BRANT RADIANT UH User Manual

Detroit Radiant Products Company

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UH Series Manual

Installation, Operation,

Maintenance and Parts

The UH Series heater is a gas-fired unit heater. This manual provides specific information related to the
UH Series models. All persons involved with the installation, operation and maintenance of the heater
system must read and understand the information in this manual.

Improper installation, adjustment, alteration, service or maintenance can cause
property damage, serious injury or death. Read and understand the installation,
operating and maintenance instruction 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,
and fire or property damage.

Do not store or use gasoline or other flammable vapors and liquids in the vicinity of
this or any appliance.

Do not use this heater in indoor living or sleeping quarters! Installation of this unit in
a residential indoor living space may result in property damage, serious injury,
asphyxiation or death.

For Your Safety

If you smell gas:

• Open windows.

• Do not touch any electrical switch.

• Extinguish any open flame.

• Do not use any phone in your building.

WARNING

• Immediately call your gas supplier from a neighbor’s phone.

• Follow the gas supplier’s instructions.

• If you cannot reach your gas supplier, call the fire department.

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)

LIOUH-Rev. 05313

Print: 1M-8/13_r2-5/14 (CDS)

Table of Contents

UH Series

Contents

1.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Overview ...................................................................... 3

Heater Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Initial Installation Considerations and Pre-Checks ...................................... 4

Product Specifications ........................................................... 5

Safety Labels and Their Locations .................................................. 6

2.0 Safety . . ................................................................... 8

Warning Symbols ............................................................... 8

Applications ................................................................... 9

Standards, Certifications and Government Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Clearance to Combustibles ....................................................... 12

3.0 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Configuring the Support Brackets................................................... 13

Hanging the Unit Heater .......................................................... 14

Suspending the Unit Using Lag Bolts/Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Suspending the Unit by Threaded Rod............................................... 14

Pre-Configuration for 180° Installation ............................................... 15

Rotated 180° Installation .......................................................... 15

Rotating the Air Louvers .......................................................... 16

Rotating the Service Access Door Panel Handle ....................................... 16

Recommended Mounting Heights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Gas Supply Installation Instructions ................................................. 17

Leak Testing ................................................................... 20

Electrical Requirements and Wiring Diagrams ......................................... 21

Internal Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Field Wiring Supply Voltage ....................................................... 22

Thermostat Connection .......................................................... 24

Thermostat Location ............................................................. 25

Venting ....................................................................... 26

Replacing Existing Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

General Venting Requirements..................................................... 27

Vertical Venting (Category I)....................................................... 29

Horizontal Venting (Category III).................................................... 30

Common Venting (Category I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Concentric Venting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Combustion Air Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Separated Combustion Systems ................................................... 34

Room Air Combustion Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Unit Start-Up (Commissioning)..................................................... 37

Pre-Start Up Checks............................................................. 37

Verify Proper Inlet Pressure ....................................................... 38

Verify Manifold Pressure .......................................................... 39

Prior to leaving the Job Site ....................................................... 40

High Altitude Operation........................................................... 41

4.0 Operation ................................................................... 43

Sequence of Operation........................................................... 43

Shutdown Procedures............................................................ 44

Troubleshooting Guide ........................................................... 46

5.0 Maintenance................................................................. 50

Limited Warranty Terms and Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Heater Assembly Components and Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Kit Contents ................................................................... 56

2

UH Series

1.0 Introduction • Overview • Heater Components

1.0 Introduction

Overview

The intent of this manual is to provide information regarding safety, design guidelines, installation,
operation and maintenance of the UH Series gas-fired unit heater. You must read and understand the
instructions and all safety warnings before installing the gas-fired unit heater. This manual is property of
the owner, and must stay with the owner or unit after 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 the entire heater contents included with your
unit. Refer to page 56 for a list of the kit contents for your heater. Materials not included with the unit
(e.g. screws, vent material, threaded rod, etc.) are the responsibility of the installer. Notify your product
representative or the factory of any discrepancy of missing items prior to installing the unit.

Figure 1.1 • Heater Subcomponents

Gas Valve

Draft

Inducer

Pressure

Switch

Rollout

Switches

Flame

Louvers

Flame Sensor

High Limit
Switch

Spark Igniter

Control

Transformer

Direct Spark
Igniter Board

3

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1.0 Introduction • Initial Considerations and Pre-Checks

UH Series

Initial Installation Considerations and Pre-Checks

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 a trained, qualified installation or service personnel may install or
service this equipment.

Placement of the heater is influenced by many factors. Aside from safety factors, considerations for
the general space and heating requirements, availability of gas and electrical supply, and proximity of
possible vent locations are a few examples of factors that should all be considered.

Inspect and evaluate the location of the heater to ensure that the structural support is adequate to
support the unit’s weight. The unit must be installed in a horizontally level position to ensure proper
operation. To reduce noise attenuation along the structure caused by vibration of the unit, the heater
should be installed within 15 feet of a primary building support. In the cases where this installation is
not practical or feasible, the use of spring vibration isolators may be used, so long as they are rated for
use of the unit’s weight (see Chart 1.1).

Adequate space around the heater must also be considered in order to maintain the published
minimum clearance to combustibles and recommended service clearances.

When designing a unit heater system, consider the following:

• Has the building’s heat loss been evaluated?

• Does the design meet the needs of the space?

• Have the recommended mounting heights been observed?

WARNING

Do not locate any gas-fired units in area where chlorinated, halogenated, or acid vapors are
present in the atmosphere. These substances can cause premature heat exchanger failure due
to corrosion, which can cause property damage, serious injury or death.

4

UH Series

1.0 Introduction • Product Specifications

Product Specifications

The UH Series unit heater is a single input warm air heater with an average thermal efficiency of 80%,
unless otherwise indicated on the rating label. All units are to be supplied with single-phase 60 Hz
120VAC power. The exterior of all models are finished with industrial-grade colored enamel. For specific
information on each model, see Chart 1.1, below.

Chart 1.1 • Specifications

Model Number

UH-30

UH-45

UH-60

UH-75

Cabinet Number

Gas Type

Nat

1

or LP

Nat

1

or LP

Nat

2

or LP

Nat

2

or LP

BTU/h Input

30,000 24,000

45,000 36,000

60,000 48,000

75,000 60,000

BTU/h Output

Physical

28” W

17” D
12” H

28” W

17” D
12” H

28” W

17” D
17” H

28” W

17” D
17” H

Dimensions

Standard Weight

68

Lbs.

68

Lbs.

88

Lbs.

88

Lbs.

Recommended

8'-12'

8'-14'

10'-16'

10'-18'

Mounting Height*

Gas Connection

1/2"

NPT

1/2"

NPT

1/2"

NPT

1/2"

NPT

Vent Connection

Inlet Connection

3” 3” CCW

3” 3” CCW

4” 4” CCW

4” 4” CCW

Axial Fan Rotation

120

VAC

120

VAC

120

VAC

120

VAC

Primary Voltage

Thermostat

Voltage

24

VAC

24

VAC

24

VAC

24

VAC

* Recommended mounting heights are provided as a guideline. Actual conditions may dictate variations
from the above data. Clearance to combustibles must always be maintained.

Figure 1.2 • Dimensional Data (see Chart 1.1 for Physical Dimensions)

Top View

ReaR View

D

H

ww

5

1.0 Introduction • Safety Labels and Their Locations

UH Series

Safety Labels and Their Locations

Product safety signs or labels should be replaced by the product user when they are no longer legible.
Contact either your local distributor or product manufacturer for obtaining replacement signs or labels.

F/N: LLUH003 - Mounting Notice

Front View

Rear View

F/N: LLV3EP6 - Gas Valve and

Pressure Switch Operation

SEPARATED COMBUSTION SYSTEM UNIT HEATER

MODEL NUMBER

NUMÉRO DE MODÈLE

TYPE OF GAS

TYPE DE GAZ

HEAT INPUT

DEBIT CALORIFIQUE

HEAT OUTPUT

REDENMENT

VENT CATAGORY

ÉVENT CATÉGORIE

THIS DESIGN COMPLIES WITH UNIT HEATER STANDARD:

ANSI Z83.8b-2006 • CSA2.6B-2006 UNIT HEATER

TOP

HAUT

DETROIT RADIANT PRODUCTS COMPANY
21400 HOOVER ROAD - WARREN, MI 48089
[phone] - www.drp-co.com

AÉROTHERME À SYSTÈME DE COMBUSTION ISOLÉ

SERIAL NUMBER

NUMÉRO DE SÉRIE

UH-30N

NATURAL

30,000
24,000

CATAGORY III

DÉGAGEMENT MINIMUM POUR MATIÉRES COMBUSIBLES

RIGHT SIDE

BOTTOM

BAS

COTÉ DROIT

INCH

INCH

1 1 1 6

1

YYMMREPCSHIPPE#### 09/12

MANIFOLD PRESSURE

PRESSION A LA TUBULURE D'ALIMENTATION

MAXIMUM INLET PRESSURE

PRESSION D'ALIMENTATION MAXIMALE

BTU/h

MINIMUM INLET PRESSURE FOR PURPOSE OF ADJ.

PRESSION D'ALIMENTATION EN GAS MIN. ADMISE

BTU/h

ORIFICE SIZE

DIM DE L'INJECTEUR

SAMPLE

MINIMUM CLEARANCE TO COMBUSTIBLE MATERIAL

LEFT SIDE

COTÉ GOUCHE

INCH INCH INCH INCH

INCHES W.C.

14.0

INCHES W.C.

INCHES W.C.

5.0

NATURAL GAS PROPANE GAS

D.M.S. D.M.S.

57

49

VENT CONNECTOR

CONNECTEUR D'AERATION

FOR COMMERCIAL / INDUSTRIAL USE.

FOR INDOOR USE ONLY.

VOLTAGE

AMPS

PHASE

FREQUENCY

LABEL REVISION

MADE IN U.S.A.

SERVICE ACCESS

COTÉ ACCÉDEZ

Rating Label (located inside of panel)

VERSION

1203.5

2.4

SINGLE

60

A

VAC

Hz

18

F/N: LLUH005
Vent Out

F/N: LLUH004
Air In

6

UH Series

1.0 Introduction • Safety Labels and Their Locations

F/N: LLWUH001 - Wiring Diagram

F/N: LLUH006
UH Vent Length Notice

F/N: LLUHCL001
For Your Safety

Service Access Door View

(Inside View)

F/N: LLUH001 - LED Status

7

2.0 Safety • Warning Symbols

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UH Series

2.0 Safety

Read and understand all safety information and warnings in this manual prior to installation, operation,
and maintenance of this unit heater. Warnings indicate a potentially hazardous situation which, if not
avoided, could result in death or injury.

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.

Warning Symbols

Safety is the most important consideration during installation, operation and maintenance of the unit
heater. You will see the following symbols and signal words when there is a hazard related to safety or
property damage.

CAUTION

NOTICE

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.

8

UH Series

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2.0 Safety • Applications

Applications

This is not an explosion proof heater. This heater may not be used in a Class 1 or Class 2 Explosive
Environment. Consult your local Fire Marshall, insurance carrier and other authorities for approval if the
proposed installation is in question.

Residential Garages

The UH Series unit heater is designed and approved for use in residential garage applications or
non-confined living space applications. If installed in a residential application, the unit must be installed
higher than 18 inches above the finished floor when measuring from the bottom of the unit. In addition,
the heater must be located or protected to avoid physical damage by vehicles.

WARNING

This unit is not to be used as a central heating furnace. This unit is not
designed for connecting to a ductwork system. Installing restrictive devices of
the inlet or outlet air discharge may result in premature failure of the
exchanger pipe, overheating of the appliance, or damage to the components.

Commercial / Industrial

The UH Series unit heater is 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 heater system. This
unit is certified for use as furnished by the manufacturer. Do not alter the fan or operate motors at a
reduced speed.

CAUTION

Installation of restrictive devices to the inlet or outlet of the fan motor may result in premature
failure of the exchanger pipe, overheating of the appliance, or damage to the components. Do
not attach ductwork, air filters, or poly-tubes to any UH Series unit heater.

9

2.0 Safety • Standards, Certifications and Government Regulations

UH Series

Standards, Certifications and Government Regulations

Installation of this gas-fired heater must conform with all applicable local, state and national
specifications, regulations and building codes. Contact the local building inspector and/or Fire Marshall
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 these Standards can be viewed or purchased at www.nfpa.org or www.scc.ca.

Chart 2.1 • Standard and Code Installation Guidelines • Building Type

Building

Type

Public

Garages

Aircraft

Hangars

Codes and Guidelines

Installation of this heater in public garages must conform to the following codes:

United States: Standard for Parking Structures NFPA 88A (latest edition) or the
Code for Motor Fuel Dispensing Facilities and Repair Garages
NFPA 30A (latest edition).

Canada: Refer to CAN/CGA B149.1: Installation Codes for Gas Burning Appliances
and applicable Standards for Public Garages.

Guidelines:

• 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.

Installation of this heater in aircraft hangars must be in accordance with the following
codes:

United States: Refer to Standard for Aircraft Hangars, ANSI/NFPA 409
(latest edition).

In Canada: Refer to Standard CAN/CGA B149.1 and applicable Standards for
Aircraft Hangars.

Guidelines:

• In aircraft storage and servicing areas, heaters shall be installed at least 10 ft. (3 m)
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 heaters for recurrent
maintenance purposes.

10

UH Series

Chart 2.2 • Standard and Code Installation Guidelines • Building Location

2.0 Safety • Standards, Certifications and Government Regulations

Building

Location

High

Altitude

Non-

Standard

BTU Gas

Chart 2.3 • Standard and Code Installation Guidelines • Building Aspect

Building

Aspect

Electrical

Guidelines

Installation of this heater is approved, without modifications, for elevations up to 2,000
feet (610 m) above MSL (sea level) in the United States. For elevations above 2,000
feet, the heater input must be derated. See page 41 for details on how to derate.

The type of gas appearing on the nameplate must be the type of gas used. Installation
must comply with national and local codes and requirements of the local gas company.

Guidelines:

Unless otherwise noted on the rating plate, this heater is designed and orificed to
operate on standard BTU gas. Contact the factory if utilizing non-standard BTU gas.

Codes and Guidelines

The heater must be electrically grounded in accordance with the following codes:

United States: Refer to National Electrical Code
Wiring must conform to the latest edition of National Electrical
Code®, local ordinances, and any special diagrams furnished.

Guidelines

®

, ANSI/NFPA 70 (latest edition).

Canada: Refer to Canadian Electrical Code CSA C22.1 Part 1 (latest
edition).

Venting

Applicable authorities governing the manufacturing or installation of this unit here include (but are not
limited to) the following organizations:

In the United States:

• NFPA 54 / ANSI Z223.1 – National Fuel Gas Code.

• ANSI Z83.8 / CSA 2.6 – Gas Unit Heater Construction Standard.

• ANSI/NFPA 70 - National Electric Code.

In the Canada:

• CAN/CGA B149.1-10 – Natural Gas and Propane Installation Code.

• ANSI Z83.8 / CSA 2.6 – Gas Unit Heater Construction Standard.

• C22.1 Part 1 – Canadian Electrical Code.

Venting must be installed in accordance with the requirements within this manual and
the following codes:

United States: Refer to NFPA 54/ANSI Z223.1 (latest edition), National Fuel
Gas Code.

Canada: Refer to CAN/CGA B149.1 Installation Codes for Gas Burning
Appliances.

11

!

2.0 Safety • Clearance to Combustibles

UH Series

Clearance to Combustibles

Clearance to combustibles is defined as the minimum distance that must exist between the specified
feature of the heater, and any combustible items. It also pertains to the distance that must be
maintained from moving objects around the unit heater. A recommended service clearance is defined
as the minimum distance that is needed to properly service the heater. When installing the unit heater,
clearances to combustible for the model heater must be maintained. Refer to Chart 2.4 to determine the
required distances for your model.

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 the heater.

Chart 2.4 • Clearances to Combustible Materials (in Inches) Residential Models

Top and

Unit Side Front

Clearance to Combustibles

Clearance to Allow Service

60 1 18 1 1 6

60 1 18 1 18 6

Bottom

Figure 2.1 • Clearance to Combustibles Diagram

FRONT VIEW

Top

Access

Side

Bottom

Access

Side

Vent

Connection

Non-Access
Side

Non-Access

Side Rear

Rear

Vent

Connection

SIDE VIEW

Top

Front

Bottom

12

UH Series

!

3.0 Installation • Configuring the Support Brackets

3.0 Installation

NOTICE

High humidity or saltwater atmospheres will accelerate heater corrosion and reduce useful life. Do not
install the heater in locations where water (in the form of rain, drips, or spray) could fall onto the gas
ignition components.

WARNING

Improper suspension of the unit 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.

Failure to maintain minimum clearance to combustibles may result in fire and/ or
explosion, property damage, serious injury or death. Always maintain minimum
clearances.

The unit is shipped ready for installation. The unit may be installed as shown in Figure 3.3 or inverted
180° depending on the desired location as governed by clearances, vent connection locations, air
direction, gas supply, electrical supply, and service accessibility. The standard installation is installed
how it was factory configured, with the controls on the left side of the heater (when looking at the front).

Configuring the Support Brackets

Standard Installation (Control Panel is on the Left Side)

1 For standard control access, remove the four (4) #10 sheet metal screws and mounting bracket

along the top edge of both the front and back of the unit.

2 Install the front bracket as shown in Figure 3.1 by aligning the screw holes on the bracket with the

screw holes on top of the edge of the unit.

3 Repeat this process for the opposite bracket on the back panel.

Figure 3.1 • Support Brackets

Mounting

Bracket

Mounting
Bracket

Sheet Metal
Screws

13

3.0 Installation • Hanging Heater • Suspending Unit with Lag Bolts/Screws or Threaded Rod

UH Series

Hanging the Unit Heater

To ensure proper operation, the heater must be installed in a level horizontal position. The units are
designed to be hung from the brackets (supplied) and must be field configured prior to hanging the unit.

The mechanism that suspends the heater from the brackets (e.g. lag screws, threaded rod, or threaded
pipe) must be adequate to support the weight of the unit (see page 5 for unit weights).

Suspending the Unit Using Lag Bolts/Screws

Determine the desired mounting points, and mark the locations for reference.

1

Using the hole spacing diagram (Figure 3.2), mark and prepare the structure mounting surface. If

2

necessary, weld blocks, drill holes, or install additional bracketing or steel channel.

NOTE: When bolting the unit directly to a wood truss, the recommended hardware is ¼”x 1-1/2”
(minimum) lag bolts with ½” washers. The unit must be supported by a minimum of four (4)
suspension points. Brackets are slotted to accommodate joists on 16 inch or 24 inch centers.

Raise the unit heater to the mounting location and secure it to the building structure using the

3

selected hardware. Ensure that the lag bolts are not stripped and are properly bearing the load of
the unit heater.

1 inch angle mounting brackets are slotted to accommodate joists on 16 inch or 24 inch center lines.

Figure 3.2 • Mounting Bracket Hole Spacing Diagram (in Inches)

0.54

0.45
.00

.00

1.3 0

0.50

4.45

2.88

6.03

9.18

7.6 0

10.50

13.91

12.33

17. 0 6

15.73

18.63

20.21

21.78

23.36

25.73

24.93

Suspending the Unit by Threaded Rod

Determine the desired mounting points, and mark the locations for reference.

1

Using the hole spacing diagram (Figure 3.2) mark and prepare the structure mounting surface. If

2

necessary, weld blocks, drill holes, or install additional bracketing or steel channel.

NOTE: The recommended hardware is 3/8”–16 threaded rod. The unit must be supported by a
minimum of four (4) suspension points.

Fasten beam clamp, screw hook, turnbuckle, steel channel, or other anchoring device to the

3

suspension points.

Determine the desired mounting height. Cut four Pieces of 3/8” -16 threaded rod of equal length in

4

which the heater will be hung. Ensure that the threads are not damaged during the cutting process.

Attach the threaded rod to the unit mounting brackets, securing with a top and bottom nut. A lock

5

washer is preferred, or a secondary jam nut may also be used.

14

UH Series

Attach threaded rod to prepared anchoring device. Adjust the threaded rod until the unit is level and

6

equal weight distribution is achieved. The threaded rod must be perpendicular with the unit heater.
Do not install threaded rods at an angle, as this can result in weakened structural integrity or undue
noise.

Figure 3.3 • Threaded Rod Support - Rear View

3.0 Installation • Rotated 180° Installation

Support Rods

Pre-Configurations for 180° Installation

Prior to installing the heater in an inverted position of 180° from the standard configuration, a few items
must be configured to accommodate this installation.

Rotated 180° Installation (Control Panel is on the Right side)

For 180° installations, remove the four (4) #10 sheet metal screws and mounting brackets along

1

the top edge of both the front and back of the unit.

Reinstall the screws into the panel, without attaching the brackets.

2

Along the opposite edge, remove the four (4) corresponding #10 sheet metal screws and affix the

3

brackets to the unit (the side that was originally the bottom now becomes the top.)

Proceed with suspending the unit normally as described here in the manual.

4

15

3.0 Installation • Rotating Air Louvers and Service Door Handle • Recommended Mounting Heights

UH Series

Rotating the Air Louvers

Remove the spring loaded air louvers from the front by compressing the spring, and swinging out

1

the louver from the mounting holes. Take care not to lose the spring.

Turn the louvers 180°, and insert the spring end in first. Compress the spring and swing in the other

2

end until it is securely in the correct mounting hole.

Adjust the louver direction so that they are in the desired position to direct the heated air downward

3

towards the floor. The louvers should not be adjusted beyond 60°.

Rotating the Service Access Door Panel Handle

1 Remove and retain screws securing the service access door.

2 Remove the two (2) screws holding the handle in place, and rotate the handle 180°. Secure

handle in new position with retained screws.

3 Reinstall the service access door, positioning the sight glass in line with the burners. The

handle should now taper up towards the new top of the unit.

Recommended Mounting Heights

Chart 3.1 • Recommended Mounting Heights*

Typical

Model

UH-30

UH-45

UH-60

UH-75

* Recommended mounting heights are provided as a guideline. Actual conditions may dictate
variations from the above data. Clearance to combustibles must always be maintained.

The recommended mounting heights of the units are critical to its performance. Refer to the Chart 3.1
for specific recommended mounting heights. The mounting height is measured from the finished floor to
the bottom of the unit. Units that are mounted higher than the recommended mounting heights may not
directly deliver heated air to the floor level.

Mounting Height

8 to 12 Ft. 26 Ft. 45°F

8 to 14 Ft. 28 Ft. 45°F

10 to 16 Ft. 37 Ft. 45°F

10 to 18 Ft. 39 Ft. 45°F

Approximate

Heat Throw

Average Air

Temperature Rise

16

UH Series

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!

3.0 Installation • Gas Supply Installation Instructions

Gas Supply Installation Instructions

The gas supply to the unit heater must be connected and tested in accordance with national, state,
provincial, and local codes along with guidelines in this manual. In the United States refer to the latest
edition of the ANSI Z223.1 (NFPA54) Standard and in Canada refer to the latest edition of the CAN/
GCA B149.1 Standard.

Supply gas piping to the unit should conform with the local and national requirements for type and
volume of gas handled, and pressure drop allowed in the line. Avoid pipe sizes smaller than 1/2”.

WARNING

Improperly connected gas lines may result in serious injury and death,
explosion, poisonous fumes, toxic gases or asphyxiation. Connect gas lines
in accordance to national, state, provincial and local codes.

Gas pressure to the appliance controls must never exceed ½” PSI (14” W.C.). Damage to the
controls may result.

CAUTION

Gas lines should be purged of air as described in ANSI Z223.1 (NFPA 54) or CSA-B149.1– latest
version. Installation of the piping must also conform with the local building codes, or in the
absence of local codes, with the latest edition of the National Fuel Gas Code (NFPA 54). In
Canada, installation must be in accordance with CSA-B149.1

NOTICE

The total input to the appliance must fall within +/- 5% of the rated input as indicated on the
rating plate. Otherwise the heat exchanger may prematurely fail.

17

3.0 Installation • Gas Supply Installation Instructions

UH Series

Refer to Chart 3.2 for natural gas and Chart 3.3 for propane to determine the cubic feet per hour (CFH)
required for the type of gas and size of unit to be installed. To determine the proper pipe diameter, use
the CFH value and the length of pipe necessary from Chart 3.4. In the case where several units are
serviced by the same main gas line, the total capacity (CFH) and length of main must be adequate to
service all appliances downstream of this main.

Chart 3.2 • Natural Gas Consumption

Model

UH-30N

UH-45N

UH-60N

UH-75N

Manifold

Pressure

(Inches W.C.)

3.5 5.0 14.0 28.6 49 DMS 2

3.5 5.0 14.0 42.9 49 DMS 3

3.5 5.0 14.0 5 7.1 49 DMS 4

3.5 5.0 14.0 71.4 49 DMS 5

Min. Inlet
Pressure

(Inches W.C.)

Max. Inlet

Pressure

(Inches W.C.)

Gas

Consumption

(CFH)*

Orifice

Size

*Assumes an average heating value of 1050 BTU/SCF and a Specific Gravity of 0.60.

Chart 3.3 • Propane Gas Consumption

Model

UH-30P

UH-45P

UH-60P

UH-75P

Manifold

Pressure

(Inches W.C.)

10.0 11. 0 14.0 12.0 0.33 57 DMS 2

10.0 11. 0 14.0 18.0 0.49 57 DMS 3

10.0 11. 0 14.0 24.0 0.66 57 DMS 4

10.0 11. 0 14.0 30.0 0.82 57 DMS 5

Min. Inlet
Pressure

(Inches W.C.)

Max. Inlet

Pressure

(Inches W.C.)

Gas

Consumption

(CFH)*

Gallons

per hour

Orifice

*

*Assumes an average heating value of 2500 BTU/SCF and a Specific Gravity of 1.53.

Size

Number

of Orifices

Number of

Orifices

Chart 3.4 allows for a 0.3 inch W.C. pressure drop in the supply pressure from the building main to the
inlet of the unit. Refer to the chart for the appropriate range of inlet pressures for each gas type. When
sizing the inlet gas pipe diameter, make sure that the unit supply pressure can be met after the 0.3 inch
W.C. pressure drop has been subtracted from the main pressure. If the 0.3 inch W.C. pressure drop is
too high, refer to NFPA 54 or the Gas Engineer’s Handbook for other gas pipe capacities.

18

UH Series

!

Chart 3.4 • Maximum capacity for Schedule 40 Metallic pipe, in CFH

3.0 Installation • Gas Supply Installation Instructions

Pipe

Length

(feet)

10’

20’

30’

40’

50’

60’

70’

80’

90’

100’

125’

150’

175’

200’

The UH Series heater is equipped to receive a gas supply line nipple of ½”NPT Schedule 40 metallic
pipe. All piping must be installed in accordance with the requirements outlined in the National Fuel Gas
Code ANSI/Z223.1 (latest edition) or CSA-B149.1 and B149.2. Support all gas supply piping with pipe
hangers, metal strapping, or other suitable material. Do not rely on the heater to support the gas pipe.

1/2” 3/4” 1” 1-1/4” 1-1/2” 2”

Nat L . P. Nat L . P. Nat L . P. Nat L .P. Nat L . P. Nat L . P.

132 86 278 182 520 340 1050 686 1600 1046 3050 1993

92 60 190 124 350 229 730 477 110 0 719 2100 1373

73 48 152 99 285 186 590 386 890 582 1650 1078

63 41 130 85 245 160 500 327 760 497 1450 948

56 37 115 75 215 141 440 288 670 438 1270 830

50 33 105 69 195 127 400 261 610 399 115 0 752

46 30 96 63 180 118 370 242 560 366 1050 686

43 28 90 59 170 111 350 229 530 346 990 647

40 26 84 55 160 105 320 209 490 320 930 608

38 25 79 52 150 98 305 199 460 301 870 569

34 22 72 47 130 85 275 180 410 268 780 510

31 20 64 42 120 78 250 163 380 248 710 464

28 18 59 39 110 72 225 147 350 229 650 425

26 17 55 36 10 0 65 210 137 320 209 610 399

When connecting piping to the unit, the use of a thread joint compound is required. The thread
compound (pipe dope) shall be resistant to the action of liquefied petroleum gas or any other chemical
constituents of the gas to be conducted through the piping. Use of Teflon

®

tape is not permitted.

WARNING

Always use two (2) opposing wrenches to tighten mating pipe connections
to prevent excessive torque on the gas valve and manifold pipe. Excessive
torque can damage the valve and/or misalign the orifice, resulting in fire,
explosion, serious injury or death.

Install a ground joint union with a brass seat and a manual shut off valve adjacent the unit for
emergency shut off and easy servicing of controls. A 1/8” NPT plugged tap that is accessible for a test
gauge connections is also recommended, as illustrated in Figure 3.4.

A sediment trap must be installed in the supply line in the lowest spot prior to connecting to the heater.
The trap length shall be at least three inches long. Ideally, the trap would be installed as close as
possible to the shut off, as shown in Figure 3.4.

19

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3.0 Installation • Gas Supply Installation Instructions • Leak Testing

Figure 3.4 • Recommended Hardware – Manual Shut Off and Sediment Trap

UH Series

Gas Supply Line

Leak Testing

Sediment

Trap

Flow of

Gas

Shut Off

To Unit

Ground Joint Union

1/8-in. NPT Test
Connection (Plugged)

3-in.

Minimum

WARNING

Use a soap solution or equivalent for leak testing. Never test for leak with an open
flame. Failure to comply could result in personal injury, property damage or death.

Always leak test final gas assembly for gas leaks according to the procedures outlined in NFPA 54 and
all local codes and/or Standards.

For leak testing on pressures below ½” PSI

Before leak testing, close the field installed manual shut off valve shown on Figure 3.4 on the supply
line to isolate the gas valve from the pressure.

NOTE: All factory installed gas connections have passed an approved leak test.

For leak testing on pressures above ½” PSI

When leak testing with pressures above ½” PSI (14 inches W.C.), the unit must be isolated from the
supply pipe. Close the field installed manual shut off valve, disconnect the supply line to the unit, and
temporarily cap the supply line for testing purposes.

WARNING

Gas pressures to the appliance controls must never exceed 14 inches W.C. (1/2”
PSI). Supply pressures greater than 14” W.C. can damage the controls, resulting in
personal injury, property damage, or death.

20

UH Series

!

3.0 Installation • Electrical Requirements and Wiring Diagrams • Internal Wiring Diagrams

Electrical Requirements and Wiring Diagrams

WARNING

Shock hazard. Disconnect power supply before making wiring connections to prevent

electrical shock and equipment damage.

Any original factory wiring that requires replacement must be replaced with wiring
material having a temperature rating of at least 105°C.

All field installed wiring to the unit heater must be must be done in accordance with the national, state,
provincial, local codes and to the guidelines in this manual. In the United States, refer to the most
current revisions to the Electrical Code ANSI/NFPA 70 and in Canada refer to the most current
revisions to the Canadian Electrical Code CSA C22.1 Part 1. The unit must be electrically grounded
according to these codes. Line polarity must be observed when making field connections.

Internal Wiring Diagrams

Before wiring this appliance, check the existing wiring; replace if necessary. If any of the original wire
supplied with the appliance must be replaced, it must be replaced with copper wiring material having a
rating of at least 600V, 105°C.

Figure 3.5 • Internal Wiring Diagram

21

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!

3.0 Installation • Field Wiring Supply Voltage

UH Series

Field Wiring Supply Voltage

Before proceeding with electrical connections, ensure that the supply voltage, frequency, phase and
current capacity meet the requirements specified on the rating plate. A dedicated line voltage supply
with properly sized wire should run directly from the main electrical panel to the heater. The power to
the unit must be protected with a circuit breaker appropriate for the load. The unit must be electrically
grounded in accordance with local codes, or in their absence, with the latest edition of the National
Electrical Code, ANSI / NFPA 70 and/or the Canadian Electrical Code CSA C22.1, latest edition.

CAUTION

The power supply to the heater must be within +/- 5% of the voltage rating as indicated on the rating
plate of the appliance. If input power does not meet these specifications, contact your utility company.

An electrical service disconnect must be provided at the furnace location. A 2 x 4 junction box can be
mounted directly to the unit panel utilizing the provided 1/2” knock-out. If conditions do not allow for this,
locate the service disconnect not more than 5 feet away from the service access panel.

The main electrical supply enters at the rear of the heater utilizing 1/2” electrical knock-out (See Figure

3.6). When routing the electrical supply conduit to the unit, ensure that it does not interfere or obstruct
the heater’s service access panel.

Unit comes with three wire leads to connect the main power supply. Connect the hot, neutral and
ground wires as shown in the field wiring diagram, Figure 3.6. When routing wires through the knock­out, use a UL Listed bushing or chase nipple to prevent damage to the wire insulation. When operating
this unit as a sealed combustion appliance, the cabinet opening to the junction box must be sealed air
tight using either a UL approved bushing or a non-reactive UL approved sealant to bushing.

WARNING

Edges of sheet metal holes may be sharp. Use gloves as a precaution when
routing wires.

22

UH Series

!

Figure 3.6 • Field Wiring

L2 (Neutral)

3.0 Installation • Field Wiring

Flexible Conduit

BX or Romex Connector

Junction Box

L1

Ground

White to L2

(Neutral)

Connect wires together with UL approved wire connectors.

Green to Ground
Black to L1
White to L2

Green
(Ground)

Black to L1
(Hot)

Note: A UL Listed switch may be installed in the 2x4 junction box for use as a service disconnect.

CAUTION

Route the field supplied power wires so that they do not come in contact with the flue wrapper or
venter housing. These hot surfaces may damage the wire’s insulation, resulting in damage to the
unit.

23

3.0 Installation • Thermostat Connection

UH Series

Thermostat Connection

NOTE: Different thermostats operate according to their particular features. Refer to the thermostat’s

specifications for details.

Each UH Series heater requires a single stage thermostat rated for 24VAC to operate. The heater
comes standard with a terminal strip for making the thermostatic connections, located on the back
panel. The thermostat terminal designations are as follows:

R: 24VAC Power

W: Call for Heat

G: Continuous Fan

C: Common for 24VAC Power

24VAC is supplied from an internal 40VA transformer. Do not supply 24 Volts to the terminal strip. A
minimum of 18 AWG low voltage thermostat wire must be used for connecting the thermostat to the
heater. Follow the field wiring diagram in Figure 3.7 for wiring to a typical single-stage thermostat.

Figure 3.7 • Field Wiring Diagram

Thermostat

Rh Rc W Y G C

R

W

G

Y

Heater Back Panel

See Detail A

24

Detail A

UH Series

3.0 Installation • Thermostat Location

Thermostat Location

The location of the thermostat should be determined by the desired heating requirements and be
mounted on an inside wall five (5) feet above the finished floor. Locate the thermostat in a conspicuous
location, away from where it could be influenced by heat from the unit or other sources, as this may
cause the unit to short cycle. Care should be given to locate the thermostat away from drafts or
frequently opened doors. To prevent drafts inside the wall from affecting the thermostat’s performance,
plug hole for the wire with insulation or suitable caulk. For further information, see the accompanying
instructions with the thermostat.

25

3.0 Installation • Venting • Replacing Existing Equipment

!

!

!

UH Series

Venting

The UH Series unit heater must be vented as described here to properly direct the flue gases from the
unit to the outside atmosphere. The venting can terminate vertically through the roof (up) or horizontally
through a sidewall (sideways).

Follow these guidelines and all applicable codes for all models prior to installing the vent material. Local
codes may vary. In the absence of local codes, refer and comply with the National Fuel Code ANSI
Z223.1 (NFPA 54) latest edition or the National Standards of Canada.

WARNING

Gas-fired heaters must be vented. Do not operate unvented.
A built in power exhauster is provided. Additional external
power exhausters are not required or permitted.

Insufficient ventilation and/or improperly sealed vents may
release gas into the building which could result in health problems, carbon monoxide poisoning or death.
Improper venting may result in fire, explosion, injury or death.

All UH Series heaters come with a factory-installed vent and combustion air adapters for attaching vent
pipe to the heater. Attach the venting material to the adapter with three (3) non-corrosive sheet metal
screws. If necessary, drill pilot holes prior to attaching the vent pipe. The venting material must not be
smaller than the factory installed adapter.

WARNING

Do not vent this appliance into another heater’s vents or through a masonry chimney.

Do not use dampers in the heater vent pipe.

Single Wall vent pipe must not pass through any unoccupied attic, inside wall, concealed space, or floor.

Un-insulated single wall vent pipe must not be used outdoors for venting appliances in regions where
winter design temperature is below freezing.

Replacing Existing Equipment

If the unit heater is replacing existing equipment and using an existing vent system, inspect the venting for
proper size and horizontal pitch as directed in these instructions and the latest edition of the National Fuel
Gas Code, ANSI Z223.1 (NFPA 54) or CSA B149.1 Installation Code.

Determine that there is not blockage or restriction, leakage, corrosion or other deficiencies that can cause
hazards. The vent pipe should be corrosion-resistant galvanized steel of a thickness that meets the
National Fuel Gas Code. Minimum thickness for connectors varies depending on the pipe diameter. Never
vent the UH Series with PVC or plastic pipe.

WARNING

If replacing an existing heater, vents may require re-sizing. Improperly sized venting
systems can result in vent gas leakage or condensation. Refer to the National Fuel Gas
Code ANSI Z223.1 (NFPA 54) or CSA B149.1 - latest edition. Failure to follow these
instructions can result in serious injury or death.

26

UH Series

3.0 Installation • General Venting Requirements

General Venting Requirements

The venting system for the UH Series heaters may terminate horizontally through a sidewall or vertically
through the roof, and may be individually or commonly vented. Configuration of the vent termination
determines the category type. All model heaters must be installed in accordance to the requirements of
this section, as well as the requirements of its category determination, as described in this manual. To
determine your applications category type, review ‘Vertical Venting’ (Category I) and ‘Horizontal Venting’
(Category III) sections of this manual.

All UH Series Model Requirements:

• Use vent pipe material that is corrosion-resistant galvanized steel of a thickness that meets the
National Fuel Gas Code.

• Do not exceed a maximum vent length of 30 feet.

• Maintain a minimum vent length of 3 feet.

• Maintain a minimum 12 inches of straight pipe from the flue outlet before any directional changes
are made in the venting system.

• Have all vent pipe seams or connectors fastened together with at least three corrosion resistant
sheet metal screws (field supplied).

• Maintain a 6 inch clearance around all single wall vent pipe from any combustible materials. For
double wall vent pipe (type B) follow the vent manufacturer’s clearance to combustibles.

• The equivalent length for a 3 inch 90° elbow is 3 feet.

• The equivalent length for a 4 inch 90° elbow is 5 feet.

• Avoid using more than two 90° directional changes in the venting system.

• Horizontal sections of the vent pipe must be installed with an upward slope from the appliance at a
pitch of ¼ inch per foot.

• Suspend and secure all horizontal runs at points no greater than 3 feet apart.

• Vent termination must maintain a minimum distance of 6 feet from any mechanical air supply inlet.

• Vent must terminate a minimum of 4 feet below, 4 feet horizontally from, or 1 foot above any window
or door that may be opened or gravity air inlet into the building.

• Vent must terminate a minimum of 4 feet above grade level and must extend beyond any
combustible overhang. Vents adjacent to the public walkways must terminate a minimum of 7 feet
above grade level.

• The vent terminal must be installed to prevent any blockage by snow and protect building material
from degradation by flue gases.

• The vent cap must be a minimum of 6 inches from the sidewall of the building.

• Vent must be a minimum of 36 inches below or extend beyond any combustible overhang.

• Consult NFPA ANSI Z223.1 Gas Vent Termination criteria for vents that terminate on a roof pitch that
exceeds 9:12.

• Canada: Vents must terminate a minimum of 3 feet from a window or door that may be opened, and
a non-mechanical air supply inlet or combustion air inlet into the building.

27

3.0 Installation • General Venting Requirements

Figure 3.8 • General Vent Requirements

24 in.

Min.*

UH Series

Vent Cap

Roof*

Double-Wall B Vent

Heater

Storm Collar
Adjustable Roof Flashing

1 in. Minimum Clearance

1 in. Minimum Clearance

Fire Stop Spacer

B to C Adapter

Clean Out Tee Fitting

Clean Out Cap

#8 Sheet Metal Screws (field supplied)

*Consult the NFPA ANSI Z223.1 Gas Vent Termination criteria if roof pitch exceeds 9:12

When possible, avoid venting through an unconditioned space. Venting through an unconditioned space
promotes condensation. When venting through an unconditioned space is unavoidable, or if the unit is
installed in an area that is prone to condensation, insulate venting runs greater than 5 feet to minimize the
production of condensation. Inspect for leakage prior to insulating the venting and only use insulation that
is non-combustible with a temperature rating of not less than 400°F. Install a tee fitting at the low point of
the vent system and provide a drip leg with a clean out cap as shown in Figure 3.8.

When venting pipe passes through a combustible interior wall or floor, a metal thimble with a diameter 4
inches greater than the vent pipe diameter must be used. If there is 6 feet or more of vent pipe prior to
passing through the combustible wall or floor, then the metal thimble need only be 2 inches greater than
the vent pipe diameter. If a metal thimble is not used, all clearance to combustibles from the vent pipe
must be 6 inches. Where permitted, type B vent may be used for the last section of vent pipe to reduce
the required clearance to combustibles when passing through a combustible wall or floor. When using
type B venting, follow the manufacturer’s recommended clearance to combustibles. Any material used to
close or insulate the opening must be non-combustible.

28

UH Series

3.0 Installation • Vertical Venting (Category I) • Vent Locations and Clearances

Vertical Venting (Category I)

An appliance that operates with a non-positive vent static pressure and with a vent gas temperature that
avoids excessive condensate production in the vent is said to be ‘Category I’. The UH Series heater is
considered a Category I appliance if the venting system meets all of the following criteria:

• The vent system terminates vertically (up).

• The length of the horizontal portion of the vent run is less than 75% of the vertical rise length. (e.g.- If

the vertical vent height is 10 feet, the horizontal run is less than 7-1/2 feet).

• The vent terminates a minimum of 5 feet above the vent connection on the unit.

For vertical vent termination, the venting must comply with all parts of this section, in addition to the
requirements of the general venting.

Category I (Vertical) venting is venting at a non-positive pressure. A furnace vented as a Category I is
considered a fan-assisted appliance and the vent system does not have to be ‘gas tight’. It is
recommended that the venting system is installed with a tee, drip leg, and clean-out cap as shown in
Figure 3.9.

Vent Locations and Clearances:

• Separate air intake duct from vent pipe by a minimum of 4 feet by placing vent pipes higher than

adjacent air intake ducts.

• Utilize a listed type B vent termination cap.

• The vent terminal must extend a minimum of 2 feet above the roof.

• Vent caps should be located a minimum of 2 feet away from adjoining structures.

All vertically vented heaters that are Category I must be connected to a chimney or vent complying with
a recognized Standard, or lined masonry (or concrete) chimney with a material acceptable to the
authority having jurisdiction. Venting into an unlined masonry chimney is not permitted. Refer to the
National Fuel Gas Code and page 27 of this manual.

Use a listed vent terminal to reduce down drafts and moisture in the vent.

29

3.0 Installation • Rooftop Venting • Horizontal Venting (Category III)

Figure 3.9 • Rooftop Venting - Side View

UH Series

Vent Cap

B to C Adapter

Clean Out Tee Fitting

Clean Out Cap

24 in. Min.*

Roof

Double-Wall B-Vent Pipe

Firestop Spacer

Heater

*Consult the NFPA ANSI Z223.1 Gas Vent Termination criteria if roof pitch exceeds 9:12.

Horizontal Venting (Category III)

An appliance that operates with a positive vent static pressure and with a vent gas temperature that
avoids excessive condensate production in the vent is said to be ‘Category III’. The UH Series heater is

considered a Category III appliance if the venting system meets all of the following criteria:

• The vent system terminates horizontally (sideways).

• The vent terminates vertically, but the length of the horizontal portion of the vent run exceeds 75% of

the vertical rise length. (e.g.- If the vertical vent height is 10 feet, the horizontal run is greater than
7-1/2 feet).

• The vent terminates below 5 feet of the vent connection on the unit.

Seal vent pipes with high temperature sealant and three (3) #8 sheet metal screws. Vent enclosed
spaces and buildings according to the guidelines in this manual and applicable national, state,
provincial and local codes.

You may either use an agency certified Category III venting system, or single wall vent pipe with all the
seams and joints sealed with metallic tape or silicone sealant suitable for temperatures up to 400°F.
Wrap the tape two full turns around the vent pipe. For single wall vent systems, one continuous section
of double wall vent pipe may be used with the vent system to pass through a wall or barrier.

All horizontal Category III vents must be terminated with a Simpson-Duravent sidewall vent cap (P/N:
SWD-4 for 4-inch venting or P/N: DB-208 for 3-inch venting).

30

UH Series

3.0 Installation • Vent Locations and Clearances • Sidewall Venting Requirements

Vent Locations and Clearances:

• Category III venting systems may NOT be common vented, and no other gas units are

allowed to be vented into it.

• Vent must terminate a minimum of 4 feet below, 4 feet horizontally from, or 1 foot above any

window or door that may be opened or gravity air inlet into the building.

• Vent must terminate a minimum of 3 feet above any forced air inlet that is located within 10

feet.

• Horizontal venting sections of the vent pipe on a Category III termination must be installed

with a downward slope from the appliance at a pitch of 1/4 inch per foot.

• The bottom of the vent terminate must be located a minimum of 12 inches above grade level

and must extend beyond any combustible overhang. Vents adjacent to public walkways
must terminate a minimum of 7 feet above grade level.

• The vent terminal must be installed to prevent blockage by snow and protect building

materials from degradation by flue gasses.

• The vent cap must be a minimum of 6 inches from the sidewall of the building.

• Vent must be a minimum of 36 inches below or extend beyond any combustible overhang.

• Vents must terminate a minimum of 3 feet from a window or door that may be opened, and a

non-mechanical air supply inlet or combustion air inlet into the building.

• Vents must terminate a minimum of 6 feet from a mechanical air supply inlet.

Never join two sections of double wall vent pipe within one horizontal vent system, as it is
impossible to verify that inner pipes are completely sealed.

Figure 3.10 • Sidewall Venting Requirements

Building**

Overhang**

36 in.

min.**

6 in.

min.**

Sidewall

Heater

B to C Adapter

Sidewall

Vent Cap

Wall Thimble

**Vent must extend beyond any combustible overhang if the vent is less than 36 in. below the combustible overhang.

Double-Wall
B-Vent

1/4 in. downward

pitch per foot

Single
Wall Vent

31

3.0 Installation • Common Venting (Category I) • Common Rooftop Venting

UH Series

Common Venting (Category I)

The common vent system and all attached appliances must be Category I.

The vent connector should be routed in the most direct route from the units to the common vent.

Where two or more vent connectors enter a common gas vent or chimney flue, the smaller
connector shall enter at the highest level consistent with the available head room or clearance to
combustible material.

Restrictions within the common vent such as elbows should be minimized. Each elbow installed
within the common portion of the vent carrying system reduces the maximum common vent
capacity by 10%. Refer to NFPA 54 IFEC tables 11.2 and 11.3 for capacity.

The vent connector capacities allow for the use of two 90° directional changes. For each
additional required elbow, the vent connector capacity is reduced by 10%.

The common vent cross sectional area must be equal to or greater than the largest vent
connector cross sectional area.

Figure 3.11 • Common Rooftop Venting - Side View

Rooftop Vent Cap

Double-Wall B-Vent

Firestop Spacer

Heater

24 in.
Min.*

Roof

Heater

Dual Exhaust Assembly

*Consult the NFPA ANSI Z223.1 Gas Vent Termination criteria if roof pitch exceeds 9:12.

32

UH Series

!

3.0 Installation • Concentric Venting • Combustion Air Requirements

Concentric Venting

Contact the factory for concentric venting requirements.

Combustion Air Requirements

Combustion air may be supplied to the heater by indoor or outdoor means. Follow these
guidelines and all applicable codes for all models prior to installing the combustion air duct work.
Local codes may vary. In the absence of local codes, refer and comply with the National Fuel
Code ANSI Z223.1 (NFPA 54) latest edition or the National Standards of Canada.

WARNING

Sufficient combustion air must be supplied to the appliance at all times.
Lack of combustion air may result in property damage, serious injury or death.

This unit comes standard equipped for connection of supplied outdoor air for combustion. It is
designed for outside air to be brought into the appliance from combustion intake ducts, and is
referred to as a “Separated Combustion” on page appliance.

This heater must operate as a separated combustion system if any of the following criteria apply:

• Chemicals such as chlorinated or fluorinated hydrocarbons (typical sources are refrigerants,
solvents, adhesives, degreasers, paints, paint removers, lubricants, pesticides, etc.) are
present in the atmosphere.

• High humidity.

• Contaminants such as sawdust, welding smoke, etc.

• Negative building pressure.

• Unusually tight construction where the air infiltration rate is less than 0.40 air changes per
hour.

If your application does not meet any of these criteria, then room air may be used as supplying
combustion air to the heater. Refer to ‘Room Air Combustion Systems’ on page 36 for details on
how to utilize room air for combustion.

33

3.0 Installation • Separated Combustion Systems

UH Series

Separated Combustion Systems

All UH Series heaters come with a factory-installed combustion air adapter for attaching air intake
ducts to the heater. Attach the air intake duct material to the adapter with three (3) non-corrosive
sheet metal screws. If necessary, drill pilot holes prior to attaching the air intake ducts. The
diameter of the intake ducts must not be smaller than the factory installed adapter.

When operating this unit as a separated combustion unit heater system, combustion air must be
supplied to the heater by outdoor means through the factory installed vent connector. The
combustion air intake duct may terminate horizontally through a sidewall or vertically through the
roof. Ideally, the intake should terminate within the same pressure zone as the venting terminates,
which should minimize the effects of wind.

All Separated Combustion systems must comply with the following items:

• Air intake ducts must be of galvanized steel or an equivalent corrosion-resistant material.

• Do not exceed a length of 30 feet.

• Do not exceed more than two (2) 90° directional changes (elbows) in the system.

• Seal all joints with metallic tape or silicone sealant. Wrap the tape two full turns around the
vent pipe.

• Slope air intake pipe ¼ inch per foot upward or downward away from the unit, as shown in
Figure 3.12.

• Do not draw air from attic space.

• Do not draw fresh air from the remaining space around a chimney liner, gas vent, special
gas vent, or plastic piping installed within masonry, metal, or factory built chimney.

• Combustion air ducts may be insulated if they pass through an unconditioned space.

• A factory approved sidewall intake cap must be used when terminating the combustion air
ducts horizontally through the sidewall.

• When combustion air ducts terminate vertically through the roof, a minimum of 18 inches
above the roof grade must be maintained (see Figure 3.13)

• Separate the air intake duct from vent pipe a minimum of 4 feet. Also, place vent pipe higher
than adjacent air intake duct.

• Air intake duct must terminate a minimum of 3 feet below any forced air vent discharge that
is located within 10 feet.

• The bottom of the air intake duct termination must be located a minimum of 12 inches above
grade level. Air intake ducts that terminate adjacent to public walkways must be installed a
minimum of 7 feet above grade level.

• The air intake duct must be installed to prevent blockage by snow, debris, or other possible
obstructions.

34

UH Series

3.0 Installation • Separated Combustion Systems

Figure 3.12 • Outside Combustion Air Sidewall Intake - Side View

Exhaust

Terminal Cap

(P/N: DB-208

or SWD-4)

Listed Wall Thimble

12 in.

Min.

Combustion Air

Intake Cap

(P/N: DB-208

or SWD-4)

Vent Termination

Support Brackets

6 in.
Min.

Clean-out

Tee

1/4 in. pitch per foot

(upward or downward)

Figure 3.13 • Outside Combustion Air Vertical Intake - Side View

Heater

Listed Exhaust Cap

(If X if less than 10 ft.)

Combustion

Air Intake

Cap

Cleanout

Tee

3 ft. Min.

X

Roof

Storm Collar
Listed

Flashing

18 in.

Min.

Heater

35

3.0 Installation • Room Air Combustion Systems

!

UH Series

Room Air Combustion Systems

When operating this unit as a room air combustion appliance, the factory installed air intake collar
may be removed and the required air for combustion can be taken into the appliance from the
space, so long as it is not a confined space. (See Figure 3.14)

A “confined space” is defined as a space whose volume is less than 50 cubic feet per 1,000
BTU/h of all the installed heating appliances.

WARNING

Do not draw combustion air from the space if the appliance is located within a confined
space. Insufficient combustion air may result in property damage, serious injury or
death. Use room air for combustion in installations with proper ventilation rates only.

Figure 3.14 • Combustion Air Intake Collar Removal

Affix label (provided in kit) when
using room air for combustion.

F/N: LLUH008

Room Air Warning

Remove air intake collar by
loosening #8 sheet metal screws.

If the combustion air is supplied from indoors, the required volume of the space must be a
minimum of 50 ft3 per 1,000 BTU/h, unless the building is of unusually tight construction. If the
building is of unusually tight construction with air infiltration rates of less than 0.40 air changes per
hour, outside combustion air is typically needed unless the sheer size of the building allows
otherwise. Contact the factory for further determination of the air infiltration rates.

The heater shall be located so as not to interfere with proper circulation of combustion air. A
minimum clearance of 12 inches all around the combustion air openings must be maintained at all
times. Special care should be taken to prevent inadvertent blockage of the combustion air inlet
holes.

Affix warning label adjacent to air intake holes as shown in Figure 3.14 (label is provided in kit). It
is the responsibility of the installer to ensure that there is a minimum 12 inch clearance around the
air intake openings.

36

UH Series

!

!

3.0 Installation • Unit Start-Up (Commissioning) • Pre-Start Up Checks

Unit Start-up (Commissioning)

Improper installation, adjustment, alteration, service or maintenance can cause
property damage, serious injury, or death. This heater must be installed and serviced
by a trained gas installation and service personnel only.

Shock Hazard.

Before attempting to perform any service or maintenance, turn electrical power to
unit OFF at disconnect switch.

Pre-Start Up Checks

WARNING

CAUTION

Verify that the installation conforms to all of the specifications of the manual, as well as with local,
state, national, and provincial codes. In absence of local codes, the unit heater must be installed
according to the current National Fuel Gas Code ANSI Z223.1 (NFPA 54). In Canada, the
installation must conform to the current National Standard of Canada CSA-B149 Sections 1 & 2.

Prior to starting up the unit, verify that:

9 The gas type listed on the rating label matches that of your application.

9 The gas connections have been purged of air and properly leak tested.

9 The voltage type and frequency listed on the rating label matches that of your application.

9 The unit is properly grounded as per the National Electrical Code, ANSI/NFPA 70 or

Canadian Electrical code CSA C22.1 Part 1.

9 The unit is properly mounted to a permanent structure able to bear the weight of the unit.

9 The proper mounting height is observed for the application.

9 All clearance to combustible distances or service clearances are maintained.

9 The unit is properly isolated or installed to prevent excessive vibration.

9 The unit is level horizontally.

9 Venting is properly installed in accordance with this manual and any applicable codes.

9 Combustion air supply is sufficient to support proper operation at all times.

37

3.0 Installation • Verify Proper Inlet Pressure

UH Series

Verify Proper Inlet Pressure

Before starting up the unit, smell all around the unit heater for gas. Be sure to smell next to the
floor because some gas is heavier than air and will settle on the floor.

When turning the gas shut off valve, only use your hand. Never use tools to turn the knobs, as it
may damage the valve resulting in a fire or explosion. If the knob is stuck, do not try to repair it,
contact a qualified service technician or your local gas company.

To verify the proper inlet pressures, follow the following steps:

1 Turn off the gas supply at the manual gas shut off valve.

2 Remove the inlet pressure tap plug on the gas control valve (see Figure 3.15).

3 Install a 1/8 inch NPT hose connector and connect the pressure gauge tube.

4 Turn on the gas supply at the manual gas shut off valve.

5 Turn on the electrical power to the unit heater.

6 To light the main burners, set the room thermostat to a point above room temperature.

NOTE: This unit heater is equipped with an ignition device, which automatically lights the
burner. This unit heater cannot be lighted manually. Do not try to light the burner by hand.

Verify

minimum

inlet gas supply pressure:

7 Turn on all other gas appliances that are on the same supply line. If the other gas appliances

have multiple inputs, set it to the maximum rating.

8 Observe the pressure rating on the pressure gauge.

The minimum inlet gas supply pressure for:

• Natural gas is 5.0 inches W.C.

• Propane gas is 11.0 inches W.C.

Verify

maximum

inlet gas supply pressure:

9 Turn off all other gas appliances on the same supply line.

10

Observe the pressure reading on the pressure gauge.

The maximum inlet gas supply pressure for:

• Natural gas is 14.0 inches W.C.

• Propane gas is 14.0 inches W.C.

IMPORTANT: If the inlet gas supply pressure is not within the minimum and maximum
range as shown on the rating plate, contact your gas supplier.

Removing pressure gauge from inlet port on gas valve.

Set thermostat or other control device to the lowest set point.

11

After heater has completed the post-purge cycle, turn off the electrical power to the unit

heater.

12

Turn off the gas supply at the manual gas shut off valve.

38

UH Series

13

Remove the pressure gauge tube and the 1/8 inch NPT hose connector.

14

Replace the inlet pressure tap plug on the gas control valve.

15

Leak check the re-installed pressure tap plug using a soap solution or equivalent method

3.0 Installation • Verifying Manifold Pressure

as described in ANSI Z223.1 (NFPA 54).

Figure 3.15 • Gas Valve Shown in ON Position

Manifold Pressure Outlet

Inlet

Pressure Port

On/Off Switch

Manifold Pressure
Adjustment Screw
(under cap)

Verify Manifold Pressure

Before starting up the unit, smell all around the unit heater for gas. Be sure to smell next to the
floor because some gas is heavier than air and will settle on the floor.

When turning the gas shut off valve, only use your hand. Never use tools to turn the knobs, as it
may damage the valve resulting in a fire or explosion. If the knob is stuck, do not try to repair it,
contact a qualified service technician or your local gas company.

To verify the proper manifold pressure, follow the following steps:

1 Turn off the gas valve with the switch located on the valve body (see Figure 3.15).

2 Remove the manifold pressure tap plug on the gas control valve(see Figure 3.15).

3 Connect the pressure gauge tube and manometer.

4 Turn on the gas valve with the switch located on the valve body.

5 Turn on the electrical power to the unit heater.

6 To light the main burners, set the room thermostat to a point above room temperature.

NOTE: This unit heater is equipped with an ignition device, which automatically lights the
burner. This unit heater cannot be lighted manually. Do not try to light the burner by hand.

Verify manifold pressure:

7 After the unit has successfully ignited, wait five minutes prior to taking any readings. The

unit heater must be in a steady state of operation prior to taking a manifold pressure reading.

39

3.0 Installation • Prior to Leaving the Job Site

UH Series

8 While waiting for the unit to stabilize, observe the characteristics of the flame. The flame

should be stable and should not lift from any burner. The burner color should be light blue,
and not create excessive noise.

9 After five minutes, observe the pressure rating on the pressure gauge.

The target manifold gas supply pressure for:

• Natural gas is 3.5 inches W.C.

• Propane gas is 10.0 inches W.C.

NOTE: Manifold pressure of the heater is pre-set at the factory. No adjustment should be
necessary.

During the verification process, a tolerance of +/- 5% of the full scale is acceptable due to varying
atmospheric conditions.

If manifold pressure is outside of this tolerance, then an adjustment may be necessary.

Removing pressure gauge from manifold port on gas valve:

10

Set thermostat or other control device to the lowest set point.

11

After heater has completed the post-purge cycle, turn off the electrical power to the unit

heater.

12

Turn off the gas valve with the switch located on the valve body (see Figure 3.15).

13

Remove the pressure gauge tube and the manometer.

14

Replace the manifold pressure tap plug on the gas control valve.

15

Leak check the re-installed pressure tap plug using a soap solution or equivalent method

as described in ANSI Z223.1 (NFPA 54).

Prior to leaving the Job Site

Prior to leaving the job site, verify that:

9 Service access door is properly secured to the unit with the sight glass aligned with the

burner side.

9 The heater is clear of any objects that would interfere with the proper air circulation or that

violate the listed clearance to combustibles.

9 Air directional louvers are adjusted for desired air flow and are not shut or adjusted beyond

60° from perpendicular to the face of the unit.

9 Manual gas shut off is ON.

9 Electrical power is ON.

9 Thermostat is set to desired temperature.

9 Properly dispose of all packaging materials.

9 Check to be sure you have all of your tools.

9 Leave the Installation, Operation, Maintenance and Parts Manual with the owner or end user.

40

UH Series

!

3.0 Installation • High Altitude Operation

High Altitude Operation

WARNING

Explosion hazard. This heater must be converted by a trained gas installation and

service personnel only. Failure to comply could result in personal injury, asphyxiation,
death, and fire or property damage.

The UH Series heater is factory configured for altitudes from 0 – 2,000 ft above sea level. If the
unit heater is being installed at an elevation above 2,000 ft, the input rate will have to be de-rated
to ensure proper operation. The deration is achieved by a gas orifice change.

The installation of the high altitude orifices must be done prior to putting the heater in operation
and prior to connecting the gas supply line. The manifold pressure may need to be re-adjusted
after orifices are installed. Refer to Charts 3.5 through 3.7 for proper high altitude conversion kit.
For altitudes above 9,500 feet, consult factory.

High Altitude Conversion Kit Installation:

1 Remove service access door by unscrewing the 5/16” (#10) sheet metal screws securing the

door.

2 Disconnect all wires connecting to the gas control valve.

3 Remove the manifold pipe from the burner assembly by removing the four mounting screws.

4 Slide the manifold pipe assembly out of the control compartment.

5 Remove gas orifices from the manifold using a 7/16” wrench.

6 Thread in the new orifices of the correct kit, starting threads by hand. Take care not to cross

thread the orifices (See Charts 3.5 through 3.7 for proper kit number and orifice size).

7 Tighten gas orifices to a torque of 150 inch pounds. No thread sealant is necessary, as the

brass is designed to seal to the steel manifold pipe at the proper torque.

8 Inspect all the newly installed orifices to ensure they are straight and aligned 90° to the

manifold pipe. Correct or replace any misaligned orifices.

9 Reinstall the manifold pipe assembly to the unit, ensuring that each orifice is properly aligned

with the burners. Secure with four 5/16” (#10) screws.

10

Reconnect all wires to the gas control valve.

11

Proceed with the installation of the gas supply line as described within this manual.

Chart 3.5 • High Altitude Conversion Kits for Elevations of 2,000 to 4,500 Feet

Kit Number Orifice Size

41

Model

UH-30

UH-45

UH-60

UH-75

Number of

Orifices

2 HKN-50_2 HKP-59_ 2 50 DMS 59 DMS

3 HKN-50_3 HKP-59_3 50 DMS 59 DMS

4 HKN-50_4 HKP-59_4 50 DMS 59 DMS

5 HKN-50_5 HKP-59_5 50 DMS 59 DMS

Natural Gas Propane Natural Gas Propane

3.0 Installation • High Altitude Operation

Chart 3.6 • High Altitude Conversion Kits for Elevations of 4,501 to 7,000 Feet

UH Series

Kit Number Orifice Size

Model

UH-30

UH-45

UH-60

UH-75

Number of

Orifices

2 HKN-51_2 HKP-60_2 51 DM S 60 DMS

3 HKN-51_3 HKP-60_3 51 DMS 60 DMS

4 HKN-51_4 HKP-60_4 51 DMS 60 DMS

5 HKN-51_5 HKP-60_5 51 DMS 60 DMS

Natural Gas Propane Natural Gas Propane

Chart 3.7 • High Altitude Conversion Kits for Elevations of 7,001 to 9,500 Feet

Kit Number Orifice Size

Model

UH-30

UH-45

UH-60

UH-75

Figure 3.16 •

Number of

Orifices

2 HKN-52_2 HKP-62_2 52 DMS 62 DMS

3 HKN-52_3 HKP-62_3 52 DMS 62 DMS

4 HKN-52_4 HKP-62_4 52 DMS 62 DMS

5 HKN-52_5 HKP-62_5 52 DMS 62 DMS

Natural Gas Propane Natural Gas Propane

High Altitude Kit Installation

Sheet Metal

Screws

Sheet Metal

Screws

Gas
Orifices

Manifold
Pipe

Note: Install gas orifices to a
torque of 150 in. lbs.

42

UH Series

!

!

4.0 Operation • Sequence of Operation

4.0 Operation

WARNING

This appliance does not have a pilot ignition. It is equipped with an ignition device
which automatically lights the burner. Do not attempt to light the system by hand.

Sequence of Operation

Standby: The ignition control continually checks for internal faults, circuit integrity and relay contact

positioning. The LED is lit indicating power is applied.

Starting Circuit: Upon a call for heat, the control verifies that the limit switch is closed and the
differential pressure switch is in the open position. The control energizes the induced draft motor. Once
operational static pressure is achieved the differential switch will close initiating the ignition sequence.
The control energizes the spark and main gas valve for 10 seconds. If the flame is not sensed, the
control will attempt to re-ignite for a total of (3) tries for ignition before proceeding to soft lockout.

Running Circuit: After ignition, the flame rod monitors burner flame. If flame sense is not established
within 10 seconds, the control will attempt two (2) additional ignition sequences before proceeding to
soft lockout. The control can be reset by briefly interrupting the power source. If flame is sensed the
control waits for a 30 second heat blower on delay and then energizes the indoor blower, the control
proceeds to steady heat mode. If sense of flame is lost, the control closes the gas valve within 1
second and a new trial sequence (identical to the starting sequence) is initiated.

Shut Down: When the thermostat is satisfied, the control closes the valve and the induced draft motor
remains on for a 5 second post-purge period. The indoor blower is de-energized after 120 seconds.

WARNING

Use only your hand to turn the manual shut off. Never use tools. If the
knob will not turn by hand, don’t try to repair it; call a qualified technician.
Force or attempted repair may result in a fire or explosion.

43

4.0 Operation • Shutdown Procedures

UH Series

Shutdown Procedures:

Set the thermostat to the lowest setting.

Turn OFF all electrical power to the appliance if service is to be performed.

Turn manual shut off knob clockwise to OFF. Do not force.

If the heater’s internal diagnostic LED displays any of the signals listed in Charts 4.1-4.2, address the
indicated problem as outlined.

Chart 4.1 • LED Diagnostic Codes - United Technologies Circuit Board

LED CODE

(# of flashes)

STEADY OFF Internal Control Fault or No Power

STEADY ON Control Ok

1 In Lockout from Failed Ignitions or Flame Losses
2 Pressure Switch Open with Inducer ON
3 Pressure Switch Closed with Inducer OFF
4 Limit Switch is OPEN
5 In Lockout from False Flame

LED CODE

(# of flashes)

FAST FLASH Flame Present With Gas Valve Off

STEADY ON Flame is Sensed

GREEN LED STATUS / ERROR

AMBER LED STATUS / ERROR

Chart 4.2 • LED Diagnostic Codes - Fenwal Circuit Board

LED CODE

(# of flashes)

SLOW FLASH Normal Operation - No Call for Heat

FAST FLASH Normal Operation - Call for Heat

2 Ignition Lockout - No Flame Detected
3 Airflow Fault - Pressure Switch Open or Closed
4 High Limit or Rollout Switch Open
5 Flame Sense Error - Gas Valve Not Energized

STEADY ON Internal Control Failure

LED CODE

(# of flashes)

OFF Flame Signal is Below Required Level / No Flame Present

STEADY ON Flame is Sensed

GREEN LED STATUS / ERROR

AMBER LED STATUS / ERROR

44

UH Series

This page intentionally left blank.

45

4.0 Troubleshooting Guide

4.0 Troubleshooting Guide

UH Series

Turn on control
device for heat.

Does the draft

inducer motor

turn on?

Yes

Does the

pressure switch

indicator light

turn on?

Yes

No

No

Limit switch is open or pressure

switch is stuck closed. Find

faulty switch and repair.

Does the air circulating

fan turn on immediately?

Is the inlet or outlet of the

heater obstructed, or is

the vent exceeding the

recommended lengths?

Yes

Remove obstruction or

correct vent lengths.

No

No

Find source of

electrical problem.

NoYes

Does the heater have 120 VAC
at the main power connection?

Check for loose wiring or

restrictions in the hose

connection to the pressure

switch. Are they acceptable?

No

Replace wiring or hose

connections.

Yes

Yes

Does the circuit

board send

spark to the

electrode?

Yes

Does the valve

indicator light

turn on?

Yes

Does the gas

valve turn on?

No

No

No

Does the electrode

appear to be

physically damaged?

No

Yes

Replace igniter.

Does the gas valve

turn on? Do you see

the burners in the

sight glass?

Yes

No

Check inlet pressure to the heater. Is

it within the minimum and maximum

allowable range as per the rating plate?

Temporarily disconnect the igniter wire

from the circuit board and check for

continuity. Is there continuity?

YesNo

Replace wire.

Gas valve

indicator light is

burned out.

Replace light.

Replace circuit

board.

Correct wiring.

No

Yes

Are the wires to and from the

gas valve properly connected?

Yes

Yes

Continued on page 48.

No

Adjust inlet

pressure.

46

UH Series

4.0 Troubleshooting Guide

NOTICE

during normal operation or the heater’s built-in safety mechanisms will be compromised.

Key

Bypassing any switch is intended for testing purposes only. Do not leave switch bypassed

Start
Question

Is there 24 VAC

across the ‘R’ and

‘C’ terminals?

After approx.

10 seconds of

operation, is there

a flash code for

‘Pressure Switch

Failure’?

No

Replace pressure switch after verifying:

• Heater, blower, and venting are clean and
free of obstructions.

• The allowable vent length is not
exceeded.

• There is not a negative pressure
experienced at the area of intake (e.g.,
high winds, attic space, tightly sealed
building).

Yes

Process
Question

No

Yes

and ‘C’ terminals?

Repair thermostat or

circuit board.

Is there 24 VAC

across the ‘W’

No

thermostat wiring.

Replace

Corrective
Action

Yes

Check fuse on circuit board and

internal controls transformer.

Is the circuit board

sending 120 VAC

to the draft inducer

motor?

No

Is the pressure

switch stuck in the

closed position?

Yes

Pressure switch is faulty.

Remove

obstruction.

Yes

Yes

Is the draft

inducer impeller

obstructed or

locked up?

No

The draft inducer motor is

faulty and must be replaced.

No

Check the

two flame roll

out switches
and the tube

temperature

limit switch. Are

they closed?

No

Yes

Monitor the voltage on

the gas valve terminals

during trial for ignition.

Is there 24 VAC present

during the spark

sequence?

Yes

No

Reset or replace

faulty limit switch.

Replace circuit board.

Gas valve is faulty.

Replace.

Check for flash

codes on the circuit

board. Replace the

ignition module.

47

4.0 Troubleshooting Guide

Continued from page 46.

UH Series

Do the burners

ignite?

Yes

Do the burners

stay lit?

Yes

No

No

Is the gas supply

valve to the heater in

the “on” position?

No

Turn on gas supply

line.

Do the burners light

and then shut off

immediately (within

1-2 seconds)?

Yes

Check inlet pressure

and limit switches.

Yes

No

Check inlet pressure to the heater. Is it within

the minimum and maximum allowable range

as per the rating plate?

No

Adjust inlet pressure.

Does the burner stay on for approximately

8-10 seconds, and then shut off?

No

Check circuit board for

flash codes. Consult

factory.

Yes

Yes

Does the air

motor fan turn

on approx. 30
seconds after

ignition?

No

Yes

Does the heater

stay on until the

call for heat ends?

Yes

Troubleshooting ends.

For more information, contact

your local representative or the

factory for further assistance.

Does the circuit board send 120
VAC to the air movement fan after
approx. 30 seconds after ignition?

Yes

Is the motor dirty, obstructed, or

damaged, inhibiting rotation?

No

The heater can shut down or stay on due to:

• Limit switch opening.

• Pressure switch opening.

• Improper grounding.

• Faulty control device.

• High winds.

• Taking combustion air from the attic.

• Dirty environment.

• Fluctuating gas pressure.

No

No

Yes

Verify wires are not

damaged. Check flash

codes, and then replace

circuit board.

Check motor starter capacitor.

Replace or repair.

Clean fan, remove obstruction, or

replace damaged parts.

48

UH Series

4.0 Troubleshooting Guide

Were the gas lines

purged of all air?

No

Purge gas lines.

Is the heater properly

grounded? Is the

heater’s polarity

correct?

No

Correct grounding or

fix polarit y.

Yes

Yes

Does the heater’s gas

type match the gas

supplied?

No

Contact local

representative or factory.

With a micro ammeter,

check micro-Amp reading

of flame sensor circuit. Is

it greater than 0.5 micro-

Amps? NOTE: Meter must

be connected in series.

Yes

Check circuit board flash

codes. Replace ignition

module.

Yes

Adjust pressure or
replace gas valve.

No

Replace circuit board.

Check manifold pressure. Are

you reading within the specified

pressures per the rating plate?

No

Yes

Check circuit board

for flash codes.
Consult factory.

LED Diagnostic Codes

United Technologies Circuit Board

LED CODE

(# of flashes)

STEADY OFF Internal Control Fault or No Power

STEADY ON Control Ok

1 In Lockout from Failed Ignitions or Flame Losses

2 Pressure Switch Open with Inducer ON

3 Pressure Switch Closed with Inducer OFF

4 Limit Switch is OPEN

5 In Lockout from False Flame

LED CODE

(# of flashes)

FAST FLASH Flame Present With Gas Valve Off

STEADY ON Flame is Sensed

GREEN LED STATUS / ERROR

AMBER LED STATUS / ERROR

Fenwal Circuit Board

LED CODE

(# of flashes)

SLOW FLASH Normal Operation - No Call for Heat

FAST FLASH Normal Operation - Call for Heat

2 Ignition Lockout - No Flame Detected

3 Airflow Fault - Pressure Switch Open or Closed

4 High Limit or Rollout Switch Open

5 Flame Sense Error - Gas Valve Not Energized

STEADY ON Internal Control Failure

LED CODE

(# of flashes)

STEADY ON Flame is Sensed

OFF Flame Signal is Below Required Level / No Flame Present

GREEN LED STATUS / ERROR

AMBER LED STATUS / ERROR

49

5.0 Maintenance

UH Series

5.0 Maintenance

To check gas tightness of the safety shut off valves, turn off the manual valve upstream of the appliance
combination control. Remove the hex head plug on the inlet side of the combination control and
connect a manometer to that tapping.

Turn the manual valve on to apply pressure to the combination control. Note the pressure reading on
the manometer, then turn the valve off. Any loss of pressure indicates a leak. If a leak is detected, use a
soap solution to check all threaded connections. If no leak is found, combination control is faulty and
must be replaced before putting appliance back in service.

Should maintenance be required, perform the following inspection and service routine:

Inspect the area near the unit to be sure that there is no combustible material located within the

1

minimum clearance requirements listed in this manual. Under no circumstances should combustible
material be located within the clearances specified in this manual. Failure to provide proper
clearance could result in personal injury or equipment damage from fire.

Turn off the manual gas valve and electrical power to the unit heater. Remove service access panel.

2

To clean or replace the burner, remove retainer from around manifold orifice, disconnect flame

3

sensor and igniter from control board, remove burner assembly mounting screws. With the burner
removed, wire brush the inside surfaces of the heat exchanger.

 Remove any dirt, dust, or other foreign matter from the burners using a wire brush or compressed

4

air. Ensure that all parts are unobstructed. Then reassemble the unit heater by replacing all parts in
reverse order.

Complete the appropriate unit startup procedure as given in the Operation section of this Manual.

5

(See lighting instructions on the unit nameplate.)

• Check the burner adjustment.

• Also check all gas control valves and pipe connections for leaks.

Check the operation of the automatic gas valve by lowering the setting of the thermostat, stopping

6

the operation of the gas unit heater. The gas valve should close tightly, completely extinguishing the
flame on the burner.

Inspect and service motor/fan assembly. To maintain efficient air flow, inspect and clean the fan

7

blades and guard to prevent buildup of foreign matter.

If combustion air is room supplied, ensure that a 12 inch clearance is maintained all around the inlet

8

openings.

Check lubrication instructions on motor. If oiling is required, add three or four drops of SAE 20 electric

9

motor oil:

• After three years or 25,000 hours (for light-duty operation).

• Annually after three years or 8,000 hours (for medium-duty operation).

• Annually after one year or 1,500 hours (for heavy-duty operation).

NOTICE

Never over-oil the motor, or premature failure may occur.

10

Check and test functions of all safety devices supplied with the heater.

50

UH Series

5.0 Maintenance • Limited Warranty

Limited Warranty Terms and Conditions

One-Year Limited Warranty. The heaters covered in this manual are warranted by Detroit Radiant Products

Company to the original user against defects in workmanship or materials under normal use for one year after
date of purchase. Any part which is determined to be defective in material or workmanship and returned to an
authorized service location, as Detroit Radiant Products Company designates, shipping costs prepaid, will be, as
the exclusive remedy, repaired or replaced at Detroit Radiant Products Company’s option. For limited warranty
claim procedures, see PROMPT DISPOSITION below. This limited warranty gives purchasers specific legal
rights which vary from jurisdiction to jurisdiction.

Additional Limited Warranty. In addition to the above mentioned one-year warranty, Detroit Radiant Products
Company warrants the original purchaser an additional extension on the heat exchangers and burners. This
extension excludes electrical/purchased components.

General Conditions. The Company will not be responsible for labor charges for the analysis of a defective
condition of the heater or for the installation of replacement parts. The warranties provided herein will not apply if
the input of the heater exceeds the rated input at time of manufacturing or if the heater in the judgment of the
Company has been subjected to misuse, excessive dust, improper conversion, negligence, accident, corrosive
atmospheres, excessive thermal shock, excessive vibration, physical damage to the heater, alterations by
unauthorized service personnel, operation contrary to the Company’s instructions or if the serial number has
been altered, defaced, or removed. The Company shall not be liable for any default or delay in the performance
of these warranties caused by contingency beyond its control, including war, government restriction or restraints,
strikes, fire, flood, short or reduced supply of raw materials, or parts.

Limitation of Liability. To the extent allowable under applicable law, Detroit Radiant Products Company’s liability
for consequential and incidental damages is expressly disclaimed. Detroit Radiant Products Company’s liability in
all events is limited to and shall not exceed the purchase price paid.

Warranty Disclaimer. Detroit Radiant Products Company has made a diligent effort to provide product
information and illustrate the products in this literature accurately; however, such information and illustrations are
for the sole purpose of identification, and do not express or imply a warranty that the products are merchantable,
or fit for a particular purpose, or that the products will necessarily conform to the illustrations or descriptions.
Except as provided below, no warranty or affirmation of fact, expressed or implied, other than as stated in the
“LIMITED WARRANTY” above is made or authorized by Detroit Radiant Products Company.

Product Suitability. Many jurisdictions have codes and regulations governing sales, construction, installation,
and/or use of products for certain purposes, which may vary from those in neighboring areas. While Detroit
Radiant Products Company attempts to assure that its products comply with as many codes, it cannot guarantee
compliance, and cannot be responsible for how the product is installed or used. Before purchase and use of a
product, review the product applications, and all applicable national and local codes and regulations, and be sure
that the product, installation, and use will comply with them. Certain aspects of disclaimers are not applicable to
consumer products:
e.g., (a) some jurisdictions do not allow the exclusion or limitation of incidental or consequential damages, so the
above limitation or exclusion may not apply to you: (b) also, some jurisdictions do not allow a limitation on how
long an implied warranty lasts, consequently the above limitation may not apply to you: and (c) by law, during the
period of this limited warranty, any implied warranties of implied merchantability or fitness for a particular purpose
applicable to consumer products purchased by consumers, may not be excluded or otherwise disclaimed.

Prompt Disposition. Detroit Radiant Products Company will make a good faith effort for prompt correction or
other adjustment with respect to any product which proves to be defective within limited warranty. For any product
believed to be defective within limited warranty, first write or call dealer from whom the product was purchased.
Dealer will give additional directions. If unable to resolve satisfactorily, write to Detroit Radiant Products Company
at 21400 Hoover Road, Warren, Michigan 48089, listing dealer’s name, address, date and number of dealer’s
invoice, and describe the nature of the defect. Title and risk of loss pass to buyer on delivery to common carrier. If
product was damaged in transit to you, file claim with carrier.

Registration. Register on-line at www.drp-co.com/warranty.

51

5.0 Maintenance • Heater Components and Parts List

UH Series Cabinet 1 (UH-30 & UH-45) Parts Listing

Figure 5.1 • Heater Assembly Components

121

1113

110 2

251

1821,

1823,

UH Series

110 3

110 4

723,

733,

732,

722,

216

231

212

1111

232

630

551

110 5

623

1101

243

200

1112

614

235

121

450

421

282

701

550

422

425

215

213

329

410,

400,

200

242

327

690

601

705

441

303

214

202

713,

712,

640

326

203

300

1463,

1462 ,

115

552

553

554

115 0

263

236

110 6

52

114

211

UH Series

5.0 Maintenance • Heater Components and Parts List

Chart 5.1 • UH Series Cabinet 1 (UH-30 & UH-45) Parts List

Part No. Description Part No. Description

CK P_ 57_ 2 Propane Conversion Kit (UH-30) U F- 4 41 Gas Orifice (Indicate Size)

CK P_ 57_ 3 Propane Conversion Kit (UH-45) UF-450 Burner Chamber Support Bracket

UF-114 Service Access Handle UF-550 Spark Igniter

UF-115 Burner Sight Glass UF-551 Spark Igniter Wire

UF-121 Mounting Rail (Qty. 2) UF-552 Spark Igniter Boot

UF-200 4" Vent Collar Gasket (Qty. 2) UF-553 Ignition Control Circuit Board

UF-202 Exhaust Collection Chamber Gasket UF-554 Wire Harness

UF-203 Restrictor Plate Gasket UF-601 Inducer Motor Assembly, Small

UF-211 #10 x 1" SMS - Point Tip UF- 614 4" Vent Collar (Qty. 2)

UF-212 #8 x 1/2" SMS - Point Tip UF-623 Fan Housing Outlet Collar

UF-213 #10 x 1/2" SMS - Point Tip UF-630 Pressure Switch Tubing

UF-214 #10-32 Ground Screw UF-640 Pressure Switch, .65" WC

UF-215 #2 Phillips Pan Head x 1/2" SMS - Blunt Tip UF-690 Restrictor Plate (Indicate Size)

UF-216 1/4" - 20 x 1" Bolt UF-701 Inshot Burner, 3/8" Port

UF-231 1/4" Flat Washer UF-705 Burner Chamber Sides

UF-232 1/4" Lock Washer UF-712 Manifold Pipe, 2 Burner

UF-235 #10 Flat Washer UF-713 Manifold Pipe, 3 Burner

UF-236 #10 Rubber Washer UF-722 Burner Mounting Rail, 2 Burner

UF-242 Strain Relief Bushing, Cordgrip UF-723 Burner Mounting Rail, 3 Burner

UF-243 1/2" Gas Pipe Grommet UF-732 Burner Chamber Body, 2 Burner

UF-251 Louver Spring UF-73 3 Burner Chamber Body, 3 Burner

UF-262 1/4" - 20 Threaded Nut Insert (not shown) U F-1101 Back Panel #1

UF-263 #10-32 Nyloc Nut UF-110 2 Left Side Panel #1

UF-271 Pressure Switch Bracket (not shown) UF-110 3 Front Panel #1

UF-282 Limit Switch Bracket UF-110 4 Bottom Panel #1

UF-300 Component Panel UF-110 5 Top Panel #1

UF-303 3 Amp ATO Fuse U F -110 6 Service Access Door #1

UF-326 40VA Transformer, 120/24 UF-1111 10" Fan Guard, Square Pattern

UF-327 Indicator Light, 24VAC UF-1112 10" Axial Fan Blade, 3/8" Hub

UF-329 Terminal Strip UF-1113 Louver

UF-400 1/2" Gas Valve - Natural Gas U F-1150 Axial Fan Motor, 1/15 HP, 1550 RPM

UF- 410 1/2" Gas Valve - Propane Gas UF-14 62 Exhaust Collection Chamber, 2 Burner

UF-421 Flame Sensor UF-1463 Exhaust Collection Chamber, 3 Burner

UF-422 Limit Switch, Flame Rollout UF-18 21 #1 Tube and Vest Panel Assembly (2 Tubes)

UF-425 Limit Switch, Tube Temperature UF-18 23 #2 Tube and Vest Panel Assembly (3 Tubes)

53

5.0 Maintenance • Heater Components and Parts List

UH Series Cabinet 2 (UH-60, UH-75) Parts Listing

Figure 5.2 • Heater Assembly Components

121

2102

1113

251

2821,

2823,

UH Series

2103

2104

724,

725,

735,

734,

216

231

2111

232

212

630

551

552

553

554

702

202

282

705

441

303

213

214

643

326

203

300

2461,

2462,

115

2105

623

261

614

121

2112

2101

200

243

450

421

425

242

329

200

614

327

400,

215

422

550

714,

715,

410,

690

601

235

2150

263

236

54

2106

114

211

UH Series

5.0 Maintenance • Heater Components and Parts List

Chart 5.2 • UH Series Cabinet 2 (UH-60, UH-75) Parts List

Part No. Description Part No. Description

CK P_ 57_ 4 Propane Conversion Kit (UH-60) U F-4 41 Gas Orifice (Indicate Size)

CKP_57_5 Propane Conversion Kit (UH-75) UF-450 Burner Chamber Support Bracket

UF-114 Service Access Handle UF-550 Spark Igniter

UF-115 Burner Sight Glass UF-551 Spark Igniter Wire

UF-121 Mounting Rail (Qty. 2) UF-552 Spark Igniter Boot

UF-200 4" Vent Collar Gasket (Qty. 2) UF-553 Ignition Control Circuit Board

UF-202 Exhaust Collection Chamber Gasket UF-554 Wire Harness

UF-203 Restrictor Plate Gasket UF-601 Inducer Motor Assembly, Small

UF-211 #10 x 1" SMS - Point Tip UF- 614 4" Vent Collar (Qty. 2)

UF-212 #8 x 1/2" SMS - Point Tip UF-623 Fan Housing Outlet Collar

UF-213 #10 x 1/2" SMS - Point Tip UF-630 Pressure Switch Tubing

UF-214 #10-32 Ground Screw UF-640 Pressure Switch, .65" WC

UF-215 #2 Phillips Pan Head x 1/2" SMS - Blunt Tip UF-690 Restrictor Plate (Indicate Size)

UF-216 1/4" - 20 x 1" Bolt UF-702 Inshot Burner, 5/16" Port

UF-231 1/4" Flat Washer UF-705 Burner Chamber Sides

UF-232 1/4" Lock Washer U F-714 Manifold Pipe, 4 Burner

UF-235 #10 Flat Washer UF-715 Manifold Pipe, 5 Burner

UF-236 #10 Rubber Washer UF-724 Burner Mounting Rail, 4 Burner

UF-242 Strain Relief Bushing, Cordgrip UF-725 Burner Mounting Rail, 5 Burner

UF-243 1/2" Gas Pipe Grommet UF-734 Burner Chamber Body, 4 Burner

UF-251 Louver Spring UF-735 Burner Chamber Body, 5 Burner

UF-261 1/4" - 20 Threaded Nut Insert UF-1113 Louver

UF-263 #10-32 Nyloc Nut UF-2101 Back Panel #2

UF-271 Pressure Switch Bracket (not shown) UF-2102 Left Side Panel #2

UF-282 Limit Switch Bracket UF-2103 Front Panel #2

UF-300 Component Panel UF-2104 Bottom Panel #2

UF-303 3 Amp ATO Fuse UF-2105 Top Panel #2

UF-326 40VA Transformer, 120/24 UF-2106 Service Access Door #2

UF-327 Indicator Light, 24VAC UF-2111 14" Fan Guard, Square Pattern

UF-329 Terminal Strip UF-2112 14" Axial Fan Blade, 3/8" Hub

UF-400 1/2" Gas Valve - Natural Gas UF-2150 Axial Fan Motor, 1/12 HP, 1625 RPM

UF- 410 1/2" Gas Valve - Propane Gas UF-2461 Exhaust Collection Chamber, 4 Burner

UF-421 Flame Sensor UF-2462 Exhaust Collection Chamber, 5 Burner

UF-422 Limit Switch, Flame Rollout UF-2821 #3 Tube and Vest Panel Assembly (4 Tubes)

UF-425 Limit Switch, Tube Temperature UF-2823 #4 Tube and Vest Panel Assembly (5 Tubes)

55

5.0 Maintenance • Kit Contents Check List

!

Kit Contents Check List

Chart 5.3 • Kit Contents for UH Series

UF-251

Springs

UH Series Kit Contents

UF-1113

Louvers

UH Series

UH Series Manual

F/N: LIOUH

Detroit Radiant Products Company

UH Series Manual

Installation, Operation,
Maintenance and Parts

The UH Series heater is a gas-fired unit heater. This manual provides specific information related to the
UH 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:

• Open windows.

• Do not touch any electrical switch.

• Extinguish any open ame.

• Do not use any phone in your building.

INSTALLER: Present this manual to the end user.

Keep these instructions in a clean and dry place for future reference.

Model#: ___________________ Serial #: _________________________

WARNI NG

Improper installation, adjustment, alteration, service or maintenance can cause
property damage, serious injury or death. Read and understand the installation,
operating and maintenance instruction 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,
and fire or property damage.

Do not store or use gasoline or other flammable vapors and liquids in the vicinity of
this or any appliance.

Do not use this heater in indoor living or sleeping quarters! Installation of this unit in
a residential indoor living space may result in property damage, serious injury,
asphyxiation or death.

• Immediately call your gas supplier from a neighbor’s phone.

• Follow the gas supplier’s instructions.

• If you cannot reach your gas supplier, call the re department.

(located on rating label)

LIOUH-Rev. 02813

Print: 1M-01/13 (DRP)

UF-616

3” to 4” Vent/Intake Adapter

Room Air Clearance Label

LLUH008

(for UH-30 and UH-45 only)

Part No. Description UH-30 UH-45 UH-60 UH-75

LIOUH UH Series Installation Manual 1 1 1 1

LLUH008 Room Air Clearance Label 1 1 1 1

UF-251 Spring 4 4 4 4

UF-616 3” to 4” Vent/Intake Adapter 2 2 0 0

UF-1113 Louver 4 4 6 6

Filled By:

Approvals

• ANSI Z83.20b and CSA 2.34.

• Indoor approval.

• Commercial approval.

• Residential garages and non-confined

Limited Warranty

• 1 year - components.

• 5 years - exchangers.

• 10 years - burner.

• See page 55 for terms and conditions.

living spaces.

© 2014 Detroit Radiant Products Co.

21400 Hoover Road • Warren, MI 48089

Phone: [phone] Fax: [phone]

www.detroitradiant.com • [e-mail]

Proudly Made

in the U.S.A.

56