initial 410a charging

[tpalmieri]

Can anybody help me out, I need step by step instructions with as much detail as possible on charging a brand new trane 410a residential split a/c system. Any help would be greatly appreciated.

[The Viking]

Aren't they pre-charged?

1. Pressure/Strength test the installation.
2. Vacuum the system (Deep and Standing vacuum required as on modern refrigerant/oil)
3. Open up service valves (If outdoor unit is pre charged, otherwise this should have been done B4 1.)
4. Add additional charge as required.

NOTE: R410a needs to be charged in liquid form.


Good luck.

P.S. Should you require more information on the individual tasks, try searching this forum. These topics has been discussed to death here.

[Brian_UK]

You could also read the manual provided with the unit. ;)

[tpalmieri]

Viking, thanks for the help. I am not sure what is done with the system off and the system on. Obviously, pressure testing and deep vacuum is done with system off. Should system still be off when you open the pre-charge valves and weigh in the additional refrigerant required for the additional line set length?
I know system has to be on to check the pressure but if some additional refrigerant is needed do you do it with system on or off? Thanks a ton for your help

[The Viking]

>>Please note: I have no experience of installing Trane split systems<<

Assuming that you calculated the additional charge from a chart or formula, then the easiest way of getting it in to the system is when the system is under vacuum. Should you not be able to get all of the additional charge in before the system pressure equalised with your cylinder's pressure, then you will have to open the valves and start the unit up.

[tpalmieri]

Viking, thanks again, one last question, if you are charging with the system on, because r410a runs at such pressure won't the system force the refrigerant back into the 410a tank rather than the refrigerant going into the system?

[coco08]

sounds like you got it from ebay or worse . you should call a proffessional:(

[GXMPLX]

The system must be off all time and in deep vacuum and you should use a recovery machine to charge independently of temperature/pressure gradient between equipment and vessel.

[star882]

Just after finishing the vacuum, charge refrigerant as a liquid into the *high side* with the compressor off until low side pressure approaches normal. (The air handler fan can be on at this point but not necessary.) Then close the high side gauge valve, open the low side gauge valve a little bit, and start the compressor.
Then finish by charging until the superheat or subcooling is correct. If charging by superheat, make sure all the vents are open, or it might result in an undercharge.