high humidity

[just_opinion]

Hello i have a 3 ton r-410 condensor and 3 ton furnace and a 3 ton r410 coil with txv. The whole system is oversized by a ton for a 1,000 square ft hom in Houston. Could i change the condenser to a 2 ton r410 and have it work with the 3 ton furnace and coil? Thank You

1 ton over-size evaporator coil won't creat more humidity if it is setting up correctly.

To simple answer your question is "YES"

[high humidity]

can you lower the blower speed any more?

When I had my furnace checked out in Oct i had the Tech lower the fan speed to medium. When i asked him if i could lower it to low he told me the coil might freeze up. The fan speed at medium don't feel much lower than the high setting? Thank you

[high humidity]

1 ton over-size evaporator coil won't creat more humidity if it is setting up correctly.

To simple answer your question is "YES"

Hello and thank you for your reply, I am confused on the answer. 1 ton over-size evaporator coil won't creat more humidity if it is setting up correctly
Will it create less humidity if it is set up right? or would dropping the fan speed to low do just as good, if the coil does not freeze up.

[just_opinion]

Hello and thank you for your reply, I am confused on the answer. 1 ton over-size evaporator coil won't creat more humidity if it is setting up correctly
Will it create less humidity if it is set up right? or would dropping the fan speed to low do just as good, if the coil does not freeze up.

That is for the qualified technician to give you the solution. I don't mean to be rude.

It is very very easy to deal with sensible heat (dry bulb temperature). And I did emphasize the word very.

But when it comes to latent heat (wet bulb temperature). It is very difficult in the sense that you don't want to compromise the punishment that the equipment will take it it is not done properly

[tinner73]

i'd start with lowering the fan to low. if you don't have freezing issues.. problem solved. if freezing occurs then get the right size equipment.

[high humidity]

i'd start with lowering the fan to low. if you don't have freezing issues.. problem solved. if freezing occurs then get the right size equipment.

Thank you very much for your time, I will have the tech do it when he comes.

[just_opinion]

i'd start with lowering the fan to low. if you don't have freezing issues.. problem solved. if freezing occurs then get the right size equipment.

Now you see what I mean by compromising the unit when you are dealing with latent (humidity ) heat.

[high humidity]

Now you see what I mean by compromising the unit when you are dealing with latent (humidity ) heat.

Thank You very much for your help

[alex_in_fl]

See Teddybear's comment for 99% answer. The other 1% is to consider a two speed compressor. That will give you good humidity control.

[teddy bear]

See Teddybear's comment for 99% answer. The other 1% is to consider a two speed compressor. That will give you good humidity control.

Appreciate your support. But with low/no cooling load, single speed or two speed will not remove enough moisture to maintain 50%RH.
Another comment of slowing the fan to a lower speed, I tuned my old system to remove max latent. If I cooled below 74^F, the a/c coil would freeze. I did not cool below 76^F. A system slowed to the minimum air flow to remove max latant will freeze-up with cooling below a cvouple degrees below your lowest temperature. I needed 10 hours of cooling load to maintain <50%RH. If you are getting an air change of fresh air every 4-5 hours with 4 occupants, you should remove 50-75 lbs. of moisture everyday. Combining a properly set-up a/c with a good whole house dehumidifier makes this a piece of cake. Set the temperature and %RH you want forget it. Plus you can have the ideal amount of fresh air for indoor air quality. Lets keep the Ventilation in HVAC. Regards TB

[dash]

Thank You very much for your help

Tinner may be correct.Find a company that can test the static,use the mfrs. fan chart and set the air floe correctly,might make all or enough of the difference needed.


Post all the model numbers and someone with the fan chart can give you a better idea.

[motoguy128]

My home system that is a 2 ton condenser with a 3 ton evap, is only .01% different S/T than they same condenser with 2 ton evap.
.

How can I determine that data? I have a 4 Ton coil for my 3 Ton XL16i and I'm concerned I made a mistake and should have gone with a 3 Ton coil which only gave up 200 BTU of cooling and 0.25 SEER. I'm especially concerned about humidity removal in low stage which is about 2.2 Tons.

I read a study from the mid 80's that showed no correlation between face area of a coil and dehumidification. I suppose the lower face velocity of the larger coil balances the slighly higher surface temerature.

On the other hand, my old 8 SEER system was being supplied almost 500 CFM/ton of airflow and it still seemed to dehumidify pretty well. It's capacity was probably reduced as well from it's age, and the mismatched coil it had.

[motoguy128]

This might be a weird idea, but instead of a whole house dehumidifier, I wonder if you could use a heat pump to defrost the indoor coil on demand? I wonder if you could use the existing coil temperature sensors to do this? Or use the heat pump to add heat to the home when you've reached the setpoint, but you need further dehumidification. What issues would you have running the heat pump at high outside temperatures?