Switching from R-22 to 410

[turbo50mike]

We have a Mitsubishi ductless split on a site. The condenser flipped over a couple days ago when we got a VIOLENT wind storm. Needless to say, it continued to run while upside-down, and either hydrolocked on oil, or siezed a bearing, and the compressor will not start now.

Anyway, we can't get a 22 condenser from ANY of the foreign ductless split companies, and have to go with a 410 system. So needless to say we have to change the indoor unit, and the outdoor to match.

My questions are -

a) Is there a piping difference between 22 and 410 systems? (i.e pipe size)

b) Are the oils used between the two different refrigerants compatible? (we don't plan on ripping all the piping out, so there may still be some oil left in the piping from the 22 system)

Excuse my ignorance on the 410 stuff, but since we are mostly a large commercial roofop type company, we haven't seen much of the 410 stuff yet (with the exception of a Carrier air cooled chiller).

Any advice is appreciated..

MJB

[BigJon3475]

No they aren't compatible.

http://www.mechanotherm.com/r-410a.php

"R-22 air conditioners use an oil known as “mineral oil” that has been used for decades. R-410A air conditioners use newer synthetic lubricants that are usually more soluble with the R-410A than the old mineral oils are with the older R-22 refrigerants. This means the synthetic lubricants and R-410A can mix and circulate more efficiently to keep the compressor and other moving parts lubricated, reducing wear and extending their life."


You should change linesets IMO to match the manufacturer specifications.

[fireye03]

change the line sets.
the two oils are not compatible.
you'll be doing yourself a favor.

[jayhawker]

Most Mitsubishi mini-splits have the metering device loacated in the condensing unit, if the old AHU is rated for R410A then you could use the old AHU if not then you would have to buy a R410A rated AHU and condenser. As far as replacing the lines if they fall in the same size guidelines from the mfg. they can also be reused, the company I work for blows them out with nitrogen and never had any problems . Moisture is more of a problem with R410A it will cause the polyoester oil to gel and it can move around the system causing intermitent problems. If you evacuate properly, use a drier rated for R410A and limit the amount of mineral oil left from the old system every thing should be OK. I was suspect at first of R410A but after seeing 1500 plus units installed and how much better they cool , dehumidify and work in a heat pump application I belive at this time its the way to go.

[fireye03]

make sure you triple evac and pull at least 500 microns.
poe oil sucks up moisture like a sponge,a good vacuum is needed.

[OregonYeti]

Most coils made for R-22 are not rated for the higher pressures of R-410A. The oils are also not compatible and you will get adverse chemical reactions if you don't change all the copper out.

[finlay]

If its the Mitsubishi Electric Power Inverter units, yes you can just change the condensing unit and indoor unit without changing the pipework.
They have a self cleaning facility in them to allow use with old R22 pipework.

Having said that, are these around in the USA?:confused:
Been around for 3-4 years in the UK and Europe:D
Makes life much easier.

[OregonYeti]

Well I hope it's not bad advice using the pipes with non-POE, with a R-410A compressor. I wouldn't be confident doing that, but then I always have more to learn.

[finlay]

Here's a link to the Mitsi website (UK) that explains how.

Daikin have also started to do this as well.


http://www.mitsubishi-aircon.co.uk/?id=148615

[turbo50mike]

Here's a link to the Mitsi website (UK) that explains how.

Daikin have also started to do this as well.


http://www.mitsubishi-aircon.co.uk/?id=148615

Thanks dude, I never would have looked at the Mitsu website.

[finlay]

Make sure the USA kit is the same spec though,
as alot of people say,
RTFM