TRANE TCD048 Rooftop Problem

[Gabrielnqn]

Hi guys..I hope someone can give me an answer:

Replaced a 4 ton (TCD048 Rooftop) Trane Compressor, which was as well replaced by a Tecumseh like 2 yrs ago.
I installed a NEW (Sealed) Copeland Hermetic 47,000 Btu/h 3PH 230V.

The old compressor's coil was grounded. Compressor burned.

I pulled all the R22 out, and cleaned the system with N2. Installed new compressor. After all solderings, I pulled high Vac for 30 min. Charged and tested, pressures were good. 65LB/240LB 88°F Outdoor.

Problem:
Inside temp only 10°F bellow Outdoor temp. I get 78°F from any supply register.
Any clue?
:(

[Gabrielnqn]

by the way, I charged by weight and charged with 12LB R22 as says in the plate.

[dandyme]

Did you replace the driers?
Are you running 100 o/o outside air?

[Gabrielnqn]

Of course, I did replace the filter...I found some dust inside the piping so I used N2. Then I installed the filter and did the solderings connecting the new compressor.

Another question.....Shoud I have add some suniso oil?

[ucp]

Just curious, but what is the return air temp before evap?

That 88 degree outdoor, did you actually measure that near condenser on roof?

That suction pressure looks a bit low if your return is warmer than 75 degrees or so.

I wouldnt think the economizer is open with that low suction press.

Can you measure temperature drop across evaporator coil,return and supply temperatures and measure suction line temperature near compressor while taking pressure readings and outdoor ambient near condensor please and post all here?

That will help us to try and get you some answers.

[Gabrielnqn]

88°F near condensor.
Yes, suction pressure seem to be too low.
I think it shoud be like 75, correct?

I will go and take temperature/pressures readings again tomorrow if needed.

[Gabrielnqn]

Unit does not have economizer.

[ucp]

Actually I dont think anyone can give you an accurate answer on what suction pressure should be untill the return/supply temperatures are known along with other goodies I mentioned.

If I had around 80 deg return I would expect near 75/80 psig, but I suspect your return temperature was higher than that considering you had a 78 degree supply after you started up and seemed some cooling was getting done with those pressures you mentioned.


Trust me, you will get some good answers here when you get the info.

[toptech]

Was trane out of compressors?
Why the re-engineering on a tcd048?
Copeland? Techumseh?
I did not know they made replacements for trane, then again, I don't get out much!!
Bernie

[Gabrielnqn]

yes, they told me the trane compressor would take 1 week ans cost $750...very expensive, the costumer will not pay that much for all the work.
Copeland came with $350 for same btu/h and performance.

[kool it man]

Originally posted by Gabrielnqn
Hi guys..I hope someone can give me an answer:

Replaced a 4 ton (TCD048 Rooftop) Trane Compressor, which was as well replaced by a Tecumseh like 2 yrs ago.
I installed a NEW (Sealed) Copeland Hermetic 47,000 Btu/h 3PH 230V.

The old compressor's coil was grounded. Compressor burned.

I pulled all the R22 out, and cleaned the system with N2. Installed new compressor. After all solderings, I pulled high Vac for 30 min. Charged and tested, pressures were good. 65LB/240LB 88°F Outdoor.

Problem:
Inside temp only 10°F bellow Outdoor temp. I get 78°F from any supply register.
Any clue?
:(



Did you clean the condensor coil?

[Gabrielnqn]

What did you mean? If I cleaned the condensor using a coli cleaning agent? No I did not. And it doesn't seam bad.

[deanm]

What is Delta-T @ Evap Coil? Cap Tube or TXV? Subcool & Superheat need to be checked. Previous replacement may not have been charged properly. Trane has great tech support but make sure you have all info above along with pressures b4 talking to them. Also M# & S#.

[seaboard]

As stated many times before in this forum, pressures mean nothing without the temps. What were the suction and liquid line temps, what type of metering device does the unit have, what were the return and supply air temps. I'm not sure what area you are in but when you first start a unit in a high humidity climate it is not unusual to not get a "good" supply temp until you have taken out some humidity. If you take the necessary readings, you will not "think" you know what the problem is, you will know what the problem is. I've had a tech on a job for two days fighting with a 50 ton split system that is tripping on oil pressure. I had another guy help him today and he found the system had no superheat, a 34 degree delta with the compressors unloaded, and the blower was running 6 amps when rated for 11. All the first guy would say is it won't run long enough to get the superheat. Take the readings and the problem will leap out at you.

[seaboard]

Originally posted by deanm
What is Delta-T @ Evap Coil? Cap Tube or TXV? Subcool & Superheat need to be checked. Previous replacement may not have been charged properly. Trane has great tech support but make sure you have all info above along with pressures b4 talking to them. Also M# & S#.

As for Trane technical support, are you calling a local office or where are you calling? I gave up on trying a long time ago, but if I called Trane for help years ago, they simply recommended me to the local Trane shop (my competition) to help me...at a fee.

[toptech]

I'm wondering if this model has a dual row condensor coil?
Things arn't always as they seem.
Bernie

[Gabrielnqn]

I went to that place this afternoon.

After read all your comments and looking at a Press./Temp Table from Trane, I decided to add more freon.

I added 4Lb 6 Oz to the existing (like 11 Lb) charge.

AND WORKED!!

Outdoor Temp= 78F
Indoor Temp (hot!!)= 86F
Temp after Evap = 70F
Suc. Press=80LB
Liquid Press=300LB
Supply Air=66F

I think this is it. Thank you guys.!!

[bruiseandy]

300psi on your high side??
with 78 degree outside air I wouldn't want to see anything higher then 245 psi or so. Seems a bit high like metering device isnt feeding enough.
What was your SH and SC btw?


edit: If you're getting a 300psi head pressure with 78 degree ambient. I wouldn't want to see that unit on a 95 degree day. HPSSW is gonna pop.

[sparks]

[QUOTE]Originally posted by deanm
Trane has great tech support but make sure you have all info above along with pressures b4 talking to them. Also M# & S#. [/QUOTE

Tech support would have hung up after "copeland" was mentioned.

Gabrielnqn, you got it, good job man!!! :eek:

Although generally I like to see my head pressures a bit lower than 300# on a 78deg day. (as previously stated) What ya gonna do when it's 100 out?? Wait.......... I know you could add an extra condensor fan.

This is definetly some awe inspiring stuff here! I too find it amazing how good compressors run when you overcharge them by 5 lbs! :D





[Edited by sparks on 07-16-2004 at 01:07 AM]

[ucp]

Originally posted by toptech
I'm wondering if this model has a dual row condensor coil?
Things arn't always as they seem.
Bernie
I thnik some of those smaller Voyagers have that double row.

[ucp]

Originally posted by Gabrielnqn
I went to that place this afternoon.

After read all your comments and looking at a Press./Temp Table from Trane, I decided to add more freon.

I added 4Lb 6 Oz to the existing (like 11 Lb) charge.

AND WORKED!!

Outdoor Temp= 78F
Indoor Temp (hot!!)= 86F
Temp after Evap = 70F
Suc. Press=80LB
Liquid Press=300LB
Supply Air=66F

I think this is it. Thank you guys.!!



Toptech mentioned something some technicians dont know about Trane RTU's. You may have a split condenser coil. You can wash and wash, it might look clean but aint. Not saying thats what you have but the head is high, maybe thats why short life on compressors in that unit.

[deanm]

Tech support at trane has changed some, & for the better. they did used to be biased to contractors but i have not had that problem in quite a while. I contact lacrosse & will post # at another time, it's not in front of me right now!
That additional charge on your rtu may be due to hot gas systems that are an aftermarket add (by a trane facility of course) that they have a tendency not to let you know about! Trane is notorious for leaving field techs in the dark about some of the things they do to their units! I was trying to remember the name of the system & to present a heads up for all. I'll get that info & post it too.

[Gabrielnqn]

As a test, I will go there this weekend and wash the condensor coil. Lets see whats happen. I will take readings before and after. Thank you guys!

[toptech]

Don't bother washing it again.
Find out if it is a double row coil.
Look where the comp discharges into to condenser. go to opposite end of coil and look to see if their are clips or
cable ties holding 2 stacks of coils together.
If so, take the top of the unit off and carefullt spread the 2 coils apart.
You'll find all kinds of neat stuff packed in between them.
Bernie

[beenthere]

Sounds like a double coil, has been taking out the compressors.
Split them and clean them, then get that over charge out.

[sparks]

Originally posted by Gabrielnqn
What did you mean? If I cleaned the condensor using a coli cleaning agent? No I did not. And it doesn't seam bad.

What method did you use to determine this??

I would, as others before me have stated.

Check for split coils, measure the condensor delta t. Take temp reading @ inlet of condensor and outlet air. More than 30deg, split the coils and clean with a chemical cleaner. Do take that overcharge out, it's what was probablly killing the other compressors.

[sparks]

Originally posted by Gabrielnqn

I added 4Lb 6 Oz to the existing (like 11 Lb) charge.


That existing (like 11lbs) seems way high already too. I don't have the eagle program but I would think the factory charge on that was only about 8-8.5 lbs. Any one else??

I always thought 10 seer was aprox 2 lbs per ton.

What was the charge on the name plate??

[Gabrielnqn]

As I said...the plate name says 12lbs...I didn't have the time to go there and wash the condensor..but I will next week.

[toptech]

Are you not acknowledging the fact that several tech's have mentioned splitting the coils on purpose? Or is it because you're not sure of what we are talking about?
Please promise us that we arn't wasting are time keeping track of your efforts.
It's a simple yes or no answer. Please, for the love of Christ and all that is good in this world, tell us if you have split the coils!!!!!!
Thanks
Bernie

[sparks]

Originally posted by toptech
Are you not acknowledging the fact that several tech's have mentioned splitting the coils on purpose? Or is it because you're not sure of what we are talking about?
Please promise us that we arn't wasting are time keeping track of your efforts.
It's a simple yes or no answer. Please, for the love of Christ and all that is good in this world, tell us if you have split the coils!!!!!!
Thanks
Bernie


:D:D:D:D:D:D:D