Page 1
©
2014 Lennox Industries Inc.
Litho U.S.A.
Corp. 1025-L5
ML193UH
Service Literature
Revised 03-2014
ML193UH SERIES UNITS
ML193UH series units are high-efficiency gas furnaces
manufactured with Lennox DuralokPlus
t
aluminized steel
clamshell-type heat exchangers, with a stainless steel con
densing coil. ML193UH units are available in heating input
capacities of 44,000 to 132,000 Btuh (13 to 38.6 kW) and
cooling applications from 2 through 5 tons (7.0 through
17.6 kW). Refer to Engineering Handbook for proper siz
ing.
Units are factory equipped for use with natural gas. A kit is
available for conversion to LPG operation. All ML193UH
units are equipped with a hot surface ignition system. The
gas valve is redundant to assure safety shut-off as required
by C.S.A.
The heat exchanger, burners and manifold assembly can
be removed for inspection and service. The maintenance
section gives a detailed description on how this is done.
All specifications are subject to change. Procedures out
lined in this manual are presented as a recommendation
only and do not supersede or replace local or state codes.
WARNING
Electric shock hazard. Can cause injury
or death. Before attempting to perform
any service or maintenance, turn the
electrical power to unit OFF at discon
nect switch(es). Unit may have multiple
power supplies.
Table of Contents
Specifications
2
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Optional Accessories
3
. . . . . . . . . . . . . . . . . . . . . . . . . .
Blower Performance Data
4
. . . . . . . . . . . . . . . . . . . . . .
I-Unit Components
7
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
II Placement and Installation
19
. . . . . . . . . . . . . . . . . . . .
III-Start-Up
40
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IV-Heating System Service Checks
41
. . . . . . . . . . . . . .
V-Typical Operating Conditions
43
. . . . . . . . . . . . . . . . .
VI-Maintenance
44
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VII-Sequence of Operation and Flow Charts
47
. . . . . .
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person
al injury or loss of life. Installation and service must
be performed by a licensed professional HVAC in
staller (or equivalent), service agency or the gas sup
plier.
WARNING
Sharp edges.
Be careful when servicing unit to avoid sharp edges
which may result in personal injury.
