Clogged condenser leading to no gas on R134a systems?

[runningonavac]

Quite often when we come across a blocked condenser on a cabinet, after cleaning the condenser or even before, the thing will appear to have lost some gas, i.e. running on balance pressure in in a slight vac. This is mainly on R134a systems. I'm aware that R134a will fine its way out of the smallest of openings, but nearly every time this happens a leak cannot be found anywhere. It's alomost like the gas has been burnt to death due to the blocked condenser and has vanished in a hermetically sealed system! I've heard that R134a burns the shilak off of the motor windings and likes to deposit it up the capillary, hence why we are forever changing blocked capillaries on R134a systems. Has anyone got any thoughts on any of these points? I am really intrigued by these mysteries!! :mad:

[monkey spanners]

I've seen something similar and both times the condenser fan motor had failed, the evaporator was frozen solid and the majoritory of the refrigerant appeared to be in the evaporator and happy to stay there resulting in a low suction pressure.

I though they looked short of refrigerant till i remembered a little voice in my head saying 'airflow, airflow' (cheers Gary) and noticed the evaps frozen up.

New condenser fan motor, evaporator defrosted, worked fine.

Jon

[Chegz]

Ive had this problem with bottle coolers on r134a, when they block up or condensor fan motor go they seem to run in a vac but evap ain't frozen up and theres no leaks on it, mystery!

[philfridge]

Hi if the refrigerant is low obviously it has leaked out of the system pipework somewhere. This may be because of increased operating pressures than would be expected the gas has leaked sooner than would have under normal conditions but the the system will now lose gas although you say you cannot detect a leak , there will be a leak most likely on the low side of the refrigeration system as r134a gas is "thinner" than other refrigerants. I have had this frequently and find evaporator coils are normally the culprit.

[Gary]

If the airflow is right, that narrows the possibilities to refrigerant charge (high side and low side) or refrigerant flow (compressor or metering device). If there is not enough refrigerant in the low side and/or not enough in the high side, the system needs gas. If there is not enough refrigerant in the low side and too much in the high side, there is a restriction in between (metering device).

You might want to start here:

http://www.refrigeration-engineer.com/forums/showthread.php?t=19701

[paddyaircon]

i have often found on 134 fridges that when condensor coil gets blocked or fan fails, then the overheating causes the refrigerant to breakdown- quite often the capillary is blocked with a black sludge causing a restriction in turn causing lower than normal back pressure which can be quite easily be mistaken as a system low on gas. i have seen an engineer cut out a copperspun drier in a "flat" system - guess where the lost gas was------

[Deniver45]

Hey!

IS MY DRYER ON BACKWARDS? :o

I have been reading this thread and need expert help. My customers 134a Hozishaki RH2 AAC 2-door reach in cooler has a Danvoss( 2001 model ) compressor on it, It IS a CAP TUBE system and with the first charge I did, it got down to 39 degree's in minutes!

Well he called initially for a charge, so I charged him up W ( 11.6 oz ) of 134a per the data plate. Again :it got down to 39 degree's in minutes!

A week later he calls me and says his digital readout is @ 65 degrees, so I got out the Big Blue with dry nitrogen = NOTHING, then I dumped some dye in there and searched with a blacklight. Even though 134a has chlorine in it; I added a bit of R-22 and went in there with my electronic halide detecor. = STILL NOTHING,

So now it is water submersion time in a swimming pool on sale at Wallmart for $15.00, Even though the condensing unit FLOATED ( the blue plastic casing ) ......... low and behold with 150 Lbs. ( with Hoshizaki's permission ) of dry nitrogen; the leak is way down on the center of the evaporator!

I order the factory evaporator and Sporlan dryer and and braze em in and the job looks better than the factory's! I had forget the top of the evap unit ( has 4 clips ), so I could NOT test my subcoolant and super heat right. STILL it got REAL cold!

I go back to his place; install it and it wont drop under 55 degrees. Also my readings are NOT right! I have 100 Lbs of low pressure ( calls for 120 lbs) and ALMOST NO HIGH PRESSURE! ( calls for 240 Lbs)........ I recover it, break out ther scale and again I dump 11.6 ounces per the data plate, NOW it is even LESS cold than before! It wont go lower than 66 degree's.

What is it? I brazed with Dry Nitrogen and at the end, I jacked it up a bit from the suction port out the high port to make sure there were no glogs.

The bottom liquid line has the dryer. I brazed it in with the flow towards the condenser per what I saw there. I am embarred to say that I FORGET to see which way the old dryer went! Still from what i saw there, I went from the suction port all the way back and determined that it went TOWARDS the condenser on the bottom line of the condenser.

1. can a dryer on backwards clog a system this bad on a 134a system.
2. ANY ADVICE OUT THERE?

I am all ears...

Thanks,
Deniver :o

[al]

Is a capillary drier(pencil drier)?, can only really be fitted one way, capillary in one end, liquid the other,if it's a standard 1/4 drier then being in backwards would affect flow;)

al

[Deniver45]

Thanks Al,

Yes it is a CAP dryer , but no, it in nowhere near the cap tube!! , The dryer ( 1/4 brazed on both ends ) is in the liquid line at the exit of the condenser. Actually the dryer IS in the right wat exiting the condenser. I called Sporlan today and the tech there said it would NOT affect pressures that much, but it would not catch debriss with it on backwards. It is a cap tube system, the only one Hoshizaki makes and continues to make. We all know the nightmares with cap tubes and r134a. I was getting real funky readings yesterday,with 100 on the low and almost nothing on the high side; yet the cooler dropped to 55 degree's. Today they were 100 on the low and a bit more on the high side, they are supposed to be 120 low and 240 on the high side, the micron gauge showed good to 300 microns as it is a small unit with a Danvoss NF11FX.

[Deniver45]

Gary,

Where can i buy your book? Can you send a link/...........maybe "amazon"??

Thanks Gary,
I have read many of your statements and advice here, and someday hope to have even a % of the knowledge you do! God knows the passion is there!

[Gary]

Gary,

Where can i buy your book? Can you send a link/...........maybe "amazon"??

Thanks Gary,
I have read many of your statements and advice here, and someday hope to have even a % of the knowledge you do! God knows the passion is there!

I am currently having problems with my website... switching services and hope to have it back up and running soon.

[GOODLOYAL]

Does any body have Physical Properties R600?

[Gary]

Gary,

Where can i buy your book? Can you send a link/...........maybe "amazon"??

Thanks Gary,
I have read many of your statements and advice here, and someday hope to have even a % of the knowledge you do! God knows the passion is there!




I am currently having problems with my website... switching services and hope to have it back up and running soon.

Good news. I am back in business: :D

http://prostores1.carrierzone.com/servlet/techmethod_com/StoreFront