Just had Trane XL20i HP, XV95 furnace and XL950 thermostat installed - not real happy

[mechanical'al]

their made to run

[pclausen]

Thanks. That's exactly what I needed to know. So heat pump all the way until it gets so cold that it can't keep up, then aux electrical heat strips in the tam8. To be safe, it probably makes sense to get the 20kw module (4 x 5kw).

I did speak briefly with my sales rep, but he had to run to a meeting. He was still trying to sell me on the furnace as being more 'comfortable' when it gets really cold outside. Reading between the lines, it sounds like a tam8 is quite a bit less expensive than a xc95m + coil. I'll stand my ground that I want the tam8.

[RyanHughes]

It sounds like you're on the right track to getting the install turned around. I like the idea of the TAM8 air handler -- they give you plenty of monitoring capabilities over various operating parameters, which you may find useful/interesting or may not.. They work well with the XL20i units. If height is an issue with the TAM8 (they are tall), they can do side return with the Hyperion air handler although a 4 ton system will require a bottom base can as well. The heat pump will keep your home comfortable at temperatures very close to design (17 deg), using mostly the high stage compressor. The staged heater package will help save electricity and keep you comfortable at colder temps. You may even be fine with the 15 kW package, if your ductwork is on the smaller side as most homes' is. The full 20 kW heater with the HP (though I'm not confident your home would ever require this condition) will instruct the unit to provide ~ 1750 cfm; without the HP 20 kW will require ~ 1500 cfm. The 4 ton XL20i will require 1400-1600 cfm on high depending on setup and 700-800 cfm on low (less when dehumidifying). Now is the time to make sure your ductwork is adequate for moving the maximum airflow the unit will require. The TAM8 will report the external static pressure which is helpful information in addressing duct issues. If warmer air temperatures are a concern, the TAM8 can be set up to raise the minimum discharge air temperature and stage the strip heat as needed to maintain that leaving air temp. This is common to many brands. I personally didn't enable this and don't feel the need to.

Definitely recommend the media filter. Helps keep the coil and blower cleaner, much less pressure drop over time, and greater cleaning capacity.

Nice looking install on the outside. Good luck and keep us posted.

[pclausen]

Thanks Ryan. I got 9ft ceilings in the basement, so I think I'll be ok height wise. The TAM8A0C48 unit is 62" tall, and I'm guessing the plenum stand/side return bottom would add another 24" or so. That takes me to 86". If I then stick a media filter between the bottom can and air handler, that adds maybe 7", taking me to 93". When I get home, I'll measure the exact distance from the floor to the bottom of the main supply duct, but I'm pretty sure it will be more than 100".

I noticed that the TAM8 has a digital control panel on the unit itself. Are all of those functions, and the monitoring capabilities also available from the XL950 tstat?

[RyanHughes]

Thanks Ryan. I got 9ft ceilings in the basement, so I think I'll be ok height wise. The TAM8A0C48 unit is 62" tall, and I'm guessing the plenum stand/side return bottom would add another 24" or so. That takes me to 86". If I then stick a media filter between the bottom can and air handler, that adds maybe 7", taking me to 93". When I get home, I'll measure the exact distance from the floor to the bottom of the main supply duct, but I'm pretty sure it will be more than 100".

I noticed that the TAM8 has a digital control panel on the unit itself. Are all of those functions, and the monitoring capabilities also available from the XL950 tstat?

The functions I was referring to are accessible via the control interface on the ahu itself. I'm not all that familiar with the 950 beyond reading the literature on it, so I can't say for certain if they are accessible through the xl950 thermostat.

[pclausen]

I spoke to my sales rep and we're all set on swapping out the xv95 furnace and coil for a TAM8 ahu with the 15kw electric backup module.

I measured the distance from floor to bottom of supply duct, and it is exactly 94". Guy said that they would fabricate the return plenum below the air ahu and make it 16" tall. The TAM8 is 22" deep, so 16 x 22 = 320 sq. in. That should be plenty to flow 1600 cfm, right? Most charts I have looked at show 12 x 24 will flow 1600 cfm, which is 288 sq. in.

That leaves 16" for adding a media filter below the ahu and a transition to the supply duct above it, which sounds like it will be enough to me.

He will call me back tomorrow to schedule coming out with one of his production managers to take measurements and make sure everything is right.

[pclausen]

They came out today and swapped out the furnace for the TAM8. Here are some pictures of the installation.

They put in a nice curved return and I went with the Trane Clean Effects communicating filter (since everything else is communicating now anyways).



They installed a pan under the ahu with a kill switch:



There is a hole in the supply duct, but that will be easy to fix with a piece of tape. I really like the line set and electrical conduit feeding the 60A and 30A circuits to the ahu. I did the electrical part as they are not licensed for that. 2 #6 and 4 #10 (one of the #10 is ground for the 60A circuit). So I went with at 15kw aux heat.



The low voltage stuff was pretty messy, but I cleaned it up.





Much cleaner. I don't have the drain pan kill switch in series with the red wires any longer. I plan to hook it up to my fish tank monitoring system instead, which already have contact sensors and emails me when something is amiss.





While I had the coil cover off, I noticed what appears to be a sensor of some sort, covered with tape (red arrow). Is that supposed to be just dangling like that?



Overall, I'm much more pleased with the install this time around!

[pclausen]

I woke up this Thursday morning to a cold house, just as I did last Thursday morning.

When looking at the XL950, everything looks ok, except the actual temp is less that what is being called for as seen here:



The system status display is showing HP Stage 2 + ID Stage 1 as seen below. Only problem is the air handler isn't running at all, nor is the outdoor unit.



Daily run time stats look very strange for today (as they did last Thursday morning):



Service Menu history report shows the same:



I'm getting the same error as last Thursday morning:



And the possible cause (which is clearly not the issue...):



Alert History shows error 126. I read in another thread that this could mean I need an updated comm board in the tam8 air handler?



The summary table of communicating devices is showing everything online...



And here are the errors shown on the tam8 ahu itself. It is also flashing the red error led 3 times.







As last Thursday morning, the fix is to power cycle the tam8. I'm pretty sure it will be fine until next Thursday when I'm betting it will happen again.

I'll call them to schedule a service visit, but what should I tell them they need to bring to fix it? A specific rev. of the tam8 comm board?

Thanks!

[pclausen]

It is running HP stage 2 + all 3 5kw emergency heating elements now bringing the temp back up to the 70 set point. I'm curious what the load value of 433 shown below indicates?



Tam8 is also showing all 5 heat stages running:



Out of curiosity, I took my clamp on amp meter and checked the amps being drawn from each breaker.

50A HP Breaker 11.8A
30A TAM8 Breaker 19.7A
60A TAM8 Breaker 41.2A

So 72.7A or 17.5Kw right now to heat my house back up. Yikes!

Probably should downsize the 50A breaker for the outdoor unit. That's the one that was running my old 10 SEER 4ton unit.

[Brent Ridley]

The TAM8 air handler and Clean Effects have communication issues. Trane has a repair bulletin out on this. A current sensing relay needs to be installed. You need to call your contractor and check and see if they have done this, if not...you will continue to have 126 faults.

From the pictures above, it doesn't look like it was installed. This is more than likely your reason for poor heating this morning and last week.

[pclausen]

Thank you, that's excatly what I was looking for!

[SkyHeating]

It also could be that its so low the thermostat has not learned when to turn on but the 126 error is a known fix with the bulletin.
I saw that you average temp had dropped from 38 down to 19 in just a few days. The thermostat uses an algorythm based on the past few days of temperature. So if it took 50 minutes to heat up monday and 60 minutes to heat up tuesday it will start heating 55 minutes early on wednesday. I don't know what you have your night setback set to but I would recomend no more than 3 degree difference. So if you want it at 70 in the morning only set it back to 67 at night especially when below freezing, otherwise you will pay through the nose for electric to help heat the house up.

[pclausen]

Appreciate the advice! The irony is that we keep the house at 70 during the day, but my wife insists that we set it to 72 at night because that is when she and our 2 little girls get cold. That is probably really messing up the algorithm...