Members, Just need to share my air-conditioning woes so others don't make the same expensive mistake! I have fried 2 ECU panels for a Marine Air 16k unit by doing the following. Shut down air in preperation for a trip, removed shore power, started genset, went to turn on air control panel to find it already indicating on but having faults. In 2 cases I fried the triac that runs the fan but this past time I cooked a relay for the water pump and did not know it. Upon resetting the panel and starting unit all seemed well, since we were traveling at this point I did not look for cooling pump discharge. I should have!!!! Compressor shut itself off from overheating. Hopefully not irreversably damaged!! Here is what Marine air had to say which was backed up by another competitor as well. It applies to any unit with electronic controls. Mr. Young, Anytime the unit is on and the generator is started, there is always the possibility of the circuit board going bad as a result of the power surge. I've spoken to many people throughout the years about this fact, and have advised them in the same way. Turn off the circuit breaker for the A/C before you start up your generator. This is a common practice that many people use with great success. If you have already fried the circuit board, there's nothing I can do for you and you'll just have to replace it. But in the future, please just follow the above mentioned procedure. Regards, Barry Cyr Dometic Environmental-Florida Senior Customer Service Representative Company: 954-973-2477 Direct: 954-633-3133 Fax: 954-979-4414 E-mail: Barry.Cyr@dometicusa.com
I'm surprised that the ECU does not have surge/spike protection/ voltage regulation in front of it as a matter of course. What voltage is the genset supposed to be feeding to the AC? Sorry about your mishap.
As far as I know it is set at 120-125 or so! see I really don't know exactly, it is displayed but I haven't committed it to memory. I was told that there is indeed a spike issue when switching to the gen and even when plugging the boat into shore power. Best practice is to turn off breaker and then open circuit when transfer is completed. 2nd best option is to get the old trusty twist knob controllers! I was told that Micro-Air makes all of the circuit boards for 2-3 brands of air units so the info applies to all of them evidently. Mark
I was just speculating that a good spike/surge supression device might help the longevity of the circuit boards. The safest way is to kill the circuit at the circuit breaker. There are still spikes being presented to the ECU panels during normal operation from shore power or the genset. Some boards suffer cumulative damage from the small everyday spikes that are frequently present in the power from shore or a genset. I'm actually looking in to this issue for a ship based application where there have been failures in a friend of mine's on board dental equipment. He measured spikes of 800 volts. The spikes were generated by a refrigeration unit every time it cycled. If you are referring to a rheostat/autoformer when you say "old trusty twist knob controllers" those devices can offer some protection but some of them also generate a certain amount of RF ( radio frequency) interference that can cause issues with communications equipment. I've tried a couple of "surge/spike" bars like the one that you should be using for your home computer but so far the inexpensive ones are pretty much crap. When I find something that actually works I'll post it since it should also help in your situation.
Codger, Thanks for the great info. I never thought about a good surge protector. I'll delve into this as well! Mark
Hi Mark Spike is just as if not more important than surge. What I've found is that the common power bar type units aren't worth a pinch of coon stuff when it comes to spike, or surge for that matter. Let me know if you find anything. I'll do the same. There are 2 that I've found that are coming to market but they are not UL approved yet and the manufacturer is telling me September this year. Apparently protects for hot grounds as well which is very important and not done or done improperly as an afterthought in the units that I've looked at so far.
