I need some AC help

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Old 02-08-06, 08:06 AM
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I need some AC help

I just bought a house and the AC unit is 19 years old and looks pretty bad. I'm not sure when it will die, but I'm trying to sort some things out before summer. I have a pretty normal setup - gas furnace inside and central air unit outside.

I just have a few central air questions:

1. I don't know what size my AC unit is (I will find out), but I know that it cooled the house perfectly last summer. Does this mean that a new unit of the exact same size (BTUs or Tons) would be the way to go? I understand that the SEER rating on a new AC unit would probably be higher, but that only means my electric bill should improve, right?

2. I have a brand new Ruud furnace. Does this mean that a Rheem or Ruud AC unit would be the way to go?

3. If the outside unit were to die and replacing it would make better financial sense, is this a DIY job (I'm sorta handy)? Is it just a matter of replacing the AC unit and hooking it up or is there inside stuff (furnace, etc.) you have to do as well?

4. Are residential AC units usually powered by 240 volts only or could they be 120/240? I have to run a new dedicated circuit for the AC unit and I want to know if I should do 3-wire or 4-wire?

Thanks very much.
 
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Old 02-08-06, 02:55 PM
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Originally Posted by XS6DFG0
I just bought a house and the AC unit is 19 years old and looks pretty bad. I'm not sure when it will die, but I'm trying to sort some things out before summer. I have a pretty normal setup - gas furnace inside and central air unit outside.
19 years is pretty much at it's end of it's life. Time to retire it if you want to save money on your electric bill.

I just have a few central air questions:

1. I don't know what size my AC unit is (I will find out), but I know that it cooled the house perfectly last summer. Does this mean that a new unit of the exact same size (BTUs or Tons) would be the way to go? I understand that the SEER rating on a new AC unit would probably be higher, but that only means my electric bill should improve, right?
On the hotest day of the year, did the system run steady? or cycled on and off? I would still sugggest having a manual J done (Heat gain) on the home to get the right sized unit.

2. I have a brand new Ruud furnace. Does this mean that a Rheem or Ruud AC unit would be the way to go?
You don't have to go that way, but you can. Rheem/Ruud are good units for A/C.. Trane are also good product.

3. If the outside unit were to die and replacing it would make better financial sense, is this a DIY job (I'm sorta handy)? Is it just a matter of replacing the AC unit and hooking it up or is there inside stuff (furnace, etc.) you have to do as well?
It can be DIY, but most home owners are NOT going to have the Cerfciation from the EPA to hande the "Freon", the tools that is needed. So best to leave it with the Pro. The coil will need to be replaced inside as well so you get the matching SEER rating. and maybe new line set.

4. Are residential AC units usually powered by 240 volts only or could they be 120/240? I have to run a new dedicated circuit for the AC unit and I want to know if I should do 3-wire or 4-wire?

Thanks very much.
You will need 220 volt on the A/C system. You may have that already. The Dealer can look to see if it needs to be brought up to code.
 
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Old 02-09-06, 05:28 AM
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Thanks for your replies.

What is a line set? Is that what you guys call the lines (insulated with foam) from the furnace to the outdoor unit?
 
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Old 02-09-06, 06:13 PM
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Line set

The line set is the two copper lines (one large & insulated, the other small) between the indoor (evaporator) coil & the outdoor (condensing) unit.
 
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Old 02-10-06, 04:43 AM
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XS6DFG0

Going down your question list.

1.Make certain new outside AC condenser is sized correctly and matches up to the blower size on your furnace. SEER refers to the operating eff of a new unit-the higher SEER, the lower operating cost.

2.I prefer a complete system from the same manufacturer and in your case , a Rudd/Rheem AC condenser would be a solid choice to consider.

3.IMO, this is not a DIY job unless you are trained and certified in HVAC. Also, you will need to include a matching evap coil that is installed in front of furnace blower. Now would be a good time to consider a good air filter cabinet unless you already have one. Insist that your lineset is replaced!

4.I suspect you already have 220v for existing system. Check your dataplate on old system to see what it calls for. Again unless you are trained for electric, I suggest you let a pro install the new AC system. You do want install to be up to code.Do you have a disconnect at your condenser?

And yes, you are at the end of an average life for an AC condenser.

Good LucK!
 
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Old 02-10-06, 06:05 AM
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Originally Posted by TigerDunes
XS6DFG0
I suspect you already have 220v for existing system. Check your dataplate on old system to see what it calls for. Again unless you are trained for electric, I suggest you let a pro install the new AC system. You do want install to be up to code.Do you have a disconnect at your condenser?

And yes, you are at the end of an average life for an AC condenser.

Good LucK!
I do have a disconnect at the condenser.

Yes, I already have a 220v line for my existing system. The problem is that there are some electrical issues between the dryer and the AC condenser (they are on the same circuit!!!!) that need to be worked out. Part of what needs done is me running a dedicated line from the panel to the condenser (disconnect). I need to know if 10-2 is OK (220v only) or 10-3 (110v/220v) is needed. I will base this on a new system, not the one I have.

I can tell from listening to you guys that this is much more involved than I thought and I don't know crap about HVAC anyway. I think I will leave this to professionals.

I know you guys hate to do this w/o seeing the project, but could you give me a ballpark figure on what this would cost? Think very broad. A Rheem or Ruud 13 SEER unit at either 2 or 2.5 tons, installed. Pittsburgh, PA
 
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Old 02-10-06, 06:43 AM
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You will need a 10-2 w/ ground.

Ball park will be $2 to 3k for the job done right.

Yeah, re do the wire that a/c and dryer shares now!
 
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Old 02-10-06, 09:00 AM
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Originally Posted by Jay11J
You will need a 10-2 w/ ground.

Ball park will be $2 to 3k for the job done right.

Yeah, re do the wire that a/c and dryer shares now!
Thanks, I figured on 10-2 w/ground. I will be running a new dryer circuit and that one will be 10-3 w/ground.

You should see this: There is a 6-2 w/ground wire from the panel (50 amp breaker) to the 30 amp dryer receptacle. A 10-2 w/ground is then connected to the receptacle and moves on the the AC condenser. The house was only built in 1986 - what inspector would sign off on this?

How much of your estimate is labor vs. parts?

Thanks
 
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Old 02-10-06, 10:02 AM
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I am not going to guesstimate on $$$ but I would say this job should take a trained HVAC tech leadman and a trained helper minimum 1/2 day to max 1 day barring any problems. I don't know labor rates for your area.

This should include removal of all old equipment along with installation of new AC condenser and new coil. And yes, please include a new matching evap coil with new lineset. I would ask for a new dryer to be installed unless your new AC includes a factory dryer.

Since this is AC only, I would not have this work performed until mid to late April at earliest. You have time to plan.

My opinion.
 
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Old 02-10-06, 11:36 AM
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Originally Posted by TigerDunes
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I would ask for a new dryer to be installed unless your new AC includes a factory dryer.
What is the "dryer" you are talking about?
 
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Old 02-10-06, 12:49 PM
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Originally Posted by XS6DFG0
What is the "dryer" you are talking about?
Tiger,

Most company already had a dryer built in the outdoor unit.

XS.

The "dryer" is a filter that keep the system clean and dry.
 
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Old 02-13-06, 07:08 AM
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Thanks everyone.
 
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