Reply to Thread

Originally Posted by hvacrmedic

How do you measure the pressure in the condenser when it's pumped down? Yesterday I checked for noncondensables by running the condenser fan, but I didn't pump the system down. (High subcooling high superheat, TXV coil.) I got a perfect match between ambient and SDT, so no noncondensables. Determined it was a restriction, like I first suspected. Then to track down the restriction I dropped subcooling at the liquid line service valve to 1 deg by reducing system charge and bypassing LP switch, then measured liquid line temp drop from the service valve to the TXV inlet. 5 deg total drop. This means that the liquid line, including the filter dryer, was using up only 6 degrees of subcooling. Not the problem. Determined that it has a bad TXV (no inlet screen). TXV to be replaced Monday.

Hi

Just curious do you guys typically find moisture in the system as showing a higher or lower pressure than what the proper temp and pressure relationship is supposed to be.

Also is there a trend that certain noncondensables tend to follow which helps to identify them?

Thanks

good tip thanks

Originally Posted by beachtech

if split system get more accuracy by pump down and just running OD fan

When valves are closed for pump down the service ports are open to line set and not the condenser... Am I missing something else?

Originally Posted by beachtech

if split system get more accuracy by pump down and just running OD fan

How do you measure the pressure in the condenser when it's pumped down? Yesterday I checked for noncondensables by running the condenser fan, but I didn't pump the system down. (High subcooling high superheat, TXV coil.) I got a perfect match between ambient and SDT, so no noncondensables. Determined it was a restriction, like I first suspected. Then to track down the restriction I dropped subcooling at the liquid line service valve to 1 deg by reducing system charge and bypassing LP switch, then measured liquid line temp drop from the service valve to the TXV inlet. 5 deg total drop. This means that the liquid line, including the filter dryer, was using up only 6 degrees of subcooling. Not the problem. Determined that it has a bad TXV (no inlet screen). TXV to be replaced Monday.

Originally Posted by beachtech

if split system get more accuracy by pump down and just running OD fan

Good point

Originally Posted by sparky05

Let me see if I can explain this, I have been told that with the system on to disconnect the compressor, leaving both indoor and outdoor fans running, attaching the gauges to the unit, the high side pressure should equal the outdoor air temp, if its 95 then high side should be 182 psig low side should equal to the pressure of the inside temp. R22 system.
This should also work with a system not running, I would be interested in hearing if there is a way to check this with the system fully functioning.

if split system get more accuracy by pump down and just running OD fan

Originally Posted by fcs

If memory sever right (thats If) within 2 to 15 ish I think.

This is good enough fcs

I honestly don't see many "wet systems" like I did when I first started out

Everybody must be getting better at this stuff

When I did it with the Digi Cool I used the DigiCool Probe. And it was quick to look a the SH reading. Also I like using the Digicool Temp Velcro Probe with long Velcro to Sat a tank.


I Try and find the number or do it again but Doing it again will most likely be in 2010 (after treatment is done.

If memory sever right (thats If) within 2 to 15 ish I think. I'll have my son see if he can find the paper with the numbers.

Don't hold to much on my Memory lately (Kemmo Brian you know)

Originally Posted by Pascone10

pressure and temp vary directly..

so if its virgin refer only, then the temp of the pipe will equal the pressure on a pt chart. if there is something else in the system then you wont have an exact pressure relationship. at least you shouldnt..

i think thats what he is doing..

fcs do you remember roughly the range of the pressure difference with the "wet" samples ?

Originally Posted by sparky05

Let me see if I can explain this, I have been told that with the system on to disconnect the compressor, leaving both indoor and outdoor fans running, attaching the gauges to the unit, the high side pressure should equal the outdoor air temp, if its 95 then high side should be 182 psig low side should equal to the pressure of the inside temp. R22 system.
This should also work with a system not running, I would be interested in hearing if there is a way to check this with the system fully functioning.

Thats what I do.

Originally Posted by Pascone10

pressure and temp vary directly..

so if its virgin refer only, then the temp of the pipe will equal the pressure on a pt chart. if there is something else in the system then you wont have an exact pressure relationship. at least you shouldnt..

i think thats what he is doing..

You got it Pascone.

Let me see if I can explain this, I have been told that with the system on to disconnect the compressor, leaving both indoor and outdoor fans running, attaching the gauges to the unit, the high side pressure should equal the outdoor air temp, if its 95 then high side should be 182 psig low side should equal to the pressure of the inside temp. R22 system.
This should also work with a system not running, I would be interested in hearing if there is a way to check this with the system fully functioning.

Originally Posted by Pascone10

pressure and temp vary directly..

so if its virgin refer only, then the temp of the pipe will equal the pressure on a pt chart. if there is something else in the system then you wont have an exact pressure relationship. at least you shouldnt..

i think thats what he is doing..

Hi

OK thanks for the reply. Im trying to wrap my mind around how the DigiCools can be used in the field to determine moisture in a system.

With what you have stated about temp and pressure relationship does this mean that in the field the only way to use the DigiCools for moisture detection is to power a system off and allow the system to sit for what 2 or 3 hours to allow all of the components in the refrigerant circuit like the compressor and the coils etc to cool off and thermally equalize with the refrigerant in the system,and then test the tubing temperature against a pressure chart for that particular refrigerant?

Would it logic that moisture would be likely to settle in a specific area and that would be the best place to test?

How about with the system running ?
Other than the fluctuation in pressures that often is observed if non condesables are in a system while running. Is there a trick with these Digicools that improves the ability at identifiying moisture in a system while it is running ?

Thanks

Originally Posted by n-e-w Jerz!

So, go out and get Digicools immediately?

Have been thinking of getting these... Went tho there web and not very much info and the difference between the 1250 and 1600.

I though the 1600 (higher#) wold be higher end unit,but they were less than the 1250. Going back to their webto see if I can figure out the difference.

I love doing the Experiments with my son (8 1/2yr)

I used to have no time and tons of energy. Now I have a lot of spare time and No energy.

Planing on 2010 being busy and fun with my Health and energy back[/QUOTE]

Continuing to think of you and remembering you in my prayers, remembered a sermon I heard a while back on the verse "it came to pass", so in time this too shall pass and 2010 is getting closer every day.

Exactly, Pascone

pressure and temp vary directly..

so if its virgin refer only, then the temp of the pipe will equal the pressure on a pt chart. if there is something else in the system then you wont have an exact pressure relationship. at least you shouldnt..

i think thats what he is doing..

Originally Posted by fcs

I made a test set up out of 1” copper 3” long Both sides crimped and brazed with Schrader on both ends Then I pressure tested them for about 1 week at 175 PSIG maybe longer I don’t remember . (x6)
Pull it to 150 microns standing vacuum test for a day. Did this for all for all 5
Took one and Filled (80 %) it with R22 sorry can’t remember the weight need to look it up on a pipe Chart. Did this amount for all Six
Chamber 1 Filled with R22 from a vacuum standing vacuum (24 hr ) of 150 microns let stand for 12hr 24 hrs at 70 deg F Stat out on the Nose 48hr.

Chamber 2 Let is stand open to Atmosphere for 20 min then filled with R22 at 70 deg F stand for 24hrs 48hr 72 hrs reading.

Repeated this above only change
Chamber 3 Let stand to Atmosphere for 2 hrs
Chamber 4 to Atmosphere for 24 hr
Chamber 5 open from a vacuum of 150 micron in shower with room air 100% RH left open for 20 min
Chamber 6 added 5 drops of water from Eye Dropper .
Digicool show changes on all of them.
Analog and Fluke 52-2 with pipe clamp Possible Moisture on 4 and moisture on 5 and 6.
Sorry I Did this near the end June of 2008 and had the numbers wrote down then in July early July The cancer Surgeries’ X3 stared so I never post the stuff. God only know were the paper with the Numbers are.
A friend brought up he Sat a tank and I decide to post. If When I find the number I’ll post them.
Or my son and I might do the experiment again when I feel better.
I (we) made the Chambers so we could learn about Temp/Pressure Relationship. Vacuum and micron ect…
I Hope this helps.
.

Hi

Please help me here im not understanding how you are able to determine moisture on the analog or the digital. What do you look for?
Analog and pipe clamp? Im totally lost at what the pipe clamp is doing... temperature??

Thanks

Originally Posted by fcs

Planing on 2010 being busy and fun with my Health and energy back

We all hope so