Mystified by a Solar Heating System I Need to Remove

[LucMan]

The line going into the bottom of the tank should be the hot coming back from the panels, don't see a valve on that line. If you put a plug in that line that should solve your problem.
The other solar line should be the line coming off the side of the tank and that valve is closed so should be ok unless the valve is leaking by.
No need to open the wall there is nothing in there except maybe some elbows.

[AzRoute66]

In the past I have used a $5 stethoscope to trace pipes (and wires actually) by having someone tap the pipe at the far end.

[PNPmacnab]

Usually the solar heating pipes are a closed system. The solar part goes into a loop coil in the tank and exits. Pump operates when hot enough. That may not be the case if your roof is leaking. From only a cursory look, the pipe you twisted up is the hot water exit to the house, the other is the cold entrance. That T looking connector is a tempering valve. It mixes cold water with the hot should the hot water be over 120F. If replacing the tank, this is where you would connect like any water heater. If you cap off the bottom and side pipe, the roof should stop leaking. Looks like you are due for a new tank.

[mike s.]

I can try doing that tomorrow, though when I bought the house I got county schematics (e.g., for the septic system) but nothing for solar. Hour+ drive each way, too.
So if no one else has suggestions, it looks like I have to take out a wall to see what pipes go where.

[Mike90250]

Check with your city and see if there is a system diagram in the permit file for your house ?

[mike s.]

Hi, I'm new to this forum. I have a solar water heating problem that I really need some help to solve. My house was built in 1981. It has a solar water heating system above the attached garage, with a large storage tank in the garage. I bought the house in 2004 and the system was already disconnected then: a controller and water pump on the water tank was unplugged, and a copper line with a Grundfos pump on the end of it comes out of the wall in my (propane) water heater room and is capped off. At least, I thought the system was disconnected. The roof is now leaking where the panel pipes come through, and the solar system has to come out. I thought it would be easy to disconnect the system, but not so.
Four pipes go into (or out of) the water storage tank. Two go through the roof to the panels, and two (one insulated, one not) come from the house. I thought I could just cut and cap the pipes coming from the house, but when I shut a valve on the non-insulated pipe just above the water tank, it shut off all hot water in the house! So I traced back the 2 pipes going into the house, hoping for a manifold or something. No manifold. The pipes come in from the garage into the house attic, and then go down into the same wall where the propane water heater lines come out to the heater.
This is very confusing. It seems like the 2 pipes from the solar tank are going directly to the propane water heater. But then, how is hot water being distributed through the house? If the propane heater is sending water to the solar tank, why is one of the lines uninsulated?
I'm guessing there must be some sort of mixer in the wall by the propane water heater, but why would anyone build it that way, with it all hidden in the wall? There is a sort of manifold system with a control valve above the water storage tank, but why would it be put there, 50 or 60 feet from the house, proper?
Since the water storage tank is still plumbed into the system and closing a valve above the tank shuts off hot water to the house, what was that capped line in the water heater room for?
Am I going to have to open up the wall in the water heater room to figure this all out? Is this something completely obvious to solar water heater professionals?
If I get pics loaded, you'll see that I twisted a copper pipe when trying to disconnect it from the storage tank. Thank goodness I stopped what I was doing before I turned the house into a "cold water only" house.
Very sorry for all the questions. I don't expect anyone to try answering all of them. I just need a few words telling me how to get this mystifying system disconnected.