[PeteSpencer]

Our U/v high voltage fly zapper has packed up only 1 year old: The suppliers have replaced it promptly F o C, but I have traced to problem to the ballast firing the 2 x 15W T8 18inch u/v tubes and I think it is repairable.

Everything else works, the rf switch fires the 2kv grid, both starters are OK, but the bulbs don't light.

The day before one of the bulbs was flickering so I replaced it but no joy.

Trouble is I can't find a compact ballast (120 x50 x 40 mm) which will fit in the casing: they're all 200mm + long.
Does anyone know where I can get a compact ballast 30W total firing 2 x 15 w blacklight u/v tubes?

Any advice would be gratefully received, particularly how critical is the wattage?

In particular would a 30 watt unit be OK for 2 x 15 watt tubes even though the spec says I lamp.

For what its worth the Ballast is a 'Gleeson Ballast GL 30' and made in China:

Googling and comprehensive search fails to reveal suitable unit, or if I find the right size its boarded for one lamp only.

It's not a big deal, I could easily bin it but repairing it would be a challenge particularly as they retail at £60 on Amazon.

TIA

Peter

[Gas Guzzler]

The usual way to connect 2x15w tubes to a single 30w ballast is basically putting the tubes in series, chances are that's how yours are wired but this arrangement does require lower voltage starters, the normal ones won't work. If they've been replaced that could be your problem. Try thesehttps://www.tlc-direct.co.uk/Products/BGFS2.html

[johnm]

How did you check the starters......

[PeteSpencer]

How did you check the starters......

I put new ones in.......

Peter

[johnm]

How did you check the starters......

I put new ones in.......

Peter

That's pretty conclusive then

[PeteSpencer]

The usual way to connect 2x15w tubes to a single 30w ballast is basically putting the tubes in series, chances are that's how yours are wired but this arrangement does require lower voltage starters, the normal ones won't work. If they've been replaced that could be your problem. Try thesehttps://www.tlc-direct.co.uk/Products/BGFS2.html

Yep looking at the diagram on the ballast cover that’s how they’re wired .

I’ve ordered two new starters of exact same spec as per your link ( new ones I put in were slightly different wattage from local B&Q) and will take it from there)

I suppose I could check starters by taking out starters from replacement unit but that’s now in place high up in kitchen and involves faff with ladders etc . I’m in no rush I’ll wait till new starters arrive.

Peter

[PeteSpencer]

How did you check the starters......

I put new ones in.......

Peter

That's pretty conclusive then

But see above!

[johnm]

Have you worked out whether the lamps are wired in series or parallel, because Tridonic and others do compact twins it depends to some extent how critical the dimensions are but 120 x 80 x 30 (roughly) are around

[PeteSpencer]

Have you worked out whether the lamps are wired in series or parallel, because Tridonic and others do compact twins it depends to some extent how critical the dimensions are but 120 x 80 x 30 (roughly) are around

They're in series: do you have a link pls?

Tridonic isn't a name that came up in google search.

120 x 80 x 30 would fit nicely.

There's another factor in that the unit has a remote RF switch (its 9ft up on a wall). That doesn't feature in the circuit diagram that comes with the unit. However whem I power it up with the casing off and stand well back, the 2KV grid comes alive so I'm kinda assuming the RF switch is OK, but I guess its possible that the light strip element of the switch is blown. I don't think so though as there's a small clear glass fuse on the rf switch which is OK.

Oh and if the power switch (3 way) is in the 'isolate RF switch/ direct on/off ' position lights still don't come on.

So my money's on the ballast.

Peter

[johnm]

https://www.tridonic.com/com/en/product ... output.asp

[PeteSpencer]

The usual way to connect 2x15w tubes to a single 30w ballast is basically putting the tubes in series, chances are that's how yours are wired but this arrangement does require lower voltage starters, the normal ones won't work. If they've been replaced that could be your problem. Try thesehttps://www.tlc-direct.co.uk/Products/BGFS2.html

I think I'm starting to understand:
My insect zapper indeed has two 15watt u/v tubes in series with a 4-22 watt starter for each light.

I've ordered (can't find locally) two new 4-22 watt starters. (but would two starters have failed simultaneously?)

As the tubes are in series , (and re- reading your post above , I guess I could use a 'single light' compact ballast of 30 w capacity or close as possible or would I need a 'two light' ballast?
I ask 'cos johnm has pointed me to a two light 'compact' ballast online but I don't want to order it if I could use a 'one light' ballast.

Main condition is ballast has to be no more than 160mm long to fit in casing.

I guess I need to take old unit to bits again and take a pic of ballast and wiring connections . Job for later today.....

Peter

[Gas Guzzler]

I've ordered (can't find locally) two new 4-22 watt starters. (but would two starters have failed simultaneously?)

As the tubes are in series , (and re- reading your post above , I guess I could use a 'single light' compact ballast of 30 w capacity or close as possible or would I need a 'two light' ballast?
I ask 'cos johnm has pointed me to a two light 'compact' ballast online but I don't want to order it if I could use a 'one light' ballast.
Peter

Unlikely 2 starters would fail at the same time but if one does fail it is quite likely due to the series nature of the whole circuit that there would not be enough current flow to operate the remaining "good" starter. If the problem does turn out to be the ballast then any 30 watt unit will do, there is no difference between a twin tube and single tube version. Good luck with t!

[cockney steve]

IIRC, the modus operandi of fluorescents, is as follows......The 2 pins at each end are bridged by a filament. one end of each filament is connected to the ballast , other ends are connected together with the starter in series.

Upon switch -on current flows ballast-filament-starter-other filament-ballast....the filaments heat the gas in the tube , it ionises and the ballast then "shorts" through the gas, causing the starter to open the series connection between the filaments.

You can see the glow at each end of a tube as the filaments heat, some flicker as the "arc" across the gas tries to establish.
A burnt-out filament will cause starting problems and sometimes stroking the tube lengthwise with your hand will assist in lighting it.
UV tubes have a short working life. food shops are recommended to replace them annually.

[PeteSpencer]

Well, I've got the correct output ballast and correct starters on order.

What could possibly go wrong?

Peter