When considering OEM replacement coils, there are multiple reasons why coils can fail prematurely. Sometimes, OEM Coils simply freeze and can never be repaired. Other times, the coil was selected incorrectly, which in turn, made the coil significantly underperform. Many times, there is substantial corrosion or something else in the system that causes the coil to fail. However, most coils, when selected correctly, and in systems that are properly maintained, can last anywhere from 10-30 years! 10-30 years is also a pretty wide range, and there are many variables in how long you can expect a coil to perform. Factors, such as ongoing maintenance, air quality, and water/steam quality all have an effect on a coil’s lifespan.
Reasons Why Coils Fail Of Old Age
- While the coil’s tubes are considered the primary surface, 70% of all coil performance is performed by the finned area on a coil, which is known as the secondary surface. The fin/tube bond is easily the most important manufacturing feature in any coil. Without the bond between the tubes and fins, the coil could never properly function. Like all things however, over time the fin/tube bond becomes less efficient with constant expansion and contraction. While the construction of the coil, as well as the fin collars, does not allow the fins on the coil to move, that fin/tube bond naturally weakens a coil’s life over time after installation. Because of this, it is not a stretch to say that a coil is easily 30% less efficient after (20) years.
- Cleaning coils often pushes dirt to the center of the coil, and this occurs even more so on wet cooling coils. Just remember that coils can become great air filters if not properly maintained. The BTU output of any coil is in direct proportion to the amount of air going through the coil. If you decrease the CFM by 20%, you are also decrease the BTU’s by 20%!
- Cleaning agents often corrode aluminum fins. Since every square inch of fin surface matters in performance, corrosion of the fin surface is always detrimental to the coil’s performance.
- Many times, there are coil leaks simply because of old age. No coils are immune to erosion. You might find the brazing in the tubes, as well as the brazing in the header/tube connections failing over time. Steam can be both erosive and corrosive under higher pressures. Water travels through the coil at 2 – 5 ft/second, so erosion is an enormous part of coil failure, regardless of how well-maintained. Erosion is always there, whether you realize it or not.
- Water/steam treatment and the corrosive effects of bad steam/water can all be causes of coil failure…which then necessitates the need for a reliable manufacturer for OEM replacement coils.
So What Is The Solution?
Some coils can last 5 years, and some coils can last 30 years. As you have read, there are numerous factors that contribute to a coil’s life. In the end, there will most likely have been multiple attempts to repair that coil to make it last as long as possible. The depressing news is that most of these “Band-Aid” attempts do not work well. The most likely outcome is that you are buying a new coil anyway, so why waste the time and money on a temporary solution?
Coil failure is a “pressure event”, which is a fancy way of saying that a coil is leaking. We’ve listed some of the most common repair methods that you are likely to come across:
- Drop leaking tubes from the circuit: Keep in mind however that every dropped tube reduces the coil’s performance by triple the surface area of the tube that is dropped. Again, while ok in the short-term, this is simply another “Band-Aid” fix. Over time, your energy costs will rise exponentially, and you will probably end up buying a new coil anyway.
- Braze over the existing braze: As mentioned above, erosion has caused the original braze to fail, so all that you are really doing is pushing the pressure to another braze, which will then begin to fail as well.
- High Pressure Cleaning: This method bends the fins, further restricts the airflow, and pushes dirt more to the center of the coil, which can never be adequately cleaned.
The real reason why coils need to be replaced rather than repaired is due to energy costs. If your coil is not operating near desired levels, you’ll need to increase the energy to make it work at its peak performance. Energy increases might be slight at first, but they are guaranteed to continue to rise over time. For example:
- Somebody adjusts the fan drive for higher speeds, higher CFM’s and higher BTU’s.
- Someone adjusts the boiler; the water and steam temperatures are higher.
- Someone adjusts the chiller (1) degree higher for colder water to the chilled water coil.
Whichever method is used, performance begins to suffer and adjustments to the system occur. These adjustments cost energy efficiency and ultimately, money!
If you have ever experienced repairing a coil, then you know it is labor intensive and typically will not work as a permanent solution. With very few exceptions, repairs should be seen as nothing more than temporary until you’re able to replace that coil!
Capital Coil & Air has seen every “repair” method used, as well its inevitable outcome, so instead of putting yourself through that, call Capital Coil and allow us to be your coil replacement experts.
Wakati wa kuzingatia coils za kubadilisha OEM, kuna sababu nyingi kwa nini coils zinaweza kushindwa mapema. Nyakati nyingine, Coils OEM tu kufungia na kamwe inaweza kurekebishwa. Nyakati nyingine, coil ilikuwa kuchaguliwa vibaya, ambayo kwa upande wake, alifanya coil kwa kiasi kikubwa underperform. Mara nyingi, kuna kutu kubwa au kitu kingine katika mfumo ambacho husababisha coil kushindwa. Hata hivyo, coils nyingi, wakati kuchaguliwa kwa usahihi, na katika mifumo ambayo ni vizuri kudumishwa, inaweza kudumu mahali popote kutoka miaka 10-30! Miaka 10 hadi 30 ni muda mrefu sana, na kuna mambo mengi yanayobadilika kuhusu muda gani unaweza kutarajia coil kufanya kazi. Mambo, kama vile matengenezo ya kuendelea, ubora wa hewa, na ubora wa maji / mvuke wote kuwa na athari juu ya maisha coil ya. Sababu za Coil Fail Of Old Age: Wakati coil ni kuchukuliwa juu ya uso wa msingi, 70% ya utendaji wote coil ni kufanyika na eneo fined juu ya coil, ambayo inajulikana kama uso wa sekondari. Finn / bomba bond ni kwa urahisi muhimu zaidi ya utengenezaji kipengele katika coil yoyote. Bila uhusiano kati ya mirija na manyoya, coil haiwezi kamwe kufanya kazi ifaavyo. Hata hivyo, kama mambo yote, baada ya muda uhusiano wa fin-tube unakuwa na ufanisi mdogo kwa kuongezeka na kupungua kwa mara kwa mara. Wakati ujenzi wa coil, kama vile collars fin, hairuhusu fins juu ya coil kusonga, kwamba fin / bomba dhamana asili dhaifu coil maisha kwa muda baada ya ufungaji. Kwa sababu hii, si stretch kusema kwamba coil ni kwa urahisi 30% chini ya ufanisi baada ya miaka 20. - Kusafisha coils mara nyingi kushinikiza uchafu kwa kituo cha coil, na hii hutokea hata zaidi juu ya coils baridi mvua. Kumbuka tu kwamba coils inaweza kuwa filters hewa kubwa kama si vizuri kudumishwa. BTU pato la coil yoyote ni katika uwiano wa moja kwa moja na kiasi cha hewa kwenda kupitia coil. Kama wewe kupunguza CFM kwa 20%, wewe pia kupunguza BTU kwa 20%! - Mara nyingi dawa za kusafisha huchafua manyoya ya alumini. Tangu kila inchi ya mraba ya uso wa fin mambo katika utendaji, kutu ya uso wa fin ni daima madhara kwa coil'utendaji. - Mara nyingi, kuna kuvuja kwa coil kwa sababu tu ya uzee. Hakuna coil ambazo haziwezi kuharibiwa na mmomonyoko. Kwa mfano, unaweza kuona brazing katika mabomba, kama vile brazing katika viunganishi header-tube kushindwa kwa muda. Mvuke unaweza kuwa erosive na corrosive chini ya shinikizo la juu. Maji husafiri kupitia coil kwa kasi ya 2 ft kwa sekunde, hivyo erosion ni sehemu kubwa ya kutofaulu kwa coil, bila kujali jinsi inavyohifadhiwa vizuri. Uharibifu ni daima huko, kama wewe kutambua hayo au la. Maji ya mvuke na athari za uharibifu wa mvuke mbaya zinaweza kuwa sababu za kutofaulu kwa coil, ambayo inahitaji mtengenezaji wa kuaminika wa coils za kubadilisha OEM. Kwa hiyo, Suluhisho Ni Nini? Baadhi ya coils inaweza kudumu kwa miaka 5 na baadhi ya coils inaweza kudumu kwa miaka 30. Kama ulivyoisoma, kuna mambo mengi yanayochangia maisha ya coil. Mwishowe, huenda ikawa kulikuwa na majaribio mengi ya kurekebisha coil hiyo ili iendelee kwa muda mrefu iwezekanavyo. Habari yenye kuhuzunisha ni kwamba majaribio mengi ya "Band-Aid" hayafanyi kazi vizuri. Kwa sababu ya hali hii, ni muhimu kununua coil mpya, kwa hiyo kwa nini kupoteza wakati na pesa kwenye suluhisho la muda? Coil kushindwa ni <unk> shinikizo tukio<unk>, ambayo ni njia ya kifahari ya kusema kwamba coil ni kuvuja. Sisi wameorodhesha baadhi ya mbinu za kawaida ya ukarabati kwamba wewe ni uwezekano wa kuja juu: - Drop kuvuja mabomba kutoka mzunguko: Kumbuka hata hivyo kwamba kila mabomba kuanguka hupunguza coil ya utendaji kwa mara tatu eneo la uso wa bomba kwamba ni kuanguka. Tena, wakati ok katika muda mfupi, hii ni tu nyingine <unk>Band-Aid<unk> kurekebisha. Baada ya muda, gharama za nishati zitaongezeka kwa kasi, na huenda ukapata coil mpya. Kama ilivyoelezwa hapo juu, uharibifu umesababisha braze ya awali kushindwa, kwa hivyo yote unayofanya ni kushinikiza shinikizo kwa braze nyingine, ambayo itaanza kushindwa pia. - Usafi wa shinikizo la juu: Njia hii bends fins, zaidi inazuia mtiririko wa hewa, na kushinikiza uchafu zaidi kwa kituo cha coil, ambayo haiwezi kamwe kusafishwa vya kutosha. Sababu halisi kwa nini coils zinahitaji kubadilishwa badala ya kurekebishwa ni kwa sababu ya gharama za nishati. Kama coil yako si kufanya kazi karibu ngazi taka, unahitaji kuongeza nishati ya kufanya kazi katika utendaji wake wa kilele. Ongezeko la nishati huenda likawa dogo mwanzoni, lakini linahakikishwa kuendelea kuongezeka kwa muda. Kwa mfano: - Mtu anashughulikia gari shabiki kwa kasi ya juu, CFMs ya juu na BTUs ya juu. - Mtu fulani husawazisha boiler; joto la maji na mvuke ni la juu zaidi. - Mtu huweka chiller (1) digrii ya juu kwa maji baridi kwa coil ya maji baridi. Njia yoyote inayotumiwa, utendaji huanza kuathiriwa na marekebisho ya mfumo hutokea. Marekebisho hayo yanagharimu ufanisi wa nishati na hatimaye, pesa! Kama umewahi uzoefu kurekebisha coil, basi unajua ni kazi-intensive na kwa kawaida si kazi kama ufumbuzi wa kudumu. Isipokuwa kwa mambo machache sana, marekebisho yapasa kuonwa kuwa ya muda tu hadi uweze kubadilisha coil hiyo! Capital Coil & Air imeona kila njia ya "kurekebisha" kutumika, pamoja na matokeo yake ya kutoweza kuepukika, hivyo badala ya kuweka mwenyewe kupitia kwamba, wito Capital Coil na kuruhusu sisi kuwa coil yako badala wataalamu.