Excessive amperage draw

[Starmstr]

What would cause a normaly functioning ballast to excessive draw a larger amp load?

Ballast in question is a 2yr old PFO dual 250 with probably 2 yr old iwasaki bulbs.

It's functioned perfectly for 2yrs but as of late has burned out 2 timmers.

Any answers from EE's more than welcome.
Steven

[PerryinCA]

I think the problem is with the lamps. As lamps age, they become less efficient and harder to light. Often the ballast compensates for the loss of efficieny and the lamps keep burning, but it does end up drawing more current.

A couple ways to help avoid problems are:

1) Put an inline fuse into the hot lead (Amperage rating of the fuse depending on the ballast type and wattage).

2) Change the lamps at 18 months

3)Set the ballasts on two different timers. Amperage draw is the highest during initial firing. by ofsetting gy just a few minutes, you can lessen the 'hit' of the lamps initial draw.

When you put new lamps in. be sure to drop the photo period, or add some screen over the top of the tank. PAR and UV intensity will be alot higher on the new lamps compared to the 2 yr old ones.

-Perry