Broken 3 1/2 Ton AC Compressor

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Old 07-12-10, 06:34 PM
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Broken 3 1/2 Ton AC Compressor

We have a small building with a 3 1/2 ton central A/C unit. However, it seems that the compressor is out.

We have a compressor for a 5 ton unit. We're wondering how feasible it will be to install the 5 ton compressor, but keep the 3 1/2 ton furnace/air handler/everything else?
 
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Old 07-12-10, 06:52 PM
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wont work sorry!!!!!!! To big an engine for the transmission.
 
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Old 07-12-10, 06:54 PM
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Welcome to our forums!

I'm afraid it would not be feasible at all.
because of being grossly oversized your main problem would be coil icing and short cycling of the outdoor unit.
There is a far to great a spread in unit sizes.
 
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Old 07-12-10, 07:55 PM
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Oops! I mean the CONDENSING unit! Sorry!

So the question should read:
We have a small building with a 3 1/2 ton central A/C unit. However, it seems that the CONDENSING UNIT is out.

We have a CONDENSING UNIT for a 5 ton unit. We're wondering how feasible it will be to install the 5 ton CONDENSING UNIT, but keep the 3 1/2 ton furnace/air handler/everything else?

Also, apparently we have a 4 ton CONDENSING UNIT as well. If its feasible, which would be better to use?
 
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Old 07-12-10, 08:27 PM
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4 ton might work if you can move a lot of air over the indoor coil. But it will not be efficient
 
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Old 07-12-10, 08:50 PM
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It could be a headache if you mismatch the unit and would be a gamble that it would not cost you more over the long run.
 
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Old 07-12-10, 09:34 PM
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Thanks guys! Let me get a little bit more clarification... my knowledge of this kind of stuff is very very basic

But anyways, both of you mentioned efficiency and cost -- I assume we're talking about reduced efficiency in performance? And cost as in more electricity?

Being that I have access to both a 4ton and a 5ton, should I not consider the 5ton?
 
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Old 07-13-10, 05:24 AM
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You can do what you want but repeating the question will not get you the answer you want to hear.

The best person to ask would be the one doing the work.
If they were prepared to install mismatched equipment maybe they would have the patience and you the money to try to make it work.
 
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Old 07-13-10, 09:36 AM
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Originally Posted by GregH View Post
You can do what you want but repeating the question will not get you the answer you want to hear.
Sorry, I'm not trying to repeat the question... I'm just trying to understand a little bit more into the "Why?" as well as understanding the details. There's not really any need for comments like that, as I have absorbed your answers and truly appreciate the comments.

Thus, if there isn't any more helpful feedback/information, then thank you once again and I guess I'll figure it out...
 
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Old 07-13-10, 11:11 AM
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There really isn't much for you to figure out.

You received two opinions saying that it would not be feasible.
airman's comment about the transmission being too small says it all..............This equipment has to be balanced to work properly.

Because of the regulations surrounding a/c repairs you will need to hire a properly certified tradesman to do this work.
If you get an answer from a forum like this and direct the tradesman to do what we suggest you will accept all liability when it doesn't work and we both are suggesting it won't.
You need to ask the person doing the work if it can be done.

It is not to say that you won't get any cooling at all, it is that the imbalance will be sure to generate a whole pile of service calls to attempt to keep it running.

I do this kind of work for a living and the only way I would do a job like this is if you handed over a blank cheque for follow up service calls!
 
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Old 07-14-10, 10:33 AM
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Originally Posted by AntiAmy View Post
Oops! I mean the CONDENSING unit! Sorry!

So the question should read:
We have a small building with a 3 1/2 ton central A/C unit. However, it seems that the CONDENSING UNIT is out.

We have a CONDENSING UNIT for a 5 ton unit. We're wondering how feasible it will be to install the 5 ton CONDENSING UNIT, but keep the 3 1/2 ton furnace/air handler/everything else?

Also, apparently we have a 4 ton CONDENSING UNIT as well. If its feasible, which would be better to use?
Does the indoor coil have a TXV metering device, or piston orifice which must match the condenser's tonnage?

Using the 4-Ton condenser:
If it does, & you can get enough air through the coil, which may even be 4-ton rated, it could work...
 

Last edited by HVAC RETIRED; 07-14-10 at 10:36 AM. Reason: Using the 4-Ton condenser:
 

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