HVAC VFD Repair
HVAC VFD repair should be taken with extreme caution. HVAC VFD repair should only be performed by technicians who have required training and experience to work with electrical equipment. Precision Electric strongly recommends to consult an expert in the field when repairing HVAC VFD equipment.
Many HVAC VFD controllers have an internal DC bus that retains a charge after power has been cut to the drive, as a result, it does not mean it’s safe to work with. Technicians working with HVAC VFD repair must always take extra precautions to ensure proper safety measures are taken, or injury or even death may occur.
Precision Electric has spent years working with electrical components and HVAC VFD controllers, DC motors and VFD controllers, servo motor and servo VFD systems, and other related industrial electrical equipment. The troubleshooting techniques for each brand of VFD can be unique, but the overall structure of troubleshooting always remains the same.The ultimate goal when performing HVAC VFD repair is to diagnose, repair and re-commission the unit as quickly as possible, and there are steps that should be taken before anydis-assembly takes place.
Precision Electric has been performing HVAC VFD repair since 1983 and all repairs performed by Precision Electric includs a 1-year in-service warranty. The Precision Electric in-service warranty begins the same day that equipment is put into service and ends 1 year later. The Precision Electric in-service warranty was implemented to give manufacturers incentive to keep spare equipment in rebuilt condition to minimize downtime and maximize production.
Here are all the steps illustrating how Precision Electric performs HVAC VFD Repair:
1. Take Notes –HVAC VFD Repair
This is often a subject that is passed by many individuals who are attempting to repair industrial electrical equipment. Before Precision Electric begins to perform HVAC VFD repair, qualified technicians take note of many important aspects of the equipment including, but not limited to:
- HVAC VFD Manufacturer
- VFD Serial Number
- Reason for Service
- Urgency (Rush Overtime or Standard)
- Visual Inspection of External Device
2. Conduct Diode and IGBT Tests –HVAC VFD Repair
There are a number of methods to test the input and output power sections of HVAC VFD repair orders, and this step is essential prior to applying power to the VFD unit. If for any reason there is a short on the input side or output side of the VFD, further damage can be caused to the unit if power is applied to it.
For this reason, Precision Electric uses meters to properly test the input and output power sections of the VFD prior to applying power to the actual unit. If a short is found, the unit can be disassembled and the cause of the short can be diagnosed and quoted for repair. If the repair is too costly, then a replacement is offered to the customer.
3. Power Up Unit –HVAC VFD Repair
If the input and output power sections test healthy during this step of the HVAC VFD repair process, Precision Electric will power the unit and perform amp reading and output frequency tests. Precision Electric prefers to slowly increase power voltage to the unit until the rated input voltage of the VFD is achieved.
Depending on whether or not the VFD provides a display will determine what further action(s) will be taken. If display is unavailable, dis-assembly and diagnosis of the internal power supply of the control section of the VFD is likely necessary to further evaluate cause of failure and establish cost and lead time for the HVAC VFD repair.
4. Run A Motor –HVAC VFD Repair
If the previous three tests have passed during the HVAC VFD repair process, then it is time to run a basic jog function of the VFD with a simple template program. Often when a VFD comes into our facility, we make sure to backup whatever program is currently stored in the VFD prior to inputting a template program and running a test procedure. This ensure we have a backup copy of the program.
The best method for backing up depends on the brand of drive, but after it has been backed up, we either reset the HVAC VFD to factory defaults through the keypad and recommission a basic start, stop and job application or closed loop if an encoder is involved. If the motor will not run, it will be necessary to check the output voltages and current ratings going to the motor to see if the VFD is functioning properly to rotate the motor.
5. Contact Customer –HVAC VFD Repair
At this point we have determined the cause of failure, estimated lead time and cost of the HVAC VFD repair. If the HVAC VFD has tested good entirely, then further underlying issues are communicated with the customer. This is when Precision Electricwill gather application specific information from the customer to establish whether or not it may be some outside issue associated with the system including, but not limited to, PLC communications, faulty IO, bad wiring or even bad cabling. There is no single way to do this step, as it really depends on a wide variety of variables.
6. Send Service Tech –HVAC VFD Repair
If the customer cannot establish failure on any other aspect of the machine and the HVAC VFD appears to test fine, then it may be necessary to send a Precision Electric field service technician on site to establish cause of failure. Precision Electricfield service technicians are trained to troubleshoot any issue ranging from standard HVAC VFD repair, to advanced robotics, PLCs and more. Precision Electric field technicians are trained to establish cause of failure and come up with solutions as quick as possible.
To learn more about HVAC VFD Repair or for HVAC VFD Repair Quotes, contact Precision Electric, Inc.
