Hi everyone, I am an instructor that uses Mike's books, but also Charles Miller and Ray Mullin. They have conflicting calculation styles concerning the blower motor of a split AC system. Miller considers the blower motor to be a non coincident load according to 220.60, and therefore used in both calculations. Mullin considers the blower motor an appliance. I think that Stallcup is also in the appliance camp. What do you think. Which is most likely to be the correct method on the PSI exam?
220.60 applies or not
- Thread starter osospark
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jumper
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I know little about mini splits, but you do mention appliance.
While a HVAC unit is an appliance, it cannot be used for 220.53.
As for the motor in a HVAC unit being a non coincident load, I have never seen it called as such, but again mini splits are not my forte.
While a HVAC unit is an appliance, it cannot be used for 220.53.
As for the motor in a HVAC unit being a non coincident load, I have never seen it called as such, but again mini splits are not my forte.
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In general the blower will always be on when the compressor is on, but there will be times when the blower is on when the compressor is off.
I would say that since the fan is always on when the compressor is on and the compressor is the larger motor, it is a coincident load.
I would say that since the fan is always on when the compressor is on and the compressor is the larger motor, it is a coincident load.
Are we talking forced-air system blower, or condenser unit fan motor here?
The latter is always included in a calculation with the condenser unit.
Typically, where a forced-air system blower is shared for both heating and cooling, it is therefore a coincidental load. Since it is typically included in the heating nameplate values (at least in my area it is), to even the calculation out simply add the blower kVA to the cooling values... so it will be included in the higher of the two as non-coincident loads.
IMO, unless you have a window-mounted unit, HVAC equipment is not an appliance.
The latter is always included in a calculation with the condenser unit.
Typically, where a forced-air system blower is shared for both heating and cooling, it is therefore a coincidental load. Since it is typically included in the heating nameplate values (at least in my area it is), to even the calculation out simply add the blower kVA to the cooling values... so it will be included in the higher of the two as non-coincident loads.
IMO, unless you have a window-mounted unit, HVAC equipment is not an appliance.
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