Hayward Heat Master keeps tripping the breaker

[JamesW]

Voltage Drop Calculator | Southwire

www.southwire.com

The maximum combined voltage drop on both installed feeder conductors and branch circuit conductors to the farthest connected load or outlet must not exceed five percent.

This is the steady-state voltage drop under normal load conditions.

 

[JamesW]

If you add up the compressor and fan amperage, it is about 29.4 amps.

If you use the nominal power it is 5,600 watts at 230 volts is 24.34 amps.

The minimum circuit ampacity is 36.2 amps.

The voltage drop should be less than 5% at 29.4 amps.

The circuit breaker should be a 40 amp, 50 amp or 60 amp breaker.

You could probably use a 40 amp breaker since the max loading of 32 amps (80%) is not expected to be exceeded as long as the voltage drop is less than 5%.

A 40 amp breaker and 40 amp wire meet the minimum ampacity as specified on the equipment label.

 

[JamesW]

You should verify that the voltage drop is less than 5% which depends on the wire size and length from the main panel.

 

[stunatu72]

Show me that in the NEC.



Show me that in the NEC.

https://www.nfpa.org/~/media/Files/Code%20or%20topic%20fact%20sheets/NECAmpacityWorkflow.pdf

 

[JamesW]

You can use a #8 AWG wire up to 283 feet with a 60 amp breaker.

 

[JamesW]

MOCP VS. MCA

In air conditioning, we are given a gift by equipment manufacturers on the equipment data tags: the minimum circuit ampacity (MCA) and MOCP or max fuse/max circuit breaker rating.

These ratings on the data tag tell us exactly what minimum ampacity the circuit must be capable of carrying as well as the maximum size the circuit breaker or fuse may be able to protect the circuit against in an overcurrent condition.

Take a look at the Lennox air conditioning condensing unit tag on Page 19.

Notice that the MCA is 28.6 amps and the maximum fuse or circuit breaker is 50 amps.

This means it is allowable to install this unit on a circuit breaker rated at 50 amps and a conductor rated at 28.6 amps, according to the NEC’s NFPA 70.

I know this goes against what many of you have been told and understood your entire career, but take a deep breath and read on.

NEC article 440 was added because air conditioning and refrigeration systems are different from typical loads, like lights and heaters. Air conditioner compressor and fan motors are largely inductive (magnetic) loads and have different characteristics than purely resistive circuits. Article 440 has specific guidelines for HVAC and refrigeration equipment manufacturers to follow when writing the equipment data tags as well as for electricians when sizing conductors.

What Most Techs Get Wrong About Wire Sizing

Over and over again, I have heard HVACR technicians and electricians quote rules of thumb regarding wiring sizing, and I have witnessed and participated in many heated debates on the topic.

www.achrnews.com

 

[JamesW]

a 3% voltage drop is a better limit for best system performance.

At a 3% allowable voltage drop, you can use #8 wire up to about 170 feet and a 40, 50 or 60 amp breaker.

 

[ajw22]

MOCP VS. MCA

In air conditioning, we are given a gift by equipment manufacturers on the equipment data tags: the minimum circuit ampacity (MCA) and MOCP or max fuse/max circuit breaker rating.

These ratings on the data tag tell us exactly what minimum ampacity the circuit must be capable of carrying as well as the maximum size the circuit breaker or fuse may be able to protect the circuit against in an overcurrent condition.

Take a look at the Lennox air conditioning condensing unit tag on Page 19.

Notice that the MCA is 28.6 amps and the maximum fuse or circuit breaker is 50 amps.

This means it is allowable to install this unit on a circuit breaker rated at 50 amps and a conductor rated at 28.6 amps, according to the NEC’s NFPA 70.

I know this goes against what many of you have been told and understood your entire career, but take a deep breath and read on.

NEC article 440 was added because air conditioning and refrigeration systems are different from typical loads, like lights and heaters. Air conditioner compressor and fan motors are largely inductive (magnetic) loads and have different characteristics than purely resistive circuits. Article 440 has specific guidelines for HVAC and refrigeration equipment manufacturers to follow when writing the equipment data tags as well as for electricians when sizing conductors.

View attachment 514180

What Most Techs Get Wrong About Wire Sizing

Over and over again, I have heard HVACR technicians and electricians quote rules of thumb regarding wiring sizing, and I have witnessed and participated in many heated debates on the topic.

www.achrnews.com

Interesting. Never knew that about HVAC circuit sizing. Always learning something new here. Thanks.

 

[JamesW]

 

[stunatu72]

If you use a 50 amp breaker, then the wire should be rated to 50 amps.

If you use a 60 amp breaker, then you should use a wire rated to at least 60 amps.

You should verify that the voltage drop is less than 5% which depends on the wire size and length from the main panel.

View attachment 514168

Thank you. The wire gauge seems fine but the 60A breaker seems to be oversized. The new thermopump I’m looking into if the old one is done is a Pentair Ultra Temp 110 which has an MCA of 42A, recommended breaker of 50 A and max breaker of 70A. Will run 6AWG wire and keep the existing 60A breaker. That seems to align much better.

 

[ajw22]

This discussion earned an entry in Electrical GFCI - Further Reading

 

[1poolman1]

Thank you. I’m actually looking for specific guidance to make changes to my setup and learn in the process. The existing heat pump has an MCA of 36A and a max breaker of 60A. No wire gauge was indicated on the Hayward label. What would have been the appropriate wire gauge to use? Everywhere I’m reading, 8AWG was sufficient for an MCA of 36A. Here’s an example: Wire Size Calculator — Electrical Guy.

What's being missed is that if you are going to put in a circuit breaker that won't trip until the 60A threshold is hit, the smaller capacity wire may cause a fire before that happens. Think of it this way, its to protect your family from the harm that a poor pool or equipment installation can cause.

 

[stunatu72]

MOCP VS. MCA

In air conditioning, we are given a gift by equipment manufacturers on the equipment data tags: the minimum circuit ampacity (MCA) and MOCP or max fuse/max circuit breaker rating.

These ratings on the data tag tell us exactly what minimum ampacity the circuit must be capable of carrying as well as the maximum size the circuit breaker or fuse may be able to protect the circuit against in an overcurrent condition.

Take a look at the Lennox air conditioning condensing unit tag on Page 19.

Notice that the MCA is 28.6 amps and the maximum fuse or circuit breaker is 50 amps.

This means it is allowable to install this unit on a circuit breaker rated at 50 amps and a conductor rated at 28.6 amps, according to the NEC’s NFPA 70.

I know this goes against what many of you have been told and understood your entire career, but take a deep breath and read on.

NEC article 440 was added because air conditioning and refrigeration systems are different from typical loads, like lights and heaters. Air conditioner compressor and fan motors are largely inductive (magnetic) loads and have different characteristics than purely resistive circuits. Article 440 has specific guidelines for HVAC and refrigeration equipment manufacturers to follow when writing the equipment data tags as well as for electricians when sizing conductors.

View attachment 514180

What Most Techs Get Wrong About Wire Sizing

Over and over again, I have heard HVACR technicians and electricians quote rules of thumb regarding wiring sizing, and I have witnessed and participated in many heated debates on the topic.

www.achrnews.com

Thx for the great summary and links. I landed on the same article as well as others to rationalize all of this.

This video also explains things well for air conditioning units but article 440 applies to heat pumps if I got it right:

. You choose a conductor size that support the MCA and a breaker that does not exceed the maximum breaker size. The Hayward label I shared only specified the max whereas the Pentair specs I shared specify a min and max breaker size. You can opt for a smaller breaker, but too small and it will be nuisance tripping all the time.

He also explains how in air conditioning and other devices covered by article 440, the circuit breaker protects against short circuits and ground faults, while the motor itself protects against overcurrent. Lastly, when the temp isn’t referenced in the product label, you default to the 60 degrees column in the table.

 

[stunatu72]

What's being missed is that if you are going to put in a circuit breaker that won't trip until the 60A threshold is hit, the smaller capacity wire may cause a fire before that happens. Think of it this way, it’s to protect your family from the harm that a poor pool or equipment installation can cause.

How I see it: I assume the reason they state the MCA and max breaker is so the installation is code compliant. Manufacturers have to state both to be code compliant. Why would the onus be on us (customers or users/electricians) to identify the “optimal” breaker size for equipment we have not manufactured or run tests on?