Uploaded May 2025 | Updated September 2026, 2 weeks ago
Let's charge it up and see what happens after fixing any known problems. One has to start somewhere. Your *constructive* commentary is welcomed.
Clarifications and amplifications:
The compressor suction line is rather rusty and my temperature probe did not want to make good contact with it. I never really got it to do so, which would throw off the superheat measurement. Due to cabling length restrictions, I couldn't measure superheat and subcooling at the most accurate positions in the system, those being right at the outlet of the evaporator and condenser, respectively. That will also reduce measurement accuracy. Some wireless probles could have given more accurate results and I'd sure like a set, only they're not in the budget.
Systems utilizing thermostatic expansion valves (TXVs) -- as this one does -- are charged by subcooling, as the TXV will do its best to keep superheat constant once the system has found its "happy place".
Runtime on the vacuum pump was about 45 minutes.
Unlike most any other kind of comfort cooling system, automotive evaporator coils I've seen run at low pressures (and thus temperatures), usually below freezing. I'm not exactly sure why that is. (As I said, I don't know everything.) I do think the TXV in this system could be slacking and will want to see the system operating in its normal environment before making further judgment. Engine RPM was at 1,500 during the charging and system tests. I do question how properly this system was converted to use a new compressor, especially as there is no low pressure or loss of charge protection. The high pressure switch exists and may even work, but appears to be switching the ground, which isn't the best.
For several years now, I have held both my EPA 608 universal and 609 MVAC cards. I attended a trade school for HVAC in residential and commercial fields. I've almost exclusively worked on residential stuff and MVAC, with a few random walk-in freezers or coolers along the way.
Refrigeration service specific tools used in the video:
- Testo 550 digital manifold (no longer sold new)
- Harbor Freight Hercules brand 20V cordless vacuum pump (harborfreight.com/20v-brushless-cordless-2-stage-vacuum-pump-tool-only-59438.html)
- Supco VG64 micron gauge (newer version, supco.com/web/supco_live/products/VG64.html)
- Elitech LMC-210A wireless/bluetooth refrigerant scale (pop over/slide over mania WARNING: elitechus.com/products/elitech-lmc-210a-wireless-refrigerant-hvac-electronic-charging-weight-recovery-scale-with-remote-overweight-protection-330-lbs-150-kg)
C&D Valve core removal tool (cdvalve.com/products/cd3930/)
...and I think that's everything.
Hopefully no one will find it pretentious or guilt inducing if I were to throw in a wish list for some refrigeration tools I'd like to have. My videos are and will always remain free to watch for anyone. There's no expectation of anything, and you can't "buy" preferential treatment, early access to my videos, early comments or anything similar. It's only and totally if you're feeling particularly generous. amazon.com/hz/wishlist/ls/3THXD80PJ287M
0:00 - Welcome back!
1:15 - Bad Schrader valve cores
2:01 - Nitrogen purge
3:12 - Tightness test
4:40 - Vacuum pump
7:37 - Time to charge
11:34 - Engine start, finishing and fine tuning the charge.
12:13 - Condenser airflow is important!
13:25 - A look at temperatures, pressures, superheat and subcooling.
13:56 - Closing comments
15:57 - BUT WAIT, there's more! (Evaporator airflow is kinda important too!)
We had one new cabin air filter to install and another is on the way. (A dirty air filter could cause low superheat, as insufficient air will be passing over the evaporator coil and the refrigerant within won't be boiling off properly. A thermostatic expansion valve (TXV) will try to throttle back in that case, though even at its minimum it may not be able to raise the superheat enough. Or, if by some chance it could do so, it might fool you into thinking things are OK at a casual glance.)
Yes, the Carl's Junior/Hardee's bag from the first video is still in the tractor cab. I think it might have even come with the tractor. No, I don't think I'll look inside it.
Let's charge it up and see what happens after fixing any known problems. One has to start somewhere. Your *constructive* commentary is welcomed.
Clarifications and amplifications:
The compressor suction line is rather rusty and my temperature probe did not want to make good contact with it. I never really got it to do so, which would throw off the superheat measurement. Due to cabling length restrictions, I couldn't measure superheat and subcooling at the most accurate positions in the system, those being right at the outlet of the evaporator and condenser, respectively. That will also reduce measurement accuracy. Some wireless probles could have given more accurate results and I'd sure like a set, only they're not in the budget.
Systems utilizing thermostatic expansion valves (TXVs) -- as this one does -- are charged by subcooling, as the TXV will do its best to keep superheat constant once the system has found its "happy place".
Runtime on the vacuum pump was about 45 minutes.
Unlike most any other kind of comfort cooling system, automotive evaporator coils I've seen run at low pressures (and thus temperatures), usually below freezing. I'm not exactly sure why that is. (As I said, I don't know everything.) I do think the TXV in this system could be slacking and will want to see the system operating in its normal environment before making further judgment. Engine RPM was at 1,500 during the charging and system tests. I do question how properly this system was converted to use a new compressor, especially as there is no low pressure or loss of charge protection. The high pressure switch exists and may even work, but appears to be switching the ground, which isn't the best.
For several years now, I have held both my EPA 608 universal and 609 MVAC cards. I attended a trade school for HVAC in residential and commercial fields. I've almost exclusively worked on residential stuff and MVAC, with a few random walk-in freezers or coolers along the way.
Refrigeration service specific tools used in the video:
- Testo 550 digital manifold (no longer sold new)
- Harbor Freight Hercules brand 20V cordless vacuum pump (harborfreight.com/20v-brushless-cordless-2-stage-vacuum-pump-tool-only-59438.html)
- Supco VG64 micron gauge (newer version, supco.com/web/supco_live/products/VG64.html)
- Elitech LMC-210A wireless/bluetooth refrigerant scale (pop over/slide over mania WARNING: elitechus.com/products/elitech-lmc-210a-wireless-refrigerant-hvac-electronic-charging-weight-recovery-scale-with-remote-overweight-protection-330-lbs-150-kg)
C&D Valve core removal tool (cdvalve.com/products/cd3930/)
...and I think that's everything.
Hopefully no one will find it pretentious or guilt inducing if I were to throw in a wish list for some refrigeration tools I'd like to have. My videos are and will always remain free to watch for anyone. There's no expectation of anything, and you can't "buy" preferential treatment, early access to my videos, early comments or anything similar. It's only and totally if you're feeling particularly generous. amazon.com/hz/wishlist/ls/3THXD80PJ287M
0:00 - Welcome back!
1:15 - Bad Schrader valve cores
2:01 - Nitrogen purge
3:12 - Tightness test
4:40 - Vacuum pump
7:37 - Time to charge
11:34 - Engine start, finishing and fine tuning the charge.
12:13 - Condenser airflow is important!
13:25 - A look at temperatures, pressures, superheat and subcooling.
13:56 - Closing comments
15:57 - BUT WAIT, there's more! (Evaporator airflow is kinda important too!)
We had one new cabin air filter to install and another is on the way. (A dirty air filter could cause low superheat, as insufficient air will be passing over the evaporator coil and the refrigerant within won't be boiling off properly. A thermostatic expansion valve (TXV) will try to throttle back in that case, though even at its minimum it may not be able to raise the superheat enough. Or, if by some chance it could do so, it might fool you into thinking things are OK at a casual glance.)
Yes, the Carl's Junior/Hardee's bag from the first video is still in the tractor cab. I think it might have even come with the tractor. No, I don't think I'll look inside it.
