HVAC stuff

[Robyn]

Well the need to do some HVAC work on the dually has prompted me to write a little ditty.

The AC system on our trucks is very simple for the most part and servicing it need not be a mystery.
I have done a buttload of AC stuff over the years and have owned most of the equipment to do such.

With the onset of the 134A juice in the mid 90's many of the tools changed.
The service ports changed to a larger quick connect type as well as many of the internal seaqls and such in the pumps.

Also the sniffers used to detect leaks have changed. Mine was an R12 unit and will not do any other materials.

Off to the NAPA store to get a new one. Now the sky is the limit as to what you can spend for a tester but the little cheap one at $179 will do the job but you need to get creative to avoid false alarms.

My system had a GROSS leak that had popped up over a day or two.
actually I think it was there all along and just took the stress of real hot weather and the higher highside pressure to reopen the wound. (crimp on the highside hose.)
You cant really find leaks without tools unless they are so obvious such as a hiss or a lot of oil seeping from a crimp area or a condenser core.

My first concern was of course OMG I hope its not the evaporator in the cab. :eek:

This is some serious work to get out of the truck.

I get the new sniffer and read the instructions (YESSSSS this is a good idea) as the folks who built it probably know more thanI do about it.

I first go to the cab and run the little devil around under the heater box and it instantly goes berzerk. :eek: :eek: :eek: Expletives deleted!!!

After stomping around and uttering things very unlady like I read the book more and it says " areas with moisture may cause a false alarm"
I head over to the Burb that has just come in from town and stuff the unit under the heater and it goes Berzerk again.

Ok, after a sigh of relief I head out front and start probing around the hoses and fittings and soon discover the real issue at hand.

The little sniffer is cherping away quite adamantly when it gets close to the highside hose crimp as it passes through the header on its way to the condenser.

Game over, evacuate the system into the holding tank and remove the hose assembly. This morning its off to the warehouse to get a new set.

Just one of those little things that can bite you in the butt.

The moral is, the better quality tools will give better results with less chance of errors but if one is careful you can do fine with the entry level stuff.

Years ago when dad and I had the shop, as dad used to say, the best is none too good.

For the home shop the entry level tools will get the job done fine.

One thing though when working on HVAC stuff. Be careful and use all the proper protection gear and be safe. While not dangerous, improper procedure can get you hurt.

Refrigerant is nasty stuff if it gets sprayed in your face or on any exposed flesh. (Super cold can cause frost bite and severely injure eyes) or worse

Dont breath the stuff either. If you have a leak in the rig, ventilate well and evacuate the system before working inside.

Just some observations that come to mind

Robyn

[More Power]

I heard a story 3-4 years ago about a fellow who bought a brand new GM Duramax/Allison equipped truck. Unfortunately, it was wrecked on the way home from the dealership. As it turned out, there was a refrigerant leak inside the cab, which was thought to impair the driver... :(

Even though the A/C system had to be recharged before the new owner could take delivery of his new truck, the principles involved (insurance companies, dealership, etc.) tried blaming the accident on driver error... I never did hear the final outcome.

One read of the cautions and warnings about R134a on the net would allow most reasonable people to conclude that an in-cab leak could cause such a problem.

Jim

[Robyn]

Agreed

I have read the MSDS on 134A and that stuff is nasty.
The envirofreeks will rant about CFC12 and such as being the bane of our very existance but the truth is its fairly benign stuff unless its in heavy concentrations.

134A is not something you want to beath at all. There is a new maeterial out there called envirosafe and it will replace both R 12 and R134A

Its a HC refrigerant and has a nice pine scent in it. If you open the car door and it smells like Pinesol you knpow right away you have an evaporator leak.

The stuff is certainly not something you want to huff but in small dilute amounts wont hurt you.

I have used the stuff and its wonderful to work with. It likes all the different oils and will work better than any of the other stuff.
The company has a replacement for almost all the popular refrigerants that are currently used that are "Good for the environment"

Takes less of the stuff to do the job and the heat coeffecient is far better too.

Real good presure temperature ratios. Takes a lot of load off the system too with colder temps to boot.

There is a lot that the environmental freeks dont want us to know. There is also a lot they dont know and they preach whatever smoke is puffed up their tail pipe. :D

R12 may not be good for the environment but R134A is not Gods gift either, not even close.

The general consensus in the HVAC trade is that R 134A will not get a car as cold as 12 will.
BS if the system is in good shape and you know the little tricks it will bloody well freeze your butt out.

You can cheat a little on the low pressure switches and get the low side down to about 18 lbs before it cuts the clutch.

I have seen guys put a variable temp stat in place of the low side cutout. You have to be careful though and not get greedy or the thing turns into a popsicle


My dually right now will dump air out of the vent on a 90F day at 40 degrees. :D

Any colder and one runs the risk of an evaporator iceover. you might get to 37 at the vents ok but its not worth an iceover to try to go there.

I still hate the stuff though just because the Govt says we have to use it. :(

12-22 and all the other great chemicals that we have had, Geeeez we used to have DDT . Got ants? trowel in a 50/50 mix of DDT and honey, no more ants. :eek:

Some of the stuff thats gone is the best thing, DDT being one of them.

But what concerns me is what will they find in 20-30 years that we have today thats far more sinister. :confused: There are so many things that are the sadistic progeny of some chemical company that cares not about us but about $$$$$$$$$$. Hmmmmmmm. we shall see.

later troops

Robyn

[twaddle]

Hi Robyn,
You may remember in an earlier post You commented on "Missy Robyn is eyeing the soapbox I was climbing down from, weren't kiddin' were Ya???? Hee hee!!

I agree with you on the misinformation that "environmentalists" are spouting and especially when the "enviromentally friendly" alternative is often worse than it's predecessor.
What worries me too, it is gathering a momentum that defies belief and the faster it gets the less common sense is used and these folks don't seem to be able to figure out, or care, who is telling the truth, or should I say "NOT telling the truth".

I heard someone on the TV (another expert) recently state that the use of crops to produce fuels should be stopped as this is taking food away from the starving.
I could not believe what I was hearing. Talk about feeling helpless and worried.
Do you think these kinda clowns will ever be happy???? I think some of them only get out at the weekends!!!!

Anyway thanks for letting me borrow my soapbox.

Thanks also for the info on the HVAC stuff, much appreciated.

Regards

Jim
Biggar Scotland

[Robyn]

Look back throughout recorded history.
It is chuck assed full of buffoons.

The sky is falling says Al Gore, ahhhh OHH chicken little, Skuuuuus me.

We are having global warming global cooling and when the water is running knee deep down the street they shut up for a day or two about the drought thats killing everything.

I recently looked over my Mothers diaries from clear back in the 30's
She wrote down such things as the weather, temp, rain snow whatever for every day that came and went here in western Oregon.
Looks pretty much the same now as it did then.
It was 105F the day I was born in 1952.
Its politics, money and power. He who holds the $$$ holds the reins.
Always been thats way always will be.

The difference is the instant access people have to information and the ability the media has to distribute their diatribe.

When I was in school a journalist's job was to gather information and report the news as it was in the real world.
Now its the journalists job to make up the news and report it to influence the real world. :eek:

Did I miss something?????????? :rolleyes:

later troops

Robyn

[Robyn]

HVAC is an area we dont discuss much here. Most likely due to the nature of the special tools required to work on it.

Its really not at all difficult to work on. Ya pump in the cold stuff and it poops the ice cubes out the bottom.. :D

I have a simple tandem gauge set with the quick couplers to access the system and a vacuum pump to pull the system down prior to the recharge.

A complete setup with a recycler and such is nice but too spendy for the average stiff to even think of owning..

The units that do the evac and auto recharge with just the right amount of juice are sweet.

I evac and then sit the jug on the scale and blow in the amount needed and let it go.

Still works just fine. I had a chance to buy a slightly damaged unit a while back. I think it fell off the delivery truck as it was beat up a tad but looked to be usable. I just could not justify the cost for the small number of units I may have to do. I quit doing it for hire LOOOOOOOOOONG ago so its just mine and a few friends stuff.

The newer automotive systems are so simple compared to the older STV systems. The big GM setups were sweet but complicated.
Used to be you had an expansion valve on the inlet side of the evaporator and then a suction throttling valve on the outlet with the filter drier on the highside and a few safety switches too just to keep it interesting.

Now its a small orifice tube and a low side cutoff switch with an accumulator to strain out excess liquid coming back from the evaporator.

Cheap but it works, usually :eek:

Robyn