R22 to R410 using existing pipework

[Dave Bristol]

Hello All,
can anyone reccomend a way of flushing out an existing R22 system with a knackered compressor so the system can be reused on R410.

Thanks

[Shibhrac]

Using HFC refrigerant to replace the existing system may not succeed. It dependes on how big your system is.if you are talking about small systems the overall cost of modifying the system may exceed the capital cost of a new system. Modifications is only temporary good for big system. You should get the manufacturer advise if you want to modify your system to use R410 as a replacement for R22

[nike123]

It is not only matter of flushing. It is also matter of witsanding higher pressures of R410a refrigerant.
Ewery single component must be safe with this higher pressure, and that is simply not case with systems designed for R22.
In short, you cannot convert R22 system to R410a but you could with R407c.

[R1976]

If he just wants to use the pipework, new units, this would be okay. Clean with endo flush or the like.

[nike123]

I think he just wants to use the pipework, this would be okay. Clean with endo flush or the like.

No, it is not OK if pipe wall thickness is not right.

[marc5180]

Not if the origional pipework was specced for r22 pressures. If that is the case then the pipewrok won't with stand the higher pressures associated with R410a

[R1976]

What's all the drama about R410A.

The pipe sold now is the same as it has been as always. There are two European standards, one for pipe work and one for equipment. Do you ask for special pipe when you order from your supplier?

[Dave Bristol]

Cheers Gents,
Endoflush sounds good but does this need to circulate in the system? (Compressor is Knackered). I intend to replace indoor and outdoor units using the existing pipework as there are major access issues on site for new.
only a split ac unit and normall I would replace the lot.

[R1976]

How about a burnout drier, you can't use it in heating mode though so run in cooling until neutralised and then take it out.

[nike123]

What's all the drama about R410A.

The pipe sold now is the same as it has been as always. There are two European standards, one for pipe work and one for equipment. Do you ask for special pipe when you order from your supplier?


When I work with R410a, I like that on my pipe insulation (preinsulated pipes for split systems) is stamped R410a.

[R1976]

The system maximum working pressure is what to look at and this is usually less than the pipe rating. If you go above 1"1/8 for the discharge then you may need 16 gauge copper.

As an example Sanyo's maximum working pressure is 41.5 bar.

[nike123]

http://farm3.static.flickr.com/2672/3918966532_c4827d7349_b_d.jpg

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[Thermatech]

Hi Dave

Three main issues
1/ tube wall thickness acceptable for R410a ?
For most R22 split system heat pumps up to 5hp the tube size did not exceed 3/4 for the gas tube & for normal tubes supplied in the UK this should still be ok for use with R410a & max operating pressure for gas tube in heat mode of around 41.5 bar which is the typical HP safety cut out pressure on R410a splits.
So double check the tube wall thickness & tube manufacturers data for max allowable working pressure.

2/ The interconnecting liquid & gas tubes for new R410a split systems are now smaller than on the old R22 systems.
If the Manufacturer will allow connection to old tubes they may have revised max lenght for the interconnect tubes to allow for the incorrect tube size depending on the tube size. So make sure to confirm this with the manufacturer.

3/ Cleaning out any old mineral oil & any contamination like acid from the tubes ?
If the compressor burnt out then there will be acid contamination which will cause premature failure of new system compressor.
There will be some old mineral oil left in the tubes which can contaminate the new synthetic oil So this all needs to be flushed out.

Some manufacturers have made split systems which are addapted for connection to the old R22 interconnect tubes. For instance the Mitsubuishi Electric Mr Slim power inverter range has a special system clean up filter built into the outdoor unit. When you first run the system you can use the clean up function which flushes all refrigerant through the system & the special filter for about 2 hours. Then the system shuts the filter circuit with a solenoid valve so that it is permanantly isolated from the system & any contamination is permanantly collected & trapped in the filter.
However there are some reduced pipe lenght limitations depending on the tube size of the interconnecting tube you are re using.

Be carefull about warrantee implications because the sales engineer can tell you that you can use the system for this application to get the sale but if you contact the UK warrantee manager for the manufacturer & explain what you intend to use the system for, you may get a totaly different reaction.