going to set up a tank heater off my water heater

[reefstarter]

I will use my reefkeeper to control a bronze or stainless pump to run water from my water heater through a pex coil in sump . done and done . that should save a ton of juice

 

[s_kelley]

Make sure u take a bunch of pics and do a build thread

 

[Gsxkid]

I'm like 99% sure there's laws you would have to follow to do that. Like a back flow preventer on your house I'm sure is one of them. Nobody is really supposed to touch plumbing unless your licensed. I like the idea you have though. You wouldn't need any special pump to do that though. Wouldn't need to be bronze or stainless. Just a standard taco 003 circ pump would be perfect. It would be a closed loop so there wouldn't be any salt going through the pump.

 

[Gsxkid]

If you have a boiler for heat then you could do this without adding a backflow preventer. Just add a zone to your boiler.

 

[iroc2zep]

It would need to be bronze or stainless because it's still part of the potable water loop... It wouldn't be separate. If it was a zone off a boiler for example then it wouldn't matter. Should work fine either way

 

[cilyjr]

I'm pretty sure reefstarter is a licensed plumber.

 

[reefstarter]

I am a master plumber and yes stainless or bronze is needed to protect the potable water. I would have to use a mixing valve if used on the boiler. I'm not comfortable using 180 degree water to heat the sump and I think that might cause temp swings. You are probably right about the back flow but I don't see a way to use one . I am confident the pex will hold up in the saltwater . Been meaning to disconnect my back up water heater anyway this will be a good excuse lol

 

[reefstarter]

I could use a mixing valve , but that's added expense

 

[jah-hoeva]

What advantage is this over the reefkeeper controlling a standard heater?

 

[reefstarter]

I can heat the water basically for free. vS 1000 watts for roughly 8 to 10 hours a day saving roughly $50 a month maybe more. I'll know in a month of running it this way

 

[reefstarter]

Just did some rough math using heat transfer rate of about 2.5 btu per square inch of pex which is about 5 btu per linear inch this different compared to say baseboard heat fin tube where an r value would be applied as heat loss . The transfer rate is higher due to the heat being "pulled" from the pex in to the aquarium water. In short I would need about 3000 btu to heat the water 1 degree or so . So I think ..... 60 feet of pex in the sump should work and not be overwhelming

 

[letoan]

Pex is a terrible conductor. Check with fish street, they sell titanium coil.

 

[reefstarter]

Oh , Might be worth checking in to . would have to figure out how much heat I could get out of it . I know I need about 3000 BTU to heat my system volume 1 degree but that can be a bit less figuring heat loss at a minimal .

 

[Gsxkid]

For the record I wasn't claiming to be a plumber lol I have never thought about it but those 003's must be bronze then because I have seen them used many times for circulating potable hot water. I obviously didn't know you were a plumber. Why not just put a backflow preventer on your house after the meter?

As far as the pex goes I'm like 99% sure they make a version that's supposed to radiate heat better. Same stuff they use for radiant floor heat.

 

[iroc2zep]

I'm curious if the tank temp will overshoot your target point after your controller shuts the pump off and the remaining 125* water or so remaining in the tubing continues to transfer remaining heat... I'll be following, I'd love to do similar thing and put recirc pump on my Rinnai. Gas cost is less for me than electricity cost.

 

[reefstarter]

No worries, yes the radiant pex is what I will be using. And that's a good point about the water sitting in the tubing but I have 4-5000 gallons an hour flow in the sump and I think it would be minimal . I will be putting a check vale to prevent thermal creep or back feeding

 

[Gsxkid]

Those fancy 500$ controllers can't be setup to compensate for the overshoot?

 

[reefstarter]

They can but not leaving it to chance

 

[Gsxkid]

Definitely keep us posted on this. I just upgraded my tank and my 200 watt heater has been running for 3 days straight and it is still 4* away from setpoint. I'm definitely going to have to upgrade it. Lol

 

[reefstarter]

So A few weeks ago I got around to installing my Coil heat exchanger in my sump . it works GREAT !!! . I am not going to post any pictures or explain it here as I think you need to know how to work on a boiler in order to do this . I may tweak it so that the boiler is controlled a little better but when the boiler fires it works best obviously . for now the boiler will not fire when my tank calls for heat . I was thinking of installing a flow switch in the line of the coil so when the pump comes on it will tell the boiler to fire. But even if the boiler water temp is only about 100 degrees it still heats the water of the tank . ( just slower ) when firing it can raise the temp a full degree in less than 10 minutes . And if it doesnt fire I am basicly heating my tank for free .