Tag Archives: Lonnie Gillilan

Troubleshooting Temperature Controllers

Posted February 1, 2017 by Pepper Hastings

Categories: Blog, field service


We often get calls for troubleshooting temperature controllers. Here are some tips that can save you some money and time.

My Field Service Technicians and I frequently are deployed to customer sites for “Failed” temperature controllers. There are numerous brands of temperature controllers in the market. Applications range from ovens to extrusion machines. Yet most temperature controllers share the same common functions. When troubleshooting temperature controllers, here are a few tips from a guy like me who’s done it plenty of times.

troubleshooting temperature controllers

When troubleshooting temperature controller, it's wise to remember that the problem usually is NOT the controller itself. But you have to rule that out, first.

Usually, the actual temperature controller is NOT the problem. Temperature controllers normally have one or two control outputs to adjust the process temperature: A heat inputand (if required) a cool output. The temperature controller also may have outputs for alarms. The temperature outputs normally control relays (solid-state or conventional) or contactors. This is because the temperature controller outputs are either low voltage DC or 120VAC and the heaters or fans require high voltage 230-460VAC.

Solid state relays are preferred because of the numerous switching (On/Off) as the unit tries to maintain temperature. A simple method of determining why a unit is not maintaining temperature is to look at the display on the controller.

Normally, Output 1 is assigned to Heat and Output 2 is assigned to Cool. As the unit is started up and a temperature higher than the “Process Value” is set, you should see Output 1 come on (Unit is calling for Heat). This should continue until the unit reaches the “Set Value.” At that point, Output 1 should go off (plus or minus 5-10 degrees). Output 2 (Unit is calling for Cool) should come on if the Process Value exceeds the Set Value and go off once the Set Value is reached (Plus or Minus 5-10 degrees).

If this is happening, the next place to check is on the actual item being controlled (relay or contactor). Observe the relay/contactor to see if it is actually operating when the output is on (normally, relays have indicator lights and contactors can be checked visually).

Also, check the input and output high voltage going to the relay/contactor. If this checks out good, then the problem lies in either the actual heating element or the fan. For heating elements, a continuity check of the element normally will tell if it is open (bad).


Hopefully these simple checks can help you when troubleshooting temperature controllers and have your equipment back in operation faster. If not, our field service team is always standing by to assist.

Lonnie Gillilan is the Dallas field service manager for Innovative-IDM. You can reach him at lonnie.gillilan@iidm.com 

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Water Damaged Control Panel Trouble Shooting

Posted May 3, 2016 by Pepper Hastings

Categories: Blog, Control Panel


As a field service technician, I see many water damaged control panels. Numerous instances of water leaking into underground vaults where electrical control panels are tucked away.

There are two types of underground vaults: Ones that leak and ones that eventually will leak. I’ll tell you how to prepare for this eventuality and one way to trouble shoot a water damaged control panel.

Under any fountain array could be water damaged control panels in a vault. It's usually not a matter of if, but when.

Under any fountain array could be water damaged control panels in a vault. It's usually not a matter of if, but when.

Just recently, it happened again, this time in an area of Dallas that is well-known as a low-lying area and prone to flash flooding. The application was a pump for a large, public water display – complete with coordinated lights, laser show, music, etc. Fun stuff....when the pump works. Not so fun when it doesn’t. The customer called our 24-hour field service line and the game was on.

The pump, motor, and controls all were all located in an underground concrete vault beneath the display. Time to troubleshoot. If you run into this problem, here are the steps I would suggest taking to troubleshoot a water damaged control panel:

  • First, check the motor contactor to see if you can manually close it and make the pump run. If so, the pump is OK.
  • Now that we know the pump is OK, I backtracked the control signal for the contactor to the main control cabinet. The relay which should have been pulling the coil of the motor contactor in was energized, but the relay contacts going to the pump contactor had no voltage.
  • I removed the relay to find that the pins for the contacts in question had corroded off because of water intrusion into the cabinet (from leaks in the ceiling of the vault).

I delivered a spare relay to the customer the next day as well as several spare relays just in case. Obviously, this could have been much worse and complications in the troubleshooting I described could be beyond the scope of this article. However, prevention is better than anything. There are several ways they can keep control panel water damage from happening again.

  • Keep water out of the cabinet, period. Make sure all seals around doors are in good shape.
  • Ensure that all connectors penetrating the enclosure and tight and water proofed.
  • Make sure the crew keeps the door to the enclosure closed.
  • If the vault leaks cannot be repaired at street level, a shield or “umbrella” of some type should be constructed to fit over the electrical cabinet. This would force any water leaking from street level away from the cabinet and hopefully minimize if not eliminate future water damage.

This was a relatively easy and inexpensive repair – a simple relay had failed. But had



other electronic components (AC Drives, PLCs, power supplies) in the control panel enclosure sustained water damage, the cost would have been substantial and the water show have been down for a significant period of time.

Lonnie Gillilan is IIDM's Dallas field service manager and an avid stock car follower. You can reach him at lonnie.gillilan@iidm.com.


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