# Trane XV90 cfm question



## key1cc (Nov 21, 2008)

lyonkster said:


> I have a question about Trane XV90, model TUY100R9V4W, which my sister had installed at her house by a local contractor. They did a pretty good job with the install, although I did have to mastic and tape some loose/open joints in the ductwork.
> 
> The question I have is regarding CFM - I was trying to figure out if the unit was running on stage 1 or 2, by looking at the flashing green LED. The instructions say that the LED flashes once per 100 cfm (commanded, not necessarily delivered), which is the same thing that my Goodman furnace does. But whereas my Goodman flashes 16 times at 1600 cfm and then shuts off for a few seconds before starting again, the Trane's green LED flashes continuously, with an occasional flash of the red LED.
> 
> ...


We have quite an interesting dilemma. I say "we" because after reading your post I went down to the basement to count my flashing lights. I have a trane XV95 and similar to you I counted 21 green flashes about 1 per second and the sequence ended with the quick double red flash. My unit is currently in the fan-only which is 640 CFMs.

Key1


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## key1cc (Nov 21, 2008)

Being the scientist that I am I decided to conduct a further experiment. I cut my heat on (which is 1000CFM) and did a recount. This time the greenlights flashed much faster (about twice as fast) and they flashed 42 times before the red light came on......not sure what it means yet but we are at the right place to get it figured out...
Key1


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## key1cc (Nov 21, 2008)

ok here is what my installation instructions have to say about it.

It is the intergrated furnace control status light.

Green light flashing slow---Normal--No call for Heat
Green light flashing fast ---Normal--Call for Heat

Any other scenario with the red light flashing indicates an error code. The error is identified by the number of red flashes from 2 to 10 or a constant red on light.

No mention about CFMs being indicated by the number of green flashes..

Key1


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## lyonkster (Nov 24, 2008)

key1cc said:


> No mention about CFMs being indicated by the number of green flashes..


Hey Key1,

I've been hoping you'd chime in, given that you are a Trane owner! .

What I am going by regarding the cfm is a note (Note 6, if it helps) in the Service Facts section, specifically the Schematic Diagram Notes, which states: 

"Green Light (CFM) flashes once per 100 cfm command".

But based on your and my observations, that seems to not be the case (?).

Leon


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## key1cc (Nov 21, 2008)

lyonkster said:


> Hey Key1,
> 
> I've been hoping you'd chime in, given that you are a Trane owner! .
> 
> ...


I did not realize that was you with your new alias :laughing:
Have'nt seen you on that other site lately.
I found the "flash per 100 CFM command" statement you referenced.
I recall looking at it during cooling and it was accurate. I will look into it and see whats going on this weekend.

Key1


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## lyonkster (Nov 24, 2008)

key1cc said:


> I did not realize that was you with your new alias :laughing:
> Have'nt seen you on that other site lately.
> I found the "flash per 100 CFM command" statement you referenced.
> I recall looking at it during cooling and it was accurate. I will look into it and see whats going on this weekend.
> ...


Yup, it's me, incognito - haven't been on the other site as I have been trying to get a life outside of HVAC . But this thing with my sister's system puzzled me.

She doesn't have an AC, just heat, so if the LED only works for cooling, I am out of luck. The only reason I opened the can of worms is that it seems to blow very hard through the vents, more than I would expect on stage 1, so I am trying to figure out which stage it's running on. The thermostat is wired for 2 stage, so I would think it should be running on stage 1, but would like to confirm. On my next visit there, I am bringing my Dwyer with me, to really let the worms out... :bangin:


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## key1cc (Nov 21, 2008)

lyonkster said:


> Yup, it's me, incognito - haven't been on the other site as I have been trying to get a life outside of HVAC . But this thing with my sister's system puzzled me.
> 
> ........... so I am trying to figure out which stage it's running on. ....


If she has a Trane TC802 or TC803 Tstat it is very easy to add a jumper wire so that a red light comes on at the tstat everytime there is a call for stage 2. Mine was wired that way until I figured out 
I did not need stage 2 and disabled it. Since I run my blower 24/7 I now have the tsat wired so the red light comes on whenever there is a call for heat (stage 1). 
Of course I confirmed the airflow change by measuring static pressure with the Dwyer (Best Hvac tool a DIY'er could have in my opinion :yes.

Key1


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## JohnH1 (Jan 9, 2009)

You only count the green flashes for example 12 flashes then a pause then 12 flashes again is 1200 cfm it can also give a quick 1/2 flash to show a additional 50 cfm. It has nothing to do with the being inbetween the red flashes. It shows cfm in both heating and cooling.
If you want to check just the 1st stage only. Disconect the T-stat from the furnace and jumper the R and W1. This will run the 1st stage only. anfter you check the 1st stage then wile the 1st stage is operating add another jumper from the W1 to the W2 and it will then go into 2nd stage. 

John


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## key1cc (Nov 21, 2008)

JohnH1 said:


> You only count the green flashes for example 12 flashes then a pause then 12 flashes again is 1200 cfm it can also give a quick 1/2 flash to show a additional 50 cfm. It has nothing to do with the being inbetween the red flashes. It shows cfm in both heating and cooling.
> If you want to check just the 1st stage only. Disconect the T-stat from the furnace and jumper the R and W1. This will run the 1st stage only. anfter you check the 1st stage then wile the 1st stage is operating add another jumper from the W1 to the W2 and it will then go into 2nd stage.
> 
> John


Thanks for chiming in.
How do I explain my 21 flashes on fan only and 42 flashes on heat?
Key1


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## lyonkster (Nov 24, 2008)

JohnH1 said:


> You only count the green flashes for example 12 flashes then a pause then 12 flashes again is 1200 cfm


John,

That is how my Goodman works - it flashes, then has a definite pause. But on the Trane, there is no pause, just an occasional red LED flash, with about 22 green LED flashes in between. SInce I know it cannot be running at 2200 cfm, I am at a loss as to what to do with the green LED...



> If you want to check just the 1st stage only. Disconect the T-stat from the furnace and jumper the R and W1.


I may end up reverting to doing that, to at least determine which stage it's running on. Thanks! 

But I am still puzzled by the green LED behavior.


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## JohnH1 (Jan 9, 2009)

I believe you are looking at the wrong green light. Look on the lower right hand corner of the board. It may be diffacult to see through the peep hole. You may need to remove the blower door and manualy hold the door switch closed to see it.


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## lyonkster (Nov 24, 2008)

JohnH1 said:


> I believe you are looking at the wrong green light. Look on the lower right hand corner of the board. It may be diffacult to see through the peep hole. You may need to remove the blower door and manualy hold the door switch closed to see it.


Ah, I was wondering about that - my Goodman green light is also very inconveniently located relative to the peep hole (do they do that on purpose???). OK, I'll have to wait till the next time I visit my sister to investigate further, unless Key chimes in before that and confirms that there are two green LEDs .


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## beenthere (Oct 11, 2008)

The green LED at the red LED is a status light. Slow flash, normal operation no heat call. Fast flash, normal operation heat call.

Not a CFM light.

As John said, look lower and to the right.


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## key1cc (Nov 21, 2008)

JohnH1 said:


> I believe you are looking at the wrong green light. Look on the lower right hand corner of the board. It may be diffacult to see through the peep hole. You may need to remove the blower door and manualy hold the door switch closed to see it.


You are correct I was looking at the incorrect light. I was looking at the one through the sight glass which I identified back in post 4 and Beenthere confirmed in post 14 as a status light. I did not realize there was a 2nd green light. I just checked and it is in the lower right corner as stated. I had to open the door and bypass the safety autoshut-off to see it operate. 

Now for the results.
First when I cut my heat on I get 10 solid green flashes then 1 quick blink (I guess to indicate it is slightly more than 1000CFM.) So that part works great since according to my settings and my measurements I should be pushing around 1006 CFM.

Now here is where it gets a little tricky.
First the background: I currently have my cooling set to run at 80% of the dip switch setting speed which is currently 80% of 400 CFM/ton or 320 CFM/ton. I have a 4-ton so I get 1280 CFM. According to my static pressure readings when I run in fan-only I get 50% of my cooling speed or 640 CFM, which is what I would expect since my service facts documents states that the fan is set up to run at 50% of the cooling speed. Now here is the interesting part. The green light blinks 8 solid times suggesting 800CFM (not 640CFM like I expected). My question is, is the green light reacting to my dip switch settings or does it actually monitor actual airflow?

Key1


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## JohnH1 (Jan 9, 2009)

Now here is where it gets a little tricky.
First the background: I currently have my cooling set to run at 80% of the dip switch setting speed which is currently 80% of 400 CFM/ton or 320 CFM/ton. I have a 4-ton so I get 1280 CFM. According to my static pressure readings when I run in fan-only I get 50% of my cooling speed or 640 CFM, which is what I would expect since my service facts documents states that the fan is set up to run at 50% of the cooling speed. Now here is the interesting part. The green light blinks 8 solid times suggesting 800CFM (not 640CFM like I expected). My question is, is the green light reacting to my dip switch settings or does it actually monitor actual airflow?

Key1[/quote]

The only avalable settings are 350 / 400 or 450 cfm per ton. You may be reffering to the comfort R setting Re: the 80% air flow.Or do you have a humidistat that drops the blower 20% durring high humidity situations. If you are a 4 ton system at 400 cfm per ton 50% of that is the 800 cfm you are running. Sounds like it is operating ok.


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## beenthere (Oct 11, 2008)

What jumper are you uing to get 80% air flow in fan only?


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## key1cc (Nov 21, 2008)

beenthere said:


> What jumper are you uing to get 80% air flow in fan only?


I don't have my log book at work so I am am going by memory but prior to cutting the BK jumper my static was ~1.1 cooling and ~0.53 on the "fan-only" setting....which is 50% of cooling (Dips were set at 400 CFM/ton). After I cut the BK jumper my static dropped on cooling to ~0.77 as expected since the airflow is 80% . Also my static dropped on "fan-only" to ~0.38 (from 0.53) which I beleive is 50% of the 80% (or 40%).

If I want the "fan-only" to run at 80% (same as cooling) I simply jumper Y-G.

Key


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## beenthere (Oct 11, 2008)

Ok.

I thought you were talking aout a dip switch jumper I didn't know about.


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## key1cc (Nov 21, 2008)

JohnH1 said:


> The only avalable settings are 350 / 400 or 450 cfm per ton.


 
Actually there are more settings for those in the know 

See the attached Trane Pocket guide.

Key1


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## beenthere (Oct 11, 2008)

I have that guide, and the other one, or back side of it.

Somewhere.


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## JohnH1 (Jan 9, 2009)

If you are trying to better controll the constant air flow. I use the TCONT402 with my XV90. It has a BK termonal that you can choose anywere from 35% to 100% air flow.


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## key1cc (Nov 21, 2008)

JohnH1 said:


> If you are trying to better controll the constant air flow. I use the TCONT402 with my XV90. It has a BK termonal that you can choose anywere from 35% to 100% air flow.


I know......I only found out they existed after I purchased the TCONT803. Also, the 402 is non-programable....not sure why they took the "35-100% airflow" flexibilty out of the supposedly higher scale programable versions like the 803. :001_unsure:
Key


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## WhatWasThat? (Apr 26, 2009)

key1cc said:


> Of course I confirmed the airflow change by measuring static pressure with the Dwyer (Best Hvac tool a DIY'er could have in my opinion :yes.
> 
> Key1


I think I need to get one of those ... _(& this scares me to ask this $$_) how much do these cost?
Whew! I made it. Glad it's DIY. 

I've read some of your HVAC threads. In fact we've conversed :thumbup:
.


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## beenthere (Oct 11, 2008)

key1cc said:


> I know......I only found out they existed after I purchased the TCONT803. Also, the 402 is non-programable....not sure why they took the "35-100% airflow" flexibilty out of the supposedly higher scale programable versions like the 803. :001_unsure:
> Key


Probably a cost issue.


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## key1cc (Nov 21, 2008)

WhatWasThat? said:


> I think I need to get one of those ... _(& this scares me to ask this $$_) how much do these cost?
> Whew! I made it. Glad it's DIY.
> 
> I've read some of your HVAC threads. In fact we've conversed :thumbup:
> .


I guess you have a different identity on HVAC-Talk. Quite a few people like to have a different identiy for some reason. Not me and BT though :no:. 
Here is the link to amazon. When I purchased it it was $60 bucks....price has gone up to $78 through Amazon (I suspect you can find it cheaper elsewhere). 
http://www.amazon.com/Dwyer-1-0-Wc-...f=sr_1_14?ie=UTF8&s=hi&qid=1240755113&sr=8-14

Don't forget the Static pressure tip....you will need that also.

Here is the link for the A303 tip 
http://www.amazon.com/s/ref=nb_ss_h...&field-keywords=static+pressure+tip&x=15&y=24

Key1


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## beenthere (Oct 11, 2008)

If he lives in MD, I think I know who he is on the other site.

I think I edited a few of his post.


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## key1cc (Nov 21, 2008)

Hey, BT
on another note. Do you know of any issues with me using pvc for my fresh air intake instead of metal duct? no one is answering me (so far) on the other site...


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## beenthere (Oct 11, 2008)

Only question would be if it is large enough for the air volume you need.

And you might have a hard time finding a damper set up for it.

PVC is used as an under ground duct(and on some high velocity systems), so no harm in using it.


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## key1cc (Nov 21, 2008)

beenthere said:


> Only question would be if it is large enough for the air volume you need.
> 
> And you might have a hard time finding a damper set up for it.
> 
> PVC is used as an under ground duct(and on some high velocity systems), so no harm in using it.


Thanks for the feedback.
I could use a 6 to 4 inch reducer and connect 6 inch metal duct to 4 inch pvc inside the house and put the damper in the 6 inch metal. My concern is that 4 inches might not be quite enough since according to my ductuputer it will flow less than 1/2 the air of 6 inch duct at my static pressures..
I have been unsuccessful finding suitble outdoor 6 inch pipe.....
Key1


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## beenthere (Oct 11, 2008)

How much air it will bring in will depend on how much leakage your house has.

Ductulator isn't good for figuring out how much air a fresh air intake will move.

At a .15 return static. It could be bringing in 32CFM, or 60CFM.
Depending on the pressure in the house.

Open the front door and it will bring in more then with the door closed.
At 0°F outside temp, and 70°F inside temp, it will bring in more then when its 50°F outside and 70°F inside.

Turn on the dryer and bathroom exhaust fan, and it CFM will also increase.

Ductulator tells you CFM for X pressure loss(FR).


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## lyonkster (Nov 24, 2008)

key1cc said:


> Here is the link to amazon. When I purchased it it was $60 bucks....price has gone up to $78 through Amazon (I suspect you can find it cheaper elsewhere).
> http://www.amazon.com/Dwyer-1-0-Wc-...f=sr_1_14?ie=UTF8&s=hi&qid=1240755113&sr=8-14


Here is one of those cheaper places that Key probably refers to, about 1/2 price of Amazon:

http://cgi.ebay.com/Dwyer-Magneheli...hash=item190254245619&_trksid=p3286.m20.l1116


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## key1cc (Nov 21, 2008)

beenthere said:


> How much air it will bring in will depend on how much leakage your house has.
> 
> Ductulator isn't good for figuring out how much air a fresh air intake will move.
> 
> ...


..Not the ductulator.....My software is called Ductuputer and works great. When I initially downloaded it, it came with a 15 day free trilal. After using it I ended up buying it for the requested $15. It is simple but it works great. I just tried to pull up a link at amazon (see below) and it states that it is currently unavailable... 
i probally still have the zip for the free trial if you want it.

http://www.amazon.com/Ductuputer-do..._1_1?ie=UTF8&s=software&qid=1240768311&sr=1-1

Key1


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## beenthere (Oct 11, 2008)

Thanks.

I have several duct sizing programs. That I have used over the years.

For some reason, I still do it long form though.


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## WhatWasThat? (Apr 26, 2009)

beenthere said:


> If he lives in MD, I think I know who he is on the other site.
> 
> I think I edited a few of his post.


:thumbsup: Ahhh, you'll probably realize who I am if I post some questions in this Forum, which I plan to do, ha.

And certainly there is legitimate reasons for the other Forum to edit as they do. No doubt about that. That's reasonable.

But I just now found this site after doing a web search on a furnace model.
And I'm glad that I'll be able to ask some questions here, without worrying that responders will go too far with their explanations. 
That's been hard to do at HVAC-TALK. 
I won't have to worry at all about that here though, which makes it easier for sure to ask questions.

It can actually be a good thing to have both of these Forums to use.


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## WhatWasThat? (Apr 26, 2009)

Hey *key1cc* & *lyonkster*, thanks for the replies, I'll check them out. 

Also key1cc, I just posted query about XV95 in this Forum, check it & let me know if you have any answers.

Thanks


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## WhatWasThat? (Apr 26, 2009)

JohnH1 said:


> If you are trying to better controll the constant air flow. I use the TCONT402 with my XV90. It has a BK termonal that you can choose anywere from 35% to 100% air flow.


Greetings *JohnH1*,

Do you use any of the integrated fan options from TCONT402? 

What about lower continuous fan speed?
Do you use an EAC (Electronic Air Cleaner)?

How do you like the TCONT402?

See my thread query:
http://www.diychatroom.com/f17/tran...humidistat-will-display-humidity-level-43398/


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