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Installation instructions and Owner’s Manual
Model # MH25NG/LP HS25NG/LP
3. GENERAL INFORMATION
• Your heater comes fully assembled and is tested
at the factory with the appropriate type of gas
and at the input pressures stated on the name-
plate.
• Upon receipt and prior to attempting installation,
be sure to inspect the heater and its packaging
for damage and/or missing components. If dam-
age is found or missing components are sus-
pected, contact your dealer. See Chapter 5 for a
complete listing of items required for the safe and
efcient installation and use of this heater.
• Never attempt to operate the heater using a
fuel other than that specically identied on the
nameplate.
• The installation of the heater must conform with
all local building codes or, in absence of gov-
erning local codes, with the National Fuel Gas
Code, ANSI Z223.1 (NFPA 54). This code can
be obtained from either the: Canadian Standards
Association, 8501 East Pleasant Valley Road,
Cleveland, OH 44131; or, NFPA, Battery March
Park, Quincy, MA 02269.
• Canadian installations must comply with CAN/
CGA-B149.1.2 gas code which can be purchased
from Canadian Gas Association, 55 Scarsdale
Road, Don Mills, Ontario M3B 2R3.
• Contact factory when appliance is to be installed
at high altitudes. Factory can supply high altitude
conversion kit with instructions and data plate.
• A plugged 1/8” N.P.T. Test Gage Connection is
provided on the heater gas control.
• See Tables 1 and 2 for heater specications:
WARNING: Improper installation, adjustment, al-
teration, service or maintenance can cause property
damage, injury or death. Read the installation, opera-
tion, and maintenance instructions thoroughly before
installing or servicing this equipment. For assistance
or additional information consult a qualied installer,
service agency, or gas supplier.
• For additional information contact Mr. Heater Toll-
Free 800-251-0001—www.mrheater.com
The following extra NFPA Manuals are helpful when
installing this heater in a location not anticipated in this
manual:
Number Related Subject
NFPA 88 Clearances to Combustible Surfaces
NFPA 409 Clearances to Combustible Surfaces
DO NOT EXCEED 1/2 PSI INLET PRESSURE TO HEATER
Provide adequate clearance to combustibles per Table 3
at control end of heater for servicing and minimum on top
and sides for ventilation and combustion air supply.
A minimum clearance of 8’ above oor for public garages
in accordance with NFPA No. 88 most recent edition, or
Figure 1; whichever is larger.
Canadian installations in public garages must comply with
CGA 149B.1.9 most recent edition.
WARNING: Maintain clearances as shown in Figure 2
or on heater nameplate.
Table 1. BTU Ratings and Supply Pressures
MODEL BTU/HR. RATING GAS SUPPLY PRESSURE (W.C.) ORIFICE
NO. GAS MIN. MAX. MANIFOLD SIZE
NATURAL PROPANE NAT. L.P. NAT. L.P. NAT. L.P. NAT. L.P.
MH/HS25NG 25,000 — 7.0” — 14” — 6” — 45 —
MH/HS25LP — 22,000 — 11” — 14” — 10” — 55
Table 2. Heater Dimensions and Orice Sizes
MODEL OPERATING ORIFICE SIZE INPUT SIZE
NO. PRESSURE BURNER PILOT BTU/H WIDTH LENGTH HEIGHT WEIGHT
MH/HS25NG 6.0”w.c. 45 .018 25.000 12-1/4” 29-3/4” 7” 20 lb.
MH/HS25LP 10”w.c. 55 .011 22,000 12-1/4” 29-3/4” 7” 20 lb.