R-22 freezer, Semi Hermetic Copeland

Harvey Ramer

Got called out on a service call this Friday. It was a little mom and pop convenience/deli/grocery store by the wayside. They have an upright, 3-door freezer that was on the fritz, not cooling at all. I found the compressor head locked up, or I should say tight enough that I had to pulse the motor in order for it to turn over. It's a 1-1/2 hp semi hermetic Copeland. It's only 2 years old. R-22 POE oil.

The evap has electric defrost in the normal configuration. The evap is at top of the freezer chest and has a txv. The suction line is 5/8" and liquid line 1/4". There is no accumulator on the suction line, however, there is an evaporator pressure regulator, right before the king valve on the compressor.

I need to figure out what caused the compressor failure and correct it so the replacement comp doesn't follow suit. Obviously I couldn't take any p/t readings since the system is down. I have not yet tore the head off the failed compressor to see how the insides look. I know it has sufficient oil in the sump, as I could see it through the sight glass. About 1/3" from the bottom up.

I'm also unsure if this is an original r-22, or a converted r-12. I couldn't find the data plate on the freezer.

According to the research I did, r-22 is bad news for freezers. At 15°F the oil will separate from the refrigerant and just kind of float on top and doesn't want to return from the evap correctly until it is forced out in globs. I'm thinking a properly sized accumulator may be in order. Also r-22 has a high heat of compression ratio, and in a freezer application that has a low suction pressure, the discharge temp can go out of bounds. That would require a liquid injection valve to cool the suction gas temp.

If I do put in an accumulator, would it be advisable to put a small heat band around the bottom of it to prevent defrost flooding and help the oil move? Should I consider installing a liquid injection valve? Should the EPR be removed if I do this stuff?

Harvey

Matt_67

All the low temp 22 systems I've worked on were rack systems with oil separators. Did you check copelands data sheet for the compressor to see if there is an alternate application? What TXV is on it? I don't think i would want POE oil in that system.

Techman

Hay Harvey. Was the st cap/run cap/ pot relay tested? The comp could be electrically locked if there is a bad component.Check the "book" for the proper components and compare . Got a model #? I think that is a CPR(CrankcasePressureRegulator) valve before the SSV(SuctionServiceValve) of the comp. If the CPR is set wrong ,then after EVERY defrost cycle the comp is killing itself. Got a grounded comp? Got a shorted(turn to turn) comp?Got acid? Got start/run components? With a new customer, I replace a lot of st/run components simply because they are the wrong size.
Those pesky name tags can be anywhere, ceiling, sides top, sides bottom,behind the kick plates.
One or two cond fan motors? How close to the back wall is the RIF?

Harvey Ramer

Terry, it is a single cond. fan motor. We have a couple inches behind the freezer and the condenser coil is not blocked up.

I checked all the electronics and they are fine. They are what the compressor calls for. Capacitors show the correct uf and the POT/R is functioning correctly. I ohm'ed all the windings and checked them to ground as well.

I attached a pic of the compressor data plate.

I think you are correct on the CPR. I have been doing a lot of research on semi hermetic compressors over the weekend. It seems that all the reference materials I read, strongly recommend the use of an accumulator when using r-22 in a freezer. They also suggest the use of a CPR and or a crankcase heater to keep the sump oil from getting diluted with refrigerant during an off cycle or a defrost cycle.

As far as the compressor superheat, I won't know what it's doing until I have the new compressor in and running. I should have pulled the head crankshaft end cap off the compressor while I was there. Then I would be able to tell if the failure resulted from overheating, oil breakdown or bearing fatigue from diluted oil or refrigerant slugging. I just didn't have enough time left in that day.

The moisture indicator is showing dry. I don't think we have an acid problem.

The customer said the compressor was knocking or thumping (making unusual sounds) before it died. That is not typical of an electronic failure but rather a mechanical one.

Harvey

Techman

Be careful when starting/charging the new comp. W/O the name tag info on charging ,how are you going to know when enough is enough, freon that is,? So, now you are going to have to charge the system the "old fashion way", Beware, frost on the suction line/CPR/ SSV does not indicate an over charge! Beware , you MUST check the comp start and run amps. Beware,the comp "running amps" at startup/pulldown is not allowed to be higher than nameplate amps , so, or/if it is, then you adjust the CPR pressure to have the comp amps at the highest possible allowable amps w/o overloading the comp motor. This is because of the following KindaSorta Rule, the higher the temp range the more dense the freon , the higher the temp range more particles of freon per cubic inch,
AC-1HP-1ton-12,000btu-KindaSorta 100particles per ci
Ref- 1HP-3/4ton-9,000btu- KindaSorta 75 particles per ci
Freezer-1HP-1/2ton-6,000btu-KindaSorta 50 particles per ci.
So at "startup/ end of defrost "the freezer comp is operating in the AC range,overloading the comp motor,then, as the box temp drops the freezer comp is operating in the refrigeration range, still overloading the comp motor, then the comp pulls down to "stabilized" conditions, and runs , for awhile.

don_9

I would question the time of year in which they heard the compressor crying out.i am going out on a limb here and venture to say that low ambients and inadequate charge to flood the condenser cause low gas velocities n poor oil return.And yes a crank case heater is a cheap security blanket.Happy hunting Harvey let us know how the replacement goes.

pecmsg

I see a sticker on their R-408A if im right this was used as a retrofit for R-502.
Is it a TXV or AXV in the case? (I’m guessing AXV)
If it was R-502 and one pump with POE has been used just change to R-404A. New drier (I’d install a SG) Evacuate and recharge.
If you have a small receiver around and the space throw it in if it’s a TXV.

Harvey Ramer

I see that sticker now. The evaporator has a TXV.

You would suggest switching to R-404A?

New driers are a given and I already have a SG/MI.

Harvey Ramer

pecmsg said:

I see a sticker on their R-408A if im right this was used as a retrofit for R-502.
Is it a TXV or AXV in the case? (I’m guessing AXV)
If it was R-502 and one pump with POE has been used just change to R-404A. New drier (I’d install a SG) Evacuate and recharge.
If you have a small receiver around and the space throw it in if it’s a TXV.

This Condensing unit sits in the bottom of the freezer cabinet and brings in air from the back of the machine. The whole thing is indoors in a conditioned space.

Harvey

Techman

Good eyes,pecmsg. Harvey, check the info on the TXV and see which froen it is for.

Harvey Ramer

Will do. I ran the model number of the comp. Copeland never manufactured the compressor in r-22. Only for 502 408 and 404. Why it had 22 on it,I'm not sure. Anyway I'm just going to replace it with the same model comp. and perhaps a crankcase heater. I'll monitor it over the next couple days and fine tune it as needed. If I have to replace the txv, I will, or any other malfunctioning components.

I'm putting in 404.

Harvey

pecmsg

If its a TXV throw in a small receiver.

pecmsg

Harvey Ramer said:

. Why it had 22 on it,I'm not sure. .



I'm putting in 404.



Harvey

Because the tech before you read 22 on the tag and A S S U M E d never realizing that was oil charge.

don_9

Are you saying that the condenser is inside the freezer cabinet and that it is recirulating the heat that it reject back into the cabinet? That odd.i have heard this being done to control humidity in some cases but have yet to wrap my head around that concept.i have also heard that it help keeps the ice crystal from forming inside the freezer when the water evaporate from a long defrost cycle.once again i am like hmmmmmmm.lol

Harvey Ramer

No the condenser sits in a separate compartment underneath the freezer. The coil sits right up against the back wall and pulls air from behind the freezer unit. The heat from the condenser compartment is allowed to naturally escape through a louvered panel in the front, that travels the entire width of the unit and hides the comp.

Techman

Hay Harvey, just as a look-see, with the RIF up and running,have a remote thermometer on the air inlet side of the cond coil, put the nice looking louvered cover in place and then look-see what the temp goes up to.Watching the pressurers would be nice also, the louvered cover has to be in place!

Harvey Ramer

Will do Terry.
I just tore the old comp. apart and the oil was green and ugly. The shaft going into the oil pump was dry on the outside. The housing where the shafts slides into to get to the pump coupler looked a little galled. In the head, the outlet valves were slightly brown and were dry. I expected a little oily residue to be in the discharge head cavity.

Harvey

pecmsg

Sounds like the first shot of POE oil cleaned up the system
Acid test & Consider a suction filter or 2.

Techman

Are you aware of a "body" credit on some comps? How about a 4-year extended comp warranty? In 36 years I've sold only one comp w/o that warranty. Another thing Mr.Harvey. If the TXV is for R502 and you swap out the freon, then almost/always the TXV SuperHeat stem has to be adjusted , to the "in" or "higher SH setting" due to the densitity/btu/specific heat/etc thing. So I'm guessing ,if you're guessing if you have to check the SH? There is no guessing ,I think.

Harvey Ramer

I didn't readjust the txv. The superheated was a bit high for my liking but on the flip side, the comp amp draw was safe but I didn't want to increase it. Not only that, the discharge temp was hanging around 190 to 200 which I was comfortable with.

I'm going to stop back in there in a day or so and check the oil level and various other things. The evap has large diameter tubes. I want to make sure the refrigerant velocity is high enough that the oil is coming back.

There is no issue with air flow or recirculation at the condenser.

Yes I am aware of the comp credit. I'm having the old one tagged for a failure report. I tried to sell them the 4 year warranty but they declined.

Techman

Morning. Harvey, my Copeland literature shows that comp MN# KATB-015E-CAV as a freon R-12 derivitave only, not 404/502. Now a MN#-KAL*-015*-CAV is a r12/r502 but the r502 btu's is only 9700btu or lower.

pecmsg

Techman you sure?
See Attached

Harvey Ramer

I chose the 60hertz 404a model.

Techman

Well I guess I'm not sure now. I got my info out of United's catoalog and a Copeland cond unit brochure. Thank you gents! I stand corrected!

Techman

Here is where I screwed up. The E after the 015E is the POE/404 desiginator.

Harvey Ramer

Stopped in today and fine tuned the system and trimmed the charge.

The thing is purring like a kitten now

Got the TXV dialed in at 12° SH and the evap settled in at -33° @ -5° box temp. Condenser is temping 96° and I trimmed the charge so the sg/mi stays full under every different operational scenario. The new receiver seems to be doing it's job, the condenser temp didn't go above a 100° after a post defrost pull down. Comp discharge temp hangs right around 190°. Oil level is good after a couple days of operation.

On a pull down, the compressor runs slightly above RLA for 2 min 28 sec. It does not trip the overload. I called United Technical and they said this is perfectly acceptable.

Now I'm anxious to see the tear-down report from Copeland in regards to the old compressor.

Harvey

Techman

Morning Harvey, how cold do these folks keep the store?How low did the condensing temp go as compared to not going above 100*? What is the SH at the comp?Is there a "frost line" on the "tail end" of the evap or the comp? What were your pressurers for "compression ratios" comparisons? That evap "temperature differential "is high as compared to an AC evap TD, AC is KindaSorta around 20*TD. When you go back to the apple/peach customer of yours check the TD on that system.I kept track of TD's on different types of boxes/rir/rif/wir/wif/soda cases/chocolate cases/ect,,,,,.The "given factory built in TD "should be on the "name tag" . Why bother?Who cares?I do. Its just another "troubleshooting tool", to help me try to be smarter than the equipment that I work on. Did you measure the amount of oil in the old comp?Knowing that will KindaSorta let you estimate the amount "out in circulation"and what to expect on/after startup . Those comps don't handle "oil slugging" very much. Just curious here, did you measure/check the voltages across CSR terminals of the comp? Kept track of them also.