Carrier CNPVP3617ATAABAA-Central Air

[candee1988]

Hi...I had this unit installed 2 years ago and it keeps too much humidity in the air. Anywhere from 45-51%.

My old Trane didnt do this. The humidity was always around 35%.

What can I do about this?

I did change the cycling per hour to 6 I believe and that didnt help.

I was also reading that putting some tablets in where the condenser is would help with the smell but how do I take the cover off?

Thanks for all the help.

[ACtechGUY]

The model number you posted was for the evaporator coil. did the condensing unit(outside) get replaced at the same time?

Where in texas are you ? if you are anywhere near the coast , 45-50 % RH is doing excellent. Here in New Orleans That humidity level is as good as you get.

Tablets of any kind will not help your situation.

A/C 's remove moisture as a side effect of cooling a space.

The longer a system runs , the more moisture it will remove.

*If a system is oversized it will not run as long resulting in higher humidity levels. DID you increase the size of the system?

[candee1988]

Yes the outside unit got replaced as well.

The model # 24ACA436A300

No not on the coast...in west Texas near the Abilene, San Angelo, Midland area.

No the size was not increased.

Could it be due to changing from the old type of freon to the Puron?

Thanks

[ACtechGUY]

AHhhh.. HOT and not very humid.......

New furnace as well maybe (M#??)? If so then maybe the cooling fan speed should be dropped down one notch from high to med-high to help with dehumidification.

The new refrigerant is not the issue. Well, maybe it could be. 410a(puron) systems run a warmer evaporator coil compared to OLDER(15+ years) R-22 systems. Colder evaporator coils dehumidify better. Lowering the fan speed will make the coil colder.

But is the system charged correctly?? That could be an issue as well. Come to think of it there could be a pile of problems..........

It is real hard to troubleshoot a system without knowing system pressures and temperatures.

[candee1988]

Yes I got a new furnace also...model # 58CTA090

My Trane unit was probably 22-25 years old.

I have had the system checked several times and it is always OK. It has done it since day 1 and but I dont like that much humidity in the summer.

Can you tell me how to reduce the fan speed?

Thanks

[ACtechGUY]

One more important question.. What Thermostat? m# or name. I guess it is new as well?

The carrier website seems to be broken tonight , so I can't look up the tech info for that furnace . They often do upgrades on sunday nights.....

Changing fan speeds will involve changing DIP switch settings on the furnace control board. AND MAN!! ,, There are quite a few dip switches on those circuit boards. We definity need the carrier info. The furnaces also sometimes have a special plug that tells the furnace what size it is.(IT COULD BE WRONG)

I got to ask about the bad smell... is it a mold smell or something else? At 2 years old the system really hasn't had enough time to grow some of the nasty stuff that can develope in an ac system.( unless they did not replace any of the ductwork)

[candee1988]

The thermostat is new also...Carrier Comfort Touch-n-Go Programable # TC-PHP

I have the install instructions for the thermostat if that helps.

The duct work was not replaced. It does smell like mold, is not that bad just noticeable the more humid it gets. It didnt smell before the new unit.

Thanks

I forgot to add that the furnace # has a 14 after it...dont know if it means anything but thought I would add it.

Model # 58CTA090-14

[ACtechGUY]

The main place mold grows is in the plenum or trunk line duct(the duct after the evaporator coil). This should have been replaced with a new install. If you have mold at the level where you can smell it, then you may need to invest in a duct cleaning service.

We often change out plenums that are disgusting with mold and gunk when we install new systems. Yet there is no smell of the mold in the house, and our normal humidity levels are much higher than your unacceptably High humidity levels.

[candee1988]

Hummm...I thought they replaced all the tubes just right up to the ducts...I'm pretty sure they did.

So are you telling me the moldy smell is from the silver tube that i can see when I open the door to the unit, or is it from my ducts?

Are you going to get back to me tomorrow about changing the air speeds after you can get to the technical stuff?

Thanks for all your help.

[ACtechGUY]

Ok, this furnace is pretty basic. NO dip switches to alter.

To change the cooling speed , First turn off power to the furnace. next remove the coverplate hiding the blower and circiut board.

Now look closly at the circuit board. Find a black relay on the board marked "COOL". It will have a Black wire plugged into it. Next locate the two wires pluggged into the connectors marked "SPARE". Those wires will be yellow and orange.

The Black wire on the relay is the high speed of the motor

The Yellow wire is the MEDIUM-High speed of the motor

The orange wire is the MEDIUM-Low speed of the motor

To lower the speed just remove the black wire from the relay, Remove the Yellow wire from the terminal and reverse the two wires.

Your furnace fan will now run at the MEDIUM-HIGH Speed.

Put panels back on and turn power back on.

****If that speed does not help humidity levels enough, You may try The MEDIUM LOW SPEED .

ALWAYS!!!! PUT THE UNUSED MOTOR LEAD ON A "PARK" TEMINAL

!!!Changing the cooling speeds comes with a possible penalty

Some of your rooms may no longer get as cool as you like, If they are far (ductwise) from the furnace.

[candee1988]

Great!

I'll have a looky in the a.m. as its 105 here today.

Thanks

[ACtechGUY]

Let me know if you don't see the wire colors that I described . There is another "obsolete" manual that could be the right one for your furnace.

[candee1988]

Okey dokey...will you be on in the a.m.? Cause thats when I'm going to attempt it.

[ACtechGUY]

Sorry, I am out saving people from the heat until about 4pm

[candee1988]

OK...so I located the wires and changed the yellow and black.

There is no orange wire.

I did see a blue and red wire but that is on the heat part.

So I cant have any lower fan speed? Since I dont have an orange wire?

Also I have the thermostat to cycle 6 times an hour...is that OK or do I need to put it back to 4.

Another thingie...I have been using cheap pleated filters. Should I be using those or the really cheap spun fiberglass filters?

Anything else I need to know?

Thanks

[ACtechGUY]

You really don't want to and can't use one of the "heat" speeds.

Less cycles per hour will keep the system running longer, which may help humidity levels.

Any pleated filter is better than the fiberglass filters.

Have you ever taken temperatures of the air to see how well it is cooling. A new system will have at minimum a 18 degree temp difference between the return air plenum and the supply air plenum. If the system is not cooling correctly then it will never take out humidity like you want.

[candee1988]

The thermostat is set at 77. The temp of the air coming out of the vent closest to the unit is 60. The temp at the return air grill about a foot off the floor is 80.

Is that OK?

[ACtechGUY]

I take it that the system cycles on and off several times per hour? If so, things are not too shabby , my friend. That tells me that it is cooling as well as it could. If my math is correct, Your temp diffence sounds like 20 degrees. right? That is all you can ever expect to get.

I hope the fan speed adjustment helps your humidity problem.

I have A thought ...... if you had(before) an old mercury bulb thermostat before , you may have been cooling the house to a (IN REALITY) lower temp. Perhaps you should try lowering your temp setting on your thermostat.

REMEMBER, the longer an a/c system runs, the more humidity is removed from the air.

[candee1988]

I did lower the temp...and it does help some. Right now the humidity is at 43% which is a lot better than 50%. I'm going to adjust the cycling in a little while.

My previous thermostat was a programable one as well and they do run about the same temp...sometimes it will be 1 degree off.

I guess this is as good as it gets.

I want to thank you so much for your help.

Thank you   Thank you   Thank you!!!

[ACtechGUY]

You are VERY are welcome.

Although you should probably never visit the gulf coast if 50% indoor humidity is uncomfortable to you. WE kiss the ground when we have indoor humidity that low here. Most of our days are 70-85% humidity outside( all year round).

WOW, and today was extra bad too. 98 degrees :burning:with 90% humidity.:drowning: Yeah , It really sucked today , even for us.

[candee1988]

I think I could handle the humidity for a visit...I do like the ocean.

Yeah, I think you all were just a tad hot today...and here I was complaining that it was 105 today.

Thank you again,

Candee