Shellab SWB715-2 - Manual (Page 14)

14 Microprocessor Control Water Baths
Problem Possible Cause Solution
Unit will not heat over a
temperature that is below set
point
OTL has activated.
Confirm that set point is set high enough and that the Over
Temperature Safety is not activated.
Temperature
calibration is not
correct.
Check calibration. Using independent thermometer, follow
instructions in Calibration.
Unit will not heat up at all
Controller Fault.
Do all controller functions work? Controller failure-call
Customer Service.
OTL has activated. Set the Over Temperature Thermostat higher.
Indicated bath temperature
unstable
Insufficient
quantity of water.
Fill bath a minimum of three-fourths (3/4) full with water.
Fluctuating by ±
0.1?
May be normal, especially without the use of bath cover.
Ambient room
temperature is
radically changing
Temperature fluctuation due to door opening or room airflow
from heaters or air conditioning. Stabilize ambient conditions.
Bath not full Assure that the bath is at least 1/3 full.
Electrical noise
Remove nearby sources of RFI including motors, arcing relays
or radio transmitters
Bad connection on
temperature sensor
or faulty sensor
Call customer service.
Will not maintain set point
Insufficient
quantity of water.
Fill bath a minimum of three-fourths (3/4) full with water.
Temperature set
too low. Assure that set point is at least 5 degrees over ambient room
temperature.
Ambient
temperature too
high.
See if ambient is fluctuating.
Cannot adjust set points or
calibration Controller hangs
up. Turn entire unit off and on to reset. If repeatedly happens, call
Customer Service.
Calibrated at one temperature,
but not at another
Set point too far
from calibration
point. This can be a normal condition when operating temperature
varies widely. For maximum accuracy, calibration should be
done as close to the set point temperature as possible.
Miscellaneous Troubleshooting
Problem Possible Cause Solution
Water Leaking Leak / Corrosion Shut the unit off and call Customer Service. Service
Tank Discoloration
Wrong type of
water Assure that clean, distilled water is used. Deionized water, tap
water and chemicals should never be used in the tank.
USE DISTILLED WATER ONLY.
Sample Spills Assure that no test samples have leaked into bath water.
Metal Racks No metallic products should be in the tank with the exception of
the oscillation rack.
Unit will not turn on
No power. Check wall power source.
Fuse blown. Check fuse/circuit breaker on unit or in wall.
Service
If this product should require service, contact your customer service representative.