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How to change an underwater light bulb

To change an underwater light bulb, here’s the process:

1. Shut off power at the breaker, and also at any other switches.

2. It is not necessary to lower the water level. Most all light fixtures have enough cord coiled up inside of the light niche to allow the fixture to be brought up onto the coping stone for repair. Remove the single stainless steel screw at the top of the light (at 12 o’clock). Once this is removed, use a flathead screwdriver to pry the fixture out of the niche. Most fixtures have a tab at the bottom (at 6 o’clock). You may need to pry and wiggle in the direction of the tab to remove the fixture. Once removed, lift it up onto the coping stone.

3. Now we will go inside of the fixture. Use quality tools of proper size, so as not to strip any of the soft metal screws, bolts, etc. On very old fixtures, screws may break easily, or be corroded from years of water and chemical exposure. Old model lights have 8 brass screws around the fixture, which tighten down on tabs. Newer models have a clamp band with only one screw or bolt/nut. Remove the screws or clamp and gently pry the glass lens out of the front of the fixture.

4. After the lens is removed, remove the bulb. Most will twist out counter-clockwise. Some spa lamps or small halogen lamps for pools have small bulbs that you need to push in and then twist to remove. Whatever it’s type, be careful in removing the bulb, old bulbs may break at the base during removal. It’s good practice to cover the bulb with a soft cloth before turning it (counter-clockwise to remove). After removing the bulb, use the cloth to wipe clean and dry all interior surfaces. Thread in a new bulb, specifically made for the fixture. Don’t use something other than the real thing.

5. Before reassembly, turn on power Very Briefly (for 1 – 2 seconds) to check that the bulb/lamp is working.

6. Reassemble the lens onto the fixture, using a NEW lens gasket. This is the rubber gasket around the lens, approx 8″ diameter. Complete the reassembly of the fixture. Make sure screws are very tight. Follow any printed instructions on the lens for proper alignment of lens to fixture.

7. Place light under water and check for air leaks (a few bubbles may come off of the fixture ring). If you have no bubbles streaming out of your gasket, you have a good seal.

8. Replace the fixture into the niche. First coil the cord around the back of the fixture, then locate the bottom tab (on the fixture) and tab receiver (on the niche). Line them up and insert the tab into position, and push the fixture flush into the niche. Then it’s just the « not always simple » task of getting the top screw back in through the light bezel ring and into the threaded hole in the niche. Tighten screw down just snug (not too tight). Test your light again.

If you change the bulb but the light still doesn’t work, use a test meter to check power at the breaker, switches and junction box. (The junction box is usually located off the deck, about a foot high {except on very old pools} near the light. A small box, about 4″ x 3″, with conduit pipes running up into the bottom. Many times they are behind or under the diving board.)

Some would say, however, that before you change the bulb, you should make sure there is power all the way to the bulb. Because you may not have a bad bulb at all.

Note : you may notice there is water behing the lens. Many times the lamp continues to burn even with water surrounding the bulb. If you notice a line of water in the lens, the fixture should be removed. Allow the lamp to dry out and replace the gasket.