Iam curious, where did you decide to place the temperature sensors in the storage tank?

No problem. I have it in the nearest bottom corner. I figured it would be the best place away from the heat exchanger coils. I did have a sensor at the top of the tank, but used it for the new large collector.

I do have one issue that has happened twice now that is stumping me that I'm sure you guys would have some insight on.

I've had water come out of the circulation resevoir to the point the the highest pipe dumping into it has a slight air gap when I find it. There are two holes on the side of the cooler resevoir where the pipes go in that were not sealed.

It looks like the water leaked out of those holes, but they are 4-5 inches above where the pipes end. Somehow the water level rose enough to drain out, but then later the water level dropped below the discharge pipe. Then i. Guessing allowing air to enter the loop. When I noticed it today the motor was so hot it was starting to melt the insulation on it! I rechaged the loop and the pump still works fine. No sign of any leaks anywhere else. It worked solid for 2 weeks straight since the first time it happened.

To "fix" it I extended the pipes another 4-5 inches to the bottom of the resevoir. I also sealed the pipe holes with silicone. My theory is that whatever caused the water level to rise that much will have more room to expand before leaking out. Then when it contracts back down it will have to go nearly to the bottom unit the siphon breaks.

My best guess is maybe boiling occurred in a section (perhaps some weird low pressure spot?) pushing the water out of the resevoir. It then either cooled off or got pushed out, leaving the difference in volume to drop the revoir to the point the siphon was broken.

How I found the resevoir. Except I had added some water. Originally the level was right below that upper pipe. You can see discoloration where the water leaked out of those holes. It's 1" pex for context.

https://ecorenovator.org/forum/attac...5&d=1598153933

What I did to hopefully fix it. Should more than double the amount of play in the water level height. Funny thing is that it will keep at a steady water level (usally a bit below the holes) for weeks at a time.

https://ecorenovator.org/forum/attac...6&d=1598154467

Just an update on the project:

1.Cut down a bunch of trees as they were starting to block the collector going into fall. More solar heat & more firewood!

2. Integrated the hot water tank with the furnace plenum heat exchanger, so I've got solar space heating. I have various thermostats & controls to make it work, but basically it has it's own dedicated thermostat in the living space and a thermostat that turns on when the tank is above 130F or so. It really blows out a good amount of heat and nice warm air. I can provide more details if anyone's interested.

3. The reservoir overflow issue has happened once since my last modification and levels stayed barely above the pipes but I think I've narrowed it down. In all circumstances the tank either reached its max temp of over 150F or the system didn't have power. So almost certainly there was boiling in the collector due to stagnation pushing the fluid out of the reservoir until it cooled enough to condense leaving the reservoir sparse. I simply refilled the reservoir with the glycol I was going to swap the water out with anyways. So the boiling point of the fluid should be higher. Also, the space heating cutting in above 130F should keep the tank below the 155F max tank temp, so the system will keep running.

Overall quite pleased so far. My electric bill is $20-25 less than last year's bills and I'm looking forward to seeing how much longer the firewood & propane lasts this winter :thumbup:

Great to hear. I'd love to see how you integrated the solar hot water with your furnace.

Sure Daox.
Plumbing: I have a Taco style pump pulling water directly from the tank and circulating it through the furnace plenum. Kept it simple with 3/4" pex and shark bites to connect with the heat exchanger. It was conveniently left over from the outdoor woodboiler that was removed.

Controls: The heart of it is the Taco Hydro Air Fan Control (HAFC201). Its powered off the 24v furnace common with a 120vac relay for the pump and controlled by 24v thermostats terminals. When the thermostat circuit is closed it turns the fan relay on the furnace & taco pump on. Really happy with the unit.

I have 2 thermostats wired in series. One for the tank with a temperature probe and a simple thermostat in the living space. I mounted them both in the living room where I can keep an eye on the tank temp and set the living space temp easily.

FyI If you need a bulb well for temperature probe, some 1/2 pex, brass plug and silicone work great!

Picture of what I'm talking about.

https://ecorenovator.org/forum/attac...4&d=1602770527

https://ecorenovator.org/forum/attac...5&d=1602770527

https://ecorenovator.org/forum/attac...6&d=1602770527

https://ecorenovator.org/forum/attac...7&d=1602770527

https://ecorenovator.org/forum/attac...8&d=1602770527