I am an HVAC Contractor in central fl and about 10% of my work is refrigeration. I am working on a small old walk in beer cooler about 10' by 6'. Cond unit is copeland with semi KAK1-0100-TAD comp. 480 3 phase. Cond unit on roof and single coil evap about 15 feet below. Evap has HF-1-FC R12 TXV. Do not know any history on unit. Original call found comp grounded. I ordered and installed rebuilt comp from johnstone. Removed what seemed like r12 and installed suct and liq filters and vacuumed and installed mp39. Operated unit about 2 min and comp started shaking intermittntly and shut doun on OL. Before shut down I was able to get an 8 amp reading on 1 leg. RLA is 1.9. opon further investigation found cond fan wires shorting on frame of motor. Ordered and installed new cond motor a few days later,(today). Started and operated for about 5 min. Everything seemed normal except 2.4 amps a little hi. Box was about 80 degrees inside. Low side 45 psi, hi side 225 psi, 90 degrees on roof. did not get superheat but suction barely sweating, maybe 65 or 70 degrees. Just as lighting started landing close and was getting ready to vacate noticed comp shaking again. Shut sys down and ran off of roof. Will call copeland tomorrow but wanted to start here. Hope you guys can help. Unit seems like it might be slugging but superheat seems hi and no differant noise coming from comp. In fact it seems very quiet for a semi comp. Thanks
Compressor woes
jjust61
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maybe, sorta, kinda, somewhat resembles a defrost cycle
:spitball:
.
i am trying to phathom that, ya:det:
maybe, sorta, kinda, somewhat resembles a defrost cycle
:spitball:.
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Off-Cycle Defrost is a standard concept
This is why, when designing refrigeration equipment installations, you use a 16 or 18 hour cooling day.
As opposed to an A/C project - where you have 24 hours to take away the heat.
In refrigeration design you don't have all 24. The reason is because of the need for defrost of some kind.
Either off-cycle defrost or an active, added heat, defrost of some type.
A 38 degree box temp. Standard 10 degree delta. 28 degree coil. Frosted coil.
This is why, when designing refrigeration equipment installations, you use a 16 or 18 hour cooling day.
As opposed to an A/C project - where you have 24 hours to take away the heat.
In refrigeration design you don't have all 24. The reason is because of the need for defrost of some kind.
Either off-cycle defrost or an active, added heat, defrost of some type.
A 38 degree box temp. Standard 10 degree delta. 28 degree coil. Frosted coil.
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ok, off cycle = defrost cycle
thanks alot Mikey
actually it's called air defrost
.
ok, off cycle = defrost cycle
thanks alot Mikey
actually it's called air defrost
.
Checked cooler today. Everything seems good. Watched it through 2 on-off cycles, 1 from box and 1 from rooftop. Stlll 12 deg superheat at evap and 25 deg at compressor. Little bit of ice forming on dist tubes a few minutes before box reaches temp. No visible ice on evap fins. Ice dissipates seconds after shutdown and evap fans run continoulsy, so I guess thats it's defrost cycle. It has apparently has been that way for 25 years. Amps=1.84-1.87. Pulls 2.0 amps at startup for about 2 seconds then down to 1.8. Thanks again everyone for all the info. Jay
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