# Knocking, clicking sound from heater



## MSG

*Does your heater have a ON indicator light?*

The clicking noise is usually the heating element turning on. It's a normal sound. 

The little chip/temp sensor inside the glass tube has determined the water is colder than the temp you set it at, so the heater switches on = click noise.


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## Public Alias

I get the same sound from my heater. Not just an occasion clicking, but I would get a continual knocking that would sometimes go on for about 10 minutes at about 1 knock every 1-2 seconds.

It seems to just do this when it has to work harder, like during winter. It works reliably though and I haven't had any issues so I wouldn't worry about it too much.


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## cprash

MSG said:


> The clicking noise is usually the heating element turning on. It's a normal sound.
> 
> The little chip/temp sensor inside the glass tube has determined the water is colder than the temp you set it at, so the heater switches on = click noise.


My clicking is a little bit closer to what Public Alias has going on. It also didn't make the on/off click last winter.


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## MSG

I've never heard KNOCKING noises before, but it could be the sound of the heating element burning out. I've seen those All Glass AQ heaters before, not the highest quality. Some of the other heaters I've noticed burned out elements on the inside. 

Take some focused pictures of the heating element every couple weeks to see if anything changes.

You may want to put a new heater on the buy list this winter just in case. 

What is the wattage of this heater?


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## cprash

MSG said:


> I've never heard KNOCKING noises before, but it could be the sound of the heating element burning out. I've seen those All Glass AQ heaters before, not the highest quality. Some of the other heaters I've noticed burned out elements on the inside.
> 
> Take some focused pictures of the heating element every couple weeks to see if anything changes.
> 
> You may want to put a new heater on the buy list this winter just in case.
> 
> What is the wattage of this heater?


It's 100 watts I believe. I'm not going to monkey around with heaters, I'll grab a new one tomorrow. Would hate to risk it.


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## cichnatic

Do you have it sitting horizontal or vertical? My old one used to click when I had it horizontal but never notice the noise when its vertical. Either way, I swapped it out with the aqueon pro for ease of mind and like it much better.


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## cprash

cichnatic said:


> Do you have it sitting horizontal or vertical? My old one used to click when I had it horizontal but never notice the noise when its vertical. Either way, I swapped it out with the aqueon pro for ease of mind and like it much better.


Yes, I had it vertical last year, horizontal this year. Odd


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## PlantedRich

This is one of the big defects designed into many heaters. 
This is a basic design heater pulled apart to show where things are located. Imagine this is all shoved back down into the tube. The controls are just above the heating element and inside the glass. Some heaters try to isolate them by shoving a bit of insulation between the two. 









Many use a bi-metal spring with contacts to turn the heat on and off. When cool the metal makes the contacts touch and the heater is on. When the heater gets the metal hot, it opens the contacts until the air in the tube cools. 

These are the bi-metal plates with a screwdriver pointing to one contact. 









The click is when the contacts snap closed to turn the heat on. If you have repeated clicking, it is the contacts opening and closing frequently. You can see that the heat from the coil is really close to the controls and bi-metal. The AIR in the tube gets hot really fast. This makes it cycle often before it gets the WATER to the set temperature. 

Every time these contacts open or close, there is a small arc which at some point is likely to weld the tiny little contacts together. More open/close cycles make this happen sooner. At that point the heater is on full time and can overheat to kill fish if the heater is too large. 

If you have a clear glass heater you may see this arcing in a dark room. Scary to think you are seeing your heater kill itself?


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## cprash

PlantedRich said:


> This is one of the big defects designed into many heaters.
> This is a basic design heater pulled apart to show where things are located. Imagine this is all shoved back down into the tube. The controls are just above the heating element and inside the glass. Some heaters try to isolate them by shoving a bit of insulation between the two.


Whoa, thanks for the graphic and explanation. I'm grabbing a more reliable one later today, I'm pretty sure this one is dead.


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## PlantedRich

You can see why it will operate differently when vertical than horizontal. When vertical the heat travels directly up to the bi metal and less directly when horizontally. 
Another small point which they don't mention when some advise to use their heater in a vertical position is a real critical item. 
If you imagine this tube vertical, think of what any moisture does if it should happen to leak. It likely will travel down the outside edge of the tube and go down near the heating coil. This often creates a cloud of steam as it evaporates. You may have seen heaters with a cloud on the inside. This indicates the seal is leaking and water is going inside. If the heater is used horizontally, this water collects near the controls and ruins them sooner. On the heater coil it evaporates but on the controls it either corrodes things or shorts something out and the heater is dead. 

They don't tell you that they know their heater seal will leak at some point, do they?


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## kevmo911

I've used a bunch of different heaters, and had that repetitious knocking going on for awhile after it turned on and got hot. I accidentally fixed it by moving a suction cup (specifically the clip for the cup) further up the heater, away from the heating element. Immediate results, and no more problem. I have no explanation for why this would work - It makes zero sense to me. But it's a thought.


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## ModusVivendi

kevmo911 said:


> I've used a bunch of different heaters, and had that repetitious knocking going on for awhile after it turned on and got hot. I accidentally fixed it by moving a suction cup (specifically the clip for the cup) further up the heater, away from the heating element. Immediate results, and no more problem. I have no explanation for why this would work - It makes zero sense to me. But it's a thought.


+1

Try moving the lower suction cup up. Water trapped between the suction cup clamp and the glass of the heater at the point closest to the heating element heats to a point of expanding enough to be forced out of the space and cause the sound repetitively. 

Sent from my Transformer Prime TF201 using Tapatalk 2


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