XL16i & Comfort R Clarification

[motoguy128]

I read through the posts related to Comfort R and the XL16i. What I'm still not sure of is how the XL16i will operate if Comfort R is enabled on the dip switches and R is jumpered to O (The installer left it this way...but I had to set the dip switches) I sat next to the furnace with a stop watch to see if the unit was ramping up at the correct times. It definitely stays at 50% for 1 minute, but I'm not sure I witnessed it ramp up again after 7.5 minutes. I tried this in both cooling and heating (I had an ideal 60-65 degree afternoon for this test)

Is the second ramp profile disabled because the XL16i uses the BK terminal to call for 1st stage? I thought if O was prowered while BK was energized it would still drop the fan speed another 20%. So it would run at 60% then ramp to 80% on 1st stage and run 80% then 100% on second stage. Is this possible?, or will Comfort R not work at all on the XL16i unless its a communicating model?

Am I just not "hearing" the ramp up form 80% to 100%? How can I tell what speed the blower is set to?

I'm concerned that since I chose a larger 4 Ton indoor coil (Installer didn't advise against the match as the SEER rating was slightly higher) that it won't dehumidify well this summer, and I was hoping the ramping function was possible on thsi unit as advertised.

Can anyone clarify this please.

[motoguy128]

Any Trane guys out there that can shed some light on this?

[furnacemaninc]

you will notice the blower volume change more in the of cycle, if you have an xl16i and your equipment is on the large side, you might want to try setting your thermostat up so it cycles the y/lo / first stage cooling(60% cap) for a longer period of time before switching over to second stage(full cap). this will make your equipment use less electricity and maximize dehumidification.

[motoguy128]

you will notice the blower volume change more in the of cycle, if you have an xl16i and your equipment is on the large side, you might want to try setting your thermostat up so it cycles the y/lo / first stage cooling(60% cap) for a longer period of time before switching over to second stage(full cap). this will make your equipment use less electricity and maximize dehumidification.

Thanks for hte reply. Yes my equipment is on the large side for more heating capacity.

Since I have a IAQ thermostat, should I then use a CPH setting of 4 for the Hi stage and leave the Lo stage at 3 or even use a 2? I wonder if going as low as 2 might cause temperature swings.

What CPH setting would you recommend? I have both compressor stages at 3 CPH now.

I read before that using a higher CPH number for the higher stage would tend to cause it to stay in lo stage longer. My observations with the furnace operation tend to support this.

I did switch my fan to "auto" in the schedule for all periods so the coil will tend to drain rather than dry off and put the moisture back into the home..

[capecool]

There is a LED light on the ECM board. Count the number of blinks to indicate "delivered CFM". ON a 16i non-communicating model with comfort-r enabled it should stage the fan, but it should not go to 100% unless you are in a call for high cool. So to answer your question if you had a call for first stage cooling only you should observe what you did. 1st min fan on @ 50%. next 7.5 min fan on @ about 80%. Fan would not ramp to 100% until the call for Y2. This is how I understand the system to operate. I think with the TCONT402 thermostat there are some other fan options.

[motoguy128]

Thanks. So Comfort-R is only going to provide 50% speed in the first 1 minute and last 3 minutes.

[Silver06]

The TCONT402 is a neat thermostat. It is not programmable though, and you do need another wire to run from the BK terminal on the thermostat to the air handler/furnace.

That being said, it has many fan profiles, for turn on and turn off. You can set the 1st stage fan speed between 55-80% range for the 16i and 35 to 60% for the 19/20i.

You can also hook up a humidistat to the inputs on the thermostat and it will act like the Vision Pro IAQ, even for non-communicating XL16i systems.

I have one and really do like its flexibility.

[motoguy128]

The TCONT402 is a neat thermostat. It is not programmable though, and you do need another wire to run from the BK terminal on the thermostat to the air handler/furnace.

That being said, it has many fan profiles, for turn on and turn off. You can set the 1st stage fan speed between 55-80% range for the 16i and 35 to 60% for the 19/20i.

You can also hook up a humidistat to the inputs on the thermostat and it will act like the Vision Pro IAQ, even for non-communicating XL16i systems.

I have one and really do like its flexibility.

OK, now how in the world does it manage to do all this? Why can't you achieve the same with a couple relays in addition to the IAQ? Why is this possible on a lower end non-programmable thermostst, but not the higher end stat?

It sounds like functionally, the 402 "manipulates" the dip switch settings on the furnace control board. The fan speed for the compressor is dependant on the dip switch settings for SW1-4. I can do the same thing at the furnace control board, but I'm locked into a 20% drop from 1st stage to second stage and the airflow for both stages would get adjusted together. There's 12 speeds available for the 3 ton blower.

[Silver06]

It sends a pulse width modulated signal to the air handler/furnace BK terminal. I know its odd that a basic thermostat does this, but I traded it in for the TCONT803 that I originally got.

As far as I know, this is the only thermostat besides Ruud/Rheem's White Rodgers stat for the modulating furnace that has a pulse width output, beside commercial controls.

I'll see if I can scan the installer menu options and post them on here.

[motoguy128]

It sends a pulse width modulated signal to the air handler/furnace BK terminal. I know its odd that a basic thermostat does this, but I traded it in for the TCONT803 that I originally got.

As far as I know, this is the only thermostat besides Ruud/Rheem's White Rodgers stat for the modulating furnace that has a pulse width output, beside commercial controls.

I'll see if I can scan the installer menu options and post them on here.

Interesting. I assume then that the PWM ouptut doesn't interfere with the call for 2nd stage heating or cooling to a XL16i.

It really is suprising that Honeywell didn't include the feature on the EIM module. I wonder if it's an agreement with Honeywell so Trane customers are forced to upgrade a communicating unit to get that features in a programamble stat.

I suspect this capability will be available in future models down the road. I get the impresion that we are still in the infancy for utilizing vairable speed technology. Modulating furnaces have taken the first step. TXV's are a start, but as others mentioned, inverter drives on compressors would be the next along with direct communications between control boards being fully utilized. The thermostat with humidity control should look at the temeprature and humidity profile and determine what fan speed and compressor capacity is needed for the correct sensible and latent capacity.

[beenthere]

Silver06.

Don't repost that again.

[motoguy128]

I'll see if I can scan the installer menu options and post them on here.

I'll go to the Honeywell website and check it out. Thanks. THere's a fine line wiht what it OK ot post vs. what isn't in terms of data sheets and installation info to discourage DIY.