New Carrier 3 ton, 16 SEER HVAC and air handler issues

[tedkidd]

... Oh, my comfort numbers are more in line with Dans, 78f at 40rh, 76 at 45, need it cold for high rh, but it ain't what id call comfortable.

[CoastalWGSD]

What are the model numbers of the indoor and outdoor unit, what thermostat do you have? If its the variable speed airhandler I think it is, there are some adjustments to it.

Carrier 25HCB3 Heat pump/AC -outside
Carrier FV4 air handler under house in crawl space
I can't recall model number but the Thermostat is a Honeywell which raises questions for me as the variable speed air handler specifies a Carrier Thermidistat

[CoastalWGSD]

It ALWAYS reads 72 I have never seen it go up to 73, but it does come on and off throughout the day...I would say in the last week, it is at 72 and keeps running when temp outside is higher....
Soze of the house is 1800 square feet (ranch)

The HVAC rep tweaked the controls on the variable speed air handler and I don't know what exactly they did, but it sounded like he reduced air flow...

[beshvac]

Carrier 25HCB3 Heat pump/AC -outside
Carrier FV4 air handler under house in crawl space
I can't recall model number but the Thermostat is a Honeywell which raises questions for me as the variable speed air handler specifies a Carrier Thermidistat

That's only a 13 seer condenser with the fv002 or 003 airhandler which is 14 or 14.5 seer rated. it has controls to adjust the airflow for better humidity control, which is unknown from not knowing what thermostat.

[tedkidd]

1800 sf ranch, 3 ton. Sigh. That's a shame, when you were here earlier didn't anybody caution against over sizing? Did anybody recommend an Infinity system?

For reference, think your ranch is built better, worse, or about the same as a double wide trailer of the same size?

I have a client with such a residence with 1.5 ton heat pump. (BTW, we can on rare occasions hit 100f, and we get more sun/solar gain/longer days than southern folks.)

So humidity is likely to be a problem under all but hottest conditions because your unit cools faster than it dehumidifies. This bears repeating because people unfortunately want "cool quick" which is actually the opposite of comfortable cool. Over sized units cool faster than they dehumidify. Comfortable cool is slow, dehumidifying faster than cooling type of cool.

Probably need an edge thermostat to manage fan speed, that might help some. It can slow airflow across the coil, making it colder, making it pull more moisture. And maybe a cooler set point.

[tedkidd]

Finally, you may want to consider that all of the Carrier air handlers, except for one or two 'builders models', have ECM motors in them. These motors are intended to reduce electrical consumption but if installed in a high static duct system, can have the opposite result. So selecting a company that does a proper load analysis (Manual 'J') and duct evaluation (Manual 'D') before recommending a replacement system is in your best interest.

Skip is one of the most experienced Carrier guys out there. This suggestion was in your original request for help last spring.

Then in July you asked a product question about performance and comfort series, apparently confusing the two levels as one:

I wanted the Carrier Performance Comfort Series

When I looked into the above Model numbers, they seem to be the bottom or base models that Carrier has...

Also not sure if we would benefit from two stage...

(Guess THAT question is answered... Wonder if they'll let you upgrade.)

And now you are having problems that likely relate to NOT having a load calc or duct diagnostics. (Dollars to doughnuts a 2 ton system would have not only cost less, you wouldn't be having these troubles.)

What are we doing wrong not helping people avoid these train wrecks? What words are we not using? Seeing this over and over again is driving me nuts!

[CoastalWGSD]

Ranch is in no way built like a double wide...Tall crawl space, originally had 3 ton 13 seer and never had this issue! Concrete and brick foundation. LOTS OF WINDOWS, all checked for seal and checked out great. Did not have this issue at all for the 12 years we had the first unit!

[CoastalWGSD]

@beshvac -I didn't have the paperwork when I responded yesterday...Outside unit is 25HBC536AW3...Carrier Variable Soeed Air Handler is FV4...Honeywell VisionPro 8000 Thermostat...

[second opinion]

@beshvac -I didn't have the paperwork when I responded yesterday...Outside unit is 25HBC536AW3...Carrier Variable Soeed Air Handler is FV4...Honeywell VisionPro 8000 Thermostat...

Have the company come out and verify and document the airflow in cfm, temperatures inside and out humidity level in house,refrigerant pressures, supply and return temperatures and post that information. If the information is measured correctly it can be determined as to what is wrong with your system. Short run times and elevated humidity are directly related to over sized equipment.

[beshvac]

@beshvac -I didn't have the paperwork when I responded yesterday...Outside unit is 25HBC536AW3...Carrier Variable Soeed Air Handler is FV4...Honeywell VisionPro 8000 Thermostat...

25HBC is 15 Seer condenser and with FV4 002 to 006 size airhandlers it ranges from 14 to 15.5 Seer.

Just a wild guess from what you have posted earlier......you paid a pretty penny for that system from the company you ended up buying it from - to keep the owner on TV with his pretty little american flag bowtie ....Keep calling them back.

[tedkidd]

Have the company come out and verify and document the airflow in cfm, temperatures inside and out humidity level in house,refrigerant pressures, supply and return temperatures and post that information. If the information is measured correctly it can be determined as to what is wrong with your system. Short run times and elevated humidity are directly related to over sized equipment.

Suggest they upgrade the outdoor unit to 2 stage, at deep discount for your troubles.

[CoastalWGSD]

One of the operations managers called today and they are sending their go to guy out on Tues to do the load calc and duct diagnostics as well as run some other tests regarding air flow, fan speed, etc...Guy said that the stats from his readers (forget what he called them) this system is running perfectly in spec and that even the humidity level is good...Offered to change out thermostat with some other "top of the line" one that adjusts for humidity? even said that if after all this, he had no problem refunding me and pulling the system out...

[CoastalWGSD]

Oh and I am the one that insisted on a carrier...They typically suggest Lennox, Trane and or Rheem