Mr. Heater mh25 Manuale Utente

E2

Installation instructions and Owner’s Manual

Model #  MH25NG/LP 

HS25NG/LP

 WARNING: Improper installation, adjustment, 

alteration, service or maintenance can cause 

property damage, injury or death. Read the 

installation, operation, and maintenance instruc-

tions thoroughly before installing or servicing this 

equipment.  For assistance or additional informa-

tion consult a qualified installer, service agency, 

or gas supplier. 

 WARNING: When used without fresh air, heater 

may give off CARBON MONOXIDE, an odorless 

poisonous gas. OPEN WINDOW AN INCH OR 

TWO FOR FRESH AIR WHEN USING HEATER.

 WARNING: This heater is equipped with a PILOT 

LIGHT SAFETY SYSTEM. DO NOT TAMPER 

WITH PILOT LIGHT SAFETY SYSTEM.

 WARNING: If heater shuts off, do not relight until 

you provide fresh air. If heater keeps shutting off, 

have it serviced. Keep burner and control clean. 

Open door for 5 minutes.
Maintain clearances as shown in Figure 2 or on 

heater nameplate.
•  DO NOT USE MATCH OR OTHER FLAME 

FOR LEAK TESTING.

•  DO NOT EXCEED 1/2 PSI INLET PRES-

SURE TO HEATER.

DANGER: Carbon monoxide poisoning may lead to 

death. 

Early signs of carbon monoxide poisoning resemble the 

flu, with headaches, dizziness, or nausea.  If you have 

these signs, the heater may not be working properly. 

Get fresh air at once! Have heater serviced.  Some 

people are more affected by carbon monoxide than oth-

ers.  These include pregnant women, persons with heart 

or lung disease or anemia, those under the influence of 

alcohol, and those at high altitudes.

•  Never connect gas valve or thermostat to line volt-

age or a transformer.

•  If the infra-red color of the grid becomes dull when 

the building furnace is operating, consult gas sup-

plier on correct gas supply piping sizes.

•  This heater is for indoor installation only!

NOTE
Gasket binder material used in this heater assembly will 

temporarily emit an odor and/or vapor. This condition 

will clear up in approximately 20 minutes and thereafter 

will not reoccur. Refer to Chapter 2 for ventilation.

I 

Introduction .............................................  E3

II 

Heater Installation ..................................  E5

III 

Heater Operating Instructions ................ E10

IV 

Operator Maintenance Instructions ........ E12

V 

Replacement Parts List .......................... E15

 

COMBUSTION BY-PRODUCTS PRODUCED 

WHEN USING THIS PRODUCT CONTAIN CAR-

BON MONOXIDE, A CHEMICAL KNOWN TO THE 

STATE OF CALIFORNIA TO CAUSE CANCER 

AND BIRTH DEFECTS (OR OTHER REPRODUC-

TIVE HARM).