2 x heaters failed in 3 days

[Cisco_Ray]

I am in the pocess of rebuilding my tank and have housed my fish in a temporary tank and on both mornings my temp dropped to 21 degrees or 69 and on both occasions the heaters have filled up with water and failed. Both heaters are used. Hopefully the 3rd one does not fail

Is this a normal occurrence for used heaters?

 

[Cisco_Ray]

The 3rd heater has condensation in it now..

 

[Magnum Man]

pretty normal on older heaters... the really old ones clip[ped on the side of the tank, with the knob above the water, and those were water proof, unless they got dropped in, or the glass broke

 

[Donya]

Hmm...I think I've had that happen only once in the many years I've kept aquariums and it was due to a crack if I remember. I have seen minor condensation form inside heaters many times, but it was a gradual thing with plenty of time to replace the equipment before the whole unit was full of water. A series of sudden water-filled failures in sequence seems kind of suspicious to me.

When you say "used" heater, are these purchased second hand or just bought a long time ago but new at the time? If it's not down to something like a shifty ebay seller sending you a box of duff equipment, then it's possible either that there's a gasket/glue/etc that is too old and therefore now water-permeable, or the heaters are not up for the job being asked of them in terms of the combined age, watts, and ambient/tank temp differential needed. When heaters are "trying too hard," one of two things happens. If the safety mechanism that controls when they turn on/off works properly, then the heater keeps doing it's on/of cycle and just fails to get the tank temperature where you want it; it can cause heating elements to pop from stress and result in an early heater death, but I wouldn't typically expect it to fill the unit with water. However, if the safety mechanism isn't doing its job (or if there is no actual overheat-protection, or if the thermostat is broken, etc.), then the unit can catastrophically overheat itself and all kinds of nasty things can happen: parts can crack/melt, seals can fail due to different expansion rates of materials, etc.

 

[Cisco_Ray]

Didnt buy them new. Just stuff I collected over the years. No cracks or damage to them. Very strange for both to fail exactly the same. Both 200w in only 70 litres of water so not really over worked. I guess just old heaters with worn out perished seals..

 

[GaryE]

Buying a used heater is unfortunately like buying a used light bulb. People often unload them when they no longer trust them. The seller can honestly say they work at the time of purchase, but their useful life can be short.

I don't know the 3rd brand, but the black fluval has been on the market for many years, and probably dried out after long use. The brown one shows rust inside. I'm told 3 years usefulness is to be expected. My black fluvals are 10 years old, but they sit in tanks when unplugged. I rarely use any heaters if I can avoid them.

I recently had an eheim turn off for good after close to 20 years, and two younger, 15 year old models can't be adjusted anymore, but are reliable at set temps. We won't see devices like that again. 3 to 5 years is doing well. Then you get scared they'll cook the fish. I retire them. Some sell them.

 

[Cisco_Ray]

The older type heaters. Are the knobs suppose to be above the water level?

 

[Magnum Man]

I'm an old man, so when I say older... those were in effect a test tube with a piece of plastic attached to the top, and a heating element stuffed into the test tube... often not even intended to be water resistant... they are older than the ones you pictured... the pictured ones appear to have been immersible, when new, but leaked at the seal... preowned items, could have been stored in unheated storage... I have too many old items to store them in the house, so any heaters outside in the Minnesota winters would be suspect...

 

[Lateral Line]

The first heaters I used were heaters, there was no thermostatic control, you used a separate device to switch the heater on and off. I recall these devices sat outside of the tank against the glass.. Was the later sixties.

 

[FranciscoB]

Most fully submersible heaters (i.e., modern ones) typically don’t do well if stored long term dry, after having been use for a while. The rubber gaskets dry out and crack, resulting in leaks. This is particularly true if stored dry in places that withstand great variations of seasonal temperature, such as garages, basements or attics.
And then, even in the best of circumstances, heaters are possibly the most fail-prone of aquarium gear. I have been lucky but always have spares. Good luck.