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© 2020 Lennox Industries Inc.
100001
10/2020
SLP99UHV
Service Literature
SLP99UHV SERIES UNITS
SLP99UHV series units are high-efficiency upflow, horizon
tal right and left) gas furnaces equipped with variable ca
pacity gas valve, variable speed combustion air inducer and
variable speed indoor blower motor. All models are de
signed only for direct vent (dual pipe) venting system.
SLP99UHV units are available in heating capacities from
66,000 to 132,000 Btuh (19.3 to 38.6 kW) and cooling ap
plications from 2 to 5 tons (7.0 kW to 17.5 kW). Refer to En
gineering Handbook for proper sizing.
Units are factory-equipped for use with natural gas. Kits are
available for conversion to LPG operation. SLP99UHV mod
els include a SureLight
®
variable capacity integrated control
that can be used with a Lennox communicating thermostat
as part of a communicating comfort system. All SLP99UHV
units meet the California Nitrogen Oxides (NO
x
) Standards
and California Seasonal Efficiency requirements.
All specifications in this manual are subject to change. Pro
cedures outlined in this manual are presented as recom
mendations only and do not supersede or replace local or
state codes. In the absence of local or state codes, the
guidelines and procedures outlined in this manual (except
where noted) are recommendations only and do not consti
tute code.
TABLE OF CONTENTS
Specifications Page 2.............................
Optional Accessories Page 3......................
Blower Data Page 4..............................
I Unit Components Page 20.......................
II Communicating Thermostat Page 44..............
III Placement and Installation Page 47..............
IV Start Up Page 63..............................
V Heating System Service Checks Page 60..........
VI Typical Operating Characteristics Page 69........
VII Maintenance Page 70..........................
VIII Wiring and Sequence of Operation Page 73.....
XI Field Wiring Page 81..........................
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
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.
CAUTION
As with any mechanical equipment, contact with
sharp sheet metal edges can result in personal injury.
Take care while handling this equipment and wear
gloves and protective clothing.
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