CHECKPRIMARYLIMITCONTROL
Thiscontlolshutsoffgascontlolsystemandenergizesair=
circulatingblowermotorif"1%m_aceoverheats,Recommended
method of checking this limit control is to gradually block off
return air aker I:m'nace has beer* opmating for a period of at least
5 minutes. As soon as limit contwl has shut offburners, return°air
opening should be unblocked to permit nom_al air circulation. By
using this method to check limit control, it can be established that
limit is flmctioning properly and operates if there is a restricted
return°air duct or motor fSilure. If limit control does not function
during this test, cause must be determined and corrected.
(HECK PRESSURE SWITCH
This control proves operation of draft inducer. Check switch
operation as follows:
1. Turn off 115°v power to I_urnace.
2. Remove main furnace door and disconnect inducer motor lead
wires ti'om wire harness.
3. Turn on 115-v power to furnace.
4. Set thermostat to call for heat and wait 1 minute. When
pressure switch is functioning properly, hot surfhce igniter
should NOT glow, and control stains code LED flashes a
Stares Code 31. If hot surfitce igniter glows when inducer
motor is disconnected, shut furnace down immediately. De=
*ermine reason pressure switch did not flmction properly and
correct condition.
5. Turn off 115=v power Go f:umace.
6. Reconnect inducer motor leads, reinstall main furnace door,
and turn on 115-v power supply.
CHECKUST
1. Put away tools and instruments Clean up debris
2. Verif}' flame rollont manual reset switch has continuity.
3. Verif}' that blower and main access doors are properly
installed.
4. (ycle test furnace with room them_ostat.
5. Check operation of accessories per manufacturer's instruc-
tions.
6. Review User's Guide with owner.
7. Leave literature I2acket near Nrnace.
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