UV Sterilizer Heating Tank?

[FL2008]

when u unplug the UV how long you checked back your temp of the water, and at the time you checked your temp, was your heater on or off?
one more thing, depend on the flow rate go through the UV, if it's slow than the recommended, then sure it will heat up the water little bit, like my coral life, it's for 250 gallon tank but i used for my 150 acrylic gallon, and on 24/7 at the recommended flow rate, my temp always at the one i adjusted. and i also use 2 eheim jager 250 watts heater for the tank, i never touched the uv light bulb but i touched the heater already, nothing happened, also my pump is Mag Drive 1200

 

[Bud8Fan]

Like I already stated, I completely unplugged the heaters. When the temperature didn't come down a few days later I then unplugged the UV. With the UV and heaters unplugged the temperature dropped from around just above 81 to just under 79 in a couple days time.

I currently have the heaters completely unplugged and the UV is now plugged into the Ranco controller. It's maintaining the tank at 80 spot on and was off when I went to work this morning.

one more thing, depend on the flow rate go through the UV, if it's slow than the recommended, then sure it will heat up the water little bit,

My water flow is optimized to the UV but once again science rules here. It has nothing to do with flow. Where does the heat go if it doesn't transfer to the water?

Not exactly the best example but what happens when you force more air through a car radiator? More heat is transferred and the radiator runs cooler. Slow the air flow and the heat can build up causing the engine to fail. So one could actually argue that more flow would encourage more heating of the water using that example.

But since my UV is completely enclosed with the bulb in the center I doubt flow has much to do at all with heat transfer. The heat will dissipate into the water at any flow. Unless of course the flow was cut to zero, then the temperature of the water in the uv would equalize with the bulb temperature and the heat would then transfer to the casing where it would escape to the outside air. If it didn't melt down first.

 

[Leptar]

That 40W UV bulb gets to 100F... factor in your Acrylic insulated tank....
That is your problem...

 

[Bud8Fan]

That 40W UV bulb gets to 100F... factor in your Acrylic insulated tank....
That is your problem...

This thread just keeps getting better. Do schools not teach science anymore?

First of all I never said it was a "problem". I simply posted an observance and asked if anybody else has noticed this happening.

100° F? Where did you pull that number from? Take a standard 40w clear incandescent bulb (preferably one of them tall skinny candle type bulbs) and turn it on in a lamp for an hour or longer. Now go unscrew that bulb while it is still turned on with your bare fingers. Come back and tell me it's 100°F. And that bulb has already lost almost all of it's produced heat to the surrounding air before you touch it.

 

[Leptar]

This thread just keeps getting better. Do schools not teach science anymore?

Yes they teach science apparently they need to structure more on reading..

First of all I never said it was a "problem". I simply posted an observance and asked if anybody else has noticed this happening.

My bad and i apologize for assuming it was a problem, I assumed you had known that the Pentair UV lamps produce more heat since they produce more UV then standard UV lamps making them that much more effective

100° F? Where did you pull that number from? Take a standard 40w clear incandescent bulb (preferably one of them tall skinny candle type bulbs) and turn it on in a lamp for an hour or longer. Now go unscrew that bulb while it is still turned on with your bare fingers. Come back and tell me it's 100°F. And that bulb has already lost almost all of it's produced heat to the surrounding air before you touch it.

From the product description they use in their advertising...

Also why mention a standard incandescent bulb?... I thought we were referencing about a Pentair 40W UV not a incandescent bulb...

Pentair Aquatics UV Sterilizers use pure hard quartz material in their bulbs, which dramatically increases the UV output as compared to other conventional bulbs of equal wattage. Pure quartz material resists solarization and improves the longevity of the UV bulb. The unique test tube like pure quartz sleeve isolates the bulb from water contact, providing an optimal bulb operating temperature of 100º F (38º C). This optimal bulb temperature results in a 35% higher UV output over conventional units without sleeves.

Now you have a heat source in a insulated enclosure that is circulating... Yes the Temperature will level off and it did in your tank from 79F to 81F, You unplugged the UV and it went back down... I'll bet if you plugged it back in it will rise to 81F again, and if you unplugged it it will drop to 79F...

 

[Bud8Fan]

I was just using the incandescent bulb to put it in laymans terms and I'm guessing the UV puts off more heat than a standard bulb but I have no proof of that.

Great post from Pentair! Isn't that saying the quartz sleeve allows the heat to dissipate more evenly into the water leaving the bulb at 100° versus water touching it draining all of it's heat? That 100° is operating temperature which means water is flowing through it drawing the heat away. I'd be interested to know how hot the bulb gets without something drawing the heat away.

I think we are just about on the same page Leptar, cheers.

I'll bet if you plugged it back in it will rise to 81F again, and if you unplugged it it will drop to 79F...

You would win most of that bet. Although it would drop to below 79° as my house temperature is around 70° right now.

I have since unplugged both of my heaters from the Ranco and plugged the Pentair into it. I set the temperature from 79° to 80° on the Ranco and so far the combination is keeping the tank at 80° spot on. I bumped it up one degree just so I have a little more "on" time for the UV. The fish don't mind it either.

So right now I have a tank that is 10°-12°F above room temperature with the only controlling heat source being a light.

 

[Bichir4Life]

Don't know if anyone else has said it but it could be a combination of the UV and the pump. With every moving parts comes friction, friction converts to heat. Thats jsut my thoughts if i'm wrong lemme know

 

[Bud8Fan]

Yup, said it earlier:

There is a Mag Drive 2400 in the sump that I'm sure contributes somewhat but the UV is obviously adding heat to this tank.

Next time I have the cover off of the sump I'll have to reach in and feel the pump to see how warm it is. The UV must be adding just enough extra to raise the tank temp over the room temp.

 

[MadRussian79]

"Take a standard 40w clear incandescent bulb" That pentair UV bulb is not incandescent (hot metal) but florescent (hot gas). The bulb would be much cooler than incandescent so 100 sounds about right. Incandescent bulbs loose much more energy to heat.

As far as other heat sources is the stand in which the light, pump, and filter standing enclosed or is it an open stand. If it's an enclosed stand the light, pump, and ballast for the light would be pumping heat into the system. If the area under the stand is warm that's part of the heat comes from. Which would be a concern if the room air circulation changed by say opening a window. If the sand is open (metal stand) then this would have a small contribution.

 

[Bud8Fan]

Under the stand is just storage. All of my filtration is in the adjacent room.

Here is an older picture. I need to take new ones one of these days:
Ignore the yellow arrow. This picture was taken for a thread long ago.

The filter room is about 3 foot lower than the room the tank is in. So the square hole in the wall you see is where the plumbing comes out of the stand.