Carrier 58MVP040 Installation, Start-Up, And Operating Instructions Manual Download

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h. Jumper R to W/W1.

i. Let furnace run for 3 minutes in low-heat operation.

j. Measure time (in sec) for gas meter to complete 1 revolu-

tion. Note reading.

k. Refer to Table 14 for cubic ft of gas per hr.

l. Multiply gas rate cu ft/hr by heating value (Btu/cu ft).

m. Move setup switch SW-2 to OFF position and jumper R

and W2 thermostat connections. (See Fig. 25.) This keeps
furnace locked in high-heat operation. Repeat items h
through k for high-heat operation.

EXAMPLE: (High-heat operation at 0—2000 ft altitude)
Furnace input from rating plate is 100,000 Btuh
Btu heating input = Btu/cu ft X cu ft/hr
Heating value of gas = 975 Btu/cu ft
Time for 1 revolution of 2-cu ft dial = 70 sec
Gas rate = 103 cu ft/hr (from Table 14)
Btu heating input = 103 X 975 = 100,425 Btuh In this
example, the orifice size and manifold pressure adjustment
is within

2 percent of the furnace input rate.

NOTE:

Measured gas inputs (high heat and low heat) must be

within

2 percent of that stated on furnace rating plate when

installed at sea level or derated per that stated above when installed
at higher altitudes.

n. Remove jumper across R, W/W1, and W2 thermostat

connections to terminate call for heat.

SET TEMPERATURE RISE

Temperature rise must be within limits specified on unit
rating plate. Recommended operation is at midpoint of rise or
above. Failure to follow this caution may result in condensing
or overheating the heat exchangers.

Furnace must operate within range of temperature rise specified on
the unit rating plate. Determine air temperature rise as follows:

1. Place thermometers in return and supply ducts as near furnace

as possible. Be sure thermometers do not see heat exchanger
so that radiant heat does not affect readings. This practice is
particularly important with straight-run ducts.

2. When thermometer readings stabilize, subtract return-air tem-

perature from supply-air temperature to determine air tem-
perature rise.

NOTE:

Temperature rise can be determined for low-fire opera-

tion by placing setup switch SW-2 on control center in ON
position. For high-heat operation, place setup switch SW-2 in OFF
position and jumper R-W2 on control center. DO NOT forget to
return setup switch to OFF position and remove R-W2 jumper
upon completion of testing. (See Fig. 25 for switch and terminal
location.)

3. This furnace is capable of automatically providing proper

airflow to maintain the temperature rise within the range
specified on unit rating plate. If temperature rise is outside this
range, proceed as follows:

a. Check gas input for low- and high-heat operation.

b. Check derate for altitude if applicable.

c. Check all return and supply ducts for excessive restrictions

causing static pressure greater than 0.5-in. wc.

d. Ensure bypass humidifier switch (BPH) setup switch SW-3

on control center is in ON position when a bypass
humidifier is used. (See Fig. 25 for switch location.)

e. Check Troubleshooting Guide for Variable-Speed 2-Stage

Electronic Condensing Furnaces.

Table 14—Gas Rate Cu Ft/Hr

SECONDS

FOR 1

REVOLUTION