Marley UH Instructions Manual

UH Series

!

Electric Space

Heater

FILE #E21609

Installation & Maintenance Instructions

SPECIFICATIONS: UH724ST

Heater Rating and Voltage

•7500 W @ 240V
6250W @ 240V
5000W @ 240V
3750W @ 240V

•5625W @ 208V
4685W @ 208V
3750W @ 208V
2812W @ 208V

• Heater is shipped from factory wired for these wattages. Heater can be field adjusted to the other wattages. Refer to “Adjusting the Heat Output” on page 4.

•• 48" (1219mm) when heater air flow is between 45° downward and vertical.

BTU per

Hr.

BTUH

25,598
21,331
17,065
12,799

19,198
15,990
12,799

9,598

Phase

Contactor

Built-in

1

1

Yes

Yes

Mounting Height, ft. (mm)

Vertical Installation

Min.

6'

(1829)

6'

(1829)

Max. Min. Max.

11'

(3353)6'(1829)8'(2439)

11'

(3353)6'(1829)8'(2439)

Horizontal Installation

Horizontal Air

Throw, ft. (mm)

18'

(5486)

18'

(5486)

Min. Distance from

Mounting Hole to

Wall, in (mm)

••13"

(330)

••13"

(330)

Read Carefully - These instructions are written to help you prevent
difficulties that might arise during installation of heaters. Studying the
instructions first may save you considerable time and money later.
Observe the following procedures, and cut your installation time to a
minimum. TO REDUCE RISK OF FIRE OR ELECTRIC SHOCK:

1. Use minimum 60° copper wire only.

2. Heater air flow must be directed parallel to, or away from,
adjacent walls.

3. Observe wall, floor, and ceiling clearance requirements.

4. All wiring must conform to national and local electrical codes and

WARNING

the heater must be grounded as a precaution against possible
electrical shock. Heater circuit must be protected with proper
fuses. See Table 1 on page 4.

5. The mounting structure and the anchoring hardware must be
capable of reliably supporting the weight of the heater and, if
used, the mounting bracket.

6. All electrical power must be disconnected at the main service box
before installing, inspecting, cleaning or servicing the heater. This
is a precaution to prevent serious electrical shock.

SAVE THESE INSTRUCTIONS

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WARNING

!

!

THIS UNIT OPERATES ON 240 OR 208 VOLTS AC. IMPROPER
INSTALLATION OR FAILURE TO FOLLOW THE PROCEDURES
AS OUTLINED IN THIS MANUAL CAN RESULT IN SERIOUS
ELECTRICAL SHOCK. DISCONNECT ALL POWER FROM THE
HEATER AT THE MAIN SERVICE BOX BEFORE ATTEMPTING
TO INSTALL OR SERVICE THIS UNIT.

WARNING

ALL ELECTRICAL WIRING MUST CONFORM TO LOCAL ELEC­TRICAL CODES. HEATER CIRCUIT MUST BE PROTECTED
WITH PROPER FUSES. SEE TABLE 1 ON PAGE 4.

INTRODUCTION

Congratulations! You have just purchased one of the most ver­satile electric space heaters available. Your new electric unit
heater has unmatched operating flexibility. It is designed to meet
a variety of heating requirements by simply switching a few easi­ly accessible wires located in the base of the unit (See output
ranges in Specifications on page 1). This unique feature lets you
use a single unit to meet a wide range of heating applications.
The UH heaterʼs unique mounting system simplifies both installa­tion and air flow control. The mounting bracket attaches to the
ceiling with a single screw and allows you to turn the entire heater
in a full circle. The mounting bolts on the sides of the heater per­mit you to adjust the air flow direction to any angle between hori­zontal and vertical. The louvers adjust up and down for even
greater control.
These features combine to make the UH heater the most versa­tile space heater available anywhere for applications ranging from
garages, basements, and workshops, to public buildings, service
stations, stores, mini-warehouses, stockrooms, or similar applica­tions. It can be installed easily by anyone in only a few minutes.
This manual shows you how to install, operate, and maintain your
UH Series electric heater.

Proper size fuses and circuit breakers in accor-

•
dance with the National Electrical Code. Also see
Table 1, page 4.
Note:

For certain applications, conduit may be

equired (see Fig. 1). Check local electrical

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codes. Also, if you run the wiring in conduit and
wish to be able to turn the heater, be sure to pur­chase enough flexible conduit to allow the heater

o be turned.

t

Fig. 1

Connectors, cable, and hardware used to wire the UH Heater

(Illustration may not apply to UH724ST due to supply wire sizes)

INSTALLATION

Location Of Heater

The heater should be installed out of traffic areas and at least 6'
off the floor. The direction of air flow should not be restricted (ie:
by columns or machinery) and the air flow should wipe exposed
walls, rather than blowing directly at them. When more than one
heater is used in an area, the heaters should be arranged so that
the air discharge of each heater supports the air flow of the oth­ers to provide best circulation of warm air, as indicated in
Figure 2.

Fig. 2

Unpacking Your New Heater

Remove the heater from the box and inspect it for any damage. If
it appears to be damaged, immediately return it to the store from
which you purchased it.
Check the contents of the box to make sure it contains one heat­ing unit and one mounting bracket.

Tools Needed

You will need the following tools to install your UH Series
electric heater:

• Screwdriver • Needle nose pliers • Pliers

• Electric Drill and 1/4" bit •Adjustable wrench

Hardware Needed

You will also need the following hardware for installation:

• Enough properly sized insulated copper conductor
(with ground) wire to run power from the
breaker/fuse to the heater. Only use copper
wire rated at least 75° C. Do not use aluminum
wire with this unit. Refer to local and national electrical

codes for proper supply wire selection.

Mounting Height

When the air flow of the heater is directed vertically, the minimum
mounting height is 6 feet (1829mm), the maximum mounting
height is 11 feet (3353mm). When the air flow of the heater is
directed horizontally the minimum mounting height is 6 feet
(1829mm) and the maximum recommended height is
11 feet (3353mm).

Distance from Walls

When the heater is mounted so that the air flow direction is at an
angle from horizontal to 45° downward and vertical, the distance
from the mounting bracket to any wall should be at least 13 inch­es (330mm). When the heater is mounted so that the direction of
air flow is at an angle between 45° downward and vertical, the
distance from the mounting bracket to any wall should be at least
48 inches (1219mm).

2

. Mounting the Bracket

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C

EILING JOIST

WASHER

3

/8"

DIAGONAL

LAG BOLT

B

RACKET

CEILING JOIST

3/8" DIAGONAL

LAG BOLTS

BRACKET

WASHERS

1

Locate a stud in the ceiling and attach the mounting bracket to the
ceiling joist as shown in figures 3-A or 3-B. You will need to
remove the mounting bracket from the heating unit by loosening
the bracket screws with a wrench and slipping the handle off over

he screw heads. Remember to place a washer on the screws

t
before you insert them through the holes in the mounting bracket
and screw them into the stud. Tighten the screws enough to
securely hold the heating unit with the air flow pointed in the prop-

r direction.

e

Fig. 3-A

ingle-Screw Mounting

/8" DIAGONAL

3

LAG BOLT

S

(Ill.1)

onnect the wire to the power terminal block located in the base

C
of the heater (See Fig. 5).

Fig. 5

NOTE: TO DECREASE THE HEAT OUTPUT OF THE HEATING
UNIT, SEE TABLE 1 AND SCHEMATIC DIAGRAMS ON PAGE 4.

Turn on the power at the main service.

Fig. 3-B

Double-Screw Mounting

Ill.2)

(

2. Hanging the Heater

Attach the heating unit to the mounting bracket. Lift the heater up
and into the mounting bracket. The bracket screws, located on
each side of the heating unit, allow the heater to be attached eas­ily to the mounting bracket by aligning the screws with the keyhole
slots in the mounting brackets. If the heater is to be tilted, it must
be positioned in the lower keyhole slots (see Fig. 4). Tighten the
bracket screws with a wrench so the unit is securely suspended
at the desired horizontal or vertical angle.

3. Connecting the Power

To connect the power to the heater, simply remove the screw from
the front of the unit. This allows the hinged bottom to open, pro­viding access to the electrical wiring and connectors. (See Fig. 4)
Attach the cable connectors to the unit (See Fig. 1, pg 2) and slide

Fig. 4

OPERATION

Setting the Thermostat

Rotate thermostat knob clockwise to high position. After room
reaches desired comfort level, rotate thermostat knob counter­clockwise until the thermostat clicks off. (Note that the fan delay
will keep the fan running until the elements cool.) Heater will cycle
on and off to maintain room temperature.

NOTE: THE FIRST TIME YOU OPERATE THE UNIT, IT MAY
SMOKE SLIGHTLY. THIS IS DUE TO THE RESIDUAL CLEAN­ING AGENTS USED TO CLEAN THE ELEMENT WHEN THE
HEATER IS MANUFACTURED. THIS IS NORMAL AND DOES
NOT INDICATE A PROBLEM WITH THE UNIT. THIS CONDI­TION WILL STOP AFTER THE HEATER HAS BEEN IN OPER­ATION FOR A FEW MINUTES.

Automatic Fan Delay: The UH heater has an automatic fan

delay. When the thermostat calls for heat, fan action is delayed
momentarily until the heating elements warm. This prevents the
circulation of cold air. When the heater raises the temperature of
the room to the thermostat set point, the heating element is turned
off but the fan will continue to run until the heating element cools
down. This prevents exposing the unit to residual heat, provides a
higher comfort level and prolonged element life.

USE BOTTOM KEYHOLE

SLOTS IF HEATER IS

TO BE TILTED DOWN

the correctly sized wire through the cable connector. Pull enough
of the wire through the connector so you will have enough wire to
work with when you make the connections.

REMOVE SCREW TO OPEN DOOR

Thermal Cutout: The UH heater is also equipped with a thermal
cutout which will automatically shut off the heater in the event of
overheating. The heater will turn on when the operating tempera­ture returns to normal. Should the unit overheat and activate the
thermal cutout cycle, the cause of the overheating should be
determined before further operation.
NOTE: If the unit is installed in an area where the temperature is
below 50° F, the fan may cycle on and off until the temperature in
the room rises above 50° F. This is normal and does not indicate
a problem with the unit. As soon as the heater warms the air in the
room above 50°, the unit will cycle normally.

3

ADJUSTING AIR FLOW DIRECTION

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ND

4

6

5

2

3

1

MOTOR

FAN

2

1

1

1

1

2

9

10

8

7

L1 L2

DCBA

ELEMENT

FAN

C

ONTROL

HI LIMIT

FIELD WIRING

POWER

T

ERMINAL

BLOCK

THERMOSTAT

WATTAGE CHANGE

TERMINAL BOARD

R

ED

YEL

BLU

BLK

T3 T2 T1

CONTACTOR

L3

2

L2

1

L1

You can adjust the direction of air flow by:
A. Turning the unit. If the unit has been installed

with a single lag bolt, as shown in Figure 6,
simply turn the entire unit as needed to adjust
air flow.

B. Tilting the unit. Loosen the bracket screws, tilt

Fig. 6

the heater to the desired position, and re-tighten
the bracket screws (see Figure 4).
NOTE: To tilt the heater it must be mounted in
bottom keyhole slots of mounting bracket to
maintain adequate clearance and prevent possible
overheating.

C. Adjusting the louvers to the desired position.

NOTE: The louvers are designed so they can not be
completely closed. Do not attempt to defeat this feature,
damage to the unit can result.

ADJUSTING HEAT OUTPUT

Heat output can be increased or decreased by switching wires at
the wattage change terminal board. The heater is factory wired to
deliver the maximum heat output for the model used. Should your
particular application require less heat output, refer to Table 1
and change the wires at the wattage change terminal board as
shown in Wiring Diagram Fig. 7.

WARNING

ig. 7

F

UH724ST Wiring Diagram

MAINTENANCE

Because of its rugged design, superior engineering, and high­quality craftsmanship, the UH heater requires little maintenance.
With proper care, your electric heater should last a lifetime, but
seasonal cleaning is recommended to maintain the efficiency of
the heater.

Cleaning the Heating Element

To clean the heating element, loosen (but do not remove) the four
Phillips head screws located behind the louvers in the corners of
the louver housing (See Fig. 8, page 5).

TO PREVENT POSSIBLE ELECTRIC SHOCK, DIS­CONNECT POWER TO THE HEATER AT THE MAIN
SERVICE BOX BEFORE ATTEMPTING TO ADJUST
THE HEAT OUTPUT OF THIS UNIT.

TABLE 1. HEAT OUTPUT ADJUSTMENTS

MAX

BTU/HR VOLTS WATTS

25,598

21,331

240 7500

240 6250 35 26.1

17,065 240 5000 30 20.9 BLUE & YELLOW
12,799 240 3750

19,198

15,990

12,799

9,598 208 2812 20 13.6 BLUE, YELLOW & RED

208 5625 40 27.1
208 4685

208 3750

FUSE

SIZE

45

HEATER

AMPS

31.3 NONE

MOVE JUMPERS

FROM C-D TO A-B

BLUE

20

15.7

30 22.3 BLUE

25 18.1 BLUE & YELLOW

BLUE, YELLOW & RED

NONE

WARNING

USE CARE TO PREVENT DAMAGE TO INTERNAL
HEATER WIRING WHEN CLEANING ELEMENT. MAKE
SURE ALL CONNECTIONS REMAIN TIGHT AND ALL
WIRING IS ROUTED AWAY FROM ELEMENT FINS
WHEN REASSEMBLING THE UNIT. ALLOWING
WIRING TO TOUCH THE ELEMENT FINS COULD
RESULT IN A FIRE HAZARD.

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Fig. 8

Heating Element Bezel Assembly & Louver Housing

Grasp the louver housing on both sides, lift up, and pull out. This
provides access to the heating element.

ote: Element, limit and fan delay wiring are attached. When

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removing Bezel Assembly, do so carefully as not to pull wiring
loose.

Remove dust or lint with a soft brush or a vacuum cleaner.

Replace the louver housing and tighten the Phillips head screws.

Fig. 9

Cleaning the Fan and Motor

Remove the protective grille from the rear of the heater. This pro­vides access to the fan and motor. Wipe off the fan and motor with
a soft cloth or brush. The fan motor does not require lubrication.
Replace protective grille (See Fig. 9).

TABLE 2.
REPLACEMENT PARTS FOR UH SERIES ELECTRIC HEATERS

QUANTITY

KEY NO. DESCRIPTION PART NUMBER UH724

1 Element 302006810 1
2 Motor 3900-2008-000 1
3 Fan Control Assembly 410148000 1
4 High Temp. Limit Control 410027000 1
5 Thermostat 5813-2050-000 1
6 Thermostat Knob 3301-2014-006 1
7 Motor Mount 1215-2235-003 1
8 Fan Blade 1210-2017-000 1

9 Ceiling Bracket (Handle) 310876001 1
10 Wire Guard 312056802 1
11 Louver 3503-2004-010 4
12 Bezel Assembly 200162902 1
13 Cover (Access Door) 310104902 1
14 Bracket Screw 400029008 2
15 Cover Wrap Assembly 200193902 1
16 Control Box Assembly 200161902 1
17 Power Terminal Block 5823-0004-005 1
18 Wattage Change Board 5823-0003-001 1
19 Power Relay 5018-0004-102 1

5

19

18

UH SERIES REPLACEMENT PARTS

All products manufactured by Marley Engineered Products are warranted against defects in workmanship and materials for one year from date of instal-

LIMITED WARRANTY

lation, except heating elements which are warranted against defects in workmanship and materials for ten years from date of installation. This warranty
does not apply to damage from accident, misuse, or alteration; nor where the connected voltage is more than 5% above the nameplate voltage; nor to
equipment improperly installed or wired or maintained in violation of the productʼs installation instructions. All claims for warranty work must be accom­panied by proof of the date of installation.

The customer shall be responsible for all costs incurred in the removal or reinstallation of products, including labor costs, and shipping costs incurred
to return products to Marley Engineered Products Service Center.Within the limitations of this warranty, inoperative units should be returned to the
nearest Marley authorized service center or the Marley Engineered Products Service Center, and we will repair or replace, at our option, at no charge
to you with return freight paid by Marley. It is agreed that such repair or replacement is the exclusive remedy available from Marley Engineered
Products.

THE ABOVE WARRANTIES ARE IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED. AND ALL IMPLIED WARRANTIES OF MER­CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE WHICH EXCEED THE AFORESAID EXPRESSED WARRANTIES ARE HEREBY
DISCLAIMED AND EXCLUDED FROM THIS AGREEMENT. MARLEY ENGINEERED PRODUCTS SHALL NOT BE LIABLE FOR CONSEQUENTIAL
DAMAGES ARISING WITH RESPECT TO THE PRODUCT, WHETHER BASED UPON NEGLIGENCE, TORT, STRICT LIABILITY, OR CONTRACT.

Some states do not allow the exclusion or limitation of incidental or consequential damages, so the above exclusion or limitation may not apply to you.
This warranty gives you specific legal rights, and you may also have other rights which vary from state to state.

For the address of your nearest authorized service center, contact Marley Engineered Products in Bennettsville, SC, at 1-800-642-4328. Merchandise
returned to the factory must be accompanied by a return authorization and service identification tag, both available from Marley Engineered Products.
When requesting return authorization, include all catalog numbers shown on the products.

HOW TO OBTAIN WARRANTY SERVICE AND
WARRANTY PARTS PLUS GENERAL INFORMATION

1. Warranty Service or Parts 1-800-642-4328

2. Purchase Replacement Parts 1-800-654-3545

3. General Product Information www.marleymep.com

Note: When obtaining service always have the following:

1. Model number of the product

2. Date of manufacture

3. Part number or description

5200-2797-001

ECR 38550

02/10

470 Beauty Spot Rd. East
Bennettsville, SC 29512 USA