HVAC question on used parts

[ScottAR]

In my somewhat limited experience, it's about $200-$300 difference between a new outside unit vs replacing just the compressor. By the time one figures in all the extra
labor to disassemble the outside unit it works out to nearly the same.

It would be higher to change the coil as well, but recommended. If they flush and reuse
the lines insist on seeing a dryer or "catch can" on the line into the outside unit.

I'm unsure on the new r410 but like it or not, it's coming. The production of r22
is stopping in 2010. It's a brave new world indeed.

 

[Richard]

Thanks all!

It's a log house... I hope that works to my benefit on size (cost)

 

[Sigarms]

I'm unsure on the new r410 but like it or not, it's coming.

R410A has been out since the 90's, first introduced by Carrier as "Puron".

Most contractors who are not familiar with it are usually afraid of two things.

1. Change
2. Operating pressure of R410A which is much higher than R22 (guys back in the 90's thought R410A would blow up). You also need some new tools for 410.

The one thing that you have to be very careful about with installing R410A is mositure. Guys who ran a vacuum pump for a half hour and felt it was fine with a R-22 unit will have nothing but problems if they have the same habits with a R410A system (habits can be hard to break). Bottom line, R410A will not let guys get away with sloppy install habits.

Long story short, R22 and R410A use different oils wich are not compatible with each other, on reason to replace the lineset as well.

Back in the 90's the cost of a jug R410A was about ten times the cost of a jug of R22. Guess what, they are now about equal in price. Next year (or perhaps this summer), I have no dobut that R22 will exceed R410A in price, which means higher service bills for R22 units.

 

[kenmac]

.

Back in the 90's the cost of a jug R410A was about ten times the cost of a jug of R22. Guess what, they are now about equal in price. Next year (or perhaps this summer), I have no dobut that R22 will exceed R410A in price,

Actually, right now.. I can buy 410 cheaper than than R22..The only thing load calc, don't take into account ( that may or may not) be a problem .. Is when you have alot of people over say for ,,, a party.. People give off heat... opening outside doors alot also allows heat / cold in... A load calc...isn't perfect,,,,but, it's close

 

[440roadrunner]

The only thing worth keeping would be the squirrel cage blower out of the air handler, they make dandy little fans in the garage or a wet basement, .

This can be a bad idea. Typical modern fans--if it's not the new variable speed, electronic controlled--are direct drive, and when the air restriction of the system is removed, IE, running in "free air" they will "overamp." You may well burn up the motor or cause a fire.

So far as replacing the unit, make SURE it is designed around the ductwork and otherwise properly sized. Back when we were doing local retrofits --removing electric, converting to NG--I ran into a number of "underducted" heat pumps. One guy had lost a couple of compressors in 10-15 years. At that rate there's certainly no savings in a heat pump.

Also make sure that the brand/ installer is WELL supported for maintenance, and find yourself a GOOD man to do yearly or at least bi-yearly checks.

The single most important thing you can do with a heat pump is NOT restrict the airflow--change filters, don't close down supply ducts

 

[Richard]

Long story short, R22 and R410A use different oils wich are not compatible with each other, on reason to replace the lineset as well.

Ok, this is probably the first thing I've read that has me nervous.

By lineset, do you mean the copper tubing connecting the air handler to the compressor outside?

I'm asking because the guy that was out on Friday said if the new stuff was put in, it was critical that it was VERY airtight (special tool to measure the vacume, compared to old system) and they would also purge/wash the connecting lines because if you mixed the two "freons" they would turn into some kind of GOO inside the line.

Your statement above is suggestive of this same thing... one bad reality... my connecting lines run through flooring AND walls for a portion of their run and I don't know that it could be easily replaced without a major major issue inside.

Hopefully you infer something different than the pipelines connecting the two? (my eyes are closed and I'm chanting "please say you are, please say you are...")

 

[2manyrocks]

Lineset means the refrigerant lines between the outdoor unit and the indoor coil.

 

[MarkV]

I know Sigarms and Kenmac are HVAC pro's so am I correct that as of next year you can no longer buy new R22 systems, EPA thing? Also when switching freon types don't you also have to change the air handler unit to be compatible?

Richard there are some government rebates currently available, up to $1500, for new energy efficient units with the newer type of freon. If parts are unavailable for your unit now and it has been an on going problem is it worth putting more money in it and possibly missing the rebate program?

MarkV

 

[dmccarty]

...
Your statement above is suggestive of this same thing... one bad reality... my connecting lines run through flooring AND walls for a portion of their run and I don't know that it could be easily replaced without a major major issue inside.

Hopefully you infer something different than the pipelines connecting the two? (my eyes are closed and I'm chanting "please say you are, please say you are...")

Ra Row. I am chanting as well. Our outside unit is on the north side of the house. The inside unit is in the attic on the south side of the house. The copper goes from the outside unit, through the brick veneer, up the outside wall and into the attic. From there its a 60-70 foot run to the south. The HVAC was installed in 2004 but it sounds their might be a chance that Rxxxx it uses might be unmixable when the system has to be replaced.

Later,
Dan

 

[tallyho8]

Ok, this is probably the first thing I've read that has me nervous.

By lineset, do you mean the copper tubing connecting the air handler to the compressor outside?

I'm asking because the guy that was out on Friday said if the new stuff was put in, it was critical that it was VERY airtight (special tool to measure the vacume, compared to old system) and they would also purge/wash the connecting lines because if you mixed the two "freons" they would turn into some kind of GOO inside the line.

Your statement above is suggestive of this same thing... one bad reality... my connecting lines run through flooring AND walls for a portion of their run and I don't know that it could be easily replaced without a major major issue inside.

Hopefully you infer something different than the pipelines connecting the two? (my eyes are closed and I'm chanting "please say you are, please say you are...")

It may be easier to run the new lines than you think. They may be able to be re-routed a different way. Besides having to clean the old lines extremely well, there is the possibility that they are leaking or that they are not the recommended size for your new unit with the new refrigerant but that the installer will go ahead and use them anyway.

Get the rebate money while you can.

PS. I only did air conditioning work for 38 years.