# basic heat pump question



## floatr (Jan 2, 2015)

Got a simple question on heat pump info.
Is 2 stage different or the same as 2 phase?
Can u define them please


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## kok328 (Jan 3, 2015)

iMO - Depends on the unit. Some stage 2 is a whole separate compressor. Some are same unit running at higher capacity and some are referring to supplemental electric coil heat.


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## floatr (Jan 7, 2015)

thanks-also if i have a oversized unit that is a 5 ton instead of a 3ton(recommended) what issues will i be looking at?


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## Speedbump (Jan 8, 2015)

I am not sure what two stage means in HVAC, but 2 phase is a term not used to describe 230 volts.  115 volts is single phase, 230 volts is 2 phase (but electricians don't use that term) and three phase power can be either 230 or 460 and higher volts.  Single phase = one hot one neutral.  Two phase = two hots no neutral and Three phase = three hots no neutral.


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## kok328 (Jan 8, 2015)

With an oversized unit you will experience short cycling of the unit. Kinda like killing a fly with a sledge hammer.


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## Speedbump (Jan 9, 2015)

> With an oversized unit you will experience short cycling of the unit. Kinda like killing a fly with a sledge hammer.


You will also have a hard time removing the humidity by short cycling while cooling.


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## floatr (Jan 11, 2015)

ok thanks.
can i tell easily and for certain by putting the 2 40 amp fuses in (required for 3 ton) instead of the current 2 60s in now(required for 5 ton) and turning on the Aux heat ? .Its a 2 stage unit though .and has a second set of 60 amps for 9.5 kw heat kit(correct size )

if its 5ton  would it then pop the 40amp ac side fuses?


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