Does Trane Comfort-R Work With Non-Trane Coil

[ramlam]

Today I had a Trane XV80 installed by a certified Trane Comfort Specialist dealer (it replaced my 22 year old Lennox furnace) and I am trying to confirm if the Comfort-R feature should be enabled or not since I don't have a Trane A-Coil. My A-Coil and AC compressor are both Lennox (the coil is about 5 years old and the compressor is 6 years old). The AC and the thermostat are both single stage (but the furnace is variable speed, 2 stage). There have been some excellent threads on Comfort-R and how to enable it (i.e. dip switches 5 and 6 on and jumper between Y and 0) and I have confirmed that it is not enabled (i.e. 5 is on, 6 is off, no jumper between Y & 0). The sales guy sold me on the benefit of the Comfort-R feature and I would like to utilize it if I can. The reason's I have doubts if I can are:
1. I just looked at the sales brochure for the XV80 and it says "If you have a Trane central AC our variable speed furnace will you more comfort during the cooling season because of the greater humidity control with our Comfort-R feature"
2. The installer didn't enable, i.e. either he did this on purpose because it won't work with my AC or he didn't know any better.
3. I read in one of the posts on this site that you could use another companies coil as long as it had something called TVX (not sure I got the letters correct and don't know what this is).

Can anyone enlighten me if I can use Comfort-R with my Lennox coil. Any help is greatly appreciated. Also, the information on this site is fantastic and has been extremely helpful.

[mayguy]

Yes, you can have Comfrot-R on any brand A/C system.

Get a two stage t-stat on that nice two stage furnace as well.

[ramlam]

Thanks for the information. A follow-up question on the t-stat, does it require additional wires as compared to a single stage t-state. I was told it did and that it would cost several hundred dollars to run the additional wires.

[mayguy]

Yes, an extra wire is needed for two stage use.

If you can't get new wire fished up, then look at the Honeywell VisionPro IAQ t-stat, that stat only use 3 wires, and you would be able to use the dehuimd mode in cooling.

[amtec services]

You need to be sure about that! Comfort R can cause liquid flood back. Not even all Trane condensers are rated for Comfort R. Wait for Mark Bieser to speak up. He's got the skinny on Trane. I do Am Stand.
...................AmTec

[ramlam]

I did find a thread that says your coil should have TXV. What is TXV and how can I confirm if my Lennox coil has it? Here's the thread: http://www.hvac-talk.com/vbb/showthread.php?t=84948&highlight=comfort-r

I want to confirm the recommendation on the Honeywell VisionPro IAQ t-stat. This will utilize my two stage furnace feature and also has a dehumidification feature to boot. Is this correct? Also, if it only requires 3 wires why would you ever want to fool with the trouble and expense of adding a 4th wire if you get the same results with 3 wires?

Thanks again for the great information.

[mayguy]

85

You may not see it since it maybe inside the coil case. is the coil case a box that you can remove covers? Do you have a model number on it as well?

The IAQ t-stat just came out, and some are not aware of it yet.

[ramlam]

Unfortunatly the coil case does not have a box that you can remove. The Lennox model number is C23-51-1. It is a 4 ton coil. Can you tell from this info if it has TXV

Follow-up questions on the t-stat.

1. Is the IAQ the only one with 3 wires? I also noticed the Honeywell VisionPro 8000 that looks like it is the same as the IAQ but less expensive. Does the 8000 require 4 wires and is there any diff between it and the IAQ?

2. Does either the IAQ or the 8000 require a professional to install it, i.e. is the wiring more complicated than a normal 3 wire thermostat? I noticed it comes with an EIB and it looks like that could be complicated to setup.

Thanks again for your help

[mark beiser]

You can use the Comfort-R function of the blower with any manufacturers AC, so long as the indoor coil has a TXV.

The Lennox C23-51-1 coil is factory equipped with piston metering, a TXV would have been a field installed option. If a TXV is installed, it is inside the case of the coil, so no way to tell just by looking from the outside.

[ramlam]

Mark - Thanks for the information. It sounds like I don't have a TXV because I never specified it from the dealer who did the install (6 years ago), he didn't mention it, and it's not mentioned on the ticket from the install. To maybe help comfirm that I don't one, I have attached a partial pic from when they installed my furnace that shows the a-coil exposed, but I think the TXV is still not visable, but thought you might see something else that would indicate if it was or not.

What would or could happen if I were to use Comfort-R without having TXV? One of the bigger selling points for me for this unit was the Comfort-R feature. I live in St. Louis and it gets very humid in the summer. Also, do you think I would get the same benefit if I had a VisionPro IAQ installed?

Thanks again for the information.
93

[mayguy]

I agree what Mark said.



Follow-up questions on the t-stat.

1. Is the IAQ the only one with 3 wires? I also noticed the Honeywell VisionPro 8000 that looks like it is the same as the IAQ but less expensive. Does the 8000 require 4 wires and is there any diff between it and the IAQ?

The IAQ uses "commucation" to the board that mounts on your return, and all the wires that would of gone up to the t-stat now goes to the this board. On a two stage set up with common you will need 6 wires.

The IAQ does alot more than just two stage.
-Two stage heating
-Two stage cooling
-Dehumid if you have variable speed blower or HRV
-Humidify if you have humidifer
-Fresh air if you have a fresh air damper



2. Does either the IAQ or the 8000 require a professional to install it, i.e. is the wiring more complicated than a normal 3 wire thermostat? I noticed it comes with an EIB and it looks like that could be complicated to setup.

Thanks again for your help

You should get a pro in to wire both t-stat to get the full warranity from Honeywell. The 8000 overall is easier to do than the IAQ. The IAQ may have to jumper wire to control dehumid or humid.. ect.. Can be complex for an avg home owner.

[ramlam]

Thanks for the information. Given that it looks like I can't use Comfort-R, my only option appears to be to use a VisionPro. I will plan to talk to the guy who put in my furnace about getting it installed. I wish he would have verified if I could use the Comfort R before selling me on it. Oh-well.

Thanks again.

[4l530]

Doesn't look like there is a TXV on that coil.
The TXV is important when you have a feature like Comfort R because the TXV is a variable orifice. It will throttle back to match the refrigerant flow to the airflow. Without a TXV you will get too much refrigerant flow to where the refrigerant can't boil off well enough in the coil, resulting in liquid entering the compressor ('floodback' or 'slugging'). Eventually such a condition will destroy the compressor.
Perhaps you could have a TXV installed. It wouldn't be that expensive.

[ramlam]

Thanks for the info. I will ask the guy who installed it to give me a price on installing a TXV

[mayguy]

Yeah, I don't see TXV on the coil as well. As 41530 Said, you can get a TXV installed, then you can get a full use of the Comfort-R, Dehumidity control on IAQ, and up your SEER rating on the A/C.

[mark beiser]

Hmm, thats not the coil Davenet showed me when I checked that model number, lol.

The coil you have definitely does not have a TXV installed. On that coil the TXV will be external to the coil where the liquid line connects.

[mayguy]

Did you get a TXV on this yet?

[ramlam]

Not yet. I have been working with the contractor to get the IAQ T-stat installed and waiting on the sales guy to get back to me with the cost of the TXV. He is pretty clueless and I am not even sure he really understands what the TXV is and why I need it. He said he is checking with his Tech's and will be getting back to me. I figure I don't need it until I need A/C, which is several months from now, so I am not in a big hurry.

[esornivram]

You can use the Comfort-R function of the blower with any manufacturers AC, so long as the indoor coil has a TXV.

The Lennox C23-51-1 coil is factory equipped with piston metering, a TXV would have been a field installed option. If a TXV is installed, it is inside the case of the coil, so no way to tell just by looking from the outside.
all my field install TXV's are on the outside of coil, for access and super heat adjustments, i seal them from condensation issues via foam, or mule tar, sticky foam,

here is an pic from an commercial install, yes its inside the case, cause there is room, however on residential i put them outside, your txv will be small than this but of similar shape and construction.

lastly buy an extended warrenty on the furnace, parts for it are out of sight if you dont have extended warrenty. they are available direct from trane. its worth double the cost of it if the furnace ever breaks down.

[ramlam]

Thanks to everyone for the great information in the previous posts. I have 3 follow-up questions that I hope you can help me out with:

-My installer gave me a quote and said that the work will take around 2 1/2 hours, mostly due to the fact that they have to remove all the Freon in the system and then have to replace it after the valve is installed. They also said they have to wait until it at least 60 degrees outside. Does all this sound consistent with what you think is involved with this effort. It's seems a little more complicated than what the earlier posts made it sound like.

-The installer also said that I shouldn't use the dehumidify feature on the Provision IAQ I just had installed without the TXV for the same reason I shouldn't use the Comfort-R without it, i.e. it could damage the compressor. Is this correct? I was thinking I would still be able to use the t-stat’s dehumidify feature without the TXV.

-What is your opinion on how noticeable the Comfort-R and/or the T-stat's dehumidify feature will improve the comfort of the house, i.e. do you think it's worth the trouble of getting the TXV installed? I live in St. Louis, which gets very humid in the summer and I have a two story house where the 2nd floor tends to get sticky and stuffy in the summer. Do you think I should definitely feel the difference?

Thanks again for everyone’s help and assistance. It is very much appreciated.

[4l530]

#1. I can see it taking 2 1/2 hours, sure. The system will have to be opened, pressure tested and vacuumed. Depending on whether your condenser has a reciprocating or scroll compressor, it may be possible to 'pump down' the refrigerant, rather than remove it entirely. I'm not sure why it would have to be re-charged with virgin refrigerant (if that's what you meant) but the refrigerant charge will most likely have to be adjusted for the TXV. I advocate having it be at least 70 degrees to check the charge accurately. I guess it does sound kind of complicated, but it's not, really.
#2. This is correct, I believe they both work by reducing fan speed and thus airflow. Liable to cause problems without the variable metering of the TXV.
#3. I'd say it would be worth it if your climate is very humid, not just from a comfort point of view, but the system will also run more efficiently. If you can lower the humidity, you can maintain a higher temperature in the home and feel comfortable with this higher temperature. I would say the difference would be noticeable, in terms of both comfort and economy.

[mayguy]

I agree with the last post..

It will be worth the better comfort adding the TXV, and get the full use of your variable speed in Comfort-R and the IAQ's dehumid control.

[aircooled53]

I would pay to have unit pumped down and piston removed and txv supplyed by Lennox. As for your comfort settings better have installer or serviceman check to insure the dip-switches are set for correct tonnage and cfm for cooling and heating also.

1
2 tonnage

3
4 cfm cooling

5 on
6 on Comfort-R (enhanced mode)

7
8 cfm heating


But , DO NOT try and set these yourself, could cause damage if not set properly.. Call your contractor back.

[t527ed]

charging by lennox approach method they only need 60deg outdoor temp. saw model of coil but not outdoor unit. if switching to txv, unit may need to have start kit installed. any 6 yr old unit should be able to be pumped down and freon reused.

[ramlam]

Thanks again for all the responses. Some additional questions/comments:

-The installer probably said they would reuse the Freon and I didn't listen close enough. I will confirm this with him.
-Do you have to remove the piston? Earlier posts said that they would be able to just add the TXV to the outside of the A-coil and not have to get inside the unit. There is no access panel and they would have to remove the sheet metal to get at the inside of the unit, which I think would add to the cost and complexity of adding the TXV. Do you have to get to the inside of the unit to add the TXV?
-Will the dehumidify on the IAQ T-stat work with the Comfort-R feature? Seems like they are doing the same thing and will conflict and confuse each other.

[mark beiser]

They have to get into the coil to remove the piston. They may also be using a TXV that has fittings so it connects where the piston used to be.

Comfort-R is a function of the blower based on time, it will do it every time the system cycles on in the cooling mode if all of the correct terminals on the furnace control board are receiving control voltage.
The dehumidification function of the IAQ thermostat is independent of Comfort-R and will limit the system to 80% of maximum airflow while dehumidification is needed.
There is no conflict between the two.

Be sure they cut the W14 jumper on the furnace control board and install a jumper wire between R and O, or Y and O, on the furnace control board.

[ramlam]

Mark,

Thanks for the reply. What are your thoughts on using the IAQ dehumidfy feature without a TXV? Will it cause the same problem as using the Comfort R without the TXV? Based on the prior posts it sounds like adding the TXV can be pretty involved and costly, especially in my case where they will have to remove the sheetmetal/ductwork right above the furnace to get at the a-coil? What are you thoughts on how hard this should be given my situation? Thanks for all your help in the prior posts.

[t527ed]

if the plenum was made properly they will not have to open anything to install txv. on that coil piston is right behind the nut where liquid line is connected. remove piston, install txv. what is model # outdoor unit?

[mark beiser]

As t527ed said, if they installed it properly, there should be a way to access the coil. If they didn't, you will need access to it at some point anyway, may as well have them cut into it now and make a proper access panel.
IMO, piston metering is garbage, get the TXV installed.

You need the TXV for the dehumidification mode due to the lower airflow. Without the TXV you run the risk of flooding liquid refrigerant back to the compressor when the thermostat is calling for dehumidification.

[ramlam]

The model number of the outside Lennox unit is H529-048-1P. It is supposed to be an 11 seer and it was installed in 2000.

I have also attached a few pic's of the outside of the a-coil and perhaps you can tell if area where the hose goes into the A-coil is a removable panel. It does have screws on it, but I can't tell if they are for an access panel or if they serve some other purpose. Any help or thoughts would be appreciated.

[mark beiser]

Well, turns out that the coil doesn't have to be opened up at all. They just need to get a TXV with the correct fittings and it will install external to the coil in place of the piston that is in the fitting where the liquid line connects.
http://www.markbeiser.com/HVAC/randomstuff/txv.jpg

[ramlam]

That sounds great! Does it still seem like a 2 1/2 hour job? I am assuming it still requires them to pump down/remove the freon, which I guess takes awhile. I really just want to make sure I get a fair quote and not taken. Thanks a lot for the information. You and everyone who has responded in this thread has been great and extremely helpful.

[esornivram]

if the condenser has valves on both lines that seal well, then all you have to do is pump the freon into the condenser coil. that saves time, however biggest time consumer is the vacuum on the line set after the install. and 2.5 hours is an fair realistic quote. make sure they insulate the discharge line after the txv, it will be cold and sweat alot if they dont, you will have problems otherwise

[t527ed]

2 1/2 sounds kind of long, pumping down is fast, changing valve is easy. replacing drier and proper vacuum will take a while.


hs29-48 listed as a scroll compressor so start kit not required.

[4l530]

Pumping down a scroll doesn't always work out too well

[ramlam]

Mark, you noted on the picture you attached of where the TXV is installed that no brazing is necessary. Does that mean they wouldn't have to install a new dryer? Is what's involved basically to pump down the system into the outside unit, unscrew the nut you circled, put in TXV valve, reinstall the nut, put Freon back into system? The vendor I received the quote from said they would remove and replace the dryer as part of the process, which appears to require welding/brazing. Would this add significantly to the amount of work required?

[aircooled53]

Mark, you noted on the picture you attached of where the TXV is installed that no brazing is necessary. Does that mean they wouldn't have to install a new dryer? Is what's involved basically to pump down the system into the outside unit, unscrew the nut you circled, put in TXV valve, reinstall the nut, put Freon back into system? The vendor I received the quote from said they would remove and replace the dryer as part of the process, which appears to require welding/brazing. Would this add significantly to the amount of work required?

You have to pump down the system, back-off fitting on discharge line, remove piston from line; install correct sized TXV. Tighten and secure sensing bulb to suction line, install external equilizer to suction line fitting.

Go back to outdoor unit, remove liquid line drier, install new one; with purge of nitrogen while welding it in,vacuum to 500microns. Open valves and charge system by sub-cooling .Check superheat and T.D... And collect from customer.:D

[ramlam]

Aircooled53, thanks for the detail explanation. It appears that the drier in the quote I received referred to the one on the outside unit and not the one next to the coil.

Earlier posts have indicated that changing the TXV is an easy/simple operation, but sounds pretty involved. Also sounds like the quote I received was appropriate, but seems like a lot, i.e. it's more than 1/2 the cost of what I paid to get the replacement a-coil installed a few years ago.

Thanks again for information and help.

[t527ed]

Aircooled53, thanks for the detail explanation. It appears that the drier in the quote I received referred to the one on the outside unit and not the one next to the coil.
:eek: :eek:


should only be one drier, if there are 2 they should both be removed and 1 new one installed.

it is not a big job as far as jobs go but it needs to be done right.