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Jebao 9w UV lamp

I bought a new UV lamp for a pond filter but I don't see any light from the inspection lens in the lamp holder. I checked the the connection in the socket and I see 240v. Does that mean the ballast is working? I've been reading as much as I can but I'm still not sure.

Jebao 9w UV lamp

Does this kind of lamp with no phosphor produce no visible light and therefore the lens at the end of the clarifier tube must have something to make the light visible? Is there any other way to test the lamp?

Replacement ballast

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    \$\begingroup\$ It does produce some visible light and this can be seen in shady conditions during daylight hours and is easily visible at night time. \$\endgroup\$
    – Andy aka
    Commented Jul 28, 2017 at 12:22

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That is a germicidal (UVB) UV lamp. I have a similar one in a UV EPROM eraser.

Here is what it looks like in a fairly dimly lit room:

enter image description here

It might be hard to see outside on a bright day, but it should be easy otherwise.

I am defeating the safety interlock with a pair of tweezers. There are risks in this as UVB can easily damage your eyesight.

If you are measuring 240V at the lamp socket with no lamp installed, the ballast would appear to be okay. This type of bi-pin lamp contains a capacitor that causes the filaments to heat at turn-on thus acting as a starter. If you are still concerned about the ballast you can test it with a similar but visible light 9W CFL lamp.

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  • \$\begingroup\$ Would an 11W lamp work just for testing? I can get one from a shop without having to wait for delivery from an online store. wickes.co.uk/Philips-11W-Pl-s-2-Pin-CFL-Bulb/p/113542 \$\endgroup\$
    – technomad
    Commented Jul 29, 2017 at 9:53
  • \$\begingroup\$ Yes, it should work , they are both G23 base. It just won't be full brightness. Your inspection port probably has a UV indicator paint that glows when exposed to UV- it might be green, for example. \$\endgroup\$
    – Spehro Pefhany
    Commented Jul 29, 2017 at 12:10
  • \$\begingroup\$ Just for info. This filter is at my parent's house in the UK. I have just arrived home again from Thailand with two new bulbs I bought for my drinking water filter in but they are 240V and I found out I needed 60V bulbs. I didn't know they existed but I tested the ballast and saw 60V. I again tested the connections and in the pond filter lamp and saw 240V but when I inserted the lamp and turned on the power the main house circuit breaker tripped. This did not happen previously. Should I just buy a new ballast? \$\endgroup\$
    – technomad
    Commented Aug 30, 2018 at 16:33
  • \$\begingroup\$ Should I post a new question? \$\endgroup\$
    – technomad
    Commented Sep 5, 2018 at 16:27

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