a. c. question June 25, 2010, 03:24:36 PM my a.c. goes from blowing cold to blowing hot{like on vent mode},while driving. For a 1986 xr 7 2.3,new compress,retro to r-134a.brought it to two guys .they tell me its ok-maybe didnt change over then for them.help any a c guys please any ideas Quote Selected
a. c. question Reply #1 – June 25, 2010, 03:54:49 PM What are your vent temps prior to it going hot?My best guess, and that's all it is, is that the evaporator is freezing up. This can be caused either by a bad cycle switch (or needs adjustment) or an undercharge. It's most likely the latter of the two.Shiny Side Up!Bill Quote Selected
a. c. question Reply #2 – June 25, 2010, 05:35:27 PM thanks bill- can anybody supply part # and cycle diagrams for ac, or info for trouble shooting a c cycle Quote Selected
a. c. question Reply #3 – June 25, 2010, 06:15:01 PM Quote from: salrock54;326462thanks bill- can anybody supply part # and cycle diagrams for ac, or info for trouble shooting a c cycleYou'll need a set of gauges to check the cycle switch. I forget the pressures, but you'll want the cycle switch to turn the compressor off at the appropriate low side pressure to keep the evaporator at 31*-32* Fahrenheit. Does the compressor cycle a lot at idle?Shiny Side Up!Bill Quote Selected
a. c. question Reply #4 – July 03, 2010, 10:30:39 AM Got this worked out yet? Here are some questions just in case you haven't. 1 When you say driving do you mean its cold while moving on the highway yet when you are going slower in town or lots of stop and go it gets warm? 2 Or its get warms just going constant down the highway at one speed? 3 These two guys you brought it to are they lic A/c professionals? It really sounds to me like your answer to #1 would be a yes. Then there are a couple different ways to get it to work better. A, get and electric fan and mount than blowing on the big cond unit out front of the rad. B, change out the R12 cond for a 94 stang r134a unit. C, Drain flush and charge the system with R12 or equivalent. D, drain and install auto adjusting orifice tube. E use a more than one of these and make it work that much less to get you cold. If your answer is #2 then sounds like something is freezing up or that orifice tube getting clogged up. On #3 they don't have to be but if I was paying for there service they sure would be. Stuckman Quote Selected
a. c. question Reply #5 – July 03, 2010, 03:01:53 PM Quote from: ProTouring442;326449What are your vent temps prior to it going hot?My best guess, and that's all it is, is that the evaporator is freezing up. This can be caused either by a bad cycle switch (or needs adjustment) or an undercharge. It's most likely the latter of the two.Shiny Side Up!BillOver charging can cause the same thing. R134 takes up less space than the R12. If the conversion's not done right, this is one of the causes. I'm not saying it's THE cause, but it may be a contributing factor? Quote Selected
a. c. question Reply #6 – July 03, 2010, 05:52:25 PM Quote from: Scott D;327175Over charging can cause the same thing. R134 takes up less space than the R12. If the conversion's not done right, this is one of the causes. I'm not saying it's THE cause, but it may be a contributing factor?True, but usually an overcharge will cause the outlet temps to warm, but in a more consistent manner while an undercharge will freeze the evaporator up and cause it to go all warm and humid. Still, you are correct, and he needs to get a set of gauges on it and see what the pressures are, both high side as well as low side.Shiny Side Up!Bill Quote Selected
Topic: a. c. question (Read 1428 times)
previous topic - next topic
