
Xtreme™ is a family of high-input, fast recovery
commercial water heaters that complies
with Low NOx Emissions
Water
Commercial Gas
Xtreme Water Heaters
Features & Benefits
Xtreme is an advanced line of fast
recovery commercial gas water heaters.
These products can deliver up to 756
gallons per hour at 100 degree F rise.
The small jacket diameter makes it a
popular choice for retro fits and it is a
versatile choice for new construction.
Models range from 500,000-715,000
Btu/h, with a maximum temperature
setting of 180 degrees Fahrenheit.
Space Saver Design
Xtreme maximizes installation
adaptability by offering models with
front and rear inlet/outlet water
connections. Short heights and small
jacket diameters result in greater
installation flexibility.
System
™
Sentinel
LED
Diagnostic
System
Our exclusive
diagnostic system,
with glowing LED
lights, verifies system
operation sequence by sequence.
Patented Multi-Flue Tank
Design
Proprietary steel formulation, patented
multi-flue design, and two coats of high
temperature porcelain enamel maximize
corrosion resistance and result in a
superior heat exchanger design.
Automatic Flue Damper
Low profile design minimizes overall
product height. Heavy duty vent hood
supports are designed to withstand
rigors of installation.
Specialized Burner Assembly
Each model features five premix burners
mounted into a metal face plate and
sealed with a Viton gasket. Patented
“quick release” manifold for easier
service.
Direct Spark-to-Pilot
Ignition System
Energy saving ignition that ignites pilot
only when there is a call for heat.
Round Premix Burners
Precision burners are formed from high
chromium stainless steel.
Low NOx Emissions
GX90-550 and GX90-640 meet low
NOx emissions of less than 40 ng/J.
Full-port, Full-flow Drain Valve
Factory installed brass drain valve
allows for faster draining and servicing.
Altitude Certifications
Standard Natural and LP models are
certified up to 2,000 feet. High altitude
models, 8,000 feet.
Anode Rods
Patented design utilizes multiple
magnesium rods to ensure long life and
corrosion resistance.
Warranty
3-Year limited tank warranty
See Commercial Warranty Certificate for
complete information.
Efficiency | All models have been tested according
to ANSI test procedures, and exceed the thermal
efficiency and standby loss requirements of current
ASHRAE standards (Part of the Federally mandated
Energy Policy Act (EPact)). Also exceeds energy
efficiency codes of all states.
Safety and Construction | These products are
design certified by U.L.: a) For operation at 180°F.
b) To meet all safety and construction requirements
of ANSI Z21.10.3-2001 c) As an automatic storage
or instantaneous water heater. d) As an automatic
circulating tank water heater. e) For operation on
combustible floors and in alcove installations.
Certified for 150 PSI maximum working pressure
(160 PSI for ASME models).
Continued next page
Rheem Xtreme
90-Gallon Capacity
500,000-715,000 Btu/h
Low NOx
Natural and LP Gas
(On Selected
Models)
IN TEGRATED AIR & WATER
PRINTED IN U.S.A. 03/15 WP FORM NO. RR102C-15 Rev. 11

Xtreme Gas Water Heaters
CSA/ASME Rated T&P Valve
Factory installed relief valve
Insulation
Sag and moisture proof fiberglass
insulation surrounds the storage tank to
minimize heat loss.
Hand-Hole Cleanout
It’s perfect for removal of lime/sediment
deposits.
Manual Reset High Limit
All models are factory equipped with a
manual reset high limit to meet the code
Gas Control System
The fully adjustable thermostat ranges
from 100°F to 180°F and 24 volt
combination gas valve includes main
gas pressure regulation, On-Off manual
valve, 120/24 volt transformer, and high
limit temperature cut-out.
requirements of many states.
RECOVERY CAPACITIES Recovery in U.S. Gallons/Hr. (GPH) and Liters/Hr. (LPH) at Various Temperature Rises.
MODEL INPUT BTU/H THERMAL 40°F 50°F 60°F 70°F 80°F 90°F 100°F 110°F 120°F 130°F 140°F
NUMBER NATURAL & L.P. EFFICIENCY UNITS
GX90-550(A) 550,000 NAT 80%
LPH 5047 4037 3364 2884 2523 2243 2019 1835 1682 1553 1442
GX90-640(A) 640,000 NAT 80%
LPH 5873 4698 3915 3356 2936 2610 2349 2135 1958 1807 1678
GX90-715(A) 715,000 NAT 80%
LPH 6561 5249 4374 3749 3280 2916 2624 2386 2187 2019 1875
GX90-500(A) 500,000 LP 80%
LPH 4588 3670 3059 2622 2294 2039 1835 1668 1529 1412 1311
GX90-600(A) 600,000 LP 80%
LPH 5506 4404 3670 3146 2753 2447 2202 2002 1835 1694 1573
GX90-680(A) 680,000 LP 80%
LPH 6240 4992 4160 3565 3120 2773 2496 2269 2080 1920 1783
Recovery ratings are based on thermal efficiencies obtained in a CSA certified laboratory. Recovery rate shown on the rating plate (80%) Thermal Efficiency in
accordance with ANSI Z21.10.3 labeling requirements. (A) indicates available ASME model.
GPH 1333 1067 889 762 667 593 533 485 444 410 381
GPH 1551 1241 1034 887 776 690 621 564 517 477 443
GPH 1733 1387 1156 991 867 770 693 630 578 533 495
GPH 1212 970 808 693 606 539 485 441 404 373 346
GPH 1455 1164 970 831 727 647 582 529 485 448 416
GPH 1649 1319 1099 942 824 733 659 599 550 507 471
22°C 28°C 33°C 39°C 45°C 50°C 56°C 61°C 67°C 72°C 78°C
MAXIMUM DELIVERY In U.S. Gallons and Liters. (Includes useable storage and recovery for indicated times.)
MODEL TANK CAPACITY INPUT BTU/H TEMP. 5 10 15 20 30 45 60 120 180 Min. to Rec.
NUMBER
GX90-550(A) 90 341 550,000 NAT
55.6°C LTR. 407 575 743 911 1248 1752 2257 4276 6294
GX90-640(A) 90 341 640,000 NAT
55.6°C LTR. 434 630 826 1022 1413 2000 2587 4936 7285
GX90-715(A) 90 341 715,000 NAT
55.6°C LTR. 457 676 894 1113 1551 2207 2863 5487 8111
GX90-500(A) 90 341 500,000 LP
55.6°C LTR. 391 544 697 850 1156 1615 2073 3909 5744
GX90-600(A) 90 341 600,000 LP
55.6°C LTR. 422 606 789 972 1340 1890 2441 4643 6845
GX90-680(A) 90 341 680,000 LP
55.6°C LTR. 446 654 862 1070 1486 2110 2886 5230 7726
GALLONS
LITERS NAT. & L.P. RISE UNITS Min. Min. Min. Min. Min. Min. Min. Min. Min. Contents
100°F GAL 107 152 196 241 330 463 596 1130 1663
100°F GAL. 115 166 218 270 373 529 684 1304 1925
100°F GAL. 121 179 236 294 410 583 756 1450 2143
100°F GAL. 103 144 184 225 305 427 548 1033 1518
100°F GAL. 112 160 209 257 354 499 645 1227 1809
100°F GAL. 118 173 228 283 393 558 722 1382 2041
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Xtreme Gas Water Heaters
DIMENSIONAL INFORMATION All Dimensions Shown in English and Metric.
WATER CONNECTIONS APPROXIMATE
MODEL FRONT REAR
NUMBER UNITS
GX90-550(A)
mm 1892 1727 768 635 254 1509 25.4 51 51 905 945
GX90-640(A)
mm 1892 1727 768 635 254 1509 25.4 51 51 905 945
GX90-715(A)
mm 1892 1727 768 635 254 1509 25.4 51 51 905 945
GX90-500(A)
mm 1892 1727 768 635 254 1509 25.4 51 51 905 945
GX90-600(A)
mm 1892 1727 768 635 254 1509 25.4 51 51 905 945
GX90-680(A)
mm 1892 1727 768 635 254 1509 25.4 51 51 905 945
All models require a 120V power source. (A) Suffix indicates ASME tank construction available.
inches 74.5 68 30 25 10 59 1 2 2 905 945
inches 74.5 68 30 25 10 59 1 2 2 905 945
inches 74.5 68 30 25 10 59 1 2 2 905 945
inches 74.5 68 30 25 10 59 1 2 2 905 945
inches 74.5 68 30 25 10 59 1 2 2 905 945
inches 74.5 68 30 25 10 59 1 2 2 905 945
A B C D E F G
SIDE SIDE STD. ASME
SHIPPING WEIGHT
CLEARANCES TO
COMBUSTIBLES
MODEL
NUMBER UNITS SIDE REAR TOP
GX90-550
mm
GX90-640
mm
GX90-715
mm
GX90-500
mm
GX90-600
mm
GX90-680
mm
Allow a minimum of 18" (457mm) front clearance for
servicing.
2.5 Amps.
inches
inches
inches
inches
inches
inches
4 4 12
102 102 305
4 4 12
102 102 305
4 4 12
102 102 305
4 4 12
102 102 305
4 4 12
102 102 305
4 4 12
102 102 305
SYSTEM
SENTINEL
G
E
OUTLET
FRONT SIDE
INLET
FRONT SIDE
T&P
c
F
D
.010
40.117
10.117
3

Water
Commercial Gas
Xtreme Water Heaters
Recommended Specifications
(for trade reference only)
Water heater(s) shall be Xtreme model ________________,
manufactured by Rheem, having gas input of __________
Btu/h and a recovery rate of _____________ GPH at a 100°F
temperature rise when tested and certified at ____________
thermal efficiency. Water heater(s) shall have a storage
capacity of 90 gallons. Water heater(s) shall have the U.L.
seal of certification and supplied with a factory installed CSA/
ASME rated temperature and pressure relief valve. Tank(s)
shall be furnished with a tube bundle having a double coating
of high temperature porcelain enamel and furnished with
magnesium anode rods rigidly supported. Water heater(s)
shall meet or exceed the thermal efficiency and standby loss
requirements of current ASHRAE standards. Tanks shall have
a working pressure rating of 150 psi, and shall be completely
factory assembled, including a pressure regulator properly
adjusted for operation on ___________ gas with chromium
stainless steel burners. Controls will be arranged for safety
shutoff in event of pilot failure. Water heater(s) shall have front
and rear side inlet/outlet water connections. Water heater(s)
shall be covered by a three year limited warranty against tank
leaks.
When ordering ASME construction,
place (A) after the model number
(for trade reference only)
Water heater(s) shall be constructed in accordance with the
requirements of the ASME Boiler and Pressure Vessel Code,
Section IV Part HLW.
In keeping with its policy of continuous progress and product improvement, Rheem reserves the right to make changes without notice.
Rheem Water Heating • 101 Bell Road
Montgomery, Alabama 36117-4305 • www.rheem.com
IN TEGRATED AIR & WATER
Rheem Canada Ltd./Ltée • 125 Edgeware Road, Unit 1
Brampton, Ontario L6Y 0P5 • www.rheem.com
PRINTED IN U.S.A. 03/15 WP FORM NO. RR102C-15 Rev. 11
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