Lochinvar XDN051G User Manual

Double Duty

Atmospheric and

Domestic Water and Space Heating
All In One

How It Works

The Double Duty, like our other popular residential water
heaters, heats water for domestic use and stores it in a triple
tested, glass-lined storage tank. While in the tank, the domestic
hot water transfers heat to the glass-coated heat exchanger that
is immersed inside the tank. Within these tubes, water for space
heating is circulated and heated. This internal heat transfer
allows the Double Duty to serve two purposes. It provides hot
water for domestic use while maintaining a comfortable space
temperature through hydronic or radiant heating for a room
addition or a apartment over a garage.

Standard Features

 2" Non-CFC Foam Insulation - Improved formulation provides

uniform tank coverage with a thick blanket of insulating
foam. This non-CFC polyurethane closed cell foam minimizes

standby losses and maximizes heat retention.

 Glass-Lined Steel Tank - The tank is automatically formed,

rolled, and welded to ensure a continuous seam for the glass
lining. The durable glass lining is fused to the interior of the
tank at 1600°F to assure lasting protection against rust and

corrosion while providing clean, clear hot water.

 Aluminum Tank Saver Anode - High capacity anode rod

provides protection from the effects of electrolytic corrosion.

 Heat Traps - Factory installed, minimizes heat loss through piping.
 Dielectric Nipples - Factory installed waterways protect the

tank from the corrosive action between dissimilar metals,
while providing piping convenience.

 Double Wall Heat Exchanger - Double Wall 1-1/2” O.D. glass

coated steel coil separates domestic water from heating fluid.
A leak path between the two walls of tubing, terminating at a
weep port on the top side of the top heat exchanger opening,
provides a visual alert should a leak occur in either tube.

 Low Heat Exchanger Head Loss - With less than 4 ft. of head

at 10 gpm flow through the coil, the required pump size for heat
exchange can be greatly reduced.

 Brass Drain Valve
 Temperature & Pressure Relief Valve

 6 Year Limited Warranty*

(See warranty for details)

 10 Year Extended Warranty Available

(In residential applications)

* 3 year limited warranty on tank and 1 year limited warranty on Parts

when installed in commercial applications

Power Vented
Gas Water Heaters

XPN075

XDN051G

Use space heating Btu/hr requirement and
supply water temperature to select appropriate
Double Duty heater.

Additional Features for Power Vented Models:

 Vertical or Sidewall Venting
 Vents up to 60 equivalent feet with 3” PVC
 Vents up to 180 equivalent feet with 4” PVC

Note: 90° elbows = 5 eq. ft.

Dimensions and Specifications

B

HOT
WATER
OUTLET

COLD
WATER
INLET

HOT
WATER
OUTLET

COLD
WATER
INLET

Top

Top

D

E

A

F

G

Power Vented

Atmospheric

Model Gal. Btu/hr GPH @ Vent Shipping
Number Cap. Input 90°F Rise AFUE A B D E F G Size Weight

Atmospheric Models
XDN051G 45 65,000 70 80.0 56-1/2” 22” 59-1/4” 50” 28” 13” 4” 238
XDL051G (LP) 45 61,000 66 80.0 56-1/2” 22” 59-1/4” 50” 28” 13” 4” 238
XDN075† 72 76,000 82 80.0 60-1/2” 26” 63-3/4” 53” 31” 16” 4” 328
XDL075 (LP)† 72 76,000 82 80.0 60-1/2” 26” 63-3/4” 53” 31” 16” 4” 328
Power Vented Models
XPN051G 45 67,000 72 82.0 56-1/2” 22” 66” 50” 28” 11-3/4” 3” 245
XPL051G (LP) 45 60,000 65 82.0 56-1/2” 22” 66” 50” 28” 11-3/4” 3” 245
XPN075† 72 76,000 82 82.0 60-1/4” 26” 69-3/4” 53” 31” 15” 3” 286
XPL075 (LP)† 72 75,500 81 82.0 60-1/4” 26” 69-3/4” 53” 31” 15” 3” 286

Notes: “G” Suffix indicates models equipped with the Shield Combustion System 110 VAC 60 HRZ 2.1 AMPS required for Power Vented models.

“X” Prefix indicates 10 year tank warranty Models fired above 75,000 Btu/Hr are certified to ANSI Z21.10.3

“N” indicates Natural gas, replace “N” with “L” for LP models and are not required to meet the NAECA or FVIR standard.

† Indicates models not equipped with Heat Traps. Performance data is based on manufacturer’s test results

All water connections are 3/4” NPT

All gas connections are 1/2” NPT

Double Duty Pressure Drop

Lochinvar Corporation • 300 Maddox Simpson Pkwy • Lebanon, TN 37090 • 615-889-8900 / Fax: [phone]

DD-09 (Replaces DD-08 5/10)

www.Lochinvar.com

FOR EASE IN ORDERING

BY MODEL NUMBER

X P N 075

DOUBLE

POWER

DUTY

VENT

GALLON

NATURAL GAS

CAPACITY

This heater is 72 gallon Double Duty

Power Vented natural gas water heater.

PDP-5M-4/11–Printed in U.S.A.