12-Step Program

1. Fans

Fans, the heart of the ventilation system, and are often overlooked.

• Visually check fan motor mounts for tightness.
• Visually check electrical wiring conduits. If not secured, they can rub on the fan guard or fan frame and cause an electrical short. A few simple zip ties can solve such a problem.
• Check fan guards for breaks or loose bolts. A damaged fan guard can cause further damage to the fan blade. Broken fan guards can be a sign of an unbalanced blade or loose motor mount, which cause vibration.
• Check fan blade for cracks, especially around the center hub. Also check for chipped blades.
• Check fan housing for cracks at welds, especially if fans are over 10 to 15 years old.
• Fan blades should be clean and free of residue which can cause a fan blade to become unbalanced. Steam cleaning or using a wire brush will get the job done.

2.Variable FrequencyDrives (VFDs)

If fans are not equipped with VFDs, consider having them installed. VFDs are a great storage management tool, reduce energy costs and have a short payback. However, they do require a little maintenance.

• Power off at the end of the storage season. This will reduce potential damage from external power events like lightning when they are not in use.
• Clean VFD heat sink, the aluminum radiator located in the back of most VFDs. The heat sink can get dirty with sprout-inhibiting chemicals or dirt. Blow out with compressed air and brush with a soft brush.
• Clean off cooling fans. On most VFDs the cooling fans run whenever the VFD is running and are necessary to keep the VFD’s electronics cool. Cooling fans are often a high-maintenance item; replace as needed.
• Inspect electrical connections. (VFDs have capacitors that can hold a charge for a few minutes. Make sure they have been powered off for at least three minutes.) Check all electrical connections for tightness; any discolored wires are a sign of overheating. VFDs mounted adjacent or near to a fan wall are susceptible to vibration, causing terminals to come loose.
• Keep water away from VFDs while cleaning electrical rooms. A drop of water or chemical into the VFD electronics can cause serious damage.

3. Motor Starters of Contactors

• Power off all electrical circuits.
• Open the contactor cover and inspect overloads for signs of overheat.
• Check for loose or discolored wires and/ or discolored terminals.
• Have a technician look at it if you are not sure if it in good working order or it needs repair.

4. Refrigeration Condensing Units

These units are expensive and should be properly maintained by a qualified mechanical contractor. However, there are a few preventative maintenance items that can be done in advance. Be absolutely certain all power is shut off before performing any of the following items.

• Visually inspect electrical panels for any discolored wiring or terminal blocks, burned contactors or relay contact points.
• Replace compressor contactors every three to four years.
• Condenser and/or compressor VFDs require the same maintenance as fan VFDs (see above).
• Check condensing fans for electro-mechanical issues such as loose motor mounts, fan blades not in line with other fans, broken motor mounts or fan guards.
• Inspect for refrigeration leaks. Leaks will appear as oil spots or oily dirt-covered areas. Refrigerant leaks can be costly and should be repaired by a qualified technician as soon as possible. The repaired area should be thoroughly cleaned from oil and dirt to avoid a false alarm in the future.
• Condenser coil cleaning
  • Ensure power is shut off to condensing unit.
  • Cover any electrical devices or junction boxes with plastic or plastic bags prior to washing.
  • Condenser coils can be cleaned with a garden hose and a flat nozzle.
  • Rinse from the downstream side first to push most of the dirt out the upstream side. Condensing fan guards may need to be removed to reach into the coil area.
  • Rinse from the upstream side. Wash as if you were combing the fins.
  • Rinsing steps may need to be repeated to get coils clean. You should be able to see light through the coils.
  • Cleaning will improve efficiency of the unit and extend its life. Annual cleaning is a must.
• Evaporator slab coils or unit coolers
  • Same steps as condenser coil cleaning, except use steam or hot water.
  • Use low-pressure steam or near-steam hot water to remove any chemicals or organic matter from the coil fins. Do not use high pressure, as it may damage the coil fins.
  • Special coil fin cleaning agents are available, but steam generally gets the job done.                 
• Check for any loose or missing electrical covers.
• Many refrigeration valves and fittings have caps or screw-on covers to prevent leakage and to protect fitting/valve from the environment. Replace if missing.
• New computerized refrigeration controls have a lot of sensor wiring. Check that all sensor cables are secure and not touching hot gas piping. A few zip ties will save a lot of hassle and possibly a service call.

5. EvaporativeCooler (Cell)

This natural refrigeration tool is often overlooked when it comes to maintenance.

• Drain and dry at the end of storage season. Drain bypass and supply plumbing. Drain water tank. Water sitting in tanks breeds bacteria. Water wicking at the bottom of media can deteriorate media.
• Use a wet/dry vac and hand towels to clean tank.
• Clean supply water filter. If supply water filter is not in place, consider installing one. Filter will reduce maintenance and assure water header is performing per design. With a filter installed, supply headers should not need any cleaning. Filter should be checked and cleaned on a regular basis during storage season.
• Check for hard water and mineral deposits on the face of the media; most will show on the upstream side. Mineral deposits are a sign there is not adequate water feed to the media. Mineral deposit is difficult to clean, but you can hose it down and use a soft brush to brush some if it off without damaging media.
• Adjust float valve so water level is just below bottom of media. Water level above the bottom of media will cause wicking. Wicking will soften and eventually deteriorate the media.
• Check media saturation. If media is not completely saturated or streaking, water distribution header may be plugged or the pump size is insufficient. Media manufacturers have a formula to calculate gallon-per-minute requirements based on total media area. Your ventilation supplier can provide you with this information.
• Tip: On a dry day with the system running and intake doors open, cell media should be fully saturated. If it’s not, you may need a larger pump.

6. Centrifugal Humidification

• Drain and clean water tank. This will extend the life of the water pump.
• Inspect the float valve for proper operation.
• Clean disk. If the disk has mineral buildup, Lime-A-Way will polish it up nicely.
• Spin the disk by hand to make sure it does not seize up before starting the new season.
• Check that disk is not binding against the teeth while it spins. Reposition the disk if necessary.

7. High-pressure Humidification

• Change or clean water filter.
• Check motor belt or direct shaft coupling.
• Clean or replace plugged nozzles.
• Some systems have a flush valve at the end of the line to flush any debris out. You could remove the last nozzle if you don’t have a flush valve.

8. Fresh AirIntake Doors

• Check for mechanical issues, loose actuator assembly, door clamp.
• Make sure intake door is sealed well in closed position; door spring should be slightly depressed.
• A shot of silicone spray on the actuator shaft will keep the actuator seals lubricated and squeak-free.

9. Control System

• Have temperature, humidity and CO2 sensors calibrated and checked by a qualified technician.
• Clean control panel.
• Check inside for water damage or signs of water presence; this may be an indication of water condensation coming into the panel during operation. A simple fix is to seal conduits entering the panel.

10. Light Tree

• Use 60-watt rough service bulb or 75-watt-equivalent LED bulbs.
• Anti-Seize lubricant on the bulb threads will reduce vibration and extend life expectancy.

11. Exhaust

The entire air system depends upon proper exhaust

• Check that exhaust dampers or exhaust doors open and close freely.
• Plastic and/or metal pivot bearings on exhaust dampers should be inspected annually.
• Exhaust doors’ absorber shocks, which reduce rapid movement in either direction, should be checked.

12. Building “Climatization”

After all maintenance is done, let the system run and “climatize” the building for two to three days before the storage season starts. This will give you confidence that everything is ready to go and prepare the building environment for product.

Proper maintenance is all about the details. A smoothly running ventilation system with accurate controls will increase produce quality, save time and increase profitability.