Fixed my heater issue today (hopefully permanently)

[jesse-99]

So twice last year in 2023 my Jandy heater wouldn't fire up on its own even when the iAqualink app was calling for it to turn on. Both times I verified the heater itself was fine if I re-installed the wiring loop on the fireman's switch (of course, the wiring loop was long since lost, but I was able to make a new one with spade connectors).


Putting that loop in place overrides any control from the Jandy iAqualink controller and instead just allows for the heater to run manually using the actual physical controls on the front of the unit. So that told me the heater itself was fine.

When this happened both times last year, I found that the voltage coming back to the fireman's switch wasn't 28VAC like it was supposed to be, it was only like 6-10VAC. My "fix" was to re-strip/re-terminate the end of the wires going to pins 1-2 of the Green 10-pin terminal bar and re-strip/re-terminate the wiring at the fireman's switch. Which seemed to get things working...




...Well fast forward to the 2024 season and I have the exact same problem so I was just going to run all NEW wiring. But this time I decided to RTFM before installing new wire because the wiring that was in place seemed very thin for 28VAC, and quickly realized the Jandy manual (on page 19) states that those wires are supposed to be 14AWG in size. The wiring that had been in place (for 12 years now?) was 22-24AWG. So this morning I replaced that older wiring with thicker gauge wiring (16AWG was all I had), but as soon as I did that, the heater started working again and I can control it from the iAqualink app once again!



Passing along in case anyone else runs into a similar issue. (Please remember to turn off breakers for the heater and control panel BEFORE doing any re-wiring)

 

[ajw22]

22-24 gauge wiring is what you find in 8 wire Cat5/6 cable.

If that is what you have twist together every two wires to make it a 4 wire cable.

 

[jesse-99]

I've replaced that older 22-24WG wiring that was previously there with 16AWG this morning , so all good... so far!

 

[JamesW]

The wire size depends on the current, not the voltage.

It is a very low current and the wire does not need to be very big.

The Mastertemp guide says 18 gauge, which is plenty.

Use 18 gauge wire with a minimum 3/64” (1.2mm) thick insulation rated for a temperature rise of at least 105°C.

The Hayward book says 22 or 20 AWG depending on length.

Jandy says Low Voltage Wiring should be at least 22 AWG, but it does show 14 AWG for the heater connection, but I think that that is probably not necessary.

In any case, always follow the manufacturer's installation instructions.




3.3 Low Voltage Wiring.

Minimum wire size should be 22 AWG.

If wire run is more than 300 feet, larger wire should be used.

https://cdn.fluidrausa.com/-/media/zodiac/global/downloads/jandy/automation/6594.pdf?

 

[JamesW]

When this happened both times last year, I found that the voltage coming back to the fireman's switch wasn't 28VAC like it was supposed to be, it was only like 6-10VAC.

You might not be measuring the voltage correctly or maybe the wire was damaged.

I do not think that a 22 gauge wire would cause that much voltage drop because there is virtually no current flowing.

Check the actual current flowing to see what it is.

In my opinion, 20 AWG or 18 AWG is sufficient for a fireman's switch.

Maybe they call for 14 AWG rated for 600 volts that is also high temp rated to 1,000 degrees, bulletproof, weatherproof, Mil-Spec XYZ123, coated in Kevlar, titanium jacket, shielded etc.

Is it necessary?

Probably not.

In any case, follow all manufacturer's instructions.

 

[JamesW]

22 AWG wire has a resistance of about 16.14 milliohms per foot or 1.6 ohms per 100 feet.

For a 100 foot wire, you have 100 feet each way for a total of 200 feet and that is 3.2 ohms.

The current is much less than 0.5 amps, so if we use 05. Amps, the voltage drop will be about 1.6 volts.

V= IR.

V = (0.5 amps)(3.2 ohms) = 1.6 volts maximum.

24 volts will drop not lower than 22.4 volts.

 

[jesse-99]

The main reason I replaced the wire was because 2x before in 2023, the heater stopped receiving the full 28VAC back from the Jandy controller board. Both times previously I fixed it (albeit temporarily, since it happened again this week when pool was opened) by re-stripping and re-terminating those wires. So this spring, when I found low voltage again at the fireman's switch, I decided it would probably be better to replace the 2 wires between the fireman's switch and the Jandy control board since it wouldn't take more than 20 minutes of my time, and in the process, I opted to use a larger gauge wire as per the manual spec of 14AWG. It's working now, hopefully permanently moving forward.

 

[JamesW]

My main point is that the smaller wire should not have been causing that much voltage drop.

Maybe it was damaged in some way or maybe there is a different issue?

Are you getting the full voltage now?

 

[jesse-99]

24 volts will drop not lower than 22.4 volts.

That's assuming my older wire was in good condition, which it may not have been. It had been kinked and bent and smooshed in numerous places, and the ends seemed a tiny bit corroded from moisture in the air... The last part being previously fixed by re-stripping the ends), so who knows if there were a lot of micro-breaks in the actual copper cabling or not in the 50foot cable run that was previously in place. My guess is, after 12 or so years, there was.... so again, better safe than sorry, I just replaced the wires completely this time with a new 6' run, and went with the spec'd gauge in the manual.

 

[jesse-99]

My main point is that the smaller wire should not have been causing that much voltage drop.

Maybe it was damaged in some way or maybe there is a different issue?

Are you getting the full voltage now?

Yes, agreed about it being damaged. I added additional information about that a few moments ago as well above.... I don't disagree that 22-24AWG -should- be good enough, I certainly can't disagree with the math. I mean, it was working fine with 22-24AWG for 11+ years before I started seeing intermittent problems, which may have been more to the corroded ends, the cable kinks, the smooshed areas, etc.