HELP: Fluorescent tubes

We have a long strip fluorescent tube light in our kitchen that's decided to blow.  The only markings on the tube are OSRAM L 36 W/23. 

Will some place like B&Q or Homebase have a replacement for this?  Will those markings be sufficient enough information for locating a replacement?

Probably.  I'd also measure it before I went.

We have a little lighting shop behind our flats that happened to have the tube.  THANK GOODNESS!  I wasn't looking forward to cooking Christmas and Boxing Day dinners in the dark.

You've already found a replacement, so it's probably immaterial now, but for a standard flurorescent tube the length, diameter, and wattage are generally sufficient to find a suitable replacement.

The most common tubes are the T12 (traditional size) and T8 types (slimline).  The number in each case actually refers to the diameter of the tube in eighths of an inch, so T8 is 1" and T12 is 1-1/2" dia.

The other letters and markings vary between manufacturer are often indicate the type of phosphor coating, e.g. white, warm white, cool white, etc.   You can replace a tube with one which has a different color temperature so long as the physical size and electrical ratings are the same.

As your tube is rated 36 watts, I would guess it's a 4 ft. size.   Osram T8 4' 36W tubes are currently £1.79 plus VAT in my trade catalog.  I expect you probably paid about double that in a local hardware store.

Yes, it was a 4' tube.  We only had those markings to go on last night and I was practically freaking at the thought of cooking Christmas dinner in the dark.  After doing some research, we found the T8 marking as it seem to be the only type that was 36 watts.

And it only cost £1.40!

I installed it, but now when I turn on the light at the switch it doesn't come on.  Instead I have to hit a button on the fixture to make it fire.    Hubby said he'd look at it when he gets home.  So fingers x'd!

That's good on the price!  Sometimes those specialist lighting places which have been family concerns for years can offer good rates though.  Prices also vary depending upon whether a well-known brand such as Osram, G.E., etc. or a lesser known equivalent.

I installed it, but now when I turn on the light at the switch it doesn't come on.  Instead I have to hit a button on the fixture to make it fire

  

Do you mean you have to turn the starter back in its socket to get the lamp to strike (light up)?   If so, then you probably need a new starter.   

Probably.  I'd also measure it before I went.

I know it's too late in this instance, but I wanted to say that when I need to replace an odd-shaped bulb, I just take the burnt-out bulb with me to the shop.

Do you mean you have to turn the starter back in its socket to get the lamp to strike (light up)? If so, then you probably need a new starter.

You'll have to forgive me, Paul, as I'm woefully ignorant about these tubes.

When the light went out last night, hubby hit a starter button on the fixture.  He said that some times you have to do that to get them to fire.  The light wouldn't fire after hitting that button on the fixture, so we were left thinking that we needed to replace the bulb.

After putting the new bulb in, I turned on the wall switch but the light wouldn't come on.  I hit the fire button on the fixture and the light turned on.  But that's only way it will come on now (turn on the wall switch then hit the fire button).  We've never had to do that before.

If it's the most common switch-start type of fitting, then there will be a starter somewhere.  The starter is a small metal- or plastic-cased unit which just plugs into the fixture:



I suspect your "fire button" might actually be the starter you are manipulating (disconnecting a malfunctioning starter will often have the same effect as the starter operating properly, as far as the rest of the light is concerned).    If you can see one of these starters, then try replacing it as well (they're cheap).   

There are other types of wiring on fluorescents though, including types which do not use a switch starter.   Let me know if you can't find one.

We'll have a look at that, Paul.  Thanks.  After two days of hitting the fire button to turn on the kitchen light, it now magically works with only the wall switch.

It does sound like a faulty starter.   They often work intermittently for a while before giving up the ghost completely.

By the way, when you switched on at the wall and the light didn't strike, could you see the filaments glowing at each end of the tube?

Nope!  Not at all.  However, if you didn't turn the starter in the right direction, it would only light at the ends.  But at least when the starter fully goes, we'll know which part to replace.  Thanks for the tip, Paul!

Ah......   When you saw nothing from the tube at all, you most likely had the starter disconnected from the circuit (turned counter-clockwise).

What happens normally is that when you switch on there is a complete circuit through the filaments at each end of the tube and the starter.  You see the ends of tube glow (normally with a yellow/orange color) and after a couple  of seconds the starter breaks the circuit. 

That stops the filaments from glowing, but the pulse of power generated by another component inside the fixture when the starter opens causes the tube to strike, and the ionized gas then results in the tube lighting as normal. 

Once the light is running, the starter plays no part, and you can actually remove it completely and the light will stay on.   If you try to switch on without the starter though, there will be no circuit to heat the filaments and at best you might see a few feeble flickers as the tube tries to strike without the appropriate heat and pulse.

Starters generally fail in two ways: Either they don't complete the circuit when you first switch on, or they fail to break the circuit once the filaments are glowing.  In the first case, the light will just sit there as if there was no starter at all. 

In the latter case, the filaments will just continue to glow but because the starter never opens the light will not strike.   That's when turning the starter to disconnect it by hand will make the light come on, as you are effectively breaking the circuit as the starter should do.   If the light just sits there indefinitely with the filaments glowing, then eventually the tube will burn out (which could be what happened to your original tube).

Sometimes as the starter goes intermittently faulty you'll find that the tube strikes, but after a while the starter closes again, extinguishing the tube and heating the filaments again.  The light will then often flicker on and off randomly.   Again, removing the starter once the tube is lit will allow it to work until it's switched off.

There is a guide to fluorescent tube markings here:
newcomer link: http://www.ohmsandwattsservices.co.uk/kbase/kb_0002_fluorescent_tubes.php [nonactive]

When the light went out last night, hubby hit a starter button on the fixture.  He said that some times you have to do that to get them to fire.  The light wouldn't fire after hitting that button on the fixture, so we were left thinking that we needed to replace the bulb.

After putting the new bulb in, I turned on the wall switch but the light wouldn't come on.  I hit the fire button on the fixture and the light turned on.  But that's only way it will come on now (turn on the wall switch then hit the fire button).  We've never had to do that before.

What?!  a 'fire' button on the fitting?
I've got a fluorescent tube out in the kitchen right now... I'll try to look at that, but the ceiling is so high, it's unlikely I can reach it.