Originally Posted By: away
This post was automatically imported from our archived forum.
Here is my guess on the situation. BTW adding that comment about the solar system clarified it for me.
The water comes in through the wall on the right, goes up the pipe on the right to the solar system. The lower valve on the right is closed to prevent water from getting to the gas WH.
After circulating through the solar system it comes back down the pipe on the left, goes through the little insulated jog in the middle to the cold water line to the gas WH. The valve on the left is closed to prevent it from going into the hot water line on the gas WH.
The water is then heated further, if needed, in the gas WH and exits normally via the hot water line.
It looks like the solar system is used to preheat the water so the gas WH doesn't have to work as hard or as long. There may also be a recirc pump as mentioned so the gas WH doesn't have to keep the storage tank hot as the solar system will do that.
The upper right valve is to isolate the solar system. Close that and water will crossover the upper bare copper then back down to the gas WH and things will be just like a "regular" setup. Well except you will have all those joints and valves that can potentially leak.
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