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Help with New Trane XL15i Match...

Posted by djyas (My Page) on
Fri, Mar 23, 12 at 0:13

To start, thank you all for sharing your knowledge, I've learned so much from this forum...

I'm about ready to have installed a new 4-ton Trane XL15i system (a 4twx5048 heat pump, bayevac10lg heat strip, and tam7a0c42 air handler) for use in Atlanta, GA. I feel great about the installer, system sizing, and modifications to my ductwork, but would really like to know:
1. Instead of the 4twx5048 should I specify the apparently newer revision of the same unit the 4twx5049e?

2. Instead of the Hyperion 7 tam7a0c42 should I specify a Hyperion 8 tam8xxxxx? I don't know if the XL15i can make use of the Hyperion 8/tam8 communication. If it can't, should I at least specify the tam7a0c48 (instead of the tam7a0c42 as it might be a better AHRI match)?

3. Apart from Trane's expensive XL950/ComfortLinkII thermostat, would the best thermostat match for the XL15i heat pump /Hyperion 7/8 air handler be the HW VisionPro IAQ? I am thinking that the 803 won't communicate with the XL15i and the HW VisionPro IAQ can adjust the Hyperion (tam7/tam8) air handler's variable speed blower instead of just over-cooling.

Thank you, Djyas

P.S. It looks like the bayevac10lg is a common heat strip for Atlanta, GA... Does anyone see any drawbacks to its use in this system?

Follow-Up Postings:

RE: Help with New Trane XL15i Match...


I will assume you are sized correctly.

I will assume your ductwork has been inspected both size, leak test, insulation, and adequate returns. Any hot/cold spots?

If this was my choice, I would want the 5049E1 condenser model with the
TAM7A0C48 H1. That is AHRI #4385471.

I don't like that 10 KW heat strip. I realize Atlanta normally has moderate winters. However, if you had a breakdown and had to go on emergency, then that yields only about 35 KBTUs. I would install Trane's two stg 7/12
KW heat strip.

I would also want the latest HW IAQ stat for best AC dehumidification. Otherwise, the 803 or HW 8321(identical) with overcooling.

If you don't have a media box filter, I would add one.

If you follow this advice, you will be fine, comfortable, and happy.


RE: Help with New Trane XL15i Match...

Thank you tigerdunes! I really appreciate your knowledge and help!

One last question... Would the tam8a0c48 do anything different / better than the tam7a0c48 h1 in this particular application (i.e. being used with the XL15i/4twx5049e and the latest HW IAQ stat)? In my research it looks like the tam8's only benefit over the tam7 is that it is communicating and I'm not sure that would even matter with a XL15i (as compared to a XL20i) and HW IAQ stat...

Thanks again, Djyas

RE: Help with New Trane XL15i Match...

I would weigh the price difference on the Tam7 and HW VP IAQ stat latest mdl versus the TAM8 and Trane 950 stat. I would expect the former would be less expensive and the latter not worth it. Either way though, it is important to qualify dealer's knowledge and installation experience with each system.


RE: Help with New Trane XL15i Match...

TD is right on about the heat strips. Connecting these in 2-stage will let you use the 7kw on those cool times when the HP cant quite get there and save you a little over the 10k. Also gives you 19kw in emergency mode.

RE: Help with New Trane XL15i Match...

I appreciate the kudos from the prior post but don't want to mislead. The two stg heat strip as mentioned has two stages, a 7 KW heat strip which yields about 24 KBTUs plus the high stage 12 KW, about 41 KBTUs. This would help you when in a defrost mode, the 10 KW heat strip would be way too lite.

Discuss with dealer. Not a detail to ignore.


RE: Help with New Trane XL15i Match...

Weedmeister and tigerdunes, you guys are the best! Thanks for your time and experience!

I've asked the contractor I feel best about for quotes on both the:

- Trane XL15i/Hyperion7 system (4twx5049e1, tam7a0c48h41, Trane 7/12kw staged strips, and Honeywell VisionPro IAQ (the YTH9421, which includes the thermostat itself (TH9421) and interface panel (THM5421) (ARI # 4385471)))

and the

- Trane XL20i/Hyperion8 system (4twz0048a, tam8a0c48v41, Trane 7/12kw staged strips, and Trane XL900 (ARI # 4770461))

Thanks again, Djyas

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