Ten Things Your Coil Vendor Never Told You
This week’s Tenuta Tech will focus on the ten things your coil vendor never told you when purchasing new or replacement coils. It’s important to keep these in mind whenever you are buying new or replacement coils to make sure that you are informed and educated going any coil discussion. We can help you get there!
- A.R.I. only randomly selects certain size coils to test throughout a full coil line. All other performances are interpolated between the tested sizes. There is plenty of room for performance diﬀerences between competing companies. Not all of these diﬀerences are honest diﬀerences, and there is more room to cheat on performance than most people realize. A.R.I. should be a guideline, but there’s more to selecting a supplier than the A.R.I. listing.
- 1/2″ O.D. tube diameter coils are generally less expensive than 5/8″ O.D. coils. There is less lbs. of copper in a 1/2″ tube coil than in the same size 5/8″ coil. As a result, the coil costs less!
- There is a huge savings to be had when building multiple coils of the same size. This means that fins, tubes and casing can all be cut at the same time for all coils, and everybody gets to save a lot of money.
- Nobody really understands how to size coils anymore. Most people who work for coil manufacturers just plug in a computer program and spit back the performance to you. This usually means that if you have a special set of performance criteria, you probably have no shot of getting help from the manufacturer. Very few people understand that there are tradeoﬀs in the selection coil process and you have to give up something to get something.
- The real secret in coil replacement is understanding why the coil failed in the first place. It’s a completely different process to replace a coil that has been in service for 20 years and has “died” of old age. Than it is to replace a coil that has failed in 2 years. When you understand why a coil failed, you can build the coil differently so that you don’t duplicate the problem.
- Coating on coils don’t last forever. It’s just like the paint on your car. When a small rust spot appears, you know that it’s going to get larger over time. The metal rusts from the inside out Coil coatings are no diﬀerent, and they eventually fail over time. It’s a cost-eﬀective method of solving a problem, but it’s not the same as changing the materials of the coil. Changing materials is easily the best way to solve the problem, but probably the costliest.
- You can circuit coils lots of diﬀerent ways, and not just the standard patterns that big companies oﬀer. When you’re trying to reach a particular pressure drop, you can really be creative to circuit the coil. Of course, most big companies have to build coils in large production quantities, so a lot of their flexibility is taken away.
- You can’t substitute steam for hot water on most hot water coils, unless it’s low pressure steam less than 5 psig. Hot water coils are circuited diﬀerently and will trap condensate in the coil. In addition, wall thickness and the brazing process is much diﬀerent. Some companies attempt to use these coils interchangeably. Don’t do it!
- Many coil manufacturers are not full line suppliers of coils. They don’t have the tooling for certain types of coils and they try to steer you into what they can build eﬀectively. You have to stick with somebody who you know can build any type of coil you require.
- Do some homework on your coil manufacturer. Make sure they are really a manufacturer and not some coil broker who just slaps his label on another manufacturer’s coil. Many of these “coil brokers” say they’re the original manufacturer, but in reality, all you’re doing is paying for an extra markup. And if a company forwards you to their manufacturing representative, you’re also paying for their markup. With Tenuta & Co., we deal direct so you know you’re getting the most competitive pricing out there.
Next Tenuta Tech: Coil Replacement: 10 Helpful Hints