JOHNSON CONTROLS
11
FORM 130.13-NOM1 (114)
PROPORTIONAL HEAT CONTROL
(SSR) TROUBLESHOOTING GUIDE
Johnson Controls Heaters
Lethal voltages are present in the
heater control enclosure. Use extreme
caution when taking measurements in
these units. Always disconnect power
before removing or re-applying any
connections.
1. Before applying power, verify wiring matches
diagram in cover of heater control enclosure, and
that correct line voltage has been wired to heater
line block.
2. Verify 24 VAC +15% or -10% between P1 and P2
of interface circuit board (ETPHCI, ETPHCV2,
etc., depending on input).
3. The table below lists responses to input signal by
interface model as explained in step 4. If any of
these inputs cannot be obtained, refer to the litera
-
ture on the device that is supposed to provide the
input. Otherwise, proceed to step 4.
INTERFACE
MODEL
“PULSE”
INPUT
FULL
OFF
INPUT
FULL
ON
INPUT
INPUTS
ETPHCI
12.0 mA
4.0 mA
20.0 mA
Sig, Com
ETPHCV2
6.0 VDC
2.0 VDC
10.0
VDC
Sig, Com
ETPHCC
50%
0 VAC
24 VAC Sig, Com
ETPHCC1
50%
0 VAC
24 VAC
+18,
Com
4. Apply Full Off Input per table above. If the unit
is three phase, verify that the LED on the SSR
(solid state relay) is off. If the unit is single phase,
measure voltage between P4 and P6 and verify 0.3
VDC + or - 0.3 VDC. Replace the interface circuit
board if the voltage is higher than specified, or the
LED is on.
5. Apply Full On Input per table above. If the unit is
three phase, verify that the LED on the SSR (solid
state relay) is on. If the unit is single phase, mea-
sure voltage between P4 and P6 and verify between
3 and 5 VDC.
6. If the module provided is an ETPHCC or ET-
PHCC1, go to step 7. Apply “Pulse” Input per
table above. If the unit is three phase, verify that
the LED on the SSR (solid state relay) is flashing
at an interval of about one second. If the unit is
single phase, the voltage between P4 and P6 of the
interface board should vary between the Full Off
and Full On voltages in steps 4 and 5 in intervals
of about one second.
Some voltmeters will not respond this
quickly, so the value of the voltages
may not appear to be correct; however,
if the voltage appears to be changing
at regular intervals, it may be as
-
sumed that this function is operating
properly.
This completes the low voltage portion of the unit
test. Go to step 8.
7. For the ETPHCC or ETPHCC1, the associated
consignment controller must be directed to output
a 50% On pulse width modulation signal. For three
phase, verify that the LED is pulsing at regular
intervals. The rate of the pulse is based on the
output from the consignment controller. If the unit
is single phase, the DC voltage between P4 and P6
of the interface board should vary between the full
Off and full On voltages in steps 4 and 5.
Some voltmeters will not respond this
quickly, so the value of the voltages
may not appear to be correct; however,
if the voltage appears to be changing
at regular intervals, it may be as
-
sumed that this function is operating
properly.
