Tweet
Here is more detail on how the water heater in my system works. One issue with any system in a aquaculture system is the possibility of poisoning from the components of the system. For example, Copper pipes will give off enough toxic elements that over time it will kill fish. All components must be inert to prevent fish loss.
The Water heater has coated steel inlet and outlets. The drop tube is plastic, the drain and overpressure valve appeared to be Galvanized and Copper (bad). I replaced the drain with a stainless steel nipple and stainless steel shutoff valve (ball valve). The pressure valve I left as I have not found a replacement. I hope its such a small part that it will be ok. The Ball valve was recommended to me by a plumber who said a ball valve allows large particles to be flushed out, where as the standard faucet tap fitting is very narrow and crude builds up in the tank that will not flush out (it should be flushed at least quarterly). Also the anode in old water heaters was ZINC which guarantees fish kills, but the new water heaters have a Magnesium anode, which is used by plants and should never reach toxic levels. So I left it in. Also the tanks are steel, but are glass lined, so safe. All connections, adapters, flex tubing is either PVC or a plastic or rubber. Essentially a galvanized-copper free system (except the overpressure valve, and Im betting the nipple is coated.
The greenhouse already had the propane plumbed for the space heater, I just hooked into that. The exhaust vent goes up and out the end wall that backs the water heater, again not difficult, just time consuming. I put the whole thing in a drain pain under some solid support, just to keep the heater off the floor.
Below is a high resolution image with notes on the various components. The key is to partially close the bypass line so that water is forced through the water heater when the sprinkler valve is opened. Because the intake and output of the water heater are smaller, if the bypass is wide open, then even if the sprinkler valve opens, no water will be forced through, by closing down the bypass, then enough water goes through the water heater to heat the tank.
I tried just setting the temperature on the water heater, but it is way to imprecise and would cook the system one day and freeze it the next. Using the controller from AquaticEco I can control the temps within 1 degree.
As mentioned below, I put the water heater on the LOWEST setting, that way energy is not wasted (as much) when during the day it is not needed.
The controller was model TC11
The sprinkler valve was just a standard sprinker valve from home depot, any will do. The transformer plugs into the controller and is activated when the temperature goes below the set point (or above if you program it for cooling). The controller powers the transformer the transformer outputs to the valve, which opens and allows water to flow through the water heater. I just bought a standard replacement transformer for $10. The controller and water heater were the expensive parts.
(Click on the picture to get a large view with labels)
Prev Post | Next Post