[lyonkster]

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.

Is it correct to assume that I should count the green LED flashes between the two flashes of the red LED? That is what I did, but I counted to 22 flashes before the red LED flashed again, which is too much cfm for either stage 1 or 2 (stage 2 should be delivering about 1300 cfm at the Low speed that is selected).

Am I counting the LED flashes incorrectly?

 

[key1cc]

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.

Is it correct to assume that I should count the green LED flashes between the two flashes of the red LED? That is what I did, but I counted to 22 flashes before the red LED flashed again, which is too much cfm for either stage 1 or 2 (stage 2 should be delivering about 1300 cfm at the Low speed that is selected).

Am I counting the LED flashes incorrectly?

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

 

[key1cc]

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

 

[key1cc]

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

 

[lyonkster]

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

 

[key1cc]

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

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

 

[lyonkster]

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

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:

 

[key1cc]

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

 

[JohnH1]

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

 

[key1cc]

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

 

[lyonkster]

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.

 

[JohnH1]

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.

 

[lyonkster]

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 .

 

[beenthere]

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.

 

[key1cc]

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

 

[JohnH1]

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.

 

[beenthere]

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

 

[key1cc]

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

 

[beenthere]

Ok.

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

 

[key1cc]

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