MOISTURE, how to know it's present

[R12rules]

what are the various ways of a technician telling there is moisture present inside a sealed system?

[Milk man]

When your TXV freezes.

[R12rules]

Originally posted by lynn rodenmayer
When your TXV freezes.


smart-allek



(snicker ...snicker)

[condenseddave]

Use a checkmate tester.

[mspanky]

Visual moisture indicator if its bad enough.

Chemical test. (oil or refrigerant gas test) whatever your flavor.

Lynn's idea would be the first giveaway.

[Makinice]

High head, high subcooling

[R12rules]

Originally posted by Makinice
High head, high subcooling

your assuming your gonna freeze up and reduce your flow of refrigerant significantly? Is that your basis?


And then to test this ... you would apply a warm wet cloth to the TXV and expect to see the pressures change?
Or maybe just spray hot water on the TXV ...

[bryan l]

how much moisture are you talking about R-12?

If there is moisture in your sys you will have
High Head, Eratic TXV opperation, Oil MAY start to become acidic, Copper plating on the heads of your compressors.

First check is the Sight glass moisture indicator.
Second is Oil test
Third Total test
Fourth pull a bit out of the system into a clean tank and let it sit, if there is moisture or non condensables you will know
Fifth pull a head off one of the compressors and look for copper plating.

[shaka]

Bob are you writing a book? Okay here goes

1) how about when water spray at you when you put your gauges. He he he.

2)Oh how about if your oil look white and milky.

3)when the customer complains the unit cools down then warms up again over and over.

4)when your compressor fails a megohm test.

5)High head due to air non condensable?

6)sight glass yellow?

7)burn out compressor?

8)oil has high acid content?

9)when your refregerant and oil test kit say you have moisture.
10) when your unit sprung a leak on the low side with no pressure switch to turn it off ran for days in a vaccum
and it has polyoil in it. my friend you have moisture...

[RobY]

Originally posted by condenseddave
Use a checkmate tester.

It is suprising how well those little tubes work. They are the best way to test in the field. To get a better answer you need to pull a refrigerant sample and send it out for lab testing. The moisture on an oil sample can be goofy sometimes because you have to vent the refrigerant off the oil prior to shipping the sample and that can change the moisture value.

[lalo56]

Isn't it true that when moisture is present in a system your head pressure will be up only by 14.7psi, unless there are other factors making it higher?

[mike h]

1). Hearing 'ice sludge' bouncing, as it travels inside the copper piping.



2). If you have a new and steady air leak--- you will see an almost instantaneous rise in 'water ppm' from an oil sample [sent to an oil lab].

If you took another oil sample in a few more days, then you will see a rise in 'acid number' [there is a delay while the water and refrigerant create acids].

Wait a few more days (or even a week or so), a third oil sample will show a fairly big rise in 'copper ppm' and 'iron ppm'. Basically you new acids are slowly corroding the metals. The 'metals ppm' will rise from a normal level (lets say 10 ppm or less for each metal)--> and go to 20,30,40....100 ppm.

3). After you fix the leaks, if you do an oil change you will throw out about 90-95% of all of the 'acid' in the system. Oil is a sponge for acids.

[R12rules]

Originally posted by lalo56
Isn't it true that when moisture is present in a system your head pressure will be up only by 14.7psi, unless there are other factors making it higher?


What about this?

[condenseddave]

Originally posted by RobY

Originally posted by condenseddave
Use a checkmate tester.

It is suprising how well those little tubes work. They are the best way to test in the field. To get a better answer you need to pull a refrigerant sample and send it out for lab testing. The moisture on an oil sample can be goofy sometimes because you have to vent the refrigerant off the oil prior to shipping the sample and that can change the moisture value.


I love the thing. Oddly, (And sadly)MOST guys I encounter in the field have no idea what it is, or worse, ho to use it.

The tubes are "pricey" in the opinion of many service managers, but IMO, they are priceless. They let you know when it's really time to get active.:D

I have nothing against the Sporlan test kits, but they are single-purpose.

[RobY]

Originally posted by R12rules

Originally posted by lalo56
Isn't it true that when moisture is present in a system your head pressure will be up only by 14.7psi, unless there are other factors making it higher?


What about this?

I have no idea what lalo56 is talking about.

To get 14.7 psig more pressure from moisture would require boiling free water at atmospheric pressure in the system. The vaporization of moisture will add to the partial pressure in the system, but not by very much. Remember you have to pull into deep vacuum to boil water at room temperature, and the water in the system will collect in the part of the system with the lowest temperature.

[RobY]

Originally posted by condenseddave

The tubes are "pricey" in the opinion of many service managers, but IMO, they are priceless. They let you know when it's really time to get active.:D
[/B]

They're only pricey because they buy 30 pound cylinders of refrigerant at exactly 100 ppm moisture in the vapor from me to calibrate the dyes in the tube. I try not to give away stuff like that as long as there are people like you willing to buy the tubes ;-)

[mikep]

Originally posted by RobY

Originally posted by condenseddave

The tubes are "pricey" in the opinion of many service managers, but IMO, they are priceless. They let you know when it's really time to get active.:D


They're only pricey because they buy 30 pound cylinders of refrigerant at exactly 100 ppm moisture in the vapor from me to calibrate the dyes in the tube. I try not to give away stuff like that as long as there are people like you willing to buy the tubes ;-)

[/B]

RobY: Who buys refrigerant with 100 ppm moisture. What stuff is being given away. I do not understand your post. I love them little(checkmate)tubes and use them on problematic systems and in general maintanence. We also send samples to the NRP lab to double check systems when indoubt. The tubes and lab fees can get expensive but those costs get past on to the customer. All in a days work.

[RobY]

The guys developing and manufacturing the Checkmate tubes use refrigerant at 100 ppm moisture in the vapor to calibrate the tubes. They pass this wet vapor through the tubes for a set time and measure how far the color change moves. That is how the scale on the tube gets set by the manufacturer so you can get the right answer when you use the tube on a system.

My lab makes up special 30 lb. cylinders that have an exact amount of moisture in them. The process takes some time as the water we add to the cylinder has to distribute itself between the refrigerant liquid, vapor and cylinder walls. Then we mix and test it multiple times over a period of weeks to make sure it has stabilized at the correct value. We then certify the result so the customer will know the true value of moisture in the refrigerant vapor. This process is not cheap which is why I say we don't give it away.

[hvacpope]

Mike whats the NRP lab? I've been sending the oil samples to Thompson lab, they are a bit pricey but the turn around and sevice is very good.

[RobY]

I'll jump in because I think Mike meant NRI (National Refrigerants, Inc., http://www.refrigerants.com) not NRP (National Refrigeration Products, http://www.nrproducts.com). United Refrigeration sells the NRI test kits.


[Edited by RobY on 08-25-2005 at 05:12 PM]

[mikep]

Correct: It is through United Refrigration lab, NRI. I have also used a lab in OH, Intertek, but we would get some really bizarre reports.