Mystified by a Solar Heating System I Need to Remove

[azdave]

Instead of opening up the wall behind the propane water heater, I plan to just "splice" together the two pipes coming from the solar tank, going into the house. Anyone see anything wrong with this approach?

Not if it closes the loop and doesn't cut off water to something you don't yet know about.

[J.P.M.]

Not knowing it was for hot water recirculation (really, there's no way to know for sure without opening up the wall), I had long ago installed another hot water recirculation pump on top of the propane heater. Though it has a sophisticated timer on it, I just wired it up to a spring loaded wall switch (like for a Jacuzzi pump) in the house. Crank it to 5 minutes of run before a shower. Saves a lot of water, important in socal. So you don't run a lot of cold water into the drain waiting for warm water.

Instead of opening up the wall behind the propane water heater, I plan to just "splice" together the two pipes coming from the solar tank, going into the house. Anyone see anything wrong with this approach?

The water saved by the luxury of instant hot water amounts to about 2.7 gal. per 100 ft. of 3/4" pipe, or about 1.3 gal./100 ft. of 1/2 " pipe. Savings - yes, but so would cutting the shower time by about a minute or less for the same water savings. Low flow shower heads will outdo any circulator savings in a hot second. No circulator also saves the cost of equipment with the added bonus of less possible hassle about switches. The water saving feature of hot water recirculators is mostly a marketing gimmick used by peddlers of such energy hogs. Bottom lines: Hot water recirculators are a waste of money, energy resources and materials, and add complexity to a plumbing system. Any advantages they may offer in terms of saving water can be more than compensated for by other easily available means for little or no cost and with less complication and increased reliability. The same savings in water for a shower can be achieved by one less toilet flush, which is where most of the positive hype about hot water recirculators belongs.

[mike s.]

Not knowing it was for hot water recirculation (really, there's no way to know for sure without opening up the wall), I had long ago installed another hot water recirculation pump on top of the propane heater. Though it has a sophisticated timer on it, I just wired it up to a spring loaded wall switch (like for a Jacuzzi pump) in the house. Crank it to 5 minutes of run before a shower. Saves a lot of water, important in socal. So you don't run a lot of cold water into the drain waiting for warm water.

Instead of opening up the wall behind the propane water heater, I plan to just "splice" together the two pipes coming from the solar tank, going into the house. Anyone see anything wrong with this approach?

[azdave]

What does having a pool got to do with a DHW recirculating system ?

I took it to mean that pools are wasteful on a whole new level above a domestic hot water circulation system. I can't disagree with that since I have plenty of experience with both.

[J.P.M.]

Pools have circulators.

And those circulators pump relatively cold water around.

My point was the thermal energy waste associated with a DHW hot water circulating system. The cost of the power to pump the water around amounts to less than peanuts compared to the thermal energy wasted by such systems, particularly during A/C season, and even when all hot water lines are very well and carefully insulated and circulating systems are on timers. They are, IMO, a waste of money made possible by user ignorance as to how much the energy they waste will cost. If people knew how much they cost in terms of energy costs not to mention added equipment costs, I bet there would be a lot fewer of them, and people who have them would stop ignorantly signing their praises.

[bcroe]

Pools have circulators.

[J.P.M.]

Do you have a pool? Bruce Roe

What does having a pool got to do with a DHW recirculating system ?

[bcroe]

Like always. Hot water recirculators in a residence for the purpose of instant, or semi-instant hot water are a complete and utter energy hog. Such systems are needed in large building. In a home, and for a lot of reasons, they are no more than an extravagant waste.

Do you have a pool? Bruce Roe

[J.P.M.]

Sometimes using a circulating pump for the HW will use more energy then just letting the main water heater keep the tank hot and losing some cold water at the taps waiting on the hot water.

Like always. Hot water recirculators in a residence for the purpose of instant, or semi-instant hot water are a complete and utter energy hog. Such systems are needed in large building. In a home, and for a lot of reasons, they are no more than an extravagant waste.

[SunEagle]

HW recirc line to keep hot water at the taps.

Sometimes using a circulating pump for the HW will use more energy then just letting the main water heater keep the tank hot and losing some cold water at the taps waiting on the hot water.

[LucMan]

Got it. Water supply goes directly into the solar tank. So I guess I have to open the wall behind the propane water heater and re-direct the water supply directly into the heater. Still want to know what the disconnected line and pump in the water heater room is all about, since all other hardware seems to be accounted for.

HW recirc line to keep hot water at the taps.

[mike s.]

Great schematic, by the way.

[mike s.]

Got it. Water supply goes directly into the solar tank. So I guess I have to open the wall behind the propane water heater and re-direct the water supply directly into the heater. Still want to know what the disconnected line and pump in the water heater room is all about, since all other hardware seems to be accounted for.

[NEOH]

This picture shows the solar heat panel ( pump (cold) line & return (hot) line ) connections into the side of the tank and
the domestic hot / cold lines on the top of the tank.
The pump draws cold water from the bottom of the heat exchanger coil inside the tank.
The connection into the side of the tank is the hot return from the solar heat panels, going into the heat exchanger coil inside the tank.

4 PIPES in the wall, from Left to Right, in your 3rd and 7th photos ...
Left Most ... Domestic Hot Water out of tank to the house
Then ... Solar Hot Water Return down from the Solar Heat Panel into the tank's coil
Then ... Solar Cold Water Supply from the tank's coil up to the Solar Heat Panel
Right Most ... Domestic Cold Water into the tank


http://www.hotwaternowco.com/images/...olarlayout.jpg

[mike s.]

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.

The closed system makes sense. The leak is from rain through panel mounts. The panels have to come off and the roof has to be redone. I plan to remove the panels and solar water tank for good. If I completely remove the solar system (tank & panels) then I guess I still have to get into the wall because the water line from the street must be in there somewhere, and I will need to connect it directly to the propane water heater.

"In the past I have used a $5 stethoscope..." I have one and good idea; I might just have to do that.

"No need to open the wall there is nothing in there except maybe some elbows." But water must be coming in from the street somewhere in that wall, and I'll need to connect it directly to the propane water heater.

Two things that still don't make sense are that: 1) both lines coming out of my propane water heater are insulated, while one of the lines going to the solar tank is uninsulated (so maybe behind the wall the street line is going directly to the solar tank...?); and 2) why is there a disconnected water line and pump in my propane water heater room?

Anybody live in Socal and have a use for the system if I ever get it out?