heater issues.

[Cory Keeper]

Ok, I have a 250w Stealth in my 29g tank. Due to my 29g being my main show tank, I moved it around the intake and kindly hidden from site. Bad idea apparently. I noticed my water was a tad on the cold side, about 74F. Granted it was a lil chilly in the room, but thats what the 250w was for. When I went to adjust the temp I noticed it was already set for 82. Now I know something was wrong, and I knew it was working cause I could see heated water rising from the heater. So I moved it into a higher flow area, right in front of my spray bar, now on the front glass.

I don't like it here but so far its keeping the tank right at 80 like it should be. So, any ideas as to what I can do here? It would be nice to plumb it inline like inside my spraybar, but not sure how to do that.

 

[CWO4GUNNER]

Because of the basic design of bimetallic thermostat which has really not changed in 60 years becasue it works so well, a strip of metal made of dissimilar metal on each side is used as one electrical contact and a metal screw connected to that knob you turn is used as the other contact.

When you turn the knob higher (righty-tighty) to increase or set temp the screw makes contact with the bimetallic strap closing the circuit and allowing the coil below to get hot. As the bimetallic strip senses ambient heat build up inside the tube it start to bend away from the screw because one part of it being dissimilar shrinks when heated while the other side will expands back once it gets cold again, until the heat rises so much bimetallic strip bends far enough and brakes contact and the heater turns off. Once cold and expanded makes contact again automatically and the whole process starts over again.

This whole process is calibrated at the factory to correlate to the numbers on the dail as best as possible. But over time the bimetallic strip starts to memorize the bend more and more, requiring you to screw the knob in more to compensate until one day your heater knob hits the plastic stop and you trash a perfectly good heater.

Early hang on heaters never had numbers or stops on the adjustment knob and you were required to calibrate your heater to a separate thermometer which worked great and every few months when you noticed a chnage you cranked on the know a little more. Consquently the old HOB heaters lasted 10's of years rather then a couple years like "modern" number dial indicator knobed submersible heaters.

The only heater switches that can accurately sustain a temperature feedback sensing is a mercury switch which requires a level consistent environment to be calibrated like in a wall for your AC & heating thermostat.

So if knob knob your heater reaches the stop and can turn no higher, rest assured that it have many full turns remaining and only the stop need to be cleared by a skilled hobbyist or ET.

 

[msjinkzd]

sometimes if you unplug the stealths for 10 minutes or so and replug them they "recalibrate" or that is how it seems anyway. Something to try before opening it up or having to replace it.

 

[CWO4GUNNER]

Agreed anything is worth a try prior to opening it up, even then the procedure although simple is not for the unskilled in electronics and electricity.

Incidentally when manufactures changed to dial indicating aquarium heaters as requested by customers the stop had to be introduced to keep people within the indicated set range. What was unexpected was the boom in profits becasue heater life unexpectedly fell by a huge margin prompting sales of new heaters , modles, and brands.

After all we are a consumer based economy.

 

[Trigger1985]

How is your spray bar connected to your filter? And what kind of filter. It could be very easy to install an inline, depending on your set up. You could also try getting a small power head, and pointing it towards the heater in it's hidden spot to get some flow on it.

 

[Jill-O]

sometimes if you unplug the stealths for 10 minutes or so and replug them they "recalibrate" or that is how it seems anyway. Something to try before opening it up or having to replace it.

That is good to know :clap:

 

[Cory Keeper]

You seem to be mistaken on the cause of the problem. I wasn't suspecting the heater cause it always seemed to be on. The problem was from the lack of flow where it was at, and wouldn't warm the entire tank. Since moving it directly in front of my spray bar its reached a warm 80F and I can see when it shuts off too.

 

[CWO4GUNNER]

You seem to be mistaken on the cause of the problem. I wasn't suspecting the heater cause it always seemed to be on.

No one was mistaken on this thread, just experienced heater owners without the benifit of having your heater in front of us to diagnose the "heater issue" that you claim now you never suspected.

The fact that you detected it was a placement issue is elementary (box instructions) and not issue, those of us that were mistaken as you put it merely assumed you knew better and needed help with what you made seem like a problem with the heater not us. All of the remedies offered were right just not applicable in this case.

v/r:grinyes: