[cygnusx2]

I have 2 fixtures that I recently replaced with 32w bulbs from 40w bulbs. Every time I turn them on they flicker. I thought they might be bad so I took them back and got different ones. They did the same thing so I checked the fixture with the old bulbs and they worked fine. Any thoughts on way they won't light:confused:

[EPMiller]

Did you change from T12 tubes (40watt) to T8 tubes (32 watt)? That usually causes problems. You will have to look at the ballast and see what tubes it is rated for. Very few ballasts can operate both T12 and T8 tubes. You can only use tubes that are compatible with the ballast or you will have early tube failure, early ballast failure, inconsistent strike, inefficient operation, a combination of the above,. and so on. Check your ballast.

If you want to go to a lower wattage tube you probably will have to change the ballast. Be careful, changing ballasts often requires changing wiring configuration unless it is the exact replacement. Rapid start magnetic ballasts and instant start electronic ballasts require major changes in hookup. The schematics are on the ballasts. Also clean the metal fixture. It is amazing what problems are caused by a dirty fixture.

[cygnusx2]

Yes, that was the problem... thank you, I'm just going to buy the 40w bulbs.

[EPMiller]

Most people do not realize that for fluorescent fixtures you have to replace tubes with the same thing as you took out even though there are all kinds that will fit. Ballasts can be finicky. Now that 40 watt T12 tubes are not manufactured any more, you have to use the 34 watt T12 tubes, which is the closest replacement made. Almost all ballasts will run the 34 watt tubes, they just might have a harder time starting at temperatures below 60 degrees F. If you take the center cover off and expose the ballast, you can read (on the ballast) what tubes can be run by that ballast. Just don't pinch any wires when you put the cover back on. And as I said before, clean the metal fixture when you have the tubes out. It is amazing what problems are caused by a dirty fixture, and a clean fixture will extend the life of the tubes.

EPM