# DIY external inline heater



## kwc1974 (Jan 4, 2006)

This is my first attempt at a DIY, so bear with me.
I saw the Hydor inline heater and needed to solve my heating issues in this way, problem is I had two perfectly good Ebo-Jager 150W heaters that I did not want to replace. I did a little bit of research and could not find where anyone has actually done this, lots of ideas and I do borrow from these (give credit where credit is due). I will be running my Eheim 2217 upstream from the heater modules.

So here is my solution to fix this problem.









The materials used are as follows
2" clear pvc pipe
2" clear pvc Tee
2"x1 1/4" pvc socket flush bushing
1" pvc compression union (cut in half)

The compression union was cut in half and the outside diameter was machined down to fit the 1 1/4" socket

The new compression fitting has a rubber boot that fits around the hard plastic piece on top of the heater, not the glass (no heat transfer and no glass breaking from the compression fit)

Here is how it looks with the heater installed









When completed, a second heater will be installed in an identical setup and a 2" U fitting (part of a p-trap) at the bottom will connect the two heaters. The inlet and outlet Tee will get 2" x 3/4"Threaded fittings so that a threaded to barbed adapter can be used to connect the filter hose to.

If anyone has any comments on how to improve on this design, please let me know. Any input would be great.


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## DelawareJim (Nov 15, 2005)

Great idea. Where does the power cord go?

Cheers.
Jim


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## kwc1974 (Jan 4, 2006)

Im sorry I will take a pic of the top tonight
If you look at the first pic, there is a hole that the heater goes into. A black rubber ring goes around the top of the heater and the compression nut tightens the rubber piece to form a seal.

like I said I'll take a pic tonight.


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## kwc1974 (Jan 4, 2006)

as promised here is a pic of the top heater connection


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## slickwillislim (Oct 11, 2005)

That looks pretty cool I hope it works well I already bought a inline heater or I would definetly consider this project. 

Can I ask where you got the clear pvc?


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## wiste (Feb 10, 2006)

Thanks for sharing this design. Definitely going to have to try this. 

I would say it seems pretty close to perfect except that you had to machine down the outside diameter the compression union. What did you use to accomplish this?


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## LilLou (Apr 23, 2006)

Do you have a way to slow the water down moving past the heaters?

I think with any decent size filter the water would move past them too quickly to effectively heat the water.

Maybe a ball valve slightly closed or some filter material to pack around them to slow the water down.

Good idea though, especially if you don't want to change your existing heaters.

Lou


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## kwc1974 (Jan 4, 2006)

Thanks for the comments...keep them coming

to answer you questions



> slickwillslim wrote:
> Can I ask where you got the clear pvc?


I feel fortunate to live in Houston, a place where if my mad scientist emerges I have my sources for hardware.
I bought the clear PVC at a local specialty plumbing supply.
I called half a dozon to get pricing before I bought the parts. To answer you question of where, it was Great Wester Supply in Houston. Don't know if thay have a web address.


> wiste wrote:
> I would say it seems pretty close to perfect except that you had to machine down the outside diameter the compression union. What did you use to accomplish this?


I shaved the outside of the compression fitting with a small rotary tool & a sanding drum bit
I really did not have to remove much at all, The differance in diameter was .05"...just enough that it would not fit into the bushing. So altering the compression fitting was fairly easy.



> LilLou Wrote:
> Do you have a way to slow the water down moving past the heaters?


The water is moving from a 1/2" I.D. tube to a 2" pipe size
The change in size (if I am correct) will slow the water down and will speed back up as it exits the heating chamber back into the hose. Although if this will slow it down enough is yet to be seen. But I figure that the Hydor heaters ae overcoming the same problem with less chamber volume than this project has.


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## niko (Jan 28, 2004)

Best looking design for an external DIY heater I've ever seen!

Things that I'd consider:
- You can get a compression fitting that fits around the electric cable. They come in many different sizes so exact matching to the diameter of the cable is possible. The fittings are actually a combination of a bulkhead and a comression fitting. No additional machining needed just tighted the bulkhead nut. Downsides - the cool temp regulating knob will be inside the housing and the centering of the heater in the housing will be a problem to resolve too.

- A straight line of water flow will result in less loss of flow. That implies that the cable should come out to the side of the "T".

- I personally am very paranoid about floods. A bad heater will melt the housing in no time. It'd be great to have a temperature sensor that shuts off the heater's power if the housing gets hotter than say 90 degrees.

Once again - beautiful design!

--Nikolay


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## jhj (Feb 18, 2006)

Its a great design, I have an extra heater and I might have to try it this weekend.


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## slickwillislim (Oct 11, 2005)

Thanks for the info.


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## BryceM (Nov 6, 2005)

Very nice way to get one more thing out of the tank.

BTW, the velocity of the water past the heater doesn't make any difference, so long as it's enough to prevent boiling. The amout of energy being transfered from the heater to the aquarium per unit of time is exactly the same regardless of flow.


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## kwc1974 (Jan 4, 2006)

> niko wrote:
> - You can get a compression fitting that fits around the electric cable. They come in many different sizes so exact matching to the diameter of the cable is possible. The fittings are actually a combination of a bulkhead and a comression fitting. No additional machining needed just tighted the bulkhead nut. Downsides - the cool temp regulating knob will be inside the housing and the centering of the heater in the housing will be a problem to resolve too.
> 
> 
> ...


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## Dave_S (May 11, 2006)

Nice job kwc. I have built my own , but like your compression fitting idea enough to think about redoing it. My PVC tube is about 18” long it has a PH probe on the inlet, a temp. probe in the middle and the heater on the output. I just had to do a PH calibration and it was a pain to take it apart, so the compression design is nice. If the heater is UL listed then theirs almost certainly a thermal fuse link on it. If there is no built in fuse then the heater would have to fail on (every heater fail I’ve seen is off or dead) and the pump would have to fail also. Whereas meltdown unlikely it’s not good design to rely on fuse links or the “unlikely” factor. This has been in back of my mind as I don’t have a backup safety device either. I’m thinking about a bimetal overload that is tuned to open at about 90deg F. They are cheap – I’ll post if I find something.


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## Dusty (Apr 30, 2006)

That's an awesome idea. I really like how it hides the heater so it's not in the tank anymore. Good job!


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## Marc (Apr 27, 2005)

Do you have a picture of it all plumbed up?


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