Mismatched HVAC Components

[cdermott]

Can you use a 2 ton compressor with a 1.5 ton air handling unit?

I am replacing downstairs with 20 seer and I want to move the 13 seer over and replace 18 yr old upstairs unit. Contractor says it is not a good idea, but won't give me the drawbacks. Can someone tell me about the consequences or whether they are just trying to sell me a new unit? thanks for your advice.

[classical]

Can you use a 2 ton compressor with a 1.5 ton air handling unit?

I am replacing downstairs with 20 seer and I want to move the 13 seer over and replace 18 yr old upstairs unit. Contractor says it is not a good idea, but won't give me the drawbacks. Can someone tell me about the consequences or whether they are just trying to sell me a new unit? thanks for your advice.

We need a great deal more information before we can give you an informed answer model numbers preferably.


It is always preferred to go with matched systems.

In most cases the air handler will be a 2-ton or 3-ton with a multi speed bower that can be adjusted to the airflow requirements of the condenser. The evaporator coil is probably not a 1.5-ton it also will be either a 2-ton or 3-ton. If you have an expansion valve matched to the condenser capacity it will most likely be just fine.

If the air handler blower was only capable of moving 600 CFM (1.5-tons) and the coil was actually a 1.5-ton then you would not achieve 2-tons of cooling and the system would most likely freeze up on all but the warmest days.

[beenthere]

The 1.5 ton air handler may not be able to move enough air for the 2 ton condenser. And cause the indoor coil to freeze up, and could cause liquid refrigerant to flood back to the compressor and damage it.

[classical]

The 1.5 ton air handler may not be able to move enough air for the 2 ton condenser. And cause the indoor coil to freeze up, and could cause liquid refrigerant to flood back to the compressor and damage it.

Do they make air handler that are actually 1.5-ton I have never seen one smaller than 2-ton?

[mark beiser]

Do they make air handler that are actually 1.5-ton I have never seen one smaller than 2-ton?

It depends on the manufacturer. 1.5 ton air handlers used to be quite common, not so much anymore.

[classical]

It depends on the manufacturer. 1.5 ton air handlers used to be quite common, not so much anymore.

I see maybe ten airhndler a yar almost everything is gas.

[beenthere]

I see maybe ten airhndler a yar almost everything is gas.

Haven't seen a "new" air handler that is only 1.5 ton. But older ones were made in a 1.5 ton version.

[mark beiser]

Haven't seen a "new" air handler that is only 1.5 ton. But older ones were made in a 1.5 ton version.

Yeah, 1.5 ton air handlers seem to have gone the way of the 1 ton outdoor unit.

[cdermott]

The newer unit outside that is currently used for downstairs is a Trane XR11 - TWR1030A1000AB - which salesperson says is 2.5 ton. This is the unit I want to move over to supply TW07224A140A0 air handler in Attic. Salesperson says he thinks this is a 1.5 ton. It was manufactured in 2005.

The old outside unit that the XR11 would replace is XE1000 - TWR024C100A2. Thanks again for your expert advice on this.

[classical]

The newer unit outside that is currently used for downstairs is a Trane XR11 - TWR1030A1000AB - which salesperson says is 2.5 ton. This is the unit I want to move over to supply TW07224A140A0 air handler in Attic. Salesperson says he thinks this is a 1.5 ton. It was manufactured in 2005.

The old outside unit that the XR11 would replace is XE1000 - TWR024C100A2. Thanks again for your expert advice on this.

Not reallya Trane guy but that looks like a 2-ton airhandler and it was matched to a 2-ton condenser. As long as you have a properly sizedexpansion valve installed on the coil it will function reasonably well, the airflow will be an issue but not a major problem. What you will get is a unit that does not produce a full 30,000 BTU's (2.5-tons) it will remove more humidity than a matched system and it could cause problems with the compressor if the tech does not know how to properly charge a system.

In the long run it will work just as well or better than a new dry charge 13 SEER 2-ton unit on the same air handler.

[beenthere]

Not reallya Trane guy but that looks like a 2-ton airhandler and it was matched to a 2-ton condenser. As long as you have a properly sizedexpansion valve installed on the coil it will function reasonably well, the airflow will be an issue but not a major problem. What you will get is a unit that does not produce a full 30,000 BTU's (2.5-tons) it will remove more humidity than a matched system and it could cause problems with the compressor if the tech does not know how to properly charge a system.

In the long run it will work just as well or better than a new dry charge 13 SEER 2-ton unit on the same air handler.

At 280CFM per ton???

[classical]

At 280CFM per ton???

If that is a two ton air handler it should be 320 CFM per ton.

[beenthere]

If that is a two ton air handler it should be 320 CFM per ton.

Bet ya its struggling to move 700 CFM. Which is fine for a 2 ton condenser.

Probably has 8-6" flex supplies. And a 14X8 return duct.

[classical]

Bet ya its struggling to move 700 CFM. Which is fine for a 2 ton condenser.

Probably has 8-6" flex supplies. And a 14X8 return duct.

This may well be true but I cannot see the job and can only answer based on the limited information given and what is possible with a competent tech.

Knowing what I do I could make this match work and last as could you.

[beenthere]

I just have little faith in the duct system being large enough, and his tech knowing how to check it, and correct it.

[hvacvegas]

Agree with bt here.

I'm trying to think back to a time I've seen a duct system in an attic that was done correctly, by other companies.