we sold a few of the condensers when thy came out. With our corrosive atmosphere they last about 2 yrs before leaks start showing up. Once we started having a run of these leaks we quit selling them. Every once in awhile we'll get a new customer who has one and the first place we go is to pull the leak detector out. If it's in warranty we'll replace the coil and be done with it, until it's out of warranty then we change the condenser.
Charging is critical. Do it by weight. They give the chart for lineset length/size/rise and how much extra you should add.
they are easy to over charge because they don't require near the same amount of refrigerant as a standard unit does. I've seen them listed as needing as little as 4 lbs for the particular lineset it was on (don't remember the length). Now you simply add 1 lbs of gas and suddenly your over charged by a full 25%.
why would they be easy to overcharge? also, we can't clean with foaming coal cleaner, but is that because it breaks down the aluminum too quickly?
A trane rep told all of our guys that chemical cleaners of any kind were not to be used on multi-channel coils. Water is sufficient and should be the only means of cleaning these coils to preserve coil life. Not sure how well this will work on some of the extreme cases but time will tell.
Let me know if anyone knows of a cleaner that is safe for this type coil.
Just as stated above, the main problem with these types of coils is over charging. They are very charge critical and can be very unforgiving with high pressure faults. Technicians must wait the required 15 minutes inbetween adjustments or they will overcharge these systems all day long.
I just checked out the microchannel coils for Nordyne. What a nightmare. Im doing a new construction job right now and am planning on installing a nordyne system. Looking at they're "quick data reference sheet" (match AH to OD unit) I have to add an additional 29 oz right off the bat. Then add for the additional lineset.
Now if Im installing a a 3.5 ton 14seer hp with the new c7 MC coil, I have to change the orfice to an field supplied txv and add 29oz. But heres the kicker, you have to change the outdoor units orfice from .55 to a .57... How stupid is that
Might have to reconsider using nordyne equipment on future jobs.
Microchannel is just another way to make the system cheaper & still get the SEER. The bottom line is it all comes down to profit. The only slight advantage for our side is they can cut the size of the equipment down a little for some of those tight spaces. Other than that the disadvantages so far have far outweighed any advantage for us.
An engineer designs what he would never work on.
A technician works on what he would never design.