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Matching an air handler to a Trane XL16i

Posted by richard904 (My Page) on
Thu, Feb 21, 13 at 10:32

I have a proposal for a Trane XL16i (model no. 4TWX6048E1000B) which is matched with a Trane air handler Hyperion XL series (model no. TAM7BOC60H51). This is an all electric home so there is a 20KW electric strip heater in the proposal. The heat pump is 4 tons and the air handler is 5 tons (I think). I cannot find on the Trane Web page the TAM7B; they do show a TAM7A. Why is it necessary to use a 5 ton air handler with a 4 ton heat pump? Is the TAM7B a new model? I cannot find it on any Internet search.


Follow-Up Postings:

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RE: Matching an air handler to a Trane XL16i

What is your location?

The air handler mdl number is good and is an excellent match for the XL16i condenser. Looks like you have a good dealer.

AHRI matching #5614957.

I question the need for a 20 KW heat strip.

What thermostat was quoted?

Any whole house filter cabinet?

Post back.

IMO

Here is a link that might be useful: AHRI HP Directory


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RE: Matching an air handler to a Trane XL16i

We are in Franklin County KS right off I35 and 36 miles SW of Olathe KS. The thermostat is the Honeywell YTH9421C1010 and the heater model no. is BAYEVBC20BK1AA.

The ducts in the house are all hidden and not accessible unless I want to almost tear the house down. There is a large window area. There is a problem of air leakage and poor insulation in some areas. The house was built in 1994 in SW Spanish style with cathedral ceilings. There is no whole house filter cabinet.


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RE: Matching an air handler to a Trane XL16i

How large is home?

You are replacing a 4 ton system? What size heat strip do you have now?

Very good thermostat. You want an outdoor sensor.

I would add a pleated filter media cabinet.

IMO


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RE: Matching an air handler to a Trane XL16i

I think a 20 KW heat strip is overkill.

I suggest a 15 KW size, three 5 KW heat strips staged. That would yield over 50 KBTUs in strip heat alone not counting the 30 KBTUs the condenser would produce at 17 degree fah temp.

Discuss with dealer.

IMO


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RE: Matching an air handler to a Trane XL16i

I want to go back to one of the questions in my original post. Why is a 5 ton air handler matched to a 4 ton heat pump? The typical 4 ton air handler is a TAM7A0C48H41SA. There are claims that sizing up from the 4 tons improves efficiency (which I presume is SEER, etc.). Is air handling sizing a dealer option within the Trane rules, or are there conditions where sizing up makes sense? Is there a downside technically to sizing up?


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RE: Matching an air handler to a Trane XL16i

You are fretting over nothing.

It is quite common to go up in size on air handler to achieve the best performance/efficiency numbers.

Your dealer has done this so you can maximize the benefits of this HP condenser. You should be concerned about both performance-BTU output in both cooling and heating mode as well as efficiency-SEER, EER, and
HSPF.

The HP condenser and air handler model quoted is an AHRI HP directory match and an excellent match.

You should be paying more attention to my comment about heat strip size especially if you are interested in operating costs in heating mode.

IMO


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RE: Matching an air handler to a Trane XL16i

Okay, I will take your point about the heat strips. I have two contractors proposing the same 20KW heat strip. I will question them more per your advice. One contractor proposed the 4 ton air handler discussed above and the Trane TCONT803 thermostat.

What I have found is that no one wants to do a Manual J new evaluation. All the thinking is to extrapolate from what I have now. Since the ducting cannot be evaluated and cannot economically be changed, there are limits to what we can do with a new heat pump. I am already investing in new windows and more insulation and trying to seal the house where there is air infiltration. Proper weatherization is my main concern.


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RE: Matching an air handler to a Trane XL16i

How large is your home and its layout?

Give me an idea of typical winter weather for your location?

Other than the heat pump, do you have any other heating source in your home-wood stove, gas logs, etc.?

I would stick with the HW VP IAQ thermostat that you were quoted. It has so many more features than the 803 Trane stat. For info, the 803 is HW mdl 8321.

Post back.

IMO


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RE: Matching an air handler to a Trane XL16i

To answer your questions:

How large is the house and the layout?
The house is about 4000 square feet. The lower level is 30 x 58 feet = 1740 square feet. The upper level is mainly a square section 45 x 45 feet plus an additonal master bedroom of 16 x 25 feet for a total of 2425 square feet. Right In the middle of the square section is a 15 x 15 kitchen and above the kitchen at the third level is a belvedere which is almost all windows (in lousy shape). All the rooms at the upper level have cathedral ceilings. So you walk up to the belvedere above the kitchen and in summer it is always hot, and in winter it is always cold. There are no heat outlets there.

Typical winter weather.
We are in Franklin County, KS, about 36 miles down I35 from Olathe, KS, a suburb of Kansas City. We have mild winters now even though we had two 12" snow storms during the last week.

Other heating sources in the house.
Other than the heat pump we use space heaters when people are occupying certain rooms. We have two fireplaces, but they are almost never used. This is an all electric house, and we do not have access to gas in our area.

An additional note.
The houses on both the east and west side of us have two heat pumps. The house on east side had a large addition, and I presume the additional heat pump was for the new addition which makes it easy. The house on the west side I am sure was built anticipating two zones. Our house has one zone, and we get what we can get that way.


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RE: Matching an air handler to a Trane XL16i

Richard904

I agree with tiger's comments above. The XL16i is a nice system when installed and configured properly. Either the 4 or 5 ton air handler would be fine (they are the same size, physically), with the 5 ton being preferable for its slightly higher combination efficiency ratings. The 5 ton has a 1 HP motor vs. a 3/4 HP motor in the 4 ton air handler; same coil. Both blowers need to be configured properly to match the outdoor unit's airflow requirements.

By the way, if a load calculation was done I'm quite sure you would find that 15 kW is plenty. It will be staged 5/10/15 kW.

This post was edited by ryanhughes on Tue, Feb 26, 13 at 22:29


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RE: Matching an air handler to a Trane XL16i

Tigerdunes mentioned that 15KW of heat strips is all that is needed, and this would be staged 5/10/15, and he mentioned that this would produce 50000 BTU's along with 30000 BTU's at 17 deg from the heat pump. How is this staged performance of the heat strips managed? Is there enough intelligence in the system to know that only one heat strip is needed to maintain house temperature at the current conditions? Thus if I have 20KW of heat strips, and 15KW is the maximum the house needs, is the system intelligent enough to only run three heat strips?

I have not done a search yet for "how heat strips work in a modern system" so this may be a dumb question. Also maybe this should be broken out as a separate posting now.


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Staging heat strips

Okay, I did searches now, and even in this forum there are postings about staging heat strips, so my questions above are answered.


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