CHARTS
FOR
TROUBLESHOOTING
THERMOCOUPLESAND
POWERPILE SYSTEMS
TROUBLESHOOTINGCHARTS
Thesechartsare to assistthe technicianin properly
diagnosingproblemswith 30 millivolt thermocouple
systemsand 750millivolt PowerpileSystems.
Charts I and 2 are for useon 30 millivolt systems.
Chart I is for useon systemswith no built in ECO
(EnergyCutoff). Chart 2 is for systemswith an ECO,
typically all water heatersare required to havean ECO
as a safetyto shut offthe millivolts to the water heater
control is the water temperaturereaches1950F. It is a
onetime fusible link devicethat if it opensit will mean
repldcingthe water heatercontrol.
Charts3 and 4 are for the older 250 millivolt controls
that were usedon a lot of wall furnacesand thru the
wall room heaters.Chart 3 is for diagnosingthe
Pilotstatpart of the control.Chart 4 is for the valvecoil
itself.
Charts 5 and 6 are for the 750millivolt valvesfor
testingand diagnosingthe power units (magnet
assembly).Chart 5 coversthe older 23 ohm assemblies.
Chart 6 is for the newercombinationgasvalvessuchas
HoneywellVS-820,Robertshawand White Rodgers
newer valves.
Chart 7 is for troubleshootingthe 750millivolt valve
circuit.
MILLIVOLT
CHARTS
TESTII{G
3O.MILLIVOLT
CIRCUITS
a
F
J
J30
)
l\
\-()
t.t.
<20
s
r{
!D
a
$ro
F
f
c
F
l
^'OUTPUT
OPEN CIRCUIT MILLIVOLTS
Chart 1-3 0 MiIIivoIt Pilotstat Control.
NO ECO
,.. 40
o
F
.J
lco
)
CHECKPILOTFLAMEANO
E L E C T R I C ACLO N N E C T I O N S
ACCEPTAELE
RANGE
z
t\
S
b
Sto
CHECK
UNIT
POWER
A N OH I L I M I T
$
s
'{l
h
s{
bro
F
f
oF
f
. '. ..;:,,-*.;OUTPVTOPEN CIRCUIT MILLIVOLTS-.'
Chart 2-30 Millivolt Piiotstat and Hi Limit.
WITH ECO
TESTING
clRculTs
250-MttlrvoLT
a
I
=
=
\
$
c
s(')
ql
o
d
F
f
(L
F
l
o
-,- *.,-"OUTPUT
OPEN CIRCUITMILLIVOLTS
Chart 3 -250 MiIIivoIt Pilotstat Control.
IMPORTANT: Make certain Powerpile valve is disconnectedwhen
testing Pilotstat control.
o
5
CHECKPILOT FLAME AND
E L E C T R I C A LC O N N E C T I O N S
-J
J
ACCEPTABLE
E
RANG
=
|\
s
(J
t
s
CHECK
POWERPILEVALVE
s
t{l
(.,
s
$
F
oF
f
....,,.,'*'-.*- OUTPUTOPE N CI RCUI T MILLIVOLTS
Chart 4-250 Millivolt Powerpile Valve.
IMPORTANT: Make certain Pilotstat power unit is disconnected
when testing Powerpile valve.
TESTING
CIRCUITS CTIART 5
T5O.MILLIVOLT
U)
F
ACCEPTABLE
RANGE
CHECKPILOTFLAMEANO
E L E C T R I C ACLO N N E C T I O N S
)
J
-)
=
}\
\
()
e 400
(J
s
qJ
(D
a
\J
()
200
F
l
(L
l
o
.,OUTPUT
OPEN CIRCUITMILLIVOLTS23 OHM
Chart 5-?50 Millivolt Piiotstat Control'
IMPORTANT : Make certain Powerpile valve is dis connectedwhen
testing Pilotstat Control.
CIIART 6 -spectnl ll oHM PowERuNtr(vsg2o4)
r 800
I
a
h
=
|\
d
CHECKPILOTFLAMEANO
ELECTRICAL
CONNECTIONS
.a 4OO
$
a
\(/)
o
:.1
s zoo
REPLAC
E
IHERMOPILE
ffi
f
F
f
-_l
;o
o
DROPOUT RANqE
44:
i
E
200
t-
400
540
800
OPEN CIRCUIT M I L L I V O
II OHM
CHART
7
.TEsrrNG
powEBprLE
vALVEcr'curr 7so
MV (NOM.l SYSTEM
t
@
CI|ECI( ?ILOT TLATE ATD ,
ltlctilcaL
corttcttoxa;i
!
o
J
J
s
()
t
600
CXECK POWERPILE
VALVE TD
ALL COXTROL3
wllH
col{TRoLl
AT VALVE
C H E C XP O W E R P I I C
VALVE
(J
a
l{
(rt
o
d
AT IN CI
F
PULL.IN RANGE $'ITH
F
o
I
NE?LACE
THERMOPILE
OUTPUT
OPEHClRCUlf utrrrvoLrs-}
SPECIAL NOTE: Shaded area in upper band is based on the
resistance of the T586A thermostat and 30 feet of 18-gage
cable. IF THERMOSTAT HAS NO HEAT ANTICIPATION
IIEATER, AND THERE IS A SHORT RUN OF WIRX TO THE
THERMOSTAT-readings falling between the upper and lower
diagonal bands also represent proper system operation