trane xl16i 2 stage, high humidity

[smittyii]

every bit of advice you have gotten here has been very good advice. the 16i doesn't remove humidity as well as single stage systems but CAN be set up to work very well. 350 cfm and comfort R is crucial in this climate. get your guys back out asap. the drain vent can be capped with a 90 cent 3/4 pvc cap. it won't do anything to remove humidity tho. call your install company.

[bobl]

every bit of advice you have gotten here has been very good advice. the 16i doesn't remove humidity as well as single stage systems but CAN be set up to work very well. 350 cfm and comfort R is crucial in this climate. get your guys back out asap. the drain vent can be capped with a 90 cent 3/4 pvc cap. it won't do anything to remove humidity tho. call your install company.

Thanks - I saw you on contractor map so I think you are S. of Austin.

That's too bad about 16i - you are second person to mention this. Everything I could get my hands on says two stage is better at humidity control.

Thanks for your patience - I will have to have tech back again to lower speed more because change from 450 to 400 didn't really make much improvement, if any.

Take a look at my post above about tstat is this correct? i.e. how do I know if it is running first or second stage?

[smittyii]

Thanks - I saw you on contractor map so I think you are S. of Austin.

That's too bad about 16i - you are second person to mention this. Everything I could get my hands on says two stage is better at humidity control.

Thanks for your patience - I will have to have tech back again to lower speed more because change from 450 to 400 didn't really make much improvement, if any.

Take a look at my post above about tstat is this correct? i.e. how do I know if it is running first or second stage?

don't stress about it too much. the 16i needs to be tweaked to work well in this climate. i have seen happy customers with 16i systems , but in almost every case it took some tweakin to get them that way. i don't have the book in front of me, but tranes tstats are geared toward certain systems (i e comfort R). the fan needs to shut off soon after system shut off and run in lower speed at start. it can be done ,just be patient.

[lynn comstock]

Make certain that the new duct connections to the equipment are air sealed.
Make sure that old duct connections were not disturbed during the installation and leaking air in or out.
Fix the drain air leak.
Slow the fan to 350 cfm and other suggestions in post 12.

[bobl]

OK - thanks. Humidity was 63% in house this morning.

The service guy wasn't really interested in my observations - he said it is normal for high volume of air to come streaming out of drain line. No idea if this is true - it wasn't with previous unit. He also said 55% is what they recommend. I know 55% is not normal.

If anyone else has 16i and access to drain line it would be good to know if this is normal as well as how I can tell if the unit is really working as two stage or one stage.

This is complicated & expensive system not working well so I appreciate the help from experienced installers.

[beenthere]

Duct work may be undersized for 4 tons. Old unit may have only been 3.5 tons.
Air handler is probably not set up right.

Blower can be set to a slower speed. Which will improve your indoor RH.

[beenthere]

Just to help the OP understand. Your video shows a duel fuel setup where the heat pump coil is on the bottom (upflow) and you can see the p-trap that was installed. The upper drain connection (that uses the tee fitting) is for condensate from the high efficiency furnace which has its own internal trap. From his description its sounds like he has an ac coil on top of furnace and that the AC coil drain uses a 'tee' fitting. Just guessing.

Upflow furnace with the coil on the return?

Improper install.

[bobl]

Update: thanks to the excellent replies on this thread. Absolutely useful and great education for me and hopefully helpful to others in future.

Root cause found to be crossed wiring at outdoor unit. Tstat was signaling for compressor to run at low and turning fan to low. However, outdoor unit was not coming on until tstat signaled for high.

Now at 42% to 45% humidity. Doesn't come on very often, when it does it's on low - very gentle air flow. No problem hold temp at 78 at 100+ outside. No sticking to floors.

One observation: when the unit was running the fan w/o compressor we noticed that our normally blast furnace like upstairs was almost same temp as down stairs. It was dramatic change. This tells me that the classic upstairs/downstairs problem might be solved with a more continuous air flow. However, it would have to be done without humidity. It will take a few days to see how things are now that unit is working correctly.

I asked about comfort-r setting, tech said he didn't set it. He wanted to try things without it.

One last question - thanks for indulging me.

What the heck is comfort-r exactly? When unit is in comfort-r what does it do that is different than when it is not in comfort-r?

[freonr22]

You should have air streaming out of only your supply outlets. Air should be streaming in only through your return grilles.

I didn't see any model numbers so I've got make some assumptions but the variable speed blower can be set for several different configurations. You need to have someone knowledgeable from the installing company pay a visit and set up and/or confirm that the blower is set as follows:

1. Airflow set for a 4-ton system.
2. Airflow set for 350 CFM/ton
3. Comfort 'R' mode selected 'On'.

It's very likely that no matter which stage the outdoor unit is using, the airflow for the system is set too high. The variables are 3.5-5.0 tons, (yours is 4.0-tons) and from 350 to 450 CFM (Cubic Feet Per Minute). The faster the airflow, the less dehumidification you'll get. Comfort 'R' is a Trane patented method of enhancing 'short cycles' by restricting blower operation to 50% of full speed for 1-minute (slow airflow to allow the indoor coil to cool faster) followed by 7-1/2 minutes of 80% of airflow. That's all to assist in greater moisture removal than would otherwise happen.

Very detailed responses... nice!

[bobl]

Ack! I read that earlier and then completely pushed it out of my brain.

Perfect description. Thanks Skippedover and freon22.

[mayguy]

Get the Comfort-R turned on. That will get the coil colder, and help with the humidity control.

[catmanacman]

I always turn on the comfort r on the 16 I

[bobl]

Thanks very much for the replies - the tech didn't set comfort-r. The unit is running really well right now. Austin has lower humidity than most place in south, but right now it is like 102 to 105F outside so maybe its the heat not the humidity for a change!

You can read about our results with the unit here. We are so impressed right now, and it is one of those rare times things work better than you hope, I am afraid to mess with it!

http://hvac-talk.com/vbb/showthread.php?t=894702&page=2

My experience seems to show that two stage can work well even in hotter than h#ll Texas. Hope this technology comes down in price.

[lynn comstock]

I don't know why Comfort R is not the default setting on those variable speed air handlers. It should be. IMO.