Carrier package a/c

[miniver]

Please help me get this figured out. I have a roof mounted 6-ton package A/C call. Compressor was replaced 1 week ago by one of our top technicians, new fil/drier, 500 micron, weighed in, all steps & pressure testing done right.Unit worked for about a week. Went back to these current Temps. & Pressures:::

Upon Arrival;Evap. coil temp was 22deg,the high side needle was blurred from 325 to 390 psig, moving fast!!
Suction line was 80 degrees 1 ft. from the compressor. I measured a 2 degree drop across the new filter/drier, but could not find the expansion device. I suspect a restriction but I don't know how to check a Manifold or Header type of Evaporator metering device. This is what I think is wrong. Please help me on this If you have knowledge of this type of Gaspack w/ A/C.

[bojedils]

I think a restriction is likley. What sort of failure was original compressor (ie mechanical, burn out)? Had a simular situation once, my service manager quoted customer on replacing entire indoor coil, did not want to mess with trying to clean up several metering devices.
I did not get to see end result...sorry!
Unit may have a small metering device in each of the evap inlets, (maybe 4 to 8 tubes of 1/4"-3/8" copper feeding evap), not easy to access!
Is it a heat pump? Install new bi-flow drier and change drier over and over (install ball valve in liquid line).


[Edited by bojedils on 06-12-2006 at 09:05 PM]

[hvacpope]

Originally posted by miniver
Please help me get this figured out. I have a roof mounted 6-ton package A/C call. Compressor was replaced 1 week ago by one of our top technicians, new fil/drier, 500 micron, weighed in, all steps & pressure testing done right.Unit worked for about a week. Went back to these current Temps. & Pressures:::

Upon Arrival;Evap. coil temp was 22deg,the high side needle was blurred from 325 to 390 psig, moving fast!!
Suction line was 80 degrees 1 ft. from the compressor. I measured a 2 degree drop across the new filter/drier, but could not find the expansion device. I suspect a restriction but I don't know how to check a Manifold or Header type of Evaporator metering device. This is what I think is wrong. Please help me on this If you have knowledge of this type of Gaspack w/ A/C.

At 22 degree the coil was a chunk of ice right? Is this a scroll comp? I think you must remove yourself from that job and let the “top tech” fix it. If the blind guides the blind both shall fall into a pit.

[ac/dc]

On some Carrier package unit models there is a stainer screen on the outlet of the condenser coil. I would check
for a temp. drop there and throughout the circuit before
concluding the metering devices are restricted. I would
be inclined to replace the entire evap coil if its the
metering dev. So were these conditions present after the
tech changed the comp?

[miniver]

Scroll compressor ran fine for 9 days. Out D.B today was 94 degrees

[berg2666]

I know you only got 2 temp drop across the drier but change it first. You may be surprised. And yes install some ball valves with the drier.

[miniver]

Is anyone familiar w/ a mdl. 50TJ-007---621-- SN. 3598G21507 package AC refrigeration circuit including metering and strainers and driers if present?

[jaxx]

I know at one time Carrier was putting orifices in the evap tubing, as the metering device. These orifices were indented in the spiders, and could not be replaced very easily. I have not seen any of these for many years, due to the problem that it did not take much to clog these orifices. Approx 9 years ago, I had a very similar proble. Another service company replaced two compressors in a very short time. I ended uop replacing the evap coil, and problem was solved.

[jrbenny]

Originally posted by miniver
Is anyone familiar w/ a mdl. 50TJ-007---621-- SN. 3598G21507 package AC refrigeration circuit including metering and strainers and driers if present?
KH11NH074 STRAINER(PSN 4699GXXXXX)

P502-8083S DRIER,FILTER(SSN 4699GXXXXX)

PSN = Prior to serial number

Your unit had a factory strainer only. A drier in there now would be field installed.

[pop]

Check for sweat on the coil or the tube turns, the dry areas tell in which part of the circuit the restriction is in, you can replace the feeder header or the entire evaporator coil.

[evildberg]

Was the strainer removed when the drier was installed? I hope so

[william antley]

An easy way I have used to find if the orifice tubes of the evap. coil are restricted is to disconnect the evap. blower and operate the unit in cooling. The non-restricted tubes will develop an ice film on them while the restricted tubes will possibly only sweat.
Same thing will happen to the strainer if there is one in the liquid line to the evaporator header.
You may need to use your manifold to bypass the coil to keep your compressor from overheating. Just give it a little bleed through every so often and you should be able to diagnose restricted orifices in short order.

[schomaker9253]

I would say that your restriction will be found in the "spun" strainer at the outlet of the condenser. Tell that "Top Tech" he needs to take out the strainer and replace the drier. I can almost guarantee that is where you will find the problem

[aggie]

We have been a Carrier Dealer for 40 years and have had this same problem with rooftops of ICP and Carrier brands of mulitple tonnage sizes. I fully agree with the other reponses you have gotten. We have developed a fix to replace orifices (if they are the problem) since your only other choice is to buy an expensive new evaporator with new orifices (sometimes hot customer will not want to wait on shipping new evap. coil)
The orifices are removed and dual accurator bodies and pistons (to match tonnage - ie: two 3ton pistons for 6ton unit) installed into repiped liquid lines to feed header at locations to equal out flow. Of course a new dryer and liquid line shutoff valve for future ease of service is standard. System flush (the R-11 replacement) is also used to hopefully remove trash particles.
I hope this helps you with this poor Carrier design!

[jrbenny]

I think they stole the engineer from Trane. They've got the same damn metering devices!

[jeep6275]

i had this problem a few years back and was able to get just the header tube for the evap coil it had the restrictors already in it. it was kind of a bear to change but was doable.

[Diceman]

They do make headers for the smaller units.
But still, in my experience, a restriciton anywhere after the condenser will cause low head after the unit pumps down, unless it is overcharged.
Didja clean the condenser??

[markwolf]

Originally posted by aggie
We have been a Carrier Dealer for 40 years and have had this same problem with rooftops of ICP and Carrier brands of mulitple tonnage sizes. I fully agree with the other reponses you have gotten. We have developed a fix to replace orifices (if they are the problem) since your only other choice is to buy an expensive new evaporator with new orifices (sometimes hot customer will not want to wait on shipping new evap. coil)
The orifices are removed and dual accurator bodies and pistons (to match tonnage - ie: two 3ton pistons for 6ton unit) installed into repiped liquid lines to feed header at locations to equal out flow. Of course a new dryer and liquid line shutoff valve for future ease of service is standard. System flush (the R-11 replacement) is also used to hopefully remove trash particles.
I hope this helps you with this poor Carrier design! If you are going through the motions why not install a txv & distributor?