New Carrier Performance Series help and suggestions

[Betacam]

Hello Everyone,

I've been looking through this forum and there seems to be a great deal of knowledge so i thought I would post my issue and hope some could offer advice or suggestions.

In January we replaced a 10yo Trane builder grade model with the following system:

17.5 SEER 2-speed Performance condenser model# 24APA748A003 and
Infinity 80 Furnace 58CVA110---1--20 and CNPVP6124ATA tin plated
evaporator Coil

Now, during the winter months the heat worked great! However, now that the heat has turned up outside in central florida, we need AC, but the new system can't seem to handle it. Our house is constantly at 81 degrees during the day and the AC is on almost 24/7.

The air coming out of the vents feels no where near as cold as the old trane system that was replaced. The old system would cool the house off pretty quickly and would only be on 24/7 when it was low on freon or there was some other issue.

Now, we've had the installer come out to check the system and they're telling us this is normal???!?!? Is this the case? How and Why is a new system less efficient then an older model? Does this sound right to the group on this board? If you don't feel this is normal, are there things that I can ask our installer to check?

I really appreciate any help, assistance or information anyone can offer. As you can imagine this is pretty frustrating, after we spent a little extra money to get the best system we could.

Thanks!

[Dr.phil]

Do you have the Infinity tstat? Is stage two ac coming on?

[Betacam]

Hey Dr. Phil Thanks for the reply.

We do have the Infinity tstat.

By Stage Two I'm assuming that means the 2nd high speed of the system. If that's not what you mean, please let me know.

Before the installer visited the system did kick into the high speed every now and then. When the installer came out he did something with the tsat and the system seems to be running at a constant speed now, I don't hear the same low to high switch over that was present before.

[woody19]

You didnt say how large your house is but, all else being equal, it doesnt sound like it is going into high stage. I have a two stage Bryant and it will run in low 80-85% of the time and only go to high stage above 105* or if I lower the set point down. I think your installer needs to come back and check it again. If we had some operating conditions it would help.

[Betacam]

Woody, I appreciate the response.

The home is 2000 s/f.

The temperature has been in the mid to high 90's for the last few days.

Wood Blinds are over all the windows.

No doors or windows are open.

inside doors for rooms have even been shut to hopefully help cool certain areas off, with no luck.

Vents for smaller areas such as bathrooms and closets have been closed to try and help.

Do you need additional operating conditions? Just let me know what and I'll be glad to explain.

NOTES:
The same components for the system were measured by multiple people and they all confirmed the tonnage is correct. It was a bit larger than the one replaced, but they all said that it evens out because of the two stages.

After the sun goes down the house starts to go down to 78/77 after a few hours, but the system still stays on practically throughout the night to maintain that temp.

Most everything is the same from the old system to the new system, besides the equipment.


I do appreciate your time and help.

[woody19]

By operating conditions we are referring to the actual pressures and temperatures associated with the system during operation. Unfortunetly you won't have these unless the tech shares them with you. Those readings let us know whether or not the system is functioning as designed. You can take the air temp coming out of the supply and also where your return air grille is located to see what the temp. difference is and that will be a start. Those units have to be charged in high stage to achieve the correct refrigerant level. Again, you should contact the contractor and have them come back out.

[Betacam]

Ok.. I just had the contractors out and they were still unable to diagnose the issue. Their next step is adding another return next week (ouch my electric bill).

If anyone has any suggestions or thoughts, anything would very much be appreciated now.

Here are the readings from the paperwork they left:

Compressor Amps 11.6 (high stage)
Condensing Fan Amps 1.43
Suction Pressure 110
Head Pressure 310
Return Temperature 79.1
Supply Temperature 58.8
Subcool 11°
Superheat 5°

[10phaseadapter]

Ok.. I just had the contractors out and they were still unable to diagnose the issue. Their next step is adding another return next week (ouch my electric bill).

If anyone has any suggestions or thoughts, anything would very much be appreciated now.

Here are the readings from the paperwork they left:

Compressor Amps 11.6 (high stage)
Condensing Fan Amps 1.43
Suction Pressure 110
Head Pressure 310
Return Temperature 79.1
Supply Temperature 58.8
Subcool 11°
Superheat 5°

is this at the coil or at a supply vent?

[crayx4]

If it's any consolation, you are not the only one! I've got a Performance too (24APA7 2 tons, on 3 ton furnace) and I've got almost exactly the same problem as yours. Check out my thread for more info. I will keep monitoring yours to see if you get a solution...

Hello Everyone,

I've been looking through this forum and there seems to be a great deal of knowledge so i thought I would post my issue and hope some could offer advice or suggestions.

In January we replaced a 10yo Trane builder grade model with the following system:

17.5 SEER 2-speed Performance condenser model# 24APA748A003 and
Infinity 80 Furnace 58CVA110---1--20 and CNPVP6124ATA tin plated
evaporator Coil

Now, during the winter months the heat worked great! However, now that the heat has turned up outside in central florida, we need AC, but the new system can't seem to handle it. Our house is constantly at 81 degrees during the day and the AC is on almost 24/7.

The air coming out of the vents feels no where near as cold as the old trane system that was replaced. The old system would cool the house off pretty quickly and would only be on 24/7 when it was low on freon or there was some other issue.

Now, we've had the installer come out to check the system and they're telling us this is normal???!?!? Is this the case? How and Why is a new system less efficient then an older model? Does this sound right to the group on this board? If you don't feel this is normal, are there things that I can ask our installer to check?

I really appreciate any help, assistance or information anyone can offer. As you can imagine this is pretty frustrating, after we spent a little extra money to get the best system we could.

Thanks!

[crayx4]

What does your stat show for CFM, Static pressure, and coil temperature?

Ok.. I just had the contractors out and they were still unable to diagnose the issue. Their next step is adding another return next week (ouch my electric bill).

If anyone has any suggestions or thoughts, anything would very much be appreciated now.

Here are the readings from the paperwork they left:

Compressor Amps 11.6 (high stage)
Condensing Fan Amps 1.43
Suction Pressure 110
Head Pressure 310
Return Temperature 79.1
Supply Temperature 58.8
Subcool 11°
Superheat 5°

[bmathews]

Hard to say without seeing everything and knowing what the outside temps are. Suction and liquid pressures seem a bit low. What does the unit say the subcooling should be?

[cuchulain]

I'll agree with bmathews in the pressures seem a bit off. it also dosen't sound like it is ramping up to second stage. hopefully when the tech came back out you told him that you had all these vents closed. Having them closed will affect the performance of the system, esp when a tech is checking for problems.

[egads]

Never cut of air flow to an Infinity system! (or most any system for that matter) The only reason to shut a supply register is because your grandmother is in the guest room and complaining. Otherwise let the system breathe.