Trane XL 19i

[Van de Bogart]

I am a consumer who had a Trane 19 i with an XL80 furnace installed in December. My question is this: I live in Tucson, AZ and our weather just started to hit around 100 the last couple of days. The system runs just about all the time in low. I have a 5 ton dual compressor. As I understand low means it is running on the 2 1/2 ton compressor. Is it normal for it to run all the time during the day? It starts this about 10 in the morning and lasts until after midnight. I am wondering just how hot it has to get for it to kick into high. I'm not complaining as it keeps the house and even 78 all day. Just curious how my electric bill will be when its on all the time. My old 5 ton trane used to cycle on and off all the time.

[Shophound]

Next time it hits 100 degrees outside, bump your thermostat down to 75 or lower. If the second stage doesn't kick on, you may have a problem that needs attention.

If it does kick on, it could be if 78 degrees is your normal setting, the system is able to hold that temperature without bringing on the second compressor. It is normal for a properly sized system to run continuously when it is near or at design conditions.

[tmoss]

It's my understanding that the second stage should run near continuously at design temp, not the first stage. I would find out what design temp was used for your system and verify the dip switches are set at 400 or 450. I had a similar issue with my 19i. My installer didn't think you could oversize a two-stage system. He was finally convinced and downsized my condenser. As a result my second stage runs plenty above 95 ODT and sp of 76. I'm in the DFW area. I used 105/75 for the design temp to downsize condenser. Design temp for Tucson is probably 110 or so. I would think your second stage should be running some at 100. If your second stage never needs to run due to the load then your system is too big and you spent more money than you needed to spend. However, it may not be running due to some problem with the unit. If it's holding setpoint I would guess that's it's working properly and 5 tons is more than you need. I'm just a HO and these opinions are based on my experiences with my 19i and info gleaned from this site. You paid alot for a quality system. I would make certain that 5 tons is what the load calcs call for and it's set up correctly. Good Luck.

[dan sw fl]

I am a consumer who had a Trane 19 i with an XL80 furnace installed in December. My question is this: I live in Tucson, AZ and our weather just started to hit around 100 the last couple of days. The system runs just about all the time in low.

Is it normal for it to run all the time during the day?
It starts this about 10 in the morning and lasts until after midnight.

I am wondering just how hot it has to get for it to kick into high. I'm not complaining as it keeps the house and even 78 all day.

Just curious how my electric bill will be when its on all the time.
My old 5 ton trane used to cycle on and off all the time.

How do you determine whether the XL19i is running in Low or High?

Low stage
2.2 kW/ hr x 15 hours total run time per day = ~ 33 kW hours per day
or in the range of $5.00 per day ( @ $0.15 /kWhr) for A/C

$150 per month for the A/C alone ( 1,000 kwHr)
and maybe another 700 kwHr ($100) for other uses.

[Van de Bogart]

I guess I am determining the hi and low by the indoor fan speed and the sound of the compressor outside. When it kicks into hi, it seems pretty easy to tell the difference. Am I wrong?

[tigerdunes]

Van

The XL19i model whether heat pump or AC condenser must be paired with either a var speed air handler or var speed furnace. The XL80 furnace while two stg does not have a var speed blower-it is not the correct furnace for the XL19i. This is the source of your problem. I hope you meant the XV80 furnace which would be correct (and it must have a 5 ton rated blower to match your condenser).

IMO

[Van de Bogart]

My mistake.....it is an XV80. Yesterday (102) it did kick into hi late in the afternoon for 2 or 3 minutes. It also kicks into hi as I have it set to pull down 2 degrees at bedtime. It runs on hi for about 3 minutes then ramps down to low speed.

[BaldLoonie]

I guess I'm with tmoss. If it spends all its time on low in 100 degree weather, gotta be way oversized! But if you regularly hit 120 :eek: maybe not!

[Van de Bogart]

I have a question for tmos.......before you downsized the unit and it ran continuously on low, what did this do to your electric bill? The house seems comfortable although it runs pretty much all the time. Of course in Tucson, humidity is not really a problem except in July and August when we get our monsoons. I guess I'm trying to determine the downside to being perhaps oversized. I guess the alternative would be a 4 ton unit? By the way, the house is about 2400 square feet with a tile roof and frame stucco construction. Thanks for the info everyone.

[dan sw fl]

The house seems comfortable although it runs pretty much all the time.

Of course in Tucson, humidity is not really a problem except in July and August when we get our monsoons.

I guess I'm trying to determine the downside to being perhaps oversized.

No downside ! !! !!!

& Do NOT down size.

[BaldLoonie]

You spent a lot of money to get what works out to be a single stage unit. But you do have reserve capacity for a party or a quick cool down. In a steamy climate you might be defeating the purpose but in the desert not as big of a deal.

[mayguy]

What do you have for t-stat?

[tmoss]

The downsize to oversize is like Baldloonie said, you paid a lot for single stage system. Price out the difference between a 5 ton single stage vs the xl 19i. What is the load on the home at design temp? Your unit may end up being ok at 120 degrees. And it should considering what these set ups cost. I wouldn't accept my oversized unit and HD made the Trane installer correct various issues including the oversized condenser. As a result, I feel I'm getting what I paid for. Remember too the high seer ratings come from units running closer to capacity, not idling on low all day. I agree sizing might not be as critical in a drier climate. Still no excuse to oversize any system.

As for what oversizing did to my bill many variables come into play when it comes to kw used. That said my unit was one of three in my home and it services the upstairs. It was replacing a 21 year old system. For the same ODT my kw usage dropped 20-25% while keeping my home 3 degrees cooler than with the older upstairs system. Your results will vary. Bigger units use more power, even on low stage.

[Van de Bogart]

The thermostat is the XL800. The evaporator is model A506021527U.

[mayguy]

That is a good t-stat, hopefully it's set up right, with 3 CPH. on all stages of heating and cooling.. If it's set up right, as some said, sounds pretty oversized.

[czkidd]

You must ensure that the thermostat compressor control wires (y/Ylo) are hooked up to the terminal board of the Air Handler/Furnace or it will not run in high speed. A Trane Thermostat will work best for this two speed system as it is designed for their systems.(propietary)Tstat Model:TCONT802. The Tstat must also be programmed for this two speed system. I've installed quite a few of the XLi 16 and 19's. Good Luck!

[Van de Bogart]

Mayguy......what is 3 CPH? Don't forget, I'm just a consumer.

[czkidd]

3 CPH = 3 cycles per hour.

[kevinmac]

For your unit to run at 95% of the time on the first stage in 100 degree heat is not unusual. The XL19i is designed to run more continiously on the first stage as compared to running on the 2 second stage. The 2nd stage will only kick on when called upon to play catch up. By keeping the 1st stage running continously provides comfort through out by continiously removing the moisture in the house. A good way to check to see if the first stage is kicking in is after the house is at the set temp, and running on the first stage, lower the temp, go outside you should hear the condenser fan motor kick into high, a short delay with no compressor running, the the 2nd stage kick in. The VS airhandler will kick up to high. So for the first stage to run continiously in that kind of heat is not abnormal. You are saving money since your first stage is a little less than 50% of the second stage,(think it is somewhere around 40 to 45% of the full system). The reason you are saving money is because you are not cycling on and off. The 1st stage compressor only draws around 8.4 amps under continious run. The continious run saves on the big draw of in rush current on startup and continious cycling.
It also provides low humidity in the house to whereas, you can raise your thermo.

Unless I am missing something i don't think you have an issue, unless of course no heat load was performed and you have the wrong size system.

[Van de Bogart]

How is a "heat load" performed? I also have a question about CPH. Do you mean that by setting it at 3 CPH the system will always cycle on and off 3 time every hour or is that the max CPH?

[kevinmac]

Heat load is done with a program called manual j. It takes into account your houses configuration sq ftg., window area, insulation, etc.. It will tell ytou the required BTUH needed.

[mayguy]

if your t-stat is set at 3CPH, it will run avg 3 times an hour if the load is not high, now if you have a hotter day, it will run longer, really hot day, run non stop, and hotest day, it should cycle into 2nd stage every now and then.

I don't have two stage a/c, but I do for heat, when we had our cold snap in Feb (about -20) my furnace ran non stop in first stage, and at times it cycled into 2nd stage.

[tmoss]

I thought cph meant the maximum number of cycles per hour, not the average. My vp 8k is set at 3 cph and it doesn't average that regardless of the load. At least I've never noticed that it does. Maybe my stat is defective but it holds setpoint to the degree. But if that is true then I can set it to 1 and possibly get better humidity removal, right? Also, I don't understand how a properly sized and installed 2 stage system wouldn't run on high stage most if not all of the time at design temp. (the hottest days). I do agree about longer runtimes, minimal inrush current and lower kw usage. However, I personally would not want a compressor that only ran on the 2% time. Don't you end up with lower seer due to the oversized coil since it always run on low stage?