Vendo 56 Square top question

[choice120]

I am in the process of restoring a v56. On the refrigeration system I have hooked up a 3 in 1 starter. As I was trouble shooting I noticed when I plug the compressor directly into an extension cord the all the coils on the evaporator get nice and frosty with a frost built up on them. When I go to run the the unit normal with the compressor plugged into the power block only the top 2 or so coils get frost  built up on them. Is this normal when the system is running in a normal configuration or not ? I have the whole unit out of the machine so there is no way to test how well it cools. Thanks Guys
Here is a pic of what the evaporator looks like when every thing is hooked up normally.


Here is the other side


When I plug in just the compressor with an extension cord the whole evaporator gets frosty like the couple coils above. 

[choice120]

Here is the evaporator with the compressor plugged directly into an extension cord. All coils are nice and frosty.




Do you think it could be the power block the compressor plugs into may be at fault since it works on an extension cord?

[collecture]

I can't see how the use of an extension cord could possibly change things, but maybe somebody more knowledgable about refrigeration systems will chime in.

[zadd]

In my experience plugging it into the extension cord directly showed that the unit had freon and worked . If the unit frosted plugged into the extension cord and not in the power block I would say it needs a new thermostat . I bought several non cooling machines and plugged them into the extension cord and had them frost then replaced the t-stat and they worked great . Just my two cents

[choice120]

figured it out. low refrigerant. Bought a can of freeze 12 added a little and she is down to 31 degrees in 30 minutes. I now know I must have a small leak and will have to either find it or replace system. whats the best way to find a leak?

[zadd]

Pressurize the system to manufacture specs with a gas (nitogen I think) and look for the leak. Also look for a oily spot around the coils or cooling lines . It could be a rusty condenser then you might be screwed . Just my two cents .

[choice120]

I think you are right rusty condenser. I may have a deck lined up from someone. Hopefully?

[johnieG]

For small & really small leaks, the best method I've used is UV leak detector dye injected into the system & a UV lightsource (FYI...UV=Ultra-Violet light ie: "Black-light") you can pickup a UV dye injection kit fairly affordably, & you can find them locally at most automotive supply shops ( Murrays, Autozone, PEP Boys, etc.) they may have them behind the counter/in the back at this time of year, so you may have to ask them to let you have a look in the back to locate a kit) or you could maybe rent an electronic refrigerant leak detector

[Yarochrehc]

You can also use some soapy water and spray it on the coils, copper lines to see if any bubbles form, if so you have found your leak

[zadd]

Looking at your photo's again . I think the coils are doing what there suppose to be doing . I would make sure both fans are working and replace the t-stat and see how she cools . I still think it's just a bad t-stat