flushing linesets

[Hvac216]

I was just informed that the boss is trllin insatallers not to flush existing linesets anymore. He says 10% oil mixture is ok. #1 I don't see any way to know that percentage, or if this is even true. #2 what kind of problems am I going to start seeing because of this. I get cutting costs but this doesn't seem like the way to do it.

[ADillon]

I had heard 5% was the number. Anyway, I know alot of guys who don't flush anymore. A good nitrogen blast or two and deep vacuum seems to suffice in most cases

[kingkaiko2002]

Interesting thread, I want to hear other experts opinion on this. I typically flushed it with rx 11 follow by a blast of nitrogen and of course nitrogen test and a good vacuum.

[garyed]

When I first started changing over to 410A I used to use a flush I think RX11 but the last few years I've been just using a plain nitro purge. I have not had any problems at all so I don't use any flush chemicals any more. As a matter of fact I haven't heard of any manufacturers recommending any flush at all. The only literature I've ever seen from a manufacturer recomended either using nitrogen or R-22 to purge the system.

[SBKold]

really depens on the install and each is different IMO.

Some units if been low for awhile or totally out may have a ton of oil in there or there may not be any.

If old unit was even slightly contaminated I hit it with a small amount of flush. I am conservative with the chemical. Just always go high to low.

Oil traps, etc... the flush does not lift in most cases in my experience. I always have to go high to low.

[garyed]

I am just as curious as the rest here so I would like someone to show me where an equipment or compressor manufacturer recommends any of these flush chemicals that are on the market. The only thing I've seen that comes close is Carrier has some specials where you get a can of flush when you purchase a system but that's used more as a marketing tool & not necessarily a manufacturers recommendation.

[Danae12]

I was taught to flush lines with r11 flush etc. if txv is the metering device for the new system I think flushing is a must.. WE are suppose to be replacing the lineset to really be doing it right to be honest. Btw pulling a vacuum is not going to pull out the e MO or AB oil.

[jtrammel]

We have been using rector seal flush. Flush then nitro purge. I don't like doing it though. It seems like if any residual amount of that stuff remains in the system it will eat away at all the internal parts in the system. I guess we will know in a few years if we start having problems. I'm thinking it may be better to just purge real good with nitro. Would like to hear what others think about this topic.

[jimj]

I am just as curious as the rest here so I would like someone to show me where an equipment or compressor manufacturer recommends any of these flush chemicals that are on the market. The only thing I've seen that comes close is Carrier has some specials where you get a can of flush when you purchase a system but that's used more as a marketing tool & not necessarily a manufacturers recommendation.

Trane recommends using the RX11 flush on burnouts when using existing lineset, nitrogen and nitrogen ONLY on all others!

[ICanHas]

Left over oil is not conductive to long lasting system, but I think what he's trying to get to is that it's not nearly as harmful as left behind flush solvent.

Flushing it right > not flushing it>>>>>>>>> flushing it wrong.

[VanIsleRefrig]

If you do it right is there really a possibility of any rx-11 Being left over in the system? I mean cut the liquid line and the vapor line at the furnace and at the heat pump. flush each line individually with 250psi nitro than weld and put it on a deep vacuum. my company does lots of re+re's and my boss gets us to flush every lineset. realistically if your gonna run nitro through the lineset you might aswell put some flush infront of it.

[nismo1]

If u have low spots in lineset where flush pools, nitro will blow right past it, same goes for oil, sat. Temp for r11x is high so it will stay liquid in ur lines. U can pull it out w vacuum but is very lengthy process and contaminates pump oil reducing efficiency. If it was a must or if new linesets were a must there would be more protocol on warranty compressor due to manufacturers not having any control over what installers are actually doing.

[SBKold]

When I did a long 1 1/8 line that has foul smelling oil residue I soldered on two access fitting and hit it with two nitrogen feeds at high psi.

Pinched the other end and man she blew some good stuff out. Worked real well. I recommend the dual feeds when
doing large lines or lengthy ones.