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T-8's and Needle Valves
> From: "Sherlock W. Wong" <wong at dt_wdc.com>
> Subject: Triton Bulbs
> I recently bought some Triton 36inch 30W bulbs that
> are 1 inch in diameter because they were on sale.
> I read in a posting that not all 1 inch diameter bulbs
> are really T8 bulbs, they might be T12's.
> So the question is: what type of ballast should I use
> on these Triton's?
> - 30W T12 with T8 endcaps
> - 30W T8 with T8 endcaps
Okay, it's time once again for that reminder...
I know it can be confusing, but it's unfortunate that we all use the term
"T-8" to mean "High-Efficiency Fluorescent" nowadays, because there are
TWO KINDS of T-8's. In the strict sense, T-8 does refer to the diameter
of the bulb, i.e. 8/8 of an inch or 1" diameter. The OLD kind of T-8 has
been around forever, and works just like the normal old T-12, but the NEW
kind requires the special ballast and is super-efficient.
How do you tell which type someone is refering to? Several methods:
1. Bulb's marking code: The new style T-8's have codes like "FO32-T8"
(4' model) and "FO17-T8" (2' model), while the old bulbs will just be
"F30-T8" (similar to "F40-T12") or "F15-T8". -> No "O" in the
2. Wattage: Old-style bulbs come in 15 watts for 18" tubes, and 30
watts for 36" tubes. These are the two common sizes (24" bulbs at 18-20
watts(?), and 48" bulbs at 40 watts come in T-12 sizes usually).
New-style T-8's are 17 watts for 24" and 32 watts for 48". I haven't seen
a new-style T-8 in 18" or 36" yet, so I don't know if they exist.
3. Context. New-fangled T-8's are commonly available in 2' and 4'
sizes. The old-style T-8's usually refer to the 18" and 36" bulbs. (I
have seen old-style T-10 4' tubes, though; don't rely on this clue
So here's the deal. If you use snug-fitting endcaps and have a T-8, you
MUST have T-8 endcaps or they will not fit! (A T-12 endcap will be 1/2
inch too big). If you're just using regular fluorescent sockets, you can
use either size in the fixture..
However, when determining which ballast to get, you will have to look at
the above 3 clues.
Perhaps I need to put a table in the FAQ. :)
> From: "Dixon, Steven" <stdixon at bechtel_com>
> Subject: CO2 Controllers
> Erik: I couldn't quite picture how you adjust the Nupro B-4MG2 valve
> for the "fully closed" position. I would hate to break mine right out
> of the box! Loosen the hex nut for the knob and do what??? Thanks.
Maybe "fully closed" is not the right term. There's a position at which
you can't turn the knob any further closed. This is determined by how
high up on the valve shaft the knob is attached. I'm making the
assumption that you hit that point based on your last e-mail. If you
loosen the hex nut, you can move the knob up a little bit (re-tighten the
nut!), allowing you to close the valve further. As Jeff noted, the valve
cannot be "fully off", but you should be able to get way more control than
you have been getting.
Check Jeff's other possibilities. I forgot about the teflon tape thing...
someone at a fitting supply store warned me about that one too. Now I use
teflon goop instead.
Erik D. Olson amazingly, at home
eriko at wrq_com