Original message
| northernfitter
 |  "pressures off in new a/c/high velocity"
, posted Sun 25 May 16:12  
Hey all, I just put a 3 ton r22 system in a 5 year old high velocity system. The original a/c in the system was a year old and was hit with a snow plow. I reused the existing coil in the air handler as well as the txv as they are matched with the air handler. I am currently getting 55psi on the low side and 160psi on the high side with the ambient conditions being around 22'C and after running it for a little while you can see the coil start to freeze up. I am not familiar with the high velocity systems and am not sure if this is just a matter of adjusting the TXV. The line set was only about 15ft so as far as I am concerned the factory charge should be enough as far as refrigerant goes. I have 13 years as a natural gas service tech but only a couple years experience doing a/c service any help would be appreciated. thanks
14years as a service tech in Ottawa and the valley. www.reliableheating.ca. For furnace manufacturer ratings go to
http://www.consumerreports.org/cro/appliances/heating-cooling-and-air/gas-furnaces/furnaces-repair-history-205/overview/index.htm?resultPageIndex=1&resultIndex=1&searchTerm=furnace
|
|
Replies:
|
| theduke03
| "Re(1):pressures off in new a/c/high velocity" , posted Mon 26 May 11:24
Nfitter, I have never seen a high V system that I liked, or one with good pressures. I would dump (I mean recover of course) some 22 out to bring up that suction temp a bit. Then run fast and never look back. Don't lose sleep over it. It's not your fault.
"My dad was the most feared furnace fighter in Northern Indiana."
|
| dwcaveney
| "Re(1):pressures off in new a/c/high velocity" , posted Mon 26 May 09:23:
Hi Northern, LTNS
TXV (subcooling)
High side pressure ____________PSIg
Saturated line temperature
(from temp/pressure chart R-22) A._____________F
Temperature of Liquid Line
(smaller, warmer of two lines at unit) B._____________F
Difference between A and B = SC:____________F
Desired Subcooling from Manufacture C._____________F
(if unknown use 12F +/- 3F)
If Subcooling is high (more than 3F) remove refrigerant.
If Subcooling is low (more than 3F) add refrigerant.
DW
[this message was edited by dwcaveney on Mon 26 May 09:28] |
| Jojo98
| "Re(1):pressures off in new a/c/high velocity" , posted Sun 25 May 22:24
I would verify that you have a proper charge first. There are so many things to check prior to messing with the TXV.
|
|
|
