[bloodedark]

I just graduated from an HVAC school. My friend has a sandwich prep table that's not cooling enough so he called me to take a look at it. I went over there and look at the system, the system will run for about a min then shut off by the pressure switch. I figure the system is low on refrigerant. But the system has a tag says R409 from 2013. I told my friend I can't get any R409 right now and he has to call someone else to fix it.
After the technician arrived, he put the gauge on and think the unit is low on refrigerant too. So he brings in a tank of R134A then charge it in the system. I was very confused. I ask him if he knows what was in the system. He told me it's ok to mix R409 and R134A.
I'm wondering if he's right or wrong. And what will you guys do if a system was serviced but there is no tag and you don't know what's in the system. like R12 R134A R409
Sorry for my writing. My grammar is very bad. Any answer will be greatly appreciated.

 

[kdean1]

Mixing is wrong. The system now has an blended refrigerant with unknown properties. You should inform the owner his table has been incorrectly charged. The only way to correct it is to recover all the refrigerant and install a correct charge.

 

[pecmsg]

No you can not MIX refrigerants and unless the oil in that compressor is POE your friend WILL have problems down the road!

 

[Gunslinger]

anytime I change refrigerants I make sure to change the drier and shraders

 

[timebuilder]

The only people that can mix refrigerants today are producers like Chemours or Arkema. Anything else is amateur hour.

An on-site mixture cannot be recycled when recovered. You have to pay to get it destroyed.

 

[rider77]

Unfortunately your friend will likely be responsible for paying the disposal fees for destroying that refrigerant blend. It cannot be reused or recycled.
This can sometimes be very expensive.

 

[Snapperhead]

yank all that 409 out and put in 134 ... it works most of the time

Make sure you can shine a flashlight thru the coil , if not , clean it , they get junk deep inside of them

 

[knave]

Well really now. How about finding the leak?

 

[Snapperhead]

How can I get more beer money if I fix the leak ?? Dont be silly

 

[knave]

How can I get more beer money if I fix the leak ?? Dont be silly

Haha well I didn’t say fix! Just nice to know where the gas is going.

 

[VTP99]

Gas and go it don't get much easier :grin2:
The idea is not to fix the leak and each time you gas and go the mix gets stronger with the R134a. Eventually it's almost all R134a utergreet:

 

[Snapperhead]

Shhhhhhhhhhh .... this will be our little secret

 

[knave]

Gas and go it don't get much easier :grin2:
The idea is not to fix the leak and each time you gas and go the mix gets stronger with the R134a. Eventually it's almost all R134a utergreet:

Yeah I was wondering how you would have to pay a recovery fee when it’s all gonna leak out anyway.
Especially on a 1 lb system.

 

[VTP99]

Yeah I was wondering how you would have to pay a recovery fee when it’s all gonna leak out anyway.
Especially on a 1 lb system.

Yeah, a whole 9ozs. :eek2:

 

[DavidDeBord]

Mixing is wrong. The system now has an blended refrigerant with unknown properties. You should inform the owner his table has been incorrectly charged. The only way to correct it is to recover all the refrigerant and install a correct charge.

:cheers:

 

[Honfor450]

Mixing is wrong. The system now has an blended refrigerant with unknown properties. You should inform the owner his table has been incorrectly charged. The only way to correct it is to recover all the refrigerant and install a correct charge.[/QUOTE

This is true and you are asking for future problems

 

[ga-hvac-tech]

To the OP...

You just graduated from school...
Then you know how to recover, LL filter, vacuum, clean it up, new charge...

Looks like you just got a job...