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PO. Box 726 n TULSA, OK 74101 n TEL 918-627-5530 n FAX 918-641-7336 n www.nelsonheaters.com
GA-2318, R1
Sheet 12 of 15
May 2008
TROUBLESHOOTING GUIDE
SYMPTOMS PROBABLE CAUSE CORRECTION
System is not operating and system
light is not lit.
No Power to SMMC-3 Turn on power using switch on front
panel.
Display is not lit and power switch
is on.
Supply not energized or power
input fuse burned out.
Check power supply. If LED above
power input terminal connection is
not lit, replace fuse (4A spare fuse )
supplied with SMMC-3.
System is not operating,
Temperature Standby on display.
The SMMC-3 is in a standby mode,
the ambient temperature outside is
above the programmed
temperature required to melt snow.
NORMAL OPERATION
Error! – SMTS-1 on display and
system not operating.
There is a communication problem
with the temperature sensor
Make sure the temperature sensor
lead wires are connected to the
terminal properly. If the sensor wire
has been extended, use 3
Conductor Instrumentation Cable,
#18AWG, unshielded, common
conductors such as twisted pair
communications wire, telephone
wire, electrical building wire and
doorbell wire is not acceptable.
Manufacturer: Belden #5301UE or
equal.
Error! – SMTS-1 on display after
corrections made.
Need to clear SMTS-1 error from
SMMC-3 program.
Turn off system using the front
panel switch, wait 10 seconds and
turn on again. The SMMC-3 should
now recognize the sensor.
Error! – SMPS-1 on display and
system not operating.
There is a communication problem
with the in-ground sensor.
Make sure the in-ground sensor
lead wires are connected to the
terminal properly. If the sensor wire
has been extended, use 4
Conductor Instrumentation Cable,
#18AWG, shielded, common
conductors such as twisted pair
communications wire, telephone
wire, electrical building wire and
doorbell wire is not acceptable.
Manufacturer: Belden #9418 or
equal.
The aerial or gutter sensors are wet
(covered in snow), the LED above
the corresponding terminal block is
lit and the system is not heating.
Possible communication problem
with the aerial or gutter sensor. No
error message will show on the
display when this occurs.
Make sure the in-ground sensor
lead wires are connected to the
terminal properly. If the sensor wire
has been extended, use 3
Conductor Instrumentation Cable,
#18-20AWG, shielded or
unshielded, common conductors
such as twisted pair
communications wire, telephone
wire, electrical building wire and
doorbell wire is not acceptable.
Manufacturer: Belden #8770 or
equal.
The in-ground sensor is wet
(covered in snow), the sensor
surface is warm and system is not
heating.
The surface of the in-ground sensor
may be dirty, possibly covered with
sealant.
Clean the sensor surface to get rid
of any contaminant, use mild
detergent and carefully scrub with
steel wool.