Carrier Fan Coil 5K Heater Circuit Breaker Size

[ATC USN]

My Carrier FE4ANB005 Fan Coil has 10K and a 5K heater pack, the 10K is fed by a 60 amp circuit the 5K is fed by a 30 amp circuit, but the fan coil has two 10K (60 amp) breakers.

The reason I’m asking is the 30 amp breaker on my load center that feeds the fan coil/5k Heater has tripped about 10 times this winter.

I replaced the 30 amp breaker Saturday, today the installer ran an electric heat test and inspected the wiring, he said he didn’t find any problems, but he also didn’t take any current readings.

This system is less than one year old.

[BaldLoonie]

The breakers on the heat kit are more of a service disconnect and dead short protection. Your 60 & 30 in the main panel are right. Maybe a bad breaker.

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[ATC USN]

I guess the installer was out of 30 amp breakers, when they installed they system they borrowed a can of spray foam and a role of aluminum tape from another contractor who was residing my house.

[beenthere]

The breakers in the unit come from the factory.

[ATC USN]

Looking at the product data sheet two 60 amp breakers is correct.
If I'm reading the product guide correctly FE4ANB005 Fan Coil with a 5K heater pack calls for 8 gauge wire and a 35 amp breaker, mine is wired with 10 gauge wire with a 30 amp breaker.
A 5KW heater should be pulling about 20 amps, that leaves 10 amps for the blower motor and electronics.

[jtrammel]

Sounds like a week breaker to me, which should be resolved now that its been changed. Has it tripped since changing the breaker?

[ATC USN]

No not since the breaker was replaced, the last time it tripped the temp was in the low 20's.
The old breaker tripped intermittently about 10 times since the winter season started.
I have an infinity tstat running the electric heat test did not trip the old breaker.

[ATC USN]

It's not the breaker the new breaker just tripped.
I was able to duplicate the problem by running the heat test for 10 minutes instead of the default 5.
The wires and breakers are warm and the technician who was out earlier didn't check the current draw.

[ATC USN]

Am I wrong?

[toocoolforschool]

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

[ATC USN]

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

Nope I checked the wiring and a technician checked it again on Monday.
Did you look at the product data sheet? The minimum ampacity is 33.5 amps, including blower motor.

[ATC USN]

I was wrong the wring and the circuit breakers are correct the technician told me I had a 5k and a 10k heater pack I don’t, I actually have a 15k heater pack. The dealer is replacing it tomorrow.

[vstech]

a 15K heater pack is actually 3 - 5 K heat strips... it's all in how it's wired.
the problem is HEAT on the conductor... 5K with 240v can pull over 22 amps, and undersized wire, with crimp connectors, with sequencers and other points of resistance and you can easily overtemp a 30 amp breaker.
if you have #10 wire, and a 30 amp breaker, you will need to upgrade the wiring to the furnace, to increase the breaker size.

if the breaker trips more than ONE TIME there is a problem that must be addressed.
if the first technician cannot find a problem, do not pay him, and get a technician that CAN find the problem.

[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.
.

[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.