AC freezing up

JohnnyCog · Post by **JohnnyCog** » Fri Aug 01, 2014 7:15 pm

Yes, this is what my mechanic is talking about doing, putting a an interrupt switch like this on the system loop. Good catch, thanks!

JETBRD66 · Post by **JETBRD66** » Fri Aug 01, 2014 7:53 pm

I hookup everything this afternoon, it works perfectly, for the moment I have the cap tube taped to the suction line as it enters the evap coil, it was really hot in Toronto today, (hot to us) low 90's , high humidity etc , it ran at 50 degrees solid, through city traffic, I have a pusher fan installed on the condenser coil also, it comes on when the comp starts, everything work A-1 will have to see what it's like on a cooler day or at night when there is less load, I may raise the t stat settings as I think 26 degrees is a little too low before it opens, time will tell , will up date latter , the true test is coming in a few weeks, Woodward Dream Cruise in Detroit Michigan , roughly 600 miles round trip + the actual cruise is a 16 mile traffic jam, LOL , 40,000 cars, 1 million people at a 1 day event, if you have never been, you should put it on your bucket list. Its a HOOT !

tbird · Post by **tbird** » Fri Aug 01, 2014 10:29 pm

By replacing the control switch with a freezestat you no longer have a method of adjusting the discharge air temperature as you loose the vacuum temperature control potion of the system which allows you to vary the control set point from the temperature lever on your consul control panel.

If you use a adjustable freezestat as JETBRD has done and install it some place that you can reach the control nob to adjust it the off the shelf control can be used, but certainly would not do the job as nicely as the original.

OZZY Stewie · Post by **OZZY Stewie** » Sat Aug 02, 2014 8:30 am

Hi JETBRD66.
I had my complete dash out and o/hauled everything. Air-con guy pressure checked evaporator and fitted new expansion valve plus new hoses. The problem you have/had is also my problem. I can't find that part 32-10904
in Australia (yet) and will probably get it from the States. Action-AC.com has alternate P/N's so I will check them out here in OZ. Freight is the killer but have a friend coming out to OZ from Canada in October so hopefully he can bring it. Keep up the post's on how your air-con is going. Love this forum.
I chucked out the original compressor and fitted a modern one. Still got condenser and dryer to go in but at least under dash is done.
How much adjustment do you have on rotary switch? I am not worried about temp output control because it gets bloody hot in summer + humidity here in Oz. I am really pleased you put up this post.
Regards, Stewie
64 HT
Australia

JETBRD66 · Post by **JETBRD66** » Sat Aug 02, 2014 8:01 pm

Hi Ozzy, there is a 7 degree temp swing in the switch, you can get all different kinds, I would hunt down you local pars jobber, these parts are not unique, allot of imports use them, in particular Mazda uses the same type of switch except it is fixed meaning it's on or off at a dedicated temps, my solution is not perfect, but being a refrigeration mechanic I have dealt with ice machines etc so I had some knowledge of frost stats, or freeze cycling switches, as I mentioned I also don't like overcharging systems to change boiling points to keep the evap from freezing, but being in the business I have juggled gases around for years, the new compressor is much more durable than the old single cyl slave iron horse that is in these cars, eventually I will go the same route, but kinda like to keep the factory look if possible, good luck , G>

OZZY Stewie · Post by **OZZY Stewie** » Sun Aug 03, 2014 7:48 am

Hi JETBRD66
Thanks for the post. I have located 3 types of thermostats in OZ but have a few questions. What length capillary should I buy?
There are three lengths, 18/24/36 inch. (rotary) Which one would suite?
Also did you attach the capillary tube length wise to the input gas tube or wind it around the tube. I was hoping to attach it to the coils like the original. P/N TSX1036 made by OEX 36" capillary is what I am thinking.
Regards, Stewie

JETBRD66 · Post by **JETBRD66** » Sun Aug 03, 2014 9:22 am

Hello again my friend from down under, I could not get at my coil so for the time being I have it strapped to the suction line (large line from the compressor) ideally it should be located in the coil as the other one is, I choose the longer length just because I had no idea where I was going to mount it (the actual switch itself) you can always just leave the extra in a coil loop like it was shipped, space is a large consideration,but yours is out of the car so you can judge accordingly, you have be careful not to kink it or the switch is junk, one of your best friends is going to be an accurate thermostat with a probe, I had one from my refrigeration days, basically the same set up as the switch, except it gives constant readings on temp only and that way I can adjust the the freeze stat accordingly , another great way to tell is when your air flow drops the coil is freezing up, just turn off the cooling for 5 minutes and leave the fan running and it will defrost and you start the whole cycle all over again, as I said its is not the perfect solution but does do the job very effectively and don't have to worry about that stupid thermostatic switch anymore, technically it was way over engineered for its time. Happy Kangaroo'in , LOL

JohnnyCog · Post by **JohnnyCog** » Tue Aug 05, 2014 3:17 pm

We haven't done anything yet, and I don't think it is the same system you have installed. When I get a better read on what my mechanic has up his sleeve and how it works I will report back with all the details.

OZZY Stewie · Post by **OZZY Stewie** » Tue Aug 12, 2014 7:35 am

Hi JETBRD66
Got the thermostat today, no mounting holes. How are you mounting yours?
Stewie

JETBRD66 · Post by **JETBRD66** » Tue Aug 12, 2014 7:12 pm

No mounting holes ? not quite following you, I mounted mine with double sided 3 m body tape to the kick panel for the time being, I extended the wires from the original thermostatic switch over there, until I am sure if it if works as intended, as of the moment , I have the bulb taped to the suction line as it enters the evap at the fire wall ( there is about 2" of solid line at that point) & it seems to be reading well at that point, I have also sightly over charged my system to stop it from icing up, I have left the vacuum controls hooked up, I have also installed an on off switch to the compressor because mine has a elect fan mounted on the condenser wired in also, so I wanted to be able to control both the fan and the compressor, especially in rush hour traffic, maybe a bit of over kill , but switches are cheap and give me full control , hope your understand what I'm talking about, I know its easy for me but explaining it is a different matter ! let me know how your making out ! mine get's the major test this week , doing a 500 + mile trip to the Woodward Dream Cruise, so will see how she does on the highway as well as in city, hopefully there is enough of adjustment in the stat !

OZZY Stewie · Post by **OZZY Stewie** » Thu Aug 14, 2014 2:54 am

Hi JETBRD66, What I meant was pull out the original thermostat and mount the new one in the same place. I was thinking of undoing nut on thermo shaft and mounting to bracket, refit nut, then fitting in same spot.
Do you have high and low pressure switches in the air-con system?
Regards, Stewie from OZ

JETBRD66 · Post by **JETBRD66** » Sat Aug 16, 2014 6:47 am

Sorry , I been Cruisin Woodward !, I left everything in place and just jumper,ed the wiring over to the new switch, I did even fool with the old stuff, I just wired the vacuum switch closed, all the rest remains the same , I re positioned the new probe on the large line from the compressor to give me some frost control , until I remove the dash or can access the coil I will leave it, work fine with minor adjustment according to temp conditions. G>

sleeper bird · Post by **sleeper bird** » Sat Aug 16, 2014 8:34 am

mind me asking how you got the pusher fan to run with the ac is turned on,how you wired it?

JETBRD66 · Post by **JETBRD66** » Sat Aug 16, 2014 6:44 pm

^^^ I wired it thru a relay, with a trigger wire spliced into the clutch fan wire, the trigger wire takes very little voltage to operate then I took direct power from the battery to the relay, which sends power to the fan, really, simple installed relay beside my starter solenoid. you can pick up them up almost anywhere, I like bosch relays the best others will work , you can get a little more in depth, and have a relay with a temp control probe into the the cond core ti come on a desired temp, but in my opinion it is not need, if you need your a/c on then you need the fan, those 390 we know to over heat at the best of times !

redstangbob · Post by **redstangbob** » Sun Aug 17, 2014 5:57 pm

This thread has taken enough turns that the original issue has been muddled. Compressor swaps, electric fans, and aftermarket switches have this looking a lot like a modified post. I'm hoping we find a way to repair the original switch, the way it operates is unique. I appreciate the input from everyone, but lets not leave this thread for future readers thinking that the way to restore these systems is by rigging in aftermarket parts. I'm locking this thread, lets continue this in modified when we have some conclusive results. Thanks, Bob C

Vintage Thunderbird Club International

AC freezing up

Thermostat

Thermostat

Thermostat

mounting