LED Light Connundrum.

[Melnox]

One of my two LED lights failed. Are you surprised?

I keep my pool at 40°F in winter. When installing LED lights, specifically Pentair Microbrite, I used the dry conduit o-ring, silicone, and teflon tape.

1) Is this enough to prevent water from entering the conduit and causing freeze damage?

1a) Will the light overheat without water in the conduit?

2) Should I pour some sort of non toxic antifreeze into the conduit in case water seeps into the conduit?

2a) Will this create a heat sink thus extending the life of the light?

It's evident that LED pool lights from all brands tend to fail before their rated lifespan. This leads to expensive replacement over the life of the pool. I can only assume this is due to overheating and possible unstable supply voltage/spikes, and general wear on the circuitry. Would a fiber optic system using a single high power light source be cheaper in the long run? Keep in mind that even if it still uses LED, the light would be above ground, with ample cooling and probably a cheaper replacement than a pool light. And if it uses metal halide or halogen, electricity is cheaper at night, and use can be occasional, so savings far outweigh the cost and inconvenience of periodic LED replacement.

So, I guess I'm looking for advice to either inconveniently replace my broken expensive pool light, and continue replacing both lights periodically, or install fiber optic and just deal with a single light source.

 

[Melnox]

UPDATE: So when I installed these lights, I used teflon tape and silicone around the o-ring. I drained the pool and took the lights out. Both conduits had water behind the lights.

I looked into a product called Megaloc by Hercules. There's also Rectorseal T plus 2. These are both used by plumbers and gas fitters etc... instead of teflon tape.

I'm going to give this a try, and then maybe I'll pour some non toxic antifreeze down the conduit to assist with heat transfer from the lights, and also as a safeguard against water leakage/freezing.

 

[Melnox]

Here goes...

 

[Melnox]

Should I pour food grade propylene glycol down the conduit?

 

[Melnox]

Has anyone used an aquarium air pump and line to force air down the LED conduit in order to cool the light in summer, and prevent freezing in case water leaks into the conduit during winter?

 

[ajw22]

I doubt an aquarium pump has enough power to push the water column down.

Even a 2 HP spa blower overheats when pushing a poorly designed water column in a spa.

 

[Melnox]

I think spa blowers are built using fans, while aquarium pumps use a piston or diaphragm so they are able to push air under higher psi water. A fan blows a larger volume of air but with less force. Maybe that's why spa blowers burn out? My light conduit are only about 12" under water, aquarium pumps are designed to push air much further.

I also see pond and hydroponic pumps that are very powerful for their wattage.

Anyhow, I hope there won't be any water down there at all and the air pump will just blow air against the light in order to cool it.

I can also use the same tube occasionally to pump out any water that leaks into the pipe, or just to see whether water has leaked or not. I think a peristaltic pump might be a good choice because it's self priming and the volume of water can't be that great.

 

[Melnox]

Maybe I should run the lights at the 14v setting from my transformer, I think this might lower the current draw and reduce the heat generated by the circuitry. I see the electrolytic caps are rated for 35v so this is probably safe I think. My wire runs are 60 and 80 feet for the two lights.

 

[Melnox]

My goal is to make the lights last a long time and so far it seems like water (freezing) and heat generated by the led itself have been causes for premature failure.

The megaloc should, I hope, eliminate water in the conduit

The air pump I hope will cool the led driver.

The 14v I hope will reduce internal heat.

I'm up for any advice you have that can help extend the life of these leds. I haven't turned the new ones on yet. I'm waiting until I have all safeguards in place.

 

[Melnox]

These leds are so expensive. If I can do any simple task to protect them I will.

Today I added a surge suppressor to my panel to protect the leds (and the other electronic equipment). I hope this helps. I'm not sure if others do this as well?

 

[ajw22]

I'm not sure if others do this as well?

Electrical Surge Protection - Further Reading

www.troublefreepool.com

 

[ajw22]

What are Canada code requirements for GFCI CBs for pumps and gas heaters?

Are the pool lights wired through a GFCI outlet?

Electrical GFCI - Further Reading

www.troublefreepool.com

 

[Melnox]

Hi, the pool lights are wired on the same breaker as a gfci outlet. The other equipment: pump, heater, swg, are far enough from the pool so they don't need gfci protection.

A concern I have is whether the position of the light switch located before the transformer (as per the owner's manual) can cause back emf.

I think Flyback emf and transient voltage spikes on the secondary winding can/will be induced and can severely damage the led circuitry. I thought of this during installation but have since taken it more seriously now that the leds actually failed.

I've seen conflicting info about leaving a transformer energized with no load. But I can simply add another switch between the transformer and led light units, and use the second switch to choose led colour and power them on/off before shutting off the transformer itself.

Any thoughts on this?

 

[Melnox]

Here's what Chat GPT has to say:

Yes, what you're describing is very plausible and transient voltage surges from switching the transformer on and off could be damaging your LED lights, especially sensitive ones like the Pentair MicroBrite.

Here’s what may be happening and why it matters:


---

1. Transformer Switching and Inductive Kickback

When power is rapidly switched on/off to the primary side of a transformer (especially a toroidal type like in the Intermatic PX100), the magnetic field collapses and can cause:

Voltage spikes on the secondary side (12–14 VAC)

These spikes are not well-controlled and can exceed the design tolerances of the LED driver circuitry.


Even though it's low-voltage on the secondary, LED drivers are highly sensitive to overvoltage conditions, especially repeated transient events.


---

2. LED Color Mode Switching Adds to the Stress

The method of changing color modes by flipping the switch rapidly (e.g., 1–5 quick toggles) adds additional:

Repetitive switching stress

Possibly incomplete magnetic field collapse, leading to erratic voltages or phase shifts


This type of rapid switching isn't great for inductive loads and may confuse or overload internal protection in the transformer or lights.


---

3. The PX100 Is Not an Electronic Transformer

The Intermatic PX100 is a magnetic (core and coil) transformer, not an electronic low-voltage driver. It is less capable of clamping transients, and doesn’t have the kind of smoothing or soft-start features you’d want for LED-sensitive applications.


---

Mitigation Options

To protect your lights:

Use a constant-on transformer, and switch the 12V side instead of toggling the 120V input. This avoids repeated core saturation/collapse events.

Install a surge protector or MOV (metal oxide varistor) across the secondary output to clamp surges.

Consider a low-voltage relay or electronic low-voltage switch that toggles just the lights, not the transformer.

Alternatively, replace the PX100 with a LED-rated electronic transformer designed for frequent on/off cycling and LED loads.



---

Next Step Recommendation

Check your PX100 output with an oscilloscope during switching events. If you see overshoot voltages (spikes above 15–16V), that’s damaging your LEDs. If so, install a TVS diode or MOV rated around 15–16V on the secondary.

Let me know if you'd like help selecting a surge protection component or transformer alternative.

 

[ajw22]

Here's what Chat GPT has to say:

Yes, what you're describing is very plausible and transient voltage surges from switching the transformer on and off could be damaging your LED lights, especially sensitive ones like the Pentair MicroBrite.

Here’s what may be happening and why it matters:


---

1. Transformer Switching and Inductive Kickback

When power is rapidly switched on/off to the primary side of a transformer (especially a toroidal type like in the Intermatic PX100), the magnetic field collapses and can cause:

Voltage spikes on the secondary side (12–14 VAC)

These spikes are not well-controlled and can exceed the design tolerances of the LED driver circuitry.


Even though it's low-voltage on the secondary, LED drivers are highly sensitive to overvoltage conditions, especially repeated transient events.


---

2. LED Color Mode Switching Adds to the Stress

The method of changing color modes by flipping the switch rapidly (e.g., 1–5 quick toggles) adds additional:

Repetitive switching stress

Possibly incomplete magnetic field collapse, leading to erratic voltages or phase shifts


This type of rapid switching isn't great for inductive loads and may confuse or overload internal protection in the transformer or lights.


---

3. The PX100 Is Not an Electronic Transformer

The Intermatic PX100 is a magnetic (core and coil) transformer, not an electronic low-voltage driver. It is less capable of clamping transients, and doesn’t have the kind of smoothing or soft-start features you’d want for LED-sensitive applications.


---

Mitigation Options

To protect your lights:

Use a constant-on transformer, and switch the 12V side instead of toggling the 120V input. This avoids repeated core saturation/collapse events.

Install a surge protector or MOV (metal oxide varistor) across the secondary output to clamp surges.

Consider a low-voltage relay or electronic low-voltage switch that toggles just the lights, not the transformer.

Alternatively, replace the PX100 with a LED-rated electronic transformer designed for frequent on/off cycling and LED loads.



---

Next Step Recommendation

Check your PX100 output with an oscilloscope during switching events. If you see overshoot voltages (spikes above 15–16V), that’s damaging your LEDs. If so, install a TVS diode or MOV rated around 15–16V on the secondary.

Let me know if you'd like help selecting a surge protection component or transformer alternative.

You are in Canada, but ChatGPT does not seem aware of the NEC listing requirements for pool light transformers. You should bring it to his attention. Unless you have been given Canada specific advice.

 

[Melnox]

You mean the isolation between 120vac and 12vac?

 

[Melnox]

Chat GPT's response:

You're absolutely right — in Canada (and the U.S.), isolation transformers are required for pool lighting to comply with CEC (Canadian Electrical Code) and NEC (National Electrical Code). These codes mandate:

Isolated secondary windings to prevent shock hazard.

Low-voltage circuits (typically 12–15V) for underwater lighting.

Grounded shield between primary and secondary (in some transformer designs) for safety.


So yes — an electronic (non-isolated) LED driver is not acceptable in pool light applications. That rules out many common LED transformers.


---

What You Can Do Within Code:

1. Use a Pool-Rated, LED-Compatible Magnetic Transformer

Some newer pool isolation transformers are specifically designed for LED lights and handle:

Frequent on/off cycles

Better transient protection

Soft start or inrush current limiting


Recommended options:

Intermatic PX300 or PX100 with added secondary protection

Jandy K1200 / K2000 series (LED-friendly pool-rated transformers)

Spa Electrics / SR Smith LED-rated pool transformers



---

2. Add Secondary Protection to the PX100

To preserve your existing PX100, you can add protection on the 12–14VAC side:

Recommended additions:

MOVs (Metal Oxide Varistors) — 18V AC-rated, across secondary terminals.

TVS Diodes — transient voltage suppressors that clamp high-frequency surges (choose around 15–18V bidirectional).

Snubber circuit — resistor + capacitor network to reduce spike energy.

Soft-start relay or electronic switch — controls lighting without hard switching the transformer.


These solutions reduce voltage spikes caused by magnetic field collapse, which is likely what's stressing the Pentair MicroBrite LEDs.


---

3. Switch on the Secondary Side Instead

Rather than switching the primary (120V) side of the transformer:

Leave the PX100 always powered on

Use a low-voltage rated switch or relay on the 12V side to control the lights or simulate mode changes


This method avoids magnetic collapse in the transformer, reducing surges.


---

Summary:

Yes, an isolation transformer is required — so stick with magnetic pool-rated ones like the PX100. But to protect your LED lights:

Avoid switching the 120V side to control lights or change modes.

Add surge protection (MOV/TVS) to the secondary side.

Consider switching the 12V side only.


Let me know if you'd like help identifying exact components (MOVs, TVS diodes, relays) that would be appropriate and code-compliant.

Great — here’s how you can protect your Pentair MicroBrite LED lights using simple, effective, and code-compliant secondary-side surge suppression, along with a safer switching strategy.


---

Goal

Reduce voltage transients caused by switching the transformer.

Protect the LED circuitry from inrush or inductive spikes.

Stay compliant with pool safety codes (use isolation transformer, low-voltage AC).



---

Wiring Setup Overview

Basic flow:

120V breaker → Switch → Intermatic PX100 → [MOV/TVS Protection] → Low-voltage switch (optional) → MicroBrite lights

We’ll add:

A MOV or TVS diode between the 12VAC terminals.

An optional low-voltage relay to control the lights without switching the transformer.



---

A. Surge Protection Options

Option 1: MOV (Metal Oxide Varistor)

Component: [EPCOS B72214S261K101 or Littelfuse V18ZA2P]

AC Voltage Rating: 18–22 VAC

Clamping Voltage: ~35V

How to wire:
Connect across the two secondary terminals (12V and COM) of the PX100.


Wiring Diagram Snippet:

PX100 Secondary:
12VAC --------------+------------------> Light +
|
[ MOV ]
|
COM ---------------+------------------> Light -


---

Option 2: TVS Diode (Transient Voltage Suppression)

Component: [Littelfuse P6KE18CA or 1.5KE18CA]

Bi-directional

Clamping at ~25–30V

More precise than MOV for fast transient suppression

Same wiring as above



---

B. Optional: Switch 12V Side Instead of 120V

Use a Low-Voltage Relay or Contactless Switch

Relay: 12VAC or DC coil, rated for 5–10A at 12VAC

SSR (Solid State Relay): Preferably zero-crossing, 12V AC rated, with opto-isolation


This avoids transformer switching and eliminates surges from magnetic collapse.


---

Wiring Option for Switching Only the Lights

1. Leave PX100 always on


2. Wire relay contacts inline with the 12VAC to the lights


3. Control the relay via a separate switch or timer




---

Part List Summary

PurposeComponentPart Number

Surge Protection (MOV)EPCOS 18V MOVB72214S261K101
Surge Protection (TVS)Littelfuse TVS Diode (18V bidir)P6KE18CA or 1.5KE18CA
Relay (Optional)12VAC/12VDC coil relay (SPST/DPST)Omron G2R-1A or similar
SSR (Optional)AC solid-state relay, 12V triggerCrydom AC series or Fotek SSR-25DA (check ratings)



---

Want a Wiring Diagram?

I can generate a clear diagram based on which surge device and switching method you prefer:

MOV or TVS?

Do you want to switch the 12V side with a relay, or keep your existing 120V switch setup?


Let me know and I’ll create a detailed image for your setup.

‐-‐-------

MOV vs TVS — Which Is Better for Your Pool Light Application?

FeatureMOV (Metal Oxide Varistor)TVS Diode (Transient Voltage Suppressor)

Response Time~25–50 nanoseconds<1 nanosecond (faster)
Energy HandlingHigh (good for big spikes)Moderate (good for fast, smaller spikes)
Voltage ClampingLess preciseMore precise, predictable
Degrades Over TimeYes, especially with frequent surgesNo (unless damaged by overvoltage)
Cost & AvailabilityCheap, easy to findSlightly more expensive



---

Which Should You Use?

For inductive switching surges from a magnetic transformer like the PX100, both have value:

MOV handles larger energy spikes and power line anomalies.

TVS diode reacts faster and clamps more precisely, protecting sensitive LED electronics.




---

Can You Use Both Together?

Yes — and it’s actually ideal in high-reliability designs.

How to wire them:

Wire MOV and TVS in parallel, across the 12V AC output terminals.

The MOV absorbs larger transients.

The TVS catches the leading edge of fast spikes.


They work together like a layered defense:

+----------------+
| |
12VAC --+---[ MOV ]------+--+
| | |
+--[ TVS Diode ]-+ |
[ Light ]
COM -----------------+

Tip: Use a bidirectional TVS diode, such as P6KE18CA or 1.5KE18CA, to handle AC polarity.


---

Final Recommendation

For your pool light setup:

Yes, use both MOV and TVS — they're complementary.

Keep them close to the PX100 output or as near to the light terminals as practical.

Make sure both parts are rated for at least 18V AC RMS (25–30V clamping).