Safety Vapor Limit Control & Indicator (SVC) – What is it and why is it important?
What is the Safety Vapor Limit Control?
The safety vapor control is an important control and indicator on your vapor degreaser. It is your first line of defense in knowing that your unit is operating correctly.
The safety vapor control is an important control and indicator on your vapor degreaser. It is your first line of defense in knowing that your unit is operating correctly. The Safety Vapor Limit Control (known as the SVC Control), turns off the power to the heaters in the event of a failure in the cooling system.
What is the Safety Vapor Control?
The Safety Vapor Limit Control (known as the SVC Control) is one of 5 safety controls on a Reliance ULTRA Vapor Degreasing system. The SVC turns off the power to the heaters in the event of a failure in the cooling system by sensing a rise in temperature above the condensation coil which is indicative of a failure of the refrigeration condensation coil to contain the solvent vapor.
Reliance ULTRA Vapor Degreasers have a temperature limit control with the primary objective of monitoring that the primary solvent vapor containment condensation coil (primary coil) to ensure it is condensing solvent vapor and containing solvent vapor effectively. Ineffective containment of the solvent vapor results in a “Safety Vapor Condition Fault”.
What is the effect of a “Safety Vapor Condition Fault” on the operation of the vapor degreaser?
A Safety Vapor Condition Fault refers to an event in which the Safety Vapor Temperature Control senses that the hot vapor is getting past the primary condensation coil. In particular, the safety vapor control is set at a temperature below the boil temperature of the solvent, so hot solvent getting past the primary condensation coil, measures a temperature on the control greater than the limit set-point. This results in the heat being turned off which in turn results vapor being generated in the boil sump. On an ULTRA degreaser, the Safety Vapor Fault Light will illuminate, and the control will say over limit and the heat switch light will no longer be illuminated.
Control Panel on the ULTRA
The yellow box shows fault indicators with the Safety Vapor Indicator (second from left). In this case, the unit is operating properly.
A Safety Vapor Fault is Detected
The safety vapor indicator is lit (second from left) and tells us something needs to be addressed.
Why Would there be a Safety Vapor Condition Fault Event?
There are false Safety Vapor Faults and Accurate Safety Vapor Condition Faults. The following are the most common causes of a Safety Vapor Fault:
FALSE - Nuisance Faults:
Incorrect temperature limit set point is selected for the Limit Set-Point for the Control (the set point will is based on a temperature that is a certain amount below the boil point of your specific solvent).
Note: Temperature set point: Refer to the solvent manufacturer’s instructions and SDS for proper setting of this control (a typical set point is 20°F less than the boiling point of the clean solvent). For our AeroTron-100 Solvent, that temperature set-point is 95 because AeroTron-100 boils at 116˚F.
2. A basket of hot parts in close proximity to the sensor.
3. Pulling a basket out of the vapor zone too fast and pulling hot vapor up with the basket making the sensor think the solvent is escaping past the refrigeration coils.
4. Placement of the basket partially in the vapor zone and partially in the refrigeration zone.
ACCURATE - Legitimate Condition Faults:
1. Air flow over the vapor degreaser – which pulls the vapor past the coils quickly making the sensor think vapor is escaping from the unit.
2. Issues with the Cooling System which most commonly include:
a. Refrigeration leaks – insufficient cooling
b. Refrigeration condenser is dirty and needs to be cleaned.
c. For chiller cooled systems – inadequate flow
d. For chiller cooled systems – too high a supply/return chilled media temperature
e. Control is improperly calibrated
f. Control is broken or operating improperly – broken control, broken thermocouple, bad connections
How do I Reset of Safety Vapor Condition Fault?
A Safety Vapor Condition Fault must be manually reset, meaning that an operator or manager must manually press the reset button. However, as a precursor, the condition that caused the fault should be determined and cured, otherwise, the hot vapor is likely to again cause the condition fault as soon as the vapor degreaser starts to generate solvent vapor again.
Conclusion
At Reliance, we have found that the safety vapor fault is one of the most common faults that get triggered in routine operation. Getting familiar with the False faults and legitimate reasons why it would trip will minimize production down time, while ensuring quick resolution of a real concern with your vapor degreaser.
If you have questions about maintenance of your vapor degreaser or if you are having part processing quality issues, please contact the Reliance Technical Support Department at 847-64-8923. We are glad to be of assistance.
