Carrier Fan Coil 5K Heater Circuit Breaker Size

[ATC USN]

I haven’t been charged for anything the system is under warranty, my dealer confirmed with Carrier that we have the correct wiring. The VP is doing the work himself hopefully the third time will be the charm.

All the wiring to the AC system was replaced when the new system was installed it was an easy run everything is less than 20 feet from the load center.

About 6 months before the new HVAC system was installed the utility Co was having problems with my transformer, we kept losing power in one side, eventually it exploded, the aluminum feeder lines to my house were cooked everything from the pole to the load center was replaced including the meter box and feeder lines. While that work was going on, I took the time to replace my old Federal Pacific load center with an Eaton we upgraded the amperage in anticipation of replacing my oil heat with electric.
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[toocoolforschool]

Just to sum things up you now have #6 awg and 70 amp breaker to serve your 10 plus 5 kw heatstrips which pulls about 62.5 amps.

[vstech]

Just to sum things up you now have #6 awg and 70 amp breaker to serve your 10 plus 5 kw heatstrips which pulls about 62.5 amps.

I do not see the numbers you are quoting on the question...

only place I see wire sizes is in his answer of #10 wire feeding the 30 amp breaker... and it should be #8 and a 40 amp breaker. 125% upsize equals 35 amps, next size breaker is 40. a 35 would be ideal, with #8 wire on the circuit. the #10 wire is heating up, and tripping the breaker.

[toocoolforschool]

I do not see the numbers you are quoting on the question...

only place I see wire sizes is in his answer of #10 wire feeding the 30 amp breaker... and it should be #8 and a 40 amp breaker. 125% upsize equals 35 amps, next size breaker is 40. a 35 would be ideal, with #8 wire on the circuit. the #10 wire is heating up, and tripping the breaker.

He said he had 15 kw of heat, so that would need a service from electrical panel of 6awg and 70 amp breaker minimum.

[vstech]

He said he had 15 kw of heat, so that would need a service from electrical panel of 6awg and 70 amp breaker minimum.

oh, OK, you were explaining what he SHOULD have. got it.
but he's got a dual disconnect setup, so it's gonna have to be split into seperate circuits. also, I don't think 6awg is large enough for 15KW...

[vstech]

I checked, electrical code on 10KW would be nearly 53 amps, so it requires a #6, and the extra 5kw needs a load of 35 amps, requiring a #8 conductor. the existing 60 amp is fine, but the 30 amp breaker is going to need upgrading to at a minimum of 35, AND the conductor needs to be upgraded to a #8

[toocoolforschool]

I checked, electrical code on 10KW would be nearly 53 amps, so it requires a #6, and the extra 5kw needs a load of 35 amps, requiring a #8 conductor. the existing 60 amp is fine, but the 30 amp breaker is going to need upgrading to at a minimum of 35, AND the conductor needs to be upgraded to a #8

If system electrical service is installed correctly that would be the way to go, but in New orleans most come off of one breaker, very rarley is it done properly i was assuming his was a single circuit from the service box.

[ATC USN]

My dealer replaced the heater pack, ran the heater test for 10 minute twice checked the current draw it was 20 amps, no more tripped breakers.

The problem was a 8 inch six section of coil was stretched out and tangled, looks to me like it got snagged during installation.

I have the Carrier data sheet with my fan coil with a 15k heater pack requires a 60 amp circuit and on 30 amp circuit the installer wired the unit correctly.
The 15KW heater pack is staged to operate at 5 KW, 10 KW and 15 KW.
The first two stages raun off the 60 amp breaker the third stage runs off the 30 amp breaker.
Ohms law states I=P/V or 5KW/230VAC = 21.7Amps 10KW/230VAC=43Amps and 15KW/230=65Amps

[toocoolforschool]

Sounds like you have a short or some loose wires or maybe a incorrectly wired heat strip. Pictures would help.

Lucky guess.

[vstech]

ohms law and national electric code do not sync...

continuous electrical loads SHALL be oversized 125%
21.75 amps x 125% is 27.875 amps. I was going on the possibility of the 5 kw being the first strip, along with the blower and xformer, it would have pushed the draw over 30 amps... around 33
if the 5kw is the last strip, then no problem. 27 is under 30, and 10 will handle it fine.

My dealer replaced the heater pack, ran the heater test for 10 minute twice checked the current draw it was 20 amps, no more tripped breakers.

The problem was a 8 inch six section of coil was stretched out and tangled, looks to me like it got snagged during installation.

I have the Carrier data sheet with my fan coil with a 15k heater pack requires a 60 amp circuit and on 30 amp circuit the installer wired the unit correctly.
The 15KW heater pack is staged to operate at 5 KW, 10 KW and 15 KW.
The first two stages raun off the 60 amp breaker the third stage runs off the 30 amp breaker.
Ohms law states I=P/V or 5KW/230VAC = 21.7Amps 10KW/230VAC=43Amps and 15KW/230=65Amps