Bohn Refrigeration FAQ: Real-World Answers from a Decade of Mistakes

Who am I? I've been handling refrigeration equipment orders for about eight years (maybe nine — I'd have to check the calendar). In that time I've personally made at least a dozen costly errors — ordering the wrong coil type, mismatching fan motors, choosing speed over specs. I now manage our team's pre-order checklist so others don't repeat my blunders. Below are the questions I wish someone had answered for me back in 2017.

1. What exactly is a bohn refrigeration product?

Bohn makes evaporators, condensers, walk-in cooler/freezer units, and heat exchangers for commercial refrigeration. Most people think "bohn" is just one model — it's actually a whole family of products. The evaporators come in low-profile, medium-profile, and heavy-duty versions. The condenser units range from fractional HP to 40+ HP. What most people don't realize is that the product name (like KHP, WL, or MLE) tells you the application: medium-temp, low-temp, or zero-temp. (I really should memorize the full nomenclature — still need the chart sometimes.)

2. How do I pick the right bohn freezer unit for my walk-in cooler?

Start with the box size, insulation thickness, and desired temperature. I once ordered a 5,000 BTU/h unit for a 6x8 walk-in freezer set to -10°F. The numbers said it would work — just barely. My gut said it would struggle. I went with the numbers because the delivery date was sooner. We had to swap it out within three weeks (ugh). The lesson: always oversize by at least 20% for freezers. Bohn's selection software actually recommends this, but at the time I skipped that step.

3. Can I use a Milwaukee blower instead of a bohn evaporator fan motor?

Short answer: don't. A few years back a customer asked if they could replace the bohn evaporator fan with a standard Milwaukee blower they had on the truck. Technically it spins, but the geometry, CFM rating, and mount pattern are different. The result was insufficient air throw — the far end of the cooler froze up while the door end ran warm. We had to pull the whole unit and install the correct bohn fan assembly. That mistake cost about $400 in labor plus the correct part. (Note to self: never let a generic motor substitution slip through approval again.)

4. Where can I buy a replacement AC condenser fan motor?

For bohn condensing units, the best source is an authorized distributor — they stock OEM fan motors with the exact shaft length, mounting holes, and capacitor rating. For other brands, online retailers like Grainger or Zoro have cross-references, but you need to match the specs precisely. In a pinch, we've used motors from Jones Stephens or Dayton that fit, but the warranty is void if it's not OEM. Looking back, I should have paid the extra $30 for the genuine bohn part instead of adapting a generic one (the bracket holes were off by 1/8 inch — had to drill new ones).

5. Should I use a Lasko heater to defrost a freezer coil?

Please don't. I actually witnessed this happen at a small deli in 2022. They had a bohn low-temp evaporator iced up, and someone put a Lasko space heater directly underneath it to speed up defrost. Two problems: first, the heater's plastic housing melted from the cold — they didn't realize the unit was already damaged; second, the hot air caused the aluminum fins to warp, ruining the coil. A proper defrost cycle (electric, hot gas, or off-cycle) is what you need. The cost of replacing that coil? $1,200 plus a week of lost cold storage. The surprise wasn't that the heater failed — it was how quickly the damage spread.

6. How many years do bohn evaporators last?

Industry standard for commercial refrigeration coils is 10–15 years with proper maintenance. Bohn's aluminum coils tend to hold up well against corrosion if you keep the fins clean and the drain pans clear. I've seen units from the early 2000s still running in low-humidity environments. But here's something vendors won't tell you: the real lifespan depends on the operating temperature range. Freezer coils (-20°F) wear out faster than cooler coils (35°F) because of repeated frost buildup and defrost cycles. In our fleet, freezer evaporators average 11 years; coolers go 14–15.

7. Can I mix bohn and other brand components in one system?

This was true 15 years ago — matching brands was almost mandatory because of pressure drop differences and TXV compatibility. Today, ASHRAE guidelines allow cross-brand mixing as long as the expansion valve and condenser are matched to the evaporator capacity. But (and this is a big but) the compressor must be sized correctly for the combined load. I once tried pairing a bohn evaporator with a generic condenser from another brand — the numbers looked fine, but the subcooling was off by 5°F because the condenser's fan speed didn't match. Ended up adding a head pressure control valve (cost $250 extra). So yes, you can, but it's easier and safer to stay within bohn's matched sets.

8. What's the single dumbest mistake you've seen with bohn installations?

In 2020, a contractor installed a bohn evaporator but ran the liquid line 80 feet without a proper trap. The TXV kept starving because of the pressure drop. The owner called us asking for a replacement "defective" unit. We sent a technician, found the issue, and added a suction-to-liquid heat exchanger. That rework cost $800 — he could have avoided it by following bohn's piping chart. The lesson? Always check the installation manual's recommended line length and trapping requirements. (I really should put that in our pre-order checklist.)

So glad I put this FAQ together — hopefully you can learn from my mistakes instead of making them yourself. If you have more questions, ask your local bohn distributor; they're usually happy to help (especially if you're buying from them).