Need some advise on Trane XV18 with 2 Stage Furnace with variable blower motor

damdolce

I have a decision to make, so I'm hoping you all could help me out.

I'm putting in a new Trane S8V2 Furnace (2 stage, variable) and wanted to go with a XV18, the issue is they only sell the XV18 heat pumps in 2, 3, 4, 5 tons and I'm rated for 2.5 tons. My installer was thinking we could do a 2 ton compressor with a 3 ton coil. I've noticed that no matching the two is NOT recommended. Would that be ok to do, or should I ask him to do a 2 ton compressor with 2.5 ton coil? Or 2 and 2, or 3 and 3?

Any help and recommendations from the HVAC guys would be appreciated!

EdTheHeaterMan

The XV18 has a variable speed compressor. That means that it will only operate at the actual size needed to cool the home. As you approach the set-point on the thermometer the compressor will become a 1 ton or a 1.2 ton or a 1.8 ton or a 2.5 ton based on the actual load of home based on the amount of heat gain in the home. Get the 3 ton. And if you only need 2.5 ton on the hottest summer day, then it will only operate at 2.5 ton.

That is a pretty incredible machine. It will modulate the home temperature based on the thermostat input to within 0.5° degree, and it takes a sample of the temperature several times a minute. That is why they don't make it in half sizes. It will cycle on and off when the home needs less cooling than the minimum running speed. Once it gets hot enough to get past that minimum speed, the compressor will never shut off. It will just modulate and maintain that exact temperature. Sounds like it is expensive to keep it on all the time, but it is actually more efficient because there are almost no stop and start cycles that use more electricity.

Your installer should know that, and should have given you that answer.

damdolce

Thank you so much, in fairness I haven't talked to him yet about it. I wanted to see what others thought before chatting with him tomorrow. Ok so your suggestion is 3 ton compressor and 3 ton coil?

EdTheHeaterMan

YES.

damdolce

Thanks Ed!

EBEBRATT-Ed

The difference between a 2 1/2 and a 2 or between a 2 1/2 and a 3 is only 6000 btu. I would use 3 tons on the condensing unit and the coil.

damdolce

Thank you as well, really appreciate your opinion.