DIY submersible water heater, build your own water heater

[Rob Nash]

***Be sure to use a GFI plug with this!***

here is a link to the Through-Wall version http://community.theaquaponicsource.com/forum/topics/diy-heater-bui...

 COPPER WARNING! most of the elements are made from nickel plated copper and should not be used!

I have not found stainless elements at Home Depot. Some of the Lowes stores have them.

A quick search on the web will find several types in the 240volt range.

Some links to try:

 1500 watt in the 120 volts stainless steel unit.

http://shop.hardwareandtools.com/search?w=stainless+steel+heater+el...

 

 here are some stainless steel options. they only make them in 4000 watt+ at 240 volts.

http://www.amazon.com/Stainless-Steel-Water-Heater-Element/dp/B000U...

 http://plumbing.hardwarestore.com/51-598-water-heater-elements/stai...

10-18-2013

I've made a few changes to the heater parts list and instructions..

 

1500-5500 watt stainless element

12 awg cord

1-1/2" rubber coupling

1-1/2" reduced to 1" threaded

1-1/2" reduced to 1/2" threaded

1/2" water tight connector

 

Temp controller

 

 

 

 

 

 

 

 

 

 

 

  

 

 

 

install the element into the 1-1/2" - 1" reducer.

...these are made to be inserted in one direction, so you will need to use a grinding wheel, or improvise, to remove the "stop" portion of the fitting.

some are sold with a round edge (pictured here) and some are squared (pictured above)

after removing the stop, connect the wires and install into the rubber coupler.

  

 

 

 

Here are a couple different

submersible options.

the top one has the wire ran inside the 1/2" irrigation "funny pipe" and fittings.

both work great!

 

 

 

 

 

 

 

 

 

I have used a heavy duty timer to control the temp. 15 mins on the hour will keep 300 gallons warm.

pex supply has thermostats    http://www.pexsupply.com/Temperature-Controllers-12741000

Use a GFI plug with this unit!

 

 

 

 

[Kym Roberts-Hardesty]

Thank you Vlad!  You guys rock!

Vlad Jovanovic said:

The 'black cup thingy' is a Net Pot (a 2 inch one, I believe) and can be found at any 'ol hydro store. The 'slotted PVC piece' can be bought from Farm Tek (and probably some other places...  http://www.farmtek.com/farm/supplies/prod1;ft_plumbing_supplies-ft_... 

...but you can cut slots into a piece of PVC with a table saw, or angle grinder...or just drill holes into it with a hand drill and a drill bit 
Kym Roberts-Hardesty said:

Where did you get the slotted PVC piece and the black cup thingy at the end, that go over the element?

[Kym Roberts-Hardesty]

What is the diameter of the piece of pvc that covers the element?

[Joe Bifano]

I see all the parts needed for this project. Can this be used in the rafts just by laying on the bottom?  Does the element have to be inclosed in PVC?

[Rob Nash]

Jeff S - Ive drained it down to about 4 inches and left the fish in there, then filled it back up.. the last time, I had a helper hold his hand over the hole while I replaced it.. only lost less than 1 gallon of water.

Joe - Yes.. the submersible unit can sit in a raft... does not need a cover.

I have one 5500 watt unit, ran at 240v warming 2500 gallons in a 36 x 8 ft raft and 1000 gallon fish tank.

[Vlad Jovanovic]

@ Joe...No, if just laid on the bottom of your skrim (touching the skrim), I think it would  it would very likely melt it (but maybe someone else can confirm this)...

No, the resistor (heating element) does not have to be encased in PVC...but it would have to be encased in something that is not as thermally conductive as the resistor (heating element) itself if it was up against the skrim...

Joe, if I remember the size and dimensions of your system...and you want to diffuse heat through the length of your troughs...you might try using gutter/roof heating cables as a more simple "ready made" approach...

https://www.google.com/search?q=gutter+heating+cable&espv=2&...

Joe Bifano said:

I see all the parts needed for this project. Can this be used in the rafts just by laying on the bottom?  Does the element have to be inclosed in PVC?

[Rob Nash]

here is a link to AES.com where they sell "Well Screens"

 http://pentairaes.com/well-screens-and-points.html

I like to DIY stuff like this my self... 

this pic is just to show how it looks with a screen on it... use the rubber coupler instead of the PVC

[Joe Bifano]

@ Rob Thanks I know I saw that image someplace. I could not get your link to work so I went their and found it but changed mine slightly for everyone so it worked.

http://pentairaes.com/well-screens-and-points.html

@Vlad I changed my other system and I am not growing in rafts in my first greenhouse. I changed things around and I am growing Beefsteak tomatoes now.

I built a new Gothic Greenhouse out of wood 20x72 and I am building those rafts in this new one. I had heated the old rafts with pex tubing and a boiler I made utilizing the radiant style heating. That cost a lot for all of the plumbing, zone controllers and the boiler stuff. I am not sure if I want to do that all again on the new greenhouse. I still use the boiler set up but it takes forever to heat my reservoir from 50(water out of the ground) to 65. I get maybe 2 degrees a day right now, in the winter, so I want to build one for the reservoir as well to get it up faster and then maybe the pex setup will maintain the temps more efficiently than the new 1500 watt heater will.

The new greenhouse will have 2 8'x44' rafts that will have 3" depth of water. That will hold about 657 gallons of water each. Not sure what size tank I will have. So 2 x 657 equals 1314 plus the tank might be 1500 to 1700 total.
So I was thinking of making either 2 1500 watt heaters for each or 1 larger one for each.

Were you thinking that the gutter/roof heating cables would be a way to maintain my heat or would these cables be as fast as Rob's Heating element idea?

I am adding over 100 gallons now per week growing Basil. The new greenhouse could use 400 gallons if it does the same things so adding that much water at 50 degrees will be a shock to the system. I might have to have a separate tank for warming that before it goes into the main system.

[Jeff S]

Rob, The only problem I've had in the past with this type submersible heater was water leaking into the cavity behind the element where the wires connect. With your set up what is the purpose of making the outside of the tank area waterproof? Seems like if you did ever develop a leak it would be better if the water didn't gather up around the wire connections.

[Jeff S]

Is there a reason the element can't be placed closer to top of the tank?

Rob Nash said:

Jeff S - Ive drained it down to about 4 inches and left the fish in there, then filled it back up.. the last time, I had a helper hold his hand over the hole while I replaced it.. only lost less than 1 gallon of water.

Joe - Yes.. the submersible unit can sit in a raft... does not need a cover.

I have one 5500 watt unit, ran at 240v warming 2500 gallons in a 36 x 8 ft raft and 1000 gallon fish tank.

[Rob Nash]

Jeff, I like to make it water proof, even in the through wall set up,. so I can rest assure the GFI will trip if it does leak. ..I advise folks with kids and skeptical wives etc, and like to take every precaution.

you want the area to hold water if it leaks, this is what makes the contact with the green ground wire, thus tripping the GFI

the most common issue I see with leaking is the hose clamps.. most folks use a flat head screw driver to tighten it, and after the rubber gets cold and contracts a bit, the hose clamp is no longer tight enough.,. so two things.. use a 5/16 nut driver to tighten it, and then re tighten it a day after its sat in the water,,, I have three of these that have been submerged for three years now, still doing the job and no leaks..

sorry for the slow reply.. haven't been on in a while.