Trying to understand my solar water heating system...

[Reinier]

The house I bought came with a solar water heating system. Its collectors are on the roof and the tank is in the basement.
I have figured out somewhat by now how it is supposed to work, but it seems to be broken. It is supposed to feed warm water into the "regular" system, which is heated by an oil furnace -- except that it doesn't seem to do that.
I would like to repair the system, but I do not know where to start. I can not even figure out the make and/or model. Would this be a good place to ask for advice?
I think the system was installed in the mid-80's. I have attached a picture to give an impression. I understand this does not say much, but maybe someone recognizes it.



Thank you in advance,
Reinier

[icarus]

Welcome to the forum.

Does it circulate domestic water, and co-mingle water, or does it use a glycol loop wi th a heat exchanger in the tank? Do the collectors have water in them?

Find out as much info as you can and report back. In short, a solar system like this probably circs water, controlled with diffential controller to turn the pump on when there is a diffence in temp. I would first try to pressurize the system, hot wire the pump and see if water circulates. Work through all the potential failure points and test them individually.

Good luck and keep in touch,

Tony

[inetdog]

Find out as much info as you can and report back. In short, a solar system like this probably circs water, controlled with diffential controller to turn the pump on when there is a diffence in temp. I would first try to pressurize the system, hot wire the pump and see if water circulates. Work through all the potential failure points and test them individually.

Good luck and keep in touch,

Tony

It goes without saying that there must be fluid in that circuit so that you do not operate the pump dry. So I will say it anyway.

A look at what the collector(s) on your roof are like will tell us a lot too.

[fix_it_guy]

One thing I would do is make a drawing of where all the pies and components are. That's just how I am. If I look at a drawing, whether it's a new idea or existing system somehow it helps me figure it out.

[BB.]

Look at www.solarroofs.com

They have some very clear drawings about the basic systems.

-Bill

[Reinier]

Welcome to the forum.

Does it circulate domestic water, and co-mingle water, or does it use a glycol loop wi th a heat exchanger in the tank? Do the collectors have water in them?

Find out as much info as you can and report back. In short, a solar system like this probably circs water, controlled with diffential controller to turn the pump on when there is a diffence in temp. I would first try to pressurize the system, hot wire the pump and see if water circulates. Work through all the potential failure points and test them individually.

Good luck and keep in touch,

Tony

Hello Tony,

I think it uses a glycol loop with a heat exchanger in the tank, but I am not sure how to come to a definite conclusion on that. All pipes disappear into this big orange tank and there is no way for me to look inside of course.
It does have a meter which I suppose is to indicate the circulation speed of the fluid, but I have never seen any fluid in there. It looks like this:



As you can see on my original picture, there is a thermometer (the circle-shaped sensor). I have seen it indicate 60C/140F at one time, but it is typically stuck at 21C/70F.

It is hard to inspect the collectors closely because they are high up on a 45 degree slanted roof. I went up there but was not able to open the lid or look through it, so I do not know if there is anything inside the collectors. However, from the fact that I have seen warm water in the tank, I conclude that fluid sometimes does flow from the collector to the tank. This contradicts the fact that I have not seen anything in that fluid meter I just showed.

Some more information: Indeed I see a differential temperature thermostat which is connected to the pump. I have never seen or heard that pump run though. But then again, I do not know how often it is supposed to run and maybe I just did not sit down there long enough. Again, from the fact that I have seen warm water in the tank, I would say that the pump must have run at least somewhat to transport the heat from the collector to the tank.

You should know I am really inexperienced. I do not know hot to pressurize the system (don't even know what it means) or hot-wire the pump. I guess the latter means I should work around the differential controller, but I am hesitant to do anything that I do not fully understand... If the advice is that I should get someone to look at it, then I am fine with that as well, but I would like to figure this out as far as I can by myself (with the help of some friendly people on the Internet ;-) )

Hope this gives you a better idea and thanks for your response,
Reinier

[Reinier]

It goes without saying that there must be fluid in that circuit so that you do not operate the pump dry. So I will say it anyway.

A look at what the collector(s) on your roof are like will tell us a lot too.

Thanks for the warning -- should I switch off the system if I do not know whether there is any fluid in the circuit?
I could go up the roof tomorrow and make a picture of the collector. But previously, I was not able to open the lid; does a picture from the outside only have any value?

Best regards,
Reinier

[Reinier]

One thing I would do is make a drawing of where all the pies and components are. That's just how I am. If I look at a drawing, whether it's a new idea or existing system somehow it helps me figure it out.

Well, the problem I have is that all pipes run into / out of this orange tank and some pipes are interconnected, and there are several valves, some of them are open and others are closed. The design is not as simple as I would expect.
So far, I have not been able to grasp the purpose of all pipes. But it is a good idea to make a drawing and see how it improves my understanding. Always good to keep around as a reference as well.

Here is a picture of (the majority of) the pipes:



Thanks,
Reinier

[Reinier]

Look at www.solarroofs.com

They have some very clear drawings about the basic systems.

-Bill

Thanks, the installation manuals already teach me a lot. It shows an expansion tank, which I have not seen anywhere. Does every system have that? Also, the manuals distinguish between models in tropical climate and freeze climate. I am in Nova Scotia, Canada, so my system (hopefully) belongs in the second category. That was a reason why I thought it was more likely that the system uses something like glycol for heat transmission. Is that a correct assumption?

Reinier

[icarus]

i would cast a net in your area (Wayne,, are you busy?) to find someone who can give you a heads up. What I mean by pressurize, is to put water in the collectors, by figuring out the valveing to see if it holds water. By hot wiring the pump, you are right, dictly bypassing the controller and t-stats to see if it circs. Given your neophyte status, finding a good plumber, and ideally one who knows about solr hot water. It may be working fine! Do this simple test. Go to Canadian tire, buy a $$20 infrared thermometer. Point it at various components when the sun is out, and see what temp things read.

Good luck, be careful and keep in touch,

Tony

Ps, from a safety point of view, a couple of things to keep in mind,,don't allow any glycol mixture to have a way into potable water. If. You don't know what a valve does, don't mess with it. Second, hot water systems can get very hot,, be ware of scalding, and more importantly, make sure that there is proper pressure/temperature relief valves, and that they work. Finally, don't run pumps dry for more than an instant or you will damage it. (a quick start stop dry probably won't hurt it.

T