How to Maintain Your Vertical Air Make Up Unit for Your Spray Booth

Air make up units are important for Spray Booths. They help replace heated air to prevent negative pressure on your building, increase the temperature in your booth for baking of your painted product, prevent shop temperature from dropping due to shop air being exhausted from your spray booth to rapidly, and also help maintain a cleaner finish by reducing any dust entering your spray booth. With such an important role in your finish work it’s critical to think about properly caring for your air make up so that your production, shop status, and finish quality are not adversely effected. With that in mind will discuss proper steps and how often they should be done to ensure your air make up runs for many years without trouble.

The ultimate resource for your air make ups maintenance recommendations will be supplied by the manufacturer. However, as a general overview of steps to take for air make up maintenance consider the following on a routine basis. To ensure operator safety ensure you have disconnected power both at the spray booth and at the air make up unit itself outside.

1. Air inlet filters – these are filters that are metal boxes at the base of your air make up unit they should be checked every 3 months (or sooner in dirty environments). Primarily you should be looking for excessive blockage of the filters pathway. Proper care can include a simple washing of the filters with the water flowing against the direction of typical air flow or replacement of the filters if they do not improve after being washed.
2. Fan unit – At the top of your air makeup is a squirrel cage style fan with a shaft through the middle and bearings at the front and back of the air make up. To properly maintain the bearings you should grease them with lithium grease about every 6 months. Be sure to never over grease the bearings as this can cause damage to the seals and lead to bearing and potentially blower failure also If you use grease other than lithium grease you may contaminate your finish.
3. Pilot Light and pilot sensing rod – On one side of your air make up unit is a pilot lighter with a pilot sensing rod directly above the pilot flame. You should remove your pilot lighter to check and ensure there has not been excessive wear. If you ever receive issues related to pilot light problems you should also check this same mechanism. If things look excessively charred or the gap between the pilot rod and sensing rod are too great consider replacing the rod and light. If they appear in ok condition, utilize light body sandpaper to essentially remove the top layer of contaminant from the pilot and sensing rod. You can reinstall this component when you are done roughing and cleaning the surface, making sure to check again every 6 months or so.
4. Flame Burners – near the base of the unit slightly above the air inlet filters are burners which provide the heat for the make up air to be heated properly. These typically sit inside a v shaped metal trough and at the base are small holes for gas to be released for ignition. The walls of the trough serve to distribute the gas for proper ignition. The main things to check at the base of the trough are if all the gas holes are free of any clogs.  If they are plugged you should utilize a broach that is smaller than the hole to properly remove any blockage, making sure that you do not alter the gas hole. Additionally, be sure to lightly sand the walls of the trough to a roughened state.  This will allow the flame to be dispersed properly for the long term. This should be done every 6 months as well.
5. Spray booth fans – while checking your air make up unit it is also a good idea to check your spray booth exhaust fan. In particular, you want to ensure that there is not excessive overspray on the blade. As little as 1/8” of overspray can cause a fan to fail due to imbalance during operation.  If excessive overspray has collected consider removing the overspray with light sanding.

Ultimately the best course of action is to follow your air make up manufacturers recommended guidelines.  That being said the above guidelines will satisfy the majority of your air make up maintenance needs.