plumbing UV sterilizer

[David3147]

I Have a 60" long 140 DT with center drain to be run with a 1.5" drain at full siphon --the UV pentair 40 W smart is roughly 44" long. I have never plumbed UV before --using for bacterial/dino control (not parasites). Couple questions:

1) Do I just run the drain directly through the UV for efficiency? (The sterilizer is rated at 900-1500 gph for bacteria).

2) I think the drain is going to zig zag a bit and change diameters a couple times on its way from main drain, through the UV, and onto the filter rolls in the sump. Will it be impossible to dial in the drain (one main drain + 1 back up)?

3) Or should I plumb it to the return line to make it less complicated?

Any other considerations?

 

[JGT]

I’d plumb it off the return. With a valve you can control the flow. You won’t be able to do that off of the drain without messing up the flow. It could become a noisy problem.

 

[David3147]

I’d plumb it off the return. With a valve you can control the flow. You won’t be able to do that off of the drain without messing up the flow. It could become a noisy problem.

Question, if plumbed directly to the in sump return, and UV is mounted between sump and DT, what happens when return pump is turned off? Can the UV light be on when dry?

 

[CoralB]

I prefer running it through a manifold system to control contact time as the water passes in front of the light but that’s me . That being said the way tour wanting to hook it up , your flow is backward as it should go from the sump thru the UV then back in the tank

 

[CoralB]

Question, if plumbed directly to the in sump return, and UV is mounted between sump and DT, what happens when return pump is turned off? Can the UV light be on when dry?

If power goes out it goes out in the UV as well . To answer your question the answer is no !! . A UV light should never run dry

 

[JGT]

Question, if plumbed directly to the in sump return, and UV is mounted between sump and DT, what happens when return pump is turned off? Can the UV light be on when

I prefer running it through a manifold system to control contact time as the water passes in front of the light but that’s me . That being said the way tour wanting to hook it up , your flow is backward as it should go from the sump thru the UV then back in the tank

Agree, this is the best way and how I have mine setup. Go from pump through manifold, into UV, out of UV and tie it back into the return line that goes to the DT.

 

[JGT]

Question, if plumbed directly to the in sump return, and UV is mounted between sump and DT, what happens when return pump is turned off? Can the UV light be on when dry?

You should set it up so if your return pump is off, so is your UV. Bulb gets hot without any water flowing through it. Could wind up cracking the sleeve when the pump is turned back on.

 

[CoralB]

running the water that goes through the UV off the manifold back into the sump is fine

 

[littlebigreef]

If you’re not running a manifold an alternative I saw in a brs video was to run two internal return pumps, that way you can dial one in as necessary and run the other (without the sterilizer) fully open. May not be feasible for every application though.

 

[David3147]

You should set it up so if your return pump is off, so is your UV. Bulb gets hot without any water flowing through it. Could wind up cracking the sleeve when the pump is turned back on.

I am thinking that if the UV is horizontal with the inlet and outlet ports pointed up (like in the diagram) the UV bulb should stay mostly submerged in the event of return pump outage? (may need to test this theory)

 

[JGT]

Potentially, yes. And there should be some water pooled in the body to keep it from getting too hot. But def test it out.

 

[littlebigreef]

I am thinking that if the UV is horizontal with the inlet and outlet ports pointed up (like in the diagram) the UV bulb should stay mostly submerged in the event of return pump outage? (may need to test this theory)

You'll want to take a look at your unit. Many, not all, are meant to be vertically oriented so you don't have air getting trapped inside.

 

[CoralB]

I am thinking that if the UV is horizontal with the inlet and outlet ports pointed up (like in the diagram) the UV bulb should stay mostly submerged in the event of return pump outage? (may need to test this theory)

If you were to lose power and even if you had it horizontal with the ports pointing up and for some reason the light would come on and the pump didn’t when power returned I’m not sure how long you would be safe as the little bit of water would get hot and more than likely boil out . The water is not supposed to come in contact with the bulb as the water passes through a quartz sleeve in front of the bulb . Imo you would still be at risk of having the quartz sleeve bursting or cracking . Plugging your UV into a separate gfci May or may not help if the water came in contact with the water . I never Had a situation where the pump and the UV never came back on together . Actually never thought about a situation like that would occur I’d have to give it more thought . I also only run mine 12 hours a day on a timer and use it to keep my water clear and glass clean . Their are so many other things that can go wrong and it would be hard to prepare for everything but in this case , not saying it hasn’t happened just that I’ve never heard of it happening . I’m sure there is probably a way to have the UV light shut off if the sleeve cracks and water comes in contact with the bulb sending electricity into the tank . Maybe like I said earlier a gfci but what if the unit itself could catch fire , do you have a auto sprinkler system put in under your tank that shoots foam retardant ( which would kill your inhabitants) . Sorry getting carried away . We have product to keep our heaters from going bad and raising the temp in our tanks , their are gfci outlets to plug our equipment into, their are grounding probes we can use to prevent getting shocked if a piece of equipment fails and throws stray voltage . We have water alarms so if we get a leak it can sound a alarm and their are controllers so we can receive notification on our phones . I’m sure I could go on but you get the picture . Hope this helps .

 

[CoralB]

The water passing through the sleeve also keeps the UV unit cool . I’m not sure what effect that would have on the unit even if water stayed full but stagnant and the sleeve stayed intact without being damaged . Would it get hot and melt or catch fire ? Even though I’ve never heard of this scenario where the light came on but the pump didn’t after a power outage you do raise a good question . Definitely although I would image it to be a rare occurrence, it’s definitely food for thought .

 

[David3147]

The water passing through the sleeve also keeps the UV unit cool . I’m not sure what effect that would have on the unit even if water stayed full but stagnant and the sleeve stayed intact without being damaged . Would it get hot and melt or catch fire ? Even though I’ve never heard of this scenario where the light came on but the pump didn’t after a power outage you do raise a good question . Definitely although I would image it to be a rare occurrence, it’s definitely food for thought .

thank you all for pointing this out, not sure I would have thought of it. Will tape a plastic stick or something to the DJ switched with these plugged next to each other. Then I wont forget to turn one off without the other. love this forum!

 

[CoralB]

Or tie a string around your finger.

 

[HoosierHero]

General question for UV’s. Would it work to run a line from the return line to the uv and then back into the sump? O