-175-50
Nat or Prop 175,000 125,000 50' 2 235 16' to 30' TP K- F, A TPK-K,G
RHT-175-60
Nat or Prop 175,000 125,000 60’ 2 265 16’ to 30’ TPK- F,C TPK-K,H
RHT-200-50
Nat or Prop 200,000 145,000 50’ 2 235 17’ to 35’ T PK- F, A TPK-K,G
RHT-200-60
Nat or Prop 200,000 145,000 60’ 2 265 17’ to 35’ TPK- F,C TPK-K,H
Chart 2.1 • Specifications
Specifications
Package ID Description Weight
TPK-A 1) 10 ft. Hot-Rolled Steel Tube 35 lbs.
TPK-B 1) 10 Ft. Aluminized and 1) 10 ft. Hot-Rolled Steel Tube 70 lbs.
TPK-C 2) 10 ft. Hot-Rolled Steel Tubes 70 lbs.
TPK-D 1) 10 Ft. Aluminized and 2) 10 ft. Hot-Rolled Steel Tubes 110 lbs.
TPK-E 1) 10 Ft. Aluminized and 3) 10 ft. Hot-Rolled Steel Tubes 145 lbs.
TPK-F 1) 10 Ft. Titanium Stabilized 1) 10 Ft. Aluminized and 2) 10 ft. Hot-Rolled Steel Tubes 145 lbs.
Package ID Description Weight
TPK-G 1) Aluminized Steel Tube 35 lbs.
TPK-H 2) Aluminized Steel Tubes 70 lbs.
TPK-I 3) Aluminized Steel Tubes 110 lbs.
TPK-K 1) Titanium Stabilized and 3) Aluminized Steel Tubes 145 lbs.
Tube packages include corresponding quantity of aluminum reflectors. All Aluminized and titanium
stabilized steel tube are black coated. Hot-Rolled steel tube are uncoated. Reference Chart 2.1 above to
determine correct burner and tube combinations for burner model.
Chart 2.2 • Tube Packages

Tube Installation Sequence
11
RHT Series
Figure 2.4 •Tube Installation Sequence
2.0 Installation •Tube Sequence •Heater Length
Important! The combustion chamber & radiant tube sections must be installed in the following order:
Key
*Aluminized steel (50,000 to 125,000 BTU/H burner models), Titanium stabilized aluminized steel (150,000
to 175,000 models). NOTE: Refer to the Tube Heater General Manual, Chart 3.6 (page 23) for secured
reflector joints.
Standard Tube Clamp
Stainless Steel Tube
Clamp (P/N: TP-220)
175-200 MBH models only - Located
between 1st and 2nd 10 ft. tube sections.
Baffle Location
Burner Control Box with
16” Burner Tube
Primary Combustion
Chamber Tube*
Secondary Aluminized Steel
Combustion Chamber
(150-175 MBH models only)
Aluminized or Hot-rolled Steel
Radiant Emitter Tube
20 Foot
50 Foot
60 Foot
30 Foot
40 Foot
Stainless steel clamp location on 150-200 MBH models (P/N: TP-220).
Aluminized steel secondary combustion chamber location on 150-200 MBH models.
Stainless steel clamp location on 150-200 MBH models (P/N: TP-220).
Aluminized steel secondary combustion chamber location on 150-200 MBH models.
Aluminized steel secondary combustion chamber location on 150 MBH models.
Stainless steel clamp location on 150 MBH models (P/N: TP-220).

12
RHT Series
3.0 RHT Series Operation • Sequence of Operation • Thermostat • Diagnostics
3.0 Operation
Sequence of Operation
Two voltages (120VAC supply and 24VAC control) must be supplied to the RHT Series burner control box
for proper operation.
Starting Circuit: Upon a call for heat, the low fire relay is energized by 24VAC from the thermostat. The
relay is closed sending 120VAC to the blower beginning the sequence of operation.
Air pressure generated by the blower causes the normally open pressure switch to close, sending
power to the ignition module. After a seven-second pre-purge, the spark electrode, transformer and
gas valve are simultaneously energized. The trial for ignition is 15 seconds.
Single Stage Running Circuit: After ignition, the electrode monitors burner flame. If sense of flame is
lost, the control immediately disrupts power to the gas valve and then re-cycle the unit (identical to
the starting sequence). If flame sense is not established within 15 seconds, the heater will attempt
two (2) additional ignition sequences before proceeding to lockout mode. The control can be reset
by briefly interrupting the power source.
Two Stage Running Circuit: High fire operation is actuated by the thermostat sending a 24VAC signal to
the high fire relay. The energized coil of the relay is closed, allowing 24VAC to continue onto the
high fire of the gas valve.
Thermostat
NOTE: Different thermostats operate according to their particular features. Refer to thermostat
specifications for details.
RHT Series heaters require a 24V, two-stage thermostat to operate. The burner control box is equipped
with either a round terminal strip that accepts three (3) 1/4-inch insulated female spade terminals or a
36-inch yellow 24VAC control wire. Do not supply 120VAC to the 24VAC connection.
Standard Configuration
With relay board (orange terminal label*):
• Required when a single thermostat controls two or more burner control boxes or when heaters are
common vented.
NOTE: Units with a relay board installed must have an external transformer (field supplied), see wiring
diagram. (Figure 2.1B) Stainless steel heaters, with a relay board, are indicated with the suffix ‘D’ on
the heater’s rating plate.
*A yellow control wire replaces the external terminal plug on stainless steel models or models with water
resistant upgrades.

13
RHT Series 3.0 Operation • Diagnostics
Diagnostics
Lockout:
The controls will automatically lockout the heater system when an external or system fault occurs. There
are two types of lockout:
Soft Lockout: The heater will attempt to light three times. In the event of a failed attempt to light, (gas
pressure, valve, no flame sense etc.), the heater will enter a soft lockout period for 30
minutes and then attempt to light three more times before entering Hard Lockout mode.
Hard Lockout: If proof of flame is not established, a component failure occurs or blockages are evident,
the heater will enter hard lockout. If lockout occurs, the control can be reset by briefly
interrupting the power source.
Figure 3.1 • LED Operation Indicator Lights
Light 1(amber)
Indicates High
Fire Mode
Light 2 (amber)
Indicates Low
Fire Mode
Operational Indicator Lights

14
RHT Series
4.0 Troubleshooting Guide
4.0 Troubleshooting Guide
Is the valve switch in
the ON position?
Check that gas pressure is within
minumum and maximum inputs
as indicated on the heater’s rating
plate. Is gas pressure ok?
Does the fan
blower turn on?
Is the blower
obstructed?
Turn up thermostat.
Is the power at the
heater 120VAC?
No
Remove obstruction
and lubricate blower.
Does the igniter
spark?
Is the igniter
physically
damaged?
No
Yes
Replace igniter.
Yes
No
Find the source of the
electrical problem.
Check the gap on the
igniter. Is the gap between
3/16 in. and 1/4 in.?
No
Adjust gap.
Yes
No
Yes
No
During the ignition
trial, does the gas
valve open?
Yes
Test for 24VAC at the gas
valve during valve opening
(typically 10 seconds after
power to the heater). Is
there 24VAC to the valve?
No
Yes
Is 120VAC being sent
to the transformer?
No
Does the burner light?
Yes
Correct problem.
Replace
gas valve.
Yes
No
Yes
Continued on page 16.
Yes
No
Switch to the ON
position.
Yes
The circuit board and/
or wiring harness
could be faulty. These
should be replaced.
No
No
Yes
Replace 24VAC
transformer.

NOTICE
Bypassing any switch is intended for testing purposes only. Do not leave switch bypassed
during normal operation or the heater’s built-in safety mechanisms will be compromised.
15
RHT Series 4.0 Troubleshooting Guide
Correct wiring or
replace relay.
The blower is faulty
and must be replaced.
Is there 120VAC coming to the
fan from the low fire relay?
Yes
Is the inlet or outlet of
the unit obstructed? i.e.
ice, birds nest, dirt, etc.
Check for loose wiring
or restrictions in hose
connections to the pressure
switch. Are they ok?
Remove obstruction
No
Yes
No
Repair wiring or hose
connections.
No
The heater is equipped with a safety differential
pressure switch. The switch is a normally
open switch and is located in the air chamber.
Temporarilly place a jumper across the terminal of
the switch. Does the igniter spark?
Yes
Replace the pressure switch after verifying the
following:
• Baffle(s) is in the tube farthest from the burner.
• Heater, blower, squirrel cage, intake and
exhaust are clean and free from dirt and
obstructions.
• The 4 in. dia. air intake pipe does not exceed
20 ft. and/or two elbows.
• There is not a negative pressure experienced
at the area of air intake (i.e. attic space, high
winds, very tight buildings, etc.)
If any of the above were occurring, please
address the problem.
Yes
While the switch is
temporarily bypassed,
check for 120VAC from
the switch to the circuit
board. Does 120VAC
enter the circuit board?
No
Replace circuit board.
Faulty wiring.
Repair or
replace wiring.
Yes
No
Key
Start
Question
Process
Question
Corrective
Action

16
RHT Series
4.0 Troubleshooting Guide
Does the burner
stay on briefly and
then shut off?
Continued from page 14.
Check the gap on the
igniter. Is the gap between
3/16 in. and 1/4 in. ?
Check that gas pressure is within minimum and maximum inputs as
indicated on the heater’s rating plate. Is gas pressure ok?
Yes
Check that gas supply pressure meets
minimum and maximum requirements.
The following can cause the heater to shut down:
• Improper grounding.
• High winds.
• Taking combustion air from the attic.
• Dirty environment.
• Baffle not located properly.
• Fluctuating gas pressure.
No
Adjust gap.
Does the burner
stay on?
No
Does the heater stay on
until the call for heat ends?
Yes
Yes
Troubleshooting ends.
Is the heater properly
grounded? Is the
polarity correct?
Yes
No
No
Yes
Yes
No
Correct problem.
No
Flame Current Check: Single Spark & Sense
To measure flame current, disconnect input voltage, then insert a 0-50 μA DC meter and capacitor in series with the
spark electrode as shown below. Reconnect input voltage and initiate call for heat. After sparking is complete and
flame is established, meter should read 1.0 μA or higher while flame is established. If meter reads below “0” on the
scale, meter leads are reversed. Disconnect power and reconnect meter lead for proper polarity.

17
RHT Series
Check that gas pressure is within
minumum and maximum inputs
as indicated on the heater’s rating
plate. Is gas pressure ok?
No
Differential switch may be faulty or there
is a restriction in the exhaust or intake.
Correct problem.
Yes
Check the gap
on the igniter.
Is the gap between
1/8 in. and 3/16 in.? Adjust gap.
No
If heater does not enter high fire mode, check the following:
Is there 24VAC across
the red wire on the
relay board and ground
on the circuit board?
Check for 24VAC across the
COM and HIGH on the 24VAC
terminal. Is there 24VAC?
No
Yes
Repair or replace faulty
wiring or thermostat
Replace
relay.
Replace
gas valve.
Yes
No
NOTE: To confirm the heater is not in high-fire mode, check the manifold pressure (3.5 inches W.C. natural gas or 10
inches W.C. propane gas). If the indicator light is not illuminated, it is faulty and should be replaced. If the manifold
pressure ranges from 2.3 to 2.8 inches W.C. natural gas (model dependent) and 6.0 to 7.5 inches W.C. propane gas
(model dependent), the heater is in low fire mode and the troubleshooting steps described below should be followed.
Were the gas lines
purged of air?
Yes
No
Purge gas lines.
Check for damaged
insulation or loose
terminals on the
high voltage spark wire.
Is it ok?
Is the differential
switch in the
closed position?
Differential switch may be
faulty or there is a restriction
in the exhaust or intake.
No
Yes Yes
Electrode sensing may be
faulty or flame signal may
be weak. Check that heater
is operating at proper gas
pressure as indicated on
the rating label. Clean or
replace electrode if needed.
Check the spark
electrode. Is the
ceramic cracked
or loose?
Yes
Replace electrode.
No
Replace.
No

18
RHT Series
5.0 Parts • Heater Components and Parts List
5.0 Parts
Figure 5.1 •Burner Assembly Components
Chart 5.1 • Parts List
* 6 feet total required to cover outer edges of the burner control box.
221
583
11
3055
321
1
NOPS
207
97
218
56C
55A
302, 302A
3051
3052
70
828
114
31B
33B
83
212
208B
TP-3140, TP-3141
223 204
201B or 3072
303
12
9
10
217
5
380, 580
15
14
16
21B
304, 804
76
31B
13
17
301
67
331
84
66
Part No. Description Part No. Description
TP-1 Control Box Cover TP-31B Control Box Mounting Bracket
TP-5 Flange Gasket TP-33B 1/2” Shut-Off Ball Valve / Inlet Tap
TP-9 Conduit Coupling TP-55A Fan Blower
TP-10 Conduit 4” x 1/2” TP-56C 1/4” Atmospheric Tube (Vinyl)
TP-11 Ignitor Box TP-65I 36” Interlocking Turbulator Baffle
TP-12 Ignitor Box Cover TP-66 2” x 4” Outlet Box
TP-13 8 x 1/2” Self-Drilling Screw TP-67 2” x 4” Outlet Box Cover
TP-14 Sight Glass Gasket TP-70 Control Box Cover Gasket (per foot*)
TP-15 Sight Glass TP-76 Rubber Grommet
TP-16 Sight Glass Washer TP-82 Reflector Center Support (RCS)
TP-17 Sight Glass Kit TP-83 24” Stainless Steel Flexible Gas Connector
TP-19B 4” Wire Hanger with Tension Spring TP-84 1/2” Female / Male Flare Fitting
TP-20C 120” Aluminum Reflector TP-97 1/4” x 1/4” Brass Int./Ext. Atmos. Barb Fitting
TP-21B 4” Standard Tube Clamp TP-105 Aluminum Reflector End Cap
TP-26A 10 ft. Coated-ALUM Combustion/Radiant Tube TP-106 Reflector End Cap Clips (8 pcs.)
TP-26B 10 ft. Coated-AL-TI Combustion Tube TP-113 Reflector Tension Spring
TP-26C 10 ft. Uncoated Hot-Rolled Steel Radiant Tube TP-114 Plastic Air Orifice w/ Screen (consult factory)
1325
550
826

19
RHT Series 5.0 Parts • Heater Components and Parts List
Figure 5.2 •Tube & Reflector Components
19B
106
105
26A, 26B
21B, 220
20C
82
26A, 26C
65I
113
Part No. Description Part No. Description
TP-201B Burner (Tan) - consult factory TP-550 Spark Transfer Wire - Orange
TP-204 Gas Orifice (consult factory) TP-580 16” Burner Tube with Flange (with fittings)
TP-207 Pressure Switch Mounting Bracket TP-583 DSI Igniter Plate
TP-208B Gas Valve Mounting Bracket TP-804 Burner Control Box Outer Shell
TP-212 1/2” x 3” Pipe Nipple TP-826 40VA Transformer
TP-217 Pressure Switch Barb TP-828 Yellow Operational Indicator Light
TP-218 Differential Switch Vinyl Exhaust Sensing Tube TP-1325 24VAC Switching Relay (Qty 2)
TP-220 Stainless Steel Tube Clamp (150-200MBH) TP-3140 Natural Gas Valve Assembly
TP-221 Spark Igniter Mounting Bracket Gasket TP-3141 Propane Gas Valve Assembly
TP-223 Gas Manifold TP-NOPS Normally Open Pressure Switch (see below)
TP-301 Center Divider Panel TP-264B Differential Pressure Switch 50-100 MBH
TP-302 End Panel, Left TP-264E Differential Pressure Switch 125-150 MBH
TP-303 End Panel, Right TP-264D Differential Pressure Switch 175 MBH
TP-304 Burner Control Box Outer Shell TP-3051 DSI Circuit Board
TP-321 Ignition Plate Gasket TP-3052 Wiring Harness
TP-331 Green Self Tap Ground Screw TP-3055 Spark Igniter Electrode
TP-380 16” Burner Tube with Flange (no fittings) TP-3072 Burner (Green) - consult factory

20
RHT Series
5.0 Parts •Kit Contents Check List
Part No. Description 20 ft. 30 ft. 40 ft. 50 ft. 60 ft.
TP-19B 4” Hanger w/ Tension Spring 34567
TP-21B 4” Tube Clamp 2345* 6*
TP-25 1/4” Female Spade Terminal** 33333
TP-33B 1/2” Shut-Off Valve & Inlet Tap 11111
TP-82 4” Reflector Center Support 23456
TP-83 24” S.S. Flexible Gas Connector 11111
TP-105 Reflector End Cap 22222
TP-106 Reflector End Cap Clips 88888
LIOGTa General Tube Heater Manual 11111
LIORHT RHT Series Insert Manual 11111
Filled By:
Chart 5.2 • Kit Contents for RHT Series - Reference the length column for your model.
TP-19B 4” Hanger with
Reflector Tension Spring
TP-105 Reflector End Cap
TP-21B* 4” Tube Clamp
TP-106
Reflector
End Cap Clips
TP-33B 1/2” Shut-Off Valve
(Ball Valve & Inlet Tap)
TP-83 24” Stainless Steel
Flexible Gas Connector
Kit Contents Check List
RHT Series Kit Contents
TP-82 4” Reflector
Center Support (RCS)
* NOTE: One 4” stainless steel tube clamp (P/N: TP-220) is provided for each 150,000 - 200,000 BTU model.
Place as shown on page 11.
** Not included with models installed with yellow control cord.
© 2014 Detroit Radiant Products Co.
21400 Hoover Road • Warren, MI 48089
Phone: [phone] Fax: [phone]
www.universalray.com • [e-mail] Printed in U. S. A.
Approvals
• CSA.
• Indoor approval.
• Outdoor approval with OD-Kit.
• Commercial approval.
Limited Warranty
• 1 year - Burner box components.
• 5 years - Combustion and radiant tubes.
• 10 years - Stainless steel burner.
• See page 36 of the General Tube Heater Manual
for terms and conditions.
TP-25** 1/4”
Female Spade
Terminal
Tube Heater
General Manual and
RHT Series Insert Manual
F/N: LIOGTa & LIORHT