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Hi Guys

Had the engineer out to try and breathe life into my Jaocbs compressor... The line had broken and everything had escaped.

He managed to bridge the gap and re-fill the compressor with gas.

The compressor now runs and frost etc has formed around the evaporator fan.

The guy said that oil had got around the whole system when it had been compromised and to let it run.

I let it run for perhaps six hours...

The temp inside the machine only got as low as fourty and the compressor never kicked off in the whole time. It was hot to touch but not boiling hot. Ice was forming on the fan.

So, I stopped the machine and looked at the seal. Its a new seal on the machine door. It sits in a resses on the cabinet and so I thought that maybe its not forming a tight enough seal. I have now placed that foam thingy stuff around the cabinet so the seal can sqeeze against that and create a tighter fit.

I let the machine run for another two hours. No kick in or kick out. Checked the temp and its still around 40.

I checked the T Stat. I turned the T Stat round to the off switch but the compressor still kept running.

I can't seem to see how the T Stat connects up with the compressor to turn it off when the desired temp is reached. The Jacobs 50 is an automatic vend unlike the other machines I have had and so there is quite a busy terminal block with alsorts of wires running all over the place. Coin mech etc. The T Stat is wired into that so it must run down to the compressor/fan.

Where I have had a problem in the past with a faulty T Stat the compressor would run and then the over ride switch would hit in and turn it off until it had cooled down and then it would run again. This didn't happen this time.

I'm going to order a new T Stat just in case this one I have is faulty. Any other hep and advice would be greatly appreciated.

Dave

Dave, It sounds like your unit is undercharged, perhaps due to an additional leak, (or maybe it was slightly undercharged from before.) I'd give your repair man a call back to have him check the system charge again, as it's easy enough to overlook something small when you repair an older system, such as a service valve that isn't closed tightly enough, or a small micro-leak elsewhere in the system.

you may want to also check that the evaporator fan is running, (no air circulation, no cold soda's)

Hi Johnnie...

Have checked the fan its running...

Today I ifred her up again and she got down to 35 after about an hour and half...
Still not cycling though...

Will phone him tomorrow...

Cheers

Dave

Dave,
Have you taken a peek at the F.L. Jacobs manual in the downloads section? It has several wiring diagrams for the J-144, J-26 & J-35. Not sure if your J-56 is the same, but probably similar. Sounds to me like your T-stat might not be wired in correctly. One of the diagrams might shed light on your issue - good luck!

I don't think it the thermostat, as the machine runs continuously, but never gets below 40-degrees, so it's not getting down cold enough to even trigger the themostat.

ah

      This tells me the thermostat is not working or has been bypassed in the wiring circuit,
but then the compressor would run constantly and freeze everything inside.  :help:

ah-ha & ha-ha

Dave,
also see what kind of thermostat you have in there, whether its' a contact or non contact type... those will have different shut off points..

sounds like it's not wired in correctly, cause even with the thermostat set at one, it should still cool down to maybe 50 degrees and then shut off, and on 2 maybe 45 degrees.. and so on.. colder as your increase the number.. so if it's not even doing that on the 1st setting.. I'd say it's not working or not wired correctly..
or again could be a contact style thermostat that is not fastened to the cooling unit.. which it would have to get pretty cold for it to shut off as they have a higher on/off point..

clear as mud?? hope it helps. GOod luck!

  Sounds like the contact point in the thermostat is welded shut. Replace the t-stat.  Have your a/c guy come back and and check that the charge is right,  have him raise the head pressure to 30 deg. above ambent temperature and monitor box temp. when it reaches set point make sure head presure is at 30deg. above ambent temperture and the charge should ok.  These boxes have a cap tube and are critically charged systems.

Thanks for your advice... The T Stat I ordered from Funtroincs arrived today... I have fitted it and its still got the same fault..

Its running and getting cold but If I turn the T Stat off the compressor just contiunes to run...

I'm at a bit of a loss....

Th is old girl is almost four years into her restoration and I thought I had it solved with the new T Stat...

Dave

Again, sounds like your compressors getting some back-feed voltage from somewhere,

so say if you'd open/disconnect the wires & insulate them (temporarily with electrical tape)from the back of the thermostat. I assume the compressor will still be running?

I know some older machines have a large start/run relay assembly that's housed in a large tin box, and the start/run relay in this type of setup is controlled by the thermostat, but the compressor doesn't get any direct line voltage delivered to it from the thermostat itself, 

if this is the case you may have a pair of spot-welded contact points in the start-run relay itself which wouldn't allow it to shut off no matter what the thermostats set at.

Hi Johnie...

The compressor doews have a large tin box with the start-run realy in it you're right...

I haven't actually put the two wires together to see if it will just continue to run but I'm gueesing that it will..

Its night time here now.. Will try the two wires togther tomorrow...

Is it possible to by pass the compressor start- run with a 3 in 1...?

Dave

Dave...I meant that you should remove the wires from the thermostats' terminals & tape them up (so they don't short out or shock you) & see if the compressor still runs continuously, 

Yes it's possible to use a 3-in-1 in place of the original start/run relay, does your compressor have three external binding posts/terminals ( three in a row, as opposed to a modern compressors three in a triangular pattern)?   

Hi Johnie

this is a picture of the terminal block on the compressor...

What do you reckon??

Dave

Is the wiring as shown original?

OK, Good...the terminal with the copper strap is definitely the "common" connection, ( sometimes marked/stamped on the metal case as "C" for "common")

the Red wire should be "Run" ( sometimes marked/stamped on the metal case as "M" for "main")

the white wire should be "start"  ( sometimes marked/stamped on the metal case as "S" for "start")

The better way to check is to remove all the wires from the terminals, & use an OHM meter to measure the Resistance readings between the COMMON terminal & the other two, the HIGHER reading is the start terminal, the LOWER reading is the run terminal.