Compressor/coil

[RBC242]

Can anyone tell me what size unit this is ? Serial # 95C29862H. I replaced the coil inside (split unit) 3 ton coil.The coil make's excessive noise when starting and stopping.Could the unit's not be matched or was the line not evacuated proprerly/at all. The coil does not get cold all the way to the top.The old coil was old and clogged in spot's I could not get to.There was also a solid 20* temp  diff. where as now it is 17.5. I was an electrician for yrs and did property management so I know my way around a bit.Any help out there ?

copeland CR13-0290-PFV-230

[Repair-man]

29,000 BTU compressor  (2.5 ton)

What do you mean, "the coil is making excessive noise"? Is it the fan or the evaporator making the noise, and describe it, please.

And for heaven's sake, what did you mean by this comment:

.Could the unit's not be matched or was the line not evacuated proprerly/at all.

Do you not know if you evacuated the system or not when you replaced the coil?
Did you change the liquid line dryer at the condenser, or better yet, add one at the evaporator?

Your condenser is 14 years old and most likely the compressor has bad reed valves, considering that the  inside coil was in bad shape and clogged. No doubt the low delta temps you are now getting is a result of  an inefficient compressor. Ordinarily a 2,5 ton compressor can handle a 3-ton coil as long as it is properly charged and maintained.

Still, you will only get 2.5 tons of cooling, which will effectively cool about 1500 sq. ft.

[RBC242]

 What do I mean ?? The match between a 2.5 ton unit 3 ton coil. Do I hear the louder gas flow ( sort of a gurgling)because the coil is bigger than the condenser - was the line not evacuated all the way ( air in line)- not enough freon or is it normal to hear.It's not a background noise,you can hear the gas moving pretty good. I thought it should be quieter. Should I be getting a lower heat transfer than 20 or 17.5 or is  20 deg.the shooting piont. Again the copper running on the outside of the coil does not get cold all the way to the top.Does the 2.5 not hold enough gas for the 3 ton coil is that why ? I'm not an expert that's why I'm here.

[Repair-man]

I'd be glad to help you with this, but to do so, I would need to know the operating pressures on the gauges outside while the unit is cooling. Gurgling at the coil usually means an undercharge.

Was the system evacuated or not?
Was a new dryer installed?

If not, the least that should be done is to recover the freon, replace the existing liquid dryer or install one if none are present, then pump the whole  system down to -28 psi for 5 minutes. New freon should be added when recharging and the suction  pressures should be between 68 and 74 psi when the system is operating efficiently.

There's more to this than just changing parts.

[jumptrout51]

 

[RBC242]

I changed out the inside unit myself and the coil was the same exact size as the old one.I had an AC guy  come out here to do the rest.He brought the gas down to the comp.and cut the line inside and left.He had other work to do elsewhere .When he came back I was done. It was short notice and this semi-retired fellow was all I could find at the moment.I know he blew a little gas in the line to pressure test it after he made up the joint's.He said he brought it all down again( I didn't actualy see it done) and added additional freon. There is and was no line dryer.I was getting a 20 deg. diff. before.I don't know if it was that the air wasn't moving across the coil as fast or what. Did this guy just give me a "that's good enough" instead of doing it right.There was compressor work done about 7 yrs ago right before I bought the place and it has alway's been a smooth runner.The air was very cold.The coil was just so dirty (from running w/o filter before I got to it)that it kept running to keep up with the rising temp outside here in fl.To me the gurgling liquid sound seem's louder than normal which is what cought my attention and the whole coil is not getting cold.Could it not be enough freon or did he not evacuate it properly. I'm trying to explain this as best I can.I was a union elec.and have alway's prided myself in my work and it burn's me up to think this guy didn't do the right thing after I did all the major work. Changed out unit,duct work,wiring,stat and re-routing line's and drain.

[RBC242]

 

[Repair-man]

Heck, it's anybody's guess. One thing's for sure, it needs to be done right. Without a way to adjust the freon or even check it, you're stuck. Don't expect that compressor to last much longer, either. Air in the lines means moisture, moisture means damage and poor condensing of the gas.

That guy was one of those "one-bun" folks I follow up behind so often


Now that forums like this are starting to get attention, it pays to propose your next project ahead of time and get the important feedback you need first. You can't rely on half-assed repair guys to always do the right thing.

[RBC242]

Thank's. The guy was pretty

[Repair-man]

If you have the opportunity to correct this situation, even with a new outside unit (which I heartily recommend), you should have a new liquid line drier installed up at the evaporator coil. Install it about 6" out from the coil on the 3/8" hi-side line going in. This will prevent moisture and any foreign contaminants that may come up from the condenser from clogging the tiny capillary tubes that serve as a metering device for the coil.

Since the outside unit is 14 years old, we can safely assume that it is about a 9 SEER unit at best. Todays units start at 13 SEER and up, so it will be more economical to replace the whole  unit versus considering a new compressor for the old condenser. In 2 years, it will have paid for the difference in price with higher energy savings.