High Altitude Instructions - Rheem (-)GRC Series Installation Instructions Manual

LP CONVERSION
NOTE: See Page 47 for Canadian
High-Altitude Derate
IMPORTANT: LP gas from trucks
used to transport liquid-based
fertilizers can contain chemicals that
will damage the furnace. Verify that
your gas supplier does not use the
same trucks to transport materials
other than LP.
The valve can be converted to use
liquified petroleum (LP) gas by
replacing the pressure regulator
spring with the conversion kit spring.
This LP kit spring allows the regulator
to maintain the proper manifold
pressure for LP gas. See Figure 40.
NOTE: Order the correct LP
conversion kit from the furnace
manufacturer. Furnace conversion to
LP gas must be performed by a
qualified installer, service agency or
the gas supplier.
ORIFICE INSTALLATION
LP Gas is a manufactured gas that
has consistent heating value across
most regions.
The Sea Level input should still be
reduced by 3.5-4% per thousand ft.
and the orifice size must be selected
based on the reduced input selection
chart below.
Altitude Orifice Size
0 to 5000
5000 -8000
To change orifice spuds for either
conversion to LP or for elevation:
1. Shut off the manual main gas
valve and remove the gas
manifold.
2. Replace the orifice spuds.
3. Reassemble in reverse order.
4. Turn the gas supply back on and
check for proper operation and
manifold pressure. See Figures
41, 42 and 43.
5. Attach the notice label alerting
the next service technician that
the furnace has been converted
to LP gas.
38
FIGURE 40
TYPICAL LP KIT CONTENTS
ORIFICE ORDERING
INFORMATION
Orifice sizes are selected by adding
the 2-digit drill size required in the
orifice part number. Drill sizes
available are 39 through 64; metric
sizes available 1.10mm (-90) and
1.15mm (-91):
Orifice Part Number 62-22175-(drill
1.15 mm
size)
1.10 mm
Example 1:
#60 drill size orifice required
Part # 62-22175-60
Example 2:
1.15mm drill size orifice required
Part # 62-22175-91
90+ HIGH ALTITUDE
INSTRUCTIONS
The GRC and GTC models do not
require any changes for high altitude
application, except L.P. conversion
case.
See the L.P. conversion section on
this page.