Reach in cooler Problem scenario

[flangehead]

Alright, here is the situation, Reach in cooler, copeland condensor package located on top, Hotshot. Ambient air temp in kitchen 95 F. condensor is clean and pulling air from screened window going to the outside of kitchen. Outside air temp 90F. cooler temp set point roughly 40F and comp. does reach setpoint. .25 inch liquid line filter drier hotter than hell, then sightglass, then dual feed cap tube. Sightglass will not clear. suct. press. 28psi, discharge press. 280psi. Remember this is hotshot (r-12). I wanted to change filter drier but did not have any .25inch driers. So all I could do was is pull the gas and draw deep vac and charge it back up , still system returned to previous conditions, by the way suction line was sweating at 50F roughly. Does anyone think the filter drier is restricted?

[pecmsg]

Pull the charge and another vacuum. Change filter/Drier. Weigh in Hot Shot for 80% of rated charge. Is this a Cap tube or X-Valve???

[flangehead]

It's a dual feed cap tube, I can see through the condenser, but did not chem clean it. I've been told that in a commercial kitchen condensors tend to get a film of grease on them that needs to come off.

[Dad]

Originally posted by flangehead
Alright, here is the situation, Reach in cooler, copeland condensor package located on top, Hotshot. Ambient air temp in kitchen 95 F. condensor is clean and pulling air from screened window going to the outside of kitchen. Outside air temp 90F. cooler temp set point roughly 40F and comp. does reach setpoint. .25 inch liquid line filter drier hotter than hell, then sightglass, then dual feed cap tube. Sightglass will not clear. suct. press. 28psi, discharge press. 280psi. Remember this is hotshot (r-12). I wanted to change filter drier but did not have any .25inch driers. So all I could do was is pull the gas and draw deep vac and charge it back up , still system returned to previous conditions, by the way suction line was sweating at 50F roughly. Does anyone think the filter drier is restricted?

You do not use a sight glass on a cap tube system so don't try to clean it. You charge to subcooling, not to superheat. HotShot sucks for that high of ambient condition, use 416. 416 will give you lower head pressures and just about 1 to 1 pressures as 12.

Your drier is not restricted. It is hot as hell because your head pressure is out of this world. You are so overcharged you are paying twice to see one movie.

Pull that Hotjunk out and get you some 416. Remove the ends of both cap tubes from the evap coil and push dry nitrogen through them... about 250 pounds worth to make sure both are clean and clear. If not... replace the one that is restricted.

Put them back in, change your drier using a Sporlan CAPT-032s and point the drier down to have a liquid seal on the cab tubes.

Your hi pressures will average 170- 190
lo pressures will average 15- 25

Don't worry about a little bit of grease film on your condensor coil... that's nothing in a kitchen.







[Edited by lusker on 06-29-2005 at 04:07 PM]

[rayr]

[QUOTE]Originally posted by lusker
[B][QUOTE]Originally posted by flangehead
[B]You do not use a sight glass on a cap tube system so don't try to clean it. You charge to subcooling, not to superheat. ????????????????????????????????????????????

[icemeister]

Originally posted by rayr
[QUOTE]Originally posted by lusker
[QUOTE]Originally posted by flangehead
You do not use a sight glass on a cap tube system so don't try to clean it. You charge to subcooling, not to superheat. ????????????????????????????????????????????


Ditto to what rayr said.

On cap tube reach-ins I charge by weight initially and adjust the charge by compressor superheat after the box has pulled down to operating temperature.......usually to around 30ºF SH or so.

I have no experience with Hot-Shot or R416 (I use MP39), but head pressures that high ain't a good thing. :(

[Edited by icemeister on 06-29-2005 at 06:36 PM]

[primmers]

speaking of 401a, has anyone ever seen head pressure
that actually meet what the PT charts say??

i always see it higher...30 to 50 psi higher..

[Dad]

Originally posted by icemeister

Originally posted by rayr
[QUOTE]Originally posted by lusker
[QUOTE]Originally posted by flangehead
You do not use a sight glass on a cap tube system so don't try to clean it. You charge to subcooling, not to superheat. ????????????????????????????????????????????


Ditto to what rayr said.

On cap tube reach-ins I charge by weight initially and adjust the charge by compressor superheat after the box has pulled down to operating temperature.......usually to around 30ºF SH or so.

I have no experience with Hot-Shot or R416 (I use MP39), but head pressures that high ain't a good thing. :(

[Edited by icemeister on 06-29-2005 at 06:36 PM]

Sorry guys... Today, I am like a hamster in the dryer and someone hit the fluff button.

Here it is in a nut shell.

1. A sight glass has no place in a cap tube system except to take up space or to act as an expensive coupling. There is no use for it in any system with cap tube metering devices.

2. In a cap tube situation your start charge is by weight and since HotJunk is not OEM anything and creates incredible head pressures due to its high content of R-22, start with less than 80% or subcooling. Yes, subcooling... I would rather do it this way. To me it is a bit more reliable than superheat by itself. Even still you will get about the same numbers on superheat as you will on subcooling with a cap tube and with a cap tube it is more important to know where your liquid is.

3. For your own good in a high ambient situation don't use HotJunk, use 416. It runs cooler in hi ambient, low condenser air areas.

4. If you use 414 or 416 do not over charge the system by going over the 80% of factory weight of R-12 and just leave it if you want to guess. If you want to be sure you must measure a cap tube system by subcooling.

Subcooling tells you, relatively, how much of the coil you are actively using to make liquid from gas. You'd like to use most of the coil to do actual condensing of the gas into liquid. Once all the gas is condensed and turns into liquid, the temperature begins to drop pretty quickly.

A big liquid temperature drop means that there is a lot of the coil just holding liquid. That leaves less of the coil to condense the gas, and you effectively reduce the size of the coil. That's what techs mean when they say that a lot of liquid is “stacking up” in the condenser. So there's less effective area of coil for heat exchange, the compressor has to work harder, raising the gas to a higher temperature, trying to get it to condense in fewer inches of the fin tubes.

On the other hand, you don't want near-zero subcooling. If the subcooling is near zero, you are sending gas bubbles to the metering device, and that reduces the system's ability to cool.

You must keep a liquid seal on the beginning of the cap tube thus you need to turn the cap tube portion of the drier down to create this seal. The drier will act as a very small receiver and a bit of liquid will stack there and keep a constant seal of liquid refrigerant.


Sorry guys… I was in a bit of a rush today… confusion everywhere ya know.


These are my opinions.... I am sure there are others but most of you know that I am a refer cab tube junky.

[orland25]

I see that tranfer among the ambient air kitchen and outside air to close 90F and 95F What happen when for moment retainer? What happen with the disch-pressure? And what happen with the oil in the system?I Thing you have too much oil in one of the cap/tube. not too much too much but something oil, This biginning the problem,

[Dad]

Originally posted by orland25
I see that tranfer among the ambient air kitchen and outside air to close 90F and 95F What happen when for moment retainer? What happen with the disch-pressure? And what happen with the oil in the system?I Thing you have too much oil in one of the cap/tube. not too much too much but something oil, This biginning the problem,

yes Orland... the unit being overcharged will create hi discharge pressure and will push more oil from the compressor into the cap tubes that the system has to pull back. too much of oil in the cap tubes is a very bad thing as you said but he can fix that with the correct refrigerant charge.

[flangehead]

Thanks guys, I'm beginning to see the light with cap tube systems,they are a whole different ball game then others.
This is a great sight. Thanks again.

[meltdown]

Replace the cap tube when lose a compressor on a cap tube system and definately replace the filter especially when hot! and the, highside itsnt in relation to the ambient and low side inconsideration to the situation at hand....so to speak, dump the hot shot and put 409 in it!!!! it wont break down like hotjunk

[badbillr]

in small kitchen appliances that use less than 1-2 lbs. of r-12 freon, i go back with r-12. it's costly but call backs cost more. i would replace the dual cap tubes and install pencil drier. shape of the pencil drier sets up the liquid feeding by design. i use 2 ways to cut cap tube, a triangle file when i can find it, but most of the time i use my wire strippers and score the tubing and snap it! both work just fine. since it has had other refrigerants other than r-12 and also has been subjected to high heat temps, i would replace the oil as well as it may be broken down. use the nitro & blow system to return any oil to compressor. remove compressor and turn up -side-down to pour oil out. be sure to carefully measure the AMOUNT OF OIL YOU POUR OUT & REPLACE THE EXACT AMOUNT ONLY!! pressure test system with 150 psi nitro and check for leaks. pull vacuum down to 500-700 microns. micron gauge will confirm no leaks. even the smallest leak, you won't get lower than 1000 microns! re-charge by weight listed on unit, usually in ounces. charge by liquid into high-side. i add a quarter ounce more to cover my hose removal. use grade 150 mineral oil with r-12. un-bolt cond. coil, raise it up, place flat pan under it to catch water. clean coil w/ cond. coil degreaser with pump sprayer. place cut-n-fit filter on front of coil, hold in place with a paper clip bent in the shape of the letter "c"

[Dad]

use a jumbo paper clip and you won't have to bend it and it will be there when you have to replace that dirty filter in two months.

never let that filter pad go more than 2 months, less in high temp/greasy areas.