Trane System Advice for SW Florida

[beestroh]

Hi there. My parents have a ~ 1600 square foot house in Naples, Florida that needs its HVAC system replaced. The house and system are about 11 years old. The current system is a 10 SEER, 3 ton AC unit with resistance heat in the air handler. The house is unoccupied roughly half the year, most of that in summer. We leave the AC on to control humidity when it's unoccupied. A separate humidistat is wired in line with the analog thermostat currently.

The contractor my parents are thinking of going with has proposed a 3 ton Trane XB 14 condenser paired to the Hyperion XR multi-speed air handler, as well as resistance heat (they are not interested in a heat pump). The contractor seems to be providing them fairly simplistic answers, and my geeky self wants some additional detail. Therefore, I have some questions about that setup:

1. The contractor claims that the multi-speed air handler will, in fact, lead to an overall SEER of 16 from the XB. That said, I thought it was usually variable-speed blowers that increased SEER, not multi-speed blowers. The Hyperion XL (variable speed) isn't out on the market yet. Is he correct in saying the XR will get a net 16 SEER with the XB 14 outdoor unit? Would the variable-speed XL unit likely have a better SEER than the multi-speed XR unit?

2. I myself have a Bryant Evolution system, and love the fact that I can control the blower speed directly from the Evolution control. I can't figure out how to use the Trane thermostats to control blower speed... or can you? If it can't be controlled from the thermostat, how does the Hyperion series adjust blower speed?

3. I like that the Evolution can control humidity more directly by slowing the blower speed. Is there an integrated Trane thermostat/humidistat that dehumidifies by slowing the blower, or do they simply overcool to dehumidify?

4. Does Trane make multi-stage heat strips, or only single stage? Which Trane control(s) allow for multi-stage heat?

5. I have looked at the ComfortLink II control, which looks interesting but also very expensive. I can't tell if it's been released to market yet. Does anyone have any real-world experience with this control?

Thanks in advance for your help.

[RyanHughes]

The XR Hyperion has a high efficiency ECM blower motor. It's an X13 motor, and not variable speed. It is true that when paired with the XB14 3 ton condenser (4TTB4036E1) it will reach 13 EER and 16 SEER. The model number for the air handler is GAM5A0B36M31. Using the 3.5 ton indoor unit, you will get slightly over 3 tons of capacity (versus slightly less with the 036 air handler) - GAM5A0C42M31. Physical space may be an issue. Not sure which one they plan to install.

The X13 motor sometimes gives a little more efficiency (EER/SEER) versus a variable speed motor in some size combinations.

The Trane TCONT900 can control the blower speed to dehumidify, but this would require a communicating air handler (and preferably the XL20i condenser). I'm told that for non-communicating heat pumps this is not an option but for straight a/c's non-communicating outdoor units can still be used with the communicating air handler and control.

Some Trane heater packages have more than one stage. What did they quote?

[BaldLoonie]

Better get a model # of the air handler or AHRI number. The 5 series is X13 (not VS) the 7 series is VS and more desirable.

You have a little more control over the blower with the communicating air handlers and the CONT900 control, but not as much as the Evolution. The communicating control or a Vision Pro IAQ or the like can trigger the dehumidify on demand slowing the blower on a VS air handler or gas furnace.

Usually can stage the heat kits in 10kw increments depending upon stats. Most have 1 stage of backup but a VP IAQ can have 2 stages so if you have more than 10kw the additional can be a 2nd stage of backup.

[beestroh]

Better get a model # of the air handler or AHRI number. The 5 series is X13 (not VS) the 7 series is VS and more desirable.

You have a little more control over the blower with the communicating air handlers and the CONT900 control, but not as much as the Evolution. The communicating control or a Vision Pro IAQ or the like can trigger the dehumidify on demand slowing the blower on a VS air handler or gas furnace.

Usually can stage the heat kits in 10kw increments depending upon stats. Most have 1 stage of backup but a VP IAQ can have 2 stages so if you have more than 10kw the additional can be a 2nd stage of backup.

Model numbers are 4TTB4036E for condenser, GAM50B036M for air handler. I tried to find this pair on the AHRI website... but couldn't. That I can't find it makes me wonder how he knows it's 16 SEER in combination.

So am I understanding that none of the Trane-branded thermostats can control blower speed on the XR (X13, 5-series) models, and that I'd need to use the Vision Pro IAQ or equivalent? How, then, does the air handler utilize these different speeds in the absence of an IAQ... or does it?

Thanks again for your help!

[BaldLoonie]

4150832

AHRI number for that combo

The fixed speed motors don't have the feature of dehumidify on demand, if you want that you'd have to get the variable speed.

From what I see of the manuals, you use low for constant fan. If a single stage outdoor unit, pick the tap that gives the desired CFM based on the outdoor unit size and static pressure the installer measures. On a 2 stage outdoor unit, you'd have a lower speed for low compressor. The manual says factory setting is speed 4 for heat & cool. A good installer would check static pressure to see if that is appropriate. With a filter in place, that is likely less than 1200 CFM for a 3 ton air handler. OK in Florida, might be light in a dry climate.