R22 to R410A retrofit

[jodem]

We have switched out 6 R22 Carrier Split Heat Pumps for 6 R410A Carrier Heat Pumps. There is over 720ft of piping in the system, is there a need to replace the linesets, also we have purged the lines with nitrogen as well had them under pressure for two weeks?

[Brian_UK]

Have you also cleaned the lines of contaminants and oil ?

Perhaps take out an accessible section of pipe and strength test it to R410a standards.

[jodem]

Could clean the line sets with PF-16 Pro-Flush, but not entirely sure that this is necessary. The line sets are 99% horizontal line sizes are 7/8" and 3/8" on the liquid side. Were just talking about 3 ton systems.

[icecube51]

i think the best is to flush them twice to be sure they are clean.

Ice

[jodem]

Think that client is going to try to make us change out the piping. This is a terrible waste of resources.

[Thermatech]

1/ Confirm wall thickness on the 7/8 tube & confirm with the copper tube manufacturer that the tube is strong enough for 410a pressure.

2/ Confirm with Carrier what the saftey HP cutout pressure is.
Some split & VRF systems have HP cutout at 41.5 bar for 410a & if the indoor unit air fillers get blocked because someone forgot to clean them or any other problem which causes reduced air flow then the system can run at over 40 bar on the 7/8 gas tube.

3/ Make sure you have an oil drain port on the compressor shell & carry out oil test with a refractrometer after the systems has been running for a few days. Then you can measure any mineral oil contamination & carry out an oil change.

[Tapas K Mitra]

The R-22 gas is used with mineral oil, but R-404a gas essentially requires synthetic lubrication oil. These two oils does not go together. Therefore abosolute cleaning is necessary

[Tony]

Jodem,

have you any more details about your flushing agent you mentioned - PF-16 Pro-Flush?

[MACT]

Be very careful, R22 7/8" pipe is not rated for 410A use. 410A runs at a much higher pressure and the wall thickness of 410A pipe is much thicker. the oil problems may the least of your problems.

[mwatts]

Be very careful, R22 7/8" pipe is not rated for 410A use. 410A runs at a much higher pressure and the wall thickness of 410A pipe is much thicker. the oil problems may the least of your problems.

whats this about? i thought fridge pipe was just that. can you get different grades then?

[BritCit_Juve]

Its all down to the gauge.
Check the link
http://www.hrponline.co.uk/hrp.static/docs/technical/refrigerant/ProdInfo18xls.pdf

the copper also has to be undamaged - no scratches/gouges or dents as they will cause weakpoints in the wall
Brit
Brit