Micro-Channel

[retube]

Have you had a bad experience yet?
:gah:

[retube]

The serviceability of a leak and blockages with-in the refrigerant circuiting is what I am concerned with.

[chilbrig]

I'm still waiting to see what happens to one after a bad burn out.

[retube]

I can tell you what happens after one bad install.

[AiResearch]

I agree with most of you guys. Micro-channel is something else. Not what we can work on and repair , what we're used to. Ya , the charge is A LOT more critical , now we have large equipment that is to be charged like an ice machine. The old stuff was repairable and flexible. Seems like all the OEM's are into reducing the total operating charge lately....look at supermarket refrigeration for example....big time there... And that is what the micro-channel is all about. Temporary satisfy the gov. We are going to see some huge fundamental changes in this industry during the next 10-20 years and this new coil is just the introduction. Why are they not using it for the evaporator??? Or are they? It is bogus and ya after one burnout or system contamination you loose many parallel circuits?? How are you supposed to deal with that?? Replace the coil?? Suuuuuuure , lets sell more parts and hopefully people recycle. Micro-channel may be more efficient , dont know , not a labratory math major. But it's old school for this guy.

[RoBoTeq]

yes i installed a guardian 2.5 ton 410a and over charged it by about 9 ounces lost a compressor in 24 hrs it was the first one i had put in amps where good superheat was there sub cooling was there had a txv thought i was fine let it run for about an hour why i was there come to find out u can over charge one by 6 ounces i do not like them i have put about 12 in now and i measure the line set and add to installation manual have yet to do the rtu micro channel r22 was not bad the 410a ridiculous
So, you had a problem on a system that was overcharged and you are blaming the coil?

[RoBoTeq]

There are a few mfg. that are using them in evaporators. The evaporator has a few more challenges than the condenser coil. Primarily the water run off from condensation and funneling it into the condensation pan. Blow by and proper airflow are more critical. This technology has been around for quite sometime especially in the automotive industry. They have been proven to be more efficient in heat transfer and do to the price of copper mfgs. have found a way to reduce costs and increase profits. They can be field repaired. I have only seen some problems with a makeup air unit and R-410 out in the desert. They all leaked, not enough airflow across coil, mfg replaced all coils with different design and problem disappeared. There is probably going to be a learning curve for everyone as more and more of these appear out in the real world.
Could you please tell us what manufacturer's are using microchannel coils for evap coils?

[AiResearch]

So we cannot use pumpdown with micro channel without a receiver , which is not normally employed with a/c duty. You loose your subcooling with a receiver. That is why.

acwizard , I respect your knowledge...care to enlighten us on how a leak repair is performed on the micro-channel coil??

Why do you loose your subcooling with a receiver? Because anytime you have refrigerant in a vessel with vapor and liquid present , you are at or close to saturation. There may be a few degrees available at the bottom but not anything to speak of.

Carrier is suggesting to abort pumpdown on larger commerical splits and instead go with a liquid line drop solenoid as well as liquid line check valves with R-410A. To prevent migration and flooded starts.

When you look at micro-channel cross section , it is hard to imagine room for condensing or even hot gas flow through those tiny , tiny , passages.

Durable and efficient it may be , cannot see it happening on a DX evaporator.

[AiResearch]

They're not using micro-channel for the evaporator coil , b/c it needs expansion. Pressure drop , not pressure increase. Sorry , but there is no room or volume for refrigerant boiling with that design. Yes micro-channel has been around forever....in automotive. Reducing the temperature of a coolant. A fluid cooler. Quite a bit different than DX refrigeration. My motorcycle has one on its radiator. Seems to work fine. Lets leave em there.

[RoBoTeq]

Their ability to shed condensate is also an issue.

[AiResearch]

You guys are on it.

[Dallas Duster]

i installed a 50 ton carrier split this winter. charged by weight. no way to pump down. this worries me. carrier says no chemicals to clean coil. dusty and planty dust will be a disaster clogger. in my opinion.

Did you order the digital scroll too.

[hvacdoctor]

Just had a to repair a Larkin unit, not many if any vendors carry any repair kits. York parts had a solder type kit we used, it worked. Many I see are epoxy type. Problem is most newer systems have POE oil in them, so you blow a charge and its open for more than 12 hours you got problems.

What do you do to clean up a hermetic scroll system besides a dryer change out?

Any better ways to repair leaks?

[jpb2]

Could you please tell us what manufacturer's are using microchannel coils for evap coils?

Nordyne.

[RoBoTeq]

Nordyne.
Hey! Thanks for the breaking histor.....er....news....:grin2: