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Kim8874 · May 21, 2007, 07:33 PM

We moved into a new home and it has an older Rheem central air unit. We are trying to figure out by using the model number (if possible) what the total tonnage is of this unit. Our fan motor (we believe) is not working and are considering upgrading to a newer unit, but want to see if the A-coil is compatible. We have a 1300 sq. ft. home.

The Rheem model number we were able to find is AT-38B1 Q. If anyone can help us figure out what this unit could be, that would be GREAT! The unit is approximately 33 yrs old.

hvac1000 · May 21, 2007, 09:23 PM

Originally Posted by Kim8874

We moved into a new home and it has an older Rheem central air unit. We are trying to figure out by using the model number (if possible) what the total tonnage is of this unit. Our fan motor (we believe) is not working and are considering upgrading to a newer unit, but want to see if the A-coil is compatible. We have a 1300 sq. ft. home.

The Rheem model number we were able to find is AT-38B1 Q. If anyone can help us figure out what this unit could be, that would be GREAT!! The unit is approximately 33 yrs old.

On that old of a unit the coil will not be compatible and it would be foolish to try and use it over on a new system. A 33 year old unit is probably a 5 or 6 SEER the new is 13 SEER minimum. Your unit could be a 3 ton by the model but I have no cross refence for that old a unit.

Kim8874 · May 22, 2007, 03:02 AM

Originally Posted by hvac1000

On that old of a unit the coil will not be compatable and it would be foolish to try and use it over on a new system. A 33 year old unit is probably a 5 or 6 SEER the new is 13 SEER minimum. Your unit could be a 3 ton by the model but I have no cross refence for that old a unit.

So would it be safe to "assume" (although I hate using that word) that if we were going to swap out the coil, that we would need to also purchase a new condenser unit? We have a price on a slightly used (2 seasons) central air conditioning 2 ton, 14 seer condenser with an a-coil for $250. Or do you think it would probably be in our best interest to simply pay the money to get a service tech out here to look at it and possibly trouble shoot the fact that it kicks on, but the fan will turn for a few seconds and then stop? In NJ a home inspection is required on all appliances and utilities (heat, a/c etc) which we had done, however it was 55 deg. When we had the inspection done, so it was too cool to be able to test the c/a unit. The day we made settlement, same thing, it was too cool to be able to test it, so we literally came into the house not knowing if the central air worked or not. We have discovered since then, that it does not.

My husband is an electrician and was thinking that perhaps we should start by replacing the fan motor, but it's a matter of FINDING one that is compatible with the unit we have. The unit appears to have been on a service contract at one time, as it was last serviced 3 years ago. However, the previous home owner passed away in February of last year, and the C/A unit was not run here through out last summer. Could it be something as simple as a bad fan motor?

hvac1000 · May 22, 2007, 03:16 AM

Your old unit could be low on gas or the motor could be bad. The unit that is not that old for 250.00 sounds like a good deal if you replaced both in and out at the same time. The problem is why is it so cheap?? You will also need to pay someone to put it in.

Kim8874 · May 22, 2007, 03:24 AM

Agreed, and we have thought about why it is so inexpensive as well. Apparently the unit is 3 years old (only used for 2 seasons as it was put in at after the end of the cooling season). The seller is getting rid of it because he upgraded to a larger unit due to an addition that added about 400 sq ft to his home.

As for paying someone to install it - we're not sure how to go about doing that. Do we contact a local HVAC company and tell them we have a unit we need it installed? Or will we have a hard time finding someone to install it considering we didn't purchase "their" unit?

hvac1000 · May 22, 2007, 03:34 AM

If you do not have a friend to install it you will get ripped off. No HVAC company is going to want to install used equiptment that they did not sell to start with. They will jack the price on you. It would actuall be much better if you get at least two estimates better with three and see what it will cost you for a new system installed.

You really do not know the history of that used unit you are talking about and it could also end up being a big problem also.
You might get the old unit looked at because it might just be short of refrigerant and they could rercharge it. Now that sounds like the cheapest way but remember the gas had to leak out to start with so they really need to find and fix the leak.

I have stated many different avenues to go with but without being there it is difficult for me to tell you which is the best one.

Kim8874 · May 22, 2007, 05:34 AM

Thanks for your help. I think it might be better to simply have an HVAC service call set up; as you said, it could be as simple as a refrigerant shortage. After reading through several other posts that other members have posted regarding their a/c unit not working, that seems to be one of the first issues that is brought up.

I will call for a tech and see what we can find out; I'll keep you posted. Thanks!