Unitary Products Group
ACCESSORY KIT INSTALLATION INSTRUCTIONS
HIGH ALTITUDE APPLICATION CONVERSION
MID-EFFICIENCY SINGLE-STAGE INDUCED COMBUSTION FURNACES
MODELS: P*HU/G8T-UH/L8T-UH/FL8 UPFLOW / HORIZONTAL
P*DN/G8T-DN/L8T-DN DOWNFLOW
035-14446-000 Rev. B (1002)
GENERAL
This instruction is intended for the conversion of new equip-
ment only, for operation at altitudes greater than 4,500 ft.
above sea level. Follow the basic unit installation instruction
for all other aspects of the installation.
All units are equipped to operate up to 4,500 feet above sea
level without a high altitude kit. Installations above 2,000 ft.
must be field derated as required by the National Fuel Gas
Code, ANSI Z223.1 (latest edition), or in Canada, CAN/CGA
B149.1 or .2 and all other applicable local codes and utility
requirements.
This instruction provides the necessary information to select
and install both the proper pressure switch and orifice for
your specific application. Data is provided for both natural
and propane (LP) gases. This high altitude pressure switch
and accessory includes a special switch and other items as
detailed below.
.
* May be any numeral 0-9.
PRESSURE SWITCH
For installations below 4500 ft., refer to furnace installation
instructions to properly derate applications which do not
require a pressure switch change. For applications above
4,500 feet, a pressure switch change is required to provide
safe and reliable operation. Table 1 indicates the correct
pressure switch accessory for each unit model applied.
This conversion kit is to be installed by a qualified service agency in accordance with the manufacturer’s instructions
and all applicable codes and requirements of the authority having jurisdiction. If the information in these instructions is
not followed exactly, a fire, an explosion or production of carbon monoxide may result causing property damage, per-
sonal injury or loss of life. The qualified service agency is responsible for the proper installation of this kit. The installa-
tion is not proper and complete until the operation of the converted appliance is checked as specified in the
manufacturer’s instructions supplied with the kit.
The conversion of new certified central heating gas appliances must conform to directions outlined in this instruction.
Installation must be made in accordance with American National Standard National Fuel Gas Code, ANSI Z223.1-lat-
est edition, unless superseded by local codes. For Canadian installations, the conversion shall be carried out in accor-
dance with the requirements of the Provincial authorities having jurisdiction and in accordance with the CAN1-B149.1
and .2 installation codes.
The manufacturer accepts no responsibility for malfunctions due to improper conversions.
Improper installation, adjustment service, or mainte-
nance can cause injury or property damage; there-
fore, only a qualified installer or qualified service
personnel should perform this conversion.
COMMON PARTS
Description
Part Number
Quantity
Conversion Label
035-11635-000
1
Install. Instruction.
035-14446-000
1
PRESSURE SWITCH
Accessory Kit
Switch Part Number
Pressure Setting
1PS0301
024-27669-00*
.35 IWG
1PS0302
024-27627-00*
.42 IWG
1PS0311
024-27626-00*
.40 IWG
1PS0312
024-27628-00*
.45 IWG
Do not adjust the original pressure switch to allow
operation at high altitude. Unsafe operation will
result.
Table 1:
HIGH ALTITUDE PRESSURE SWITCH USAGE
INPUT
(MBH)
OUTPUT
(MBH)
ACCESSORY
PART NUMBER
Upflow / Horizontal & Downflow Models
40
32
1PS0301
57
46
1PS0301
80
64
1PS0301
100
80
1PS0311
115
92
1PS0311
130
104
1PS0311
160
130
1PS0301
