HHP PBNU-LD20N140 Installation Instructions Manual - Page 19

Browse online or download pdf Installation Instructions Manual for Furnace HHP PBNU-LD20N140. HHP PBNU-LD20N140 20 pages. Gas-fired furnaces high-efficiency upflow condensing models

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"SC(..,.HtoftC�QIWII"'"'V f (fll
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WHITE-RODGERS
tat
Turn the
rmos
(controller) to
call for heat
Power at transformer
nominal)?
(25 vac
YES
Venter begins
to operate
YES
-
Hot surface
i
igniter beg
n
s
to glow?
YES
Main burner lights?
YES
-
System ru. n s until
call for heat ends?
YES
Call for heat ends
System shuts off?
YES
ends
NOTE: Models with dia:;; n ostic light have sslf-diagnostk; capabilities. If the light on the
module is on continously, the fault is likely to be internal to the module. To make
sure, interrupt the line or 25 voir thermostat power for a few seconds and then
restore power. If internal fault is indicated again, and flame sensor is not shorted
to ground, replace control. A flas
in the external components or wmng. Procee d followmg the troulbleshooting table
below. If 120 vac p ower wiring to furnace is reversed, module will lockout.
50E47 SYSTEM TROUBLESHOOTING TABLE
NOTE: Before troubleshooting, familiarize yourself
with the startup and checkout procedures.
-
Check line voltage power, low voltage transformer
thermostat (controller) . a nd wiring
Place jumper
on
.
1
pressure switch
LP
between "C" & "NC"
Venter Okay?
Check hoses connected to pressure switch
Check for k>oseness of pressure tap in burner
l
ri
cal connections between pressure
Check e
ct
e
s'Nitch and plug connections.
If checks are Okay, replace pressure switch
Check that pressure switches 2LP, 3LP& 4LP are closed. If
no check for loose hoses or loose pressure tap on burner box.
If checks are Okay, replace pressure switch 2LP, 3LP or 4LP.
Check electrical cont inuity of flusible link (replace
and continuity of tne
!mit
Check for cracks in hot surface igniter (replace if required)
Check for 25vac
S
on
voltage, replace SOE47.
Check electrical connections between 50E47
If Okay, replace gas v
Check continuity of sensor wire and ground wire.
po<X
Note: If ground is
occur occasionally even though operation
normal
is
at the .time of check<;>ut.
If checks are Okay, replace 50E47module.
Check for proper thermostat (controller) operation.
Re
ve MV lead at
SOE4
mo
not.
SOE47. If
replace gas valve
Repeat procec_jure until troub lelree
�!
ng light also indica
es the problem is most likely
Place jumper
on relay 3R
between "1"
& "3"
?
Venter Okay
YES
1
LP.
box.
1
LP.
switch.
OE4
7 acrosss MV terminals. If no
&
alv
e
.
or erratic, shutdown may
If
7
valve closes, replace
.
-
e
t
n
i
is
op
ra
o
obtained.
venter
it
open)
gas vaJve.