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bennelson · 10-13-11, 04:48 PM

Hey Guys,

I have been collecting parts for some time for a (closed-loop glycol) solar hot water system.

As it is right now, I have a 4'x10' flat plate collector, 65 gallon rock-lined heat-exchanger storage tank, and 12VDC pump.

The tank is USED, in which I got the tank for "free" by trading the tank for my labor of removing it from the guy's basement. (I did NOT realize at the time I made the deal HOW HEAVY this thing is!)

Anyways, I might try to get the panel mounted in position (ground-mount, south-east corner of my house) while a person can still dig in the ground (winter's coming!)

But, I don't even know the condition of the tank yet, so... I thought I could start with pressure testing, just to make sure the tank didn't leak to start with.

On the domestic water side, the tank has 3 ports - one for cold water in, one for hot water out, and a temperature and pressure relief valve. I capped off the two side ports, to prepare to pressurize with air.

The idea of AIR pressurizing the tank is that you can test for leaks WITHOUT getting water all over. Air is light-weight, easy to work with, and all around us.

It also meant that I needed some way to get air into the tank. On car tires, the valve stem lets you put in air from a typical air compressor. I thought I would do the same on the water tank.

I went to the hardware store and got pipe adapters and a Schrader Valve - the same thing as a bicycle valve stem, only with pipe threads on it.

With the Schrader valve threaded in to the pipe adapters, it was now the right size to connect to the top of the heat exchanger tank, and add air. I just used my portable tire inflator, and pumped it up to 30 psi.

I checked the pressure, and marked it down, along with the time. I put the little plastic cap on the Schrader valve, and will let it sit overnight. Tomorrow, I'll check the pressure and see if it dropped any.

Already, I have run into one bump in the road... When I first saw the tank, it was still hooked up to plumbing. The guy who had it told me that he would have his son-in-law come over and disconnect it. After waiting all summer for that to happen, I finally got to go back to pick up the tank. Of course, the son-in-law just happened to CUT the connections off.

Instead of threaded ports, I just have two stubs of copper sticking out!

And here's the weird part - they don't seem to match typical American copper plumbing sizes. The wall of the pipe is extra thick, about 1/8", instead of the usual 1/16th. It's too big for 3/4" and too small for 1". The interior diameter of the pipe is just a hair larger than 3/4", and the outside diameter is about 1+1/16th". A coupler that would go over standard 1" is just a little too big.

When I looked INSIDE the two copper tubes, I CAN see that they aren't that long. They just seem to go through the foam insulation, at which point it connects to the inner wall of the tank (or at least the heat-exchanger part, I guess.) I wish I could get a photo of that, but it's hard enough just looking in there with a flashlight.

I really don't want to, but I suppose I could cut away the foam insulation to see what the copper goes back to. I don't know how the copper connects to the rest of the tank, but I can see from the inside that there is some type of connection.

The copper sticking out of the tank doesn't seem to be of any standard. I did stop at an HVAC place, to ask them (thinking maybe it was refridgeration copper?) and I got a few ideas, but nothing that has panned out. The HVAC guy also mentioned "swagging" a piece of copper pipe to fit over it, so I suppose that can be a possibility as well.

It's an American-made tank, and the other ports are standard 3/4".

Any suggestions?

10-13-11, 04:48 PM	#1
bennelson Home-Wrecker Join Date: Sep 2008 Location: SE Wisconsin Posts: 546 Thanks: 3 Thanked 165 Times in 96 Posts	Ben's <$1000 solar hot water system Hey Guys, I have been collecting parts for some time for a (closed-loop glycol) solar hot water system. As it is right now, I have a 4'x10' flat plate collector, 65 gallon rock-lined heat-exchanger storage tank, and 12VDC pump. The tank is USED, in which I got the tank for "free" by trading the tank for my labor of removing it from the guy's basement. (I did NOT realize at the time I made the deal HOW HEAVY this thing is!) Anyways, I might try to get the panel mounted in position (ground-mount, south-east corner of my house) while a person can still dig in the ground (winter's coming!) But, I don't even know the condition of the tank yet, so... I thought I could start with pressure testing, just to make sure the tank didn't leak to start with. On the domestic water side, the tank has 3 ports - one for cold water in, one for hot water out, and a temperature and pressure relief valve. I capped off the two side ports, to prepare to pressurize with air. The idea of AIR pressurizing the tank is that you can test for leaks WITHOUT getting water all over. Air is light-weight, easy to work with, and all around us. It also meant that I needed some way to get air into the tank. On car tires, the valve stem lets you put in air from a typical air compressor. I thought I would do the same on the water tank. I went to the hardware store and got pipe adapters and a Schrader Valve - the same thing as a bicycle valve stem, only with pipe threads on it. With the Schrader valve threaded in to the pipe adapters, it was now the right size to connect to the top of the heat exchanger tank, and add air. I just used my portable tire inflator, and pumped it up to 30 psi. I checked the pressure, and marked it down, along with the time. I put the little plastic cap on the Schrader valve, and will let it sit overnight. Tomorrow, I'll check the pressure and see if it dropped any. Already, I have run into one bump in the road... When I first saw the tank, it was still hooked up to plumbing. The guy who had it told me that he would have his son-in-law come over and disconnect it. After waiting all summer for that to happen, I finally got to go back to pick up the tank. Of course, the son-in-law just happened to CUT the connections off. Instead of threaded ports, I just have two stubs of copper sticking out! And here's the weird part - they don't seem to match typical American copper plumbing sizes. The wall of the pipe is extra thick, about 1/8", instead of the usual 1/16th. It's too big for 3/4" and too small for 1". The interior diameter of the pipe is just a hair larger than 3/4", and the outside diameter is about 1+1/16th". A coupler that would go over standard 1" is just a little too big. When I looked INSIDE the two copper tubes, I CAN see that they aren't that long. They just seem to go through the foam insulation, at which point it connects to the inner wall of the tank (or at least the heat-exchanger part, I guess.) I wish I could get a photo of that, but it's hard enough just looking in there with a flashlight. I really don't want to, but I suppose I could cut away the foam insulation to see what the copper goes back to. I don't know how the copper connects to the rest of the tank, but I can see from the inside that there is some type of connection. The copper sticking out of the tank doesn't seem to be of any standard. I did stop at an HVAC place, to ask them (thinking maybe it was refridgeration copper?) and I got a few ideas, but nothing that has panned out. The HVAC guy also mentioned "swagging" a piece of copper pipe to fit over it, so I suppose that can be a possibility as well. It's an American-made tank, and the other ports are standard 3/4". Any suggestions? __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.