a/c clutch cycles

[IRKillroy]

you do realize that you can over fill your system, and the amount you put in will not change the pressure... your pump and orifice are what create pressure on the low and high side... when you over fill it you get liquid in your pump and the pump breaks.... very ugly.... you go by weight, look it up in your A/C handbook... if I must I'll go and PDF my book for you to read over. (rather unlikely though as I'm not willing to put that much effort into this)
the right way to charge a system

 

[LittleHorse]

I'm not just some random guy on an internet forum...I work as an engineer and service coordinator for a custom heavy commercial and industrial refrigeration and air conditioning manufacturer.

In the absence of a sight glass, the only reliable way to charge is by weight. I've never seen a shop that didn't charge it by weight. Usually out of a tank on a scale, short of that a small scale and the little parts store cans is the next best thing.

If you've charged by pressure and it worked, it was nothing more than luck, and even then, there's a decent chance it wasn't working as well as it could have been.

 

[warrior24]

So without have to take it to a garage to have em put air in how many lbs does a 92 ranger need? Or how much would it cost to have em put it in for me? I live in AZ.

I think I can borrow a scale.

 

[warrior24]

And if I evac It do i need to add new oil?

 

[LittleHorse]

cost of refrigerant plus whatever their labor rate is...probably count on 2 hours. It only takes probably 15 minutes of actual work but it takes a while for the machine to pump down enough to check for leaks and charge it. They might be nice enough to only charge you for their actual time spent but not likely.

Also keep in mind that a shop will not charge it if it has a leak.

If you evacuate you will need to add oil. The system oil capacity should be published together with the refrigerant capacity.

R-134a is pretty cheap, IIRC less than $10 a pound.

 

[warrior24]

I guess by evac I mean put the vacuum on.

 

[IRKillroy]

evac as in take out the old... and then charge is put it back in... put it to vacuum is to test for leaks.

if there is a leak then you'd put nitrogen to it and check for air/nitrogen bubbles...


I'm really glad I got someone else backing me on the A/C charging thing... I know I didn't goto school and get my MACs cert for nothing... though I'm not sure if that means anything anymore since r-12 isn't being sold....

 

[skippy]

evac as in take out the old... and then charge is put it back in... put it to vacuum is to test for leaks.

if there is a leak then you'd put nitrogen to it and check for air/nitrogen bubbles...


I'm really glad I got someone else backing me on the A/C charging thing... I know I didn't goto school and get my MACs cert for nothing... though I'm not sure if that means anything anymore since r-12 isn't being sold....

Removing the refrigerant is called recovery.Leak checking with nitrogen is done on an empty system.If the system has refrigerant still in it at satisfactory pressure a halogen leak detector or soap bubbles can be used to locate the leak.If the system has been determined not to have a leak,then Evacuation is done with a vacuum pump,pulled down to acceptable values with a thermister micron guage.

System charge can be installed by weighing in or by pressure.Either method requires scales in my trade as I have to document every ounce used,recovered,recycled,reclaimed or disposed of per EPA.

I can put a charge in by pressure because I charge by superheat and subcooling.I use this method when no tag is present indicating system charge or I was able to fix a leak without removing the charge.

I don't recognize the large air system you showed earlier,haven't seen one in Atlanta yet.

 

[skippy]

Removing the refrigerant is called recovery.Leak checking with nitrogen is done on an empty system.If the system has refrigerant still in it at satisfactory pressure a halogen leak detector or soap bubbles can be used to locate the leak.If the system has been determined not to have a leak,then Evacuation is done with a vacuum pump,pulled down to acceptable values with a thermister micron guage.

System charge can be installed by weighing in or by pressure.Either method requires scales in my trade as I have to document every ounce used,recovered,recycled,reclaimed or disposed of per EPA.

I can put a charge in by pressure because I charge by superheat and subcooling.I use this method when no tag is present indicating system charge or I was able to fix a leak without removing the charge.

I don't recognize the large air system you showed earlier,haven't seen one in Atlanta yet.

P.S. r-12 is being sold,I can buy unlimited quantities.It is however very,very expensive.R-22,as in your home air conditioners is starting down the phaseout path now and is starting to get pricey.

 

[LittleHorse]

I don't recognize the large air system you showed earlier,haven't seen one in Atlanta yet.

was this intended for me?

My company is kind of a niche market manufacturer, we have catalog models but most, like the one I pictured is built to customer spec. Called Technical Systems, Inc. We build the stuff that the mass production companies like Trane and Carrier won't do...we actually sell stuff through Trane from time to time. They buy it from us and mark it up. We do have reps in the Atlanta region so it's around.

That particular unit pictured was the larger end of what we build in terms of physical size - 50 feet long...it's a 300 ton air conditioning chiller, evaporative cooled, 4 refrigerant circuits with screw compressors, variable primary flow and water side economizer coils for low ambient operation. List price well into the seven figures. Shipped it to Boston.

It took 900 pounds of R-22

 

[skippy]

was this intended for me?

My company is kind of a niche market manufacturer, we have catalog models but most, like the one I pictured is built to customer spec. Called Technical Systems, Inc. We build the stuff that the mass production companies like Trane and Carrier won't do...we actually sell stuff through Trane from time to time. They buy it from us and mark it up. We do have reps in the Atlanta region so it's around.

That particular unit pictured was the larger end of what we build in terms of physical size - 50 feet long...it's a 300 ton air conditioning chiller, evaporative cooled, 4 refrigerant circuits with screw compressors, variable primary flow and water side economizer coils for low ambient operation. List price well into the seven figures. Shipped it to Boston.

It took 900 pounds of R-22

Think I worked on a technical systems unit in 1998.It was a little complicated in as much as it had some serious low ambient controls and txv's.Im pretty sure of it now because it was built in Pryor,ok.

Yeah,You and I deal in Hundreds of pounds,and tons of cooling.

 

[4x4junkie]

In the absence of a sight glass, the only reliable way to charge is by weight.

Orifice Tube systems (no sight glass) can be charged by running the system at max and filling it until the outlet of the evaporator core suddenly becomes cold (within 10° of the inlet) as the boiling refrigerant begins to flow into the accumulator. Then add a small additional amount depending on how hot it is outside so there will always be some refrigerant in reserve in the accumulator.

 

[LittleHorse]

Orifice Tube systems (no sight glass) can be charged by running the system at max and filling it until the outlet of the evaporator core suddenly becomes cold (within 10° of the inlet) as the boiling refrigerant begins to flow into the accumulator. Then add a small additional amount depending on how hot it is outside so there will always be some refrigerant in reserve in the accumulator.

I'll have to try that some time, maybe when it comes time to charge my Bronco II. I don't work on much that doesn't have a TXV. I've always charged orifice tube systems by weight and never had a problem with it.

Better yet, I'll note the weight I've put in when I have ~10° of superheat and see how it compares to the published capacity.

 

[LittleHorse]

Think I worked on a technical systems unit in 1998.It was a little complicated in as much as it had some serious low ambient controls and txv's.Im pretty sure of it now because it was built in Pryor,ok.

Yeah,You and I deal in Hundreds of pounds,and tons of cooling.

Pryor, OK, that's us.

We also have a branch for commercial refrigeration called Century Refrigeration. It's a lot more standardized than TSI in terms of structure, but there are a lot of available options.

We do quite a bit of low ambient stuff and our controls can be pretty complicated. Lately we've been building some here and there with multiple PLC's. We've been doing so much with our PLC programming that we're down to where we can only control one screw compressor with a Johnson DX9100 due to memory shortage. Stuff like that is now almost exclusively using one or more FX16's. I'd be interested to know what you worked on.

I'm getting to a point where I'm getting tired of being on the engineering side and really find myself enjoying the diagnosis stuff. My boss has named me the engineering contact for the service department - which basically means service takes the phone call and sends it on to me. They are mainly old school refrigeration guys so they're lost when they see anything with a PLC.


*feeling guilty about the thread jack*

 

[skippy]

Pryor, OK, that's us.

We also have a branch for commercial refrigeration called Century Refrigeration. It's a lot more standardized than TSI in terms of structure, but there are a lot of available options.

We do quite a bit of low ambient stuff and our controls can be pretty complicated. Lately we've been building some here and there with multiple PLC's. We've been doing so much with our PLC programming that we're down to where we can only control one screw compressor with a Johnson DX9100 due to memory shortage. Stuff like that is now almost exclusively using one or more FX16's. I'd be interested to know what you worked on.

I'm getting to a point where I'm getting tired of being on the engineering side and really find myself enjoying the diagnosis stuff. My boss has named me the engineering contact for the service department - which basically means service takes the phone call and sends it on to me. They are mainly old school refrigeration guys so they're lost when they see anything with a PLC.


*feeling guilty about the thread jack*

The unit I worked on was a split system dx condenser hooked to a 15 or 20 ton multi-zone air handler in a library.3 condenser fans,1 copeland compressor and a Desuperheater setup.All the control wiring was red

It had hot gas bypass for low ambient/low load conditions.It was maybe from late 70's early 80's.And my personal favorite,Pneumatic controls for control of dampers and solenoids.

By the time I was Maintaining it,it had seen some less than professional attention.