Is there such a thing as a reverse pressure relief valve?

[mathjak107]

and the answer is :

ACV! Automatic Control Valve pressure controlled solenoid operated


boy my guys are good , even on a sunday i get answers .


i will be in the office wed if you need me to research it  for you , that is my day of the month to go in .

i believe we have access to the watts line .  see below cuts on the valves

http://media.wattswater.com/C-CACV.pdf

THE CATALOG LINK IS HERE

[Pointedstick]

Thanks mathjak. Those things are… heavy duty!

[mathjak107]

yes , the ones we use have to be precise and reliable .

before i retired i was a a designer of pump and motor controls both for the municipality's and the industrial's . i did a lot of water pumping stations and sewage treatment plants on long island .

anything we use has to be first rate . watts makes excellent products.

[Mark Leavy]

PS, does the water circulating in the solar heater have to physically mix with the potable water in the house system?  Can you use a closed circuit heat exchanger (i.e. coil of flex copper tubing) and put oil or a water/anti-freeze mix in the external circuit?  I'm just brain storming simple and reliable...

[Pointedstick]

PS, does the water circulating in the solar heater have to physically mix with the potable water in the house system?  Can you use a closed circuit heat exchanger (i.e. coil of flex copper tubing) and put oil or a water/anti-freeze mix in the external circuit?  I'm just brain storming simple and reliable...

That's the approach I'm moving towards. It solves two other problems, too: scale in the collectors and not meeting code by using the water heater for something it wasn't designed for.

[dragoncar]

PS, does the water circulating in the solar heater have to physically mix with the potable water in the house system?  Can you use a closed circuit heat exchanger (i.e. coil of flex copper tubing) and put oil or a water/anti-freeze mix in the external circuit?  I'm just brain storming simple and reliable...

That's the approach I'm moving towards. It solves two other problems, too: scale in the collectors and not meeting code by using the water heater for something it wasn't designed for.

Seems like a lot of work vs. slapping some electric panels up there and calling it a day.  Do you have really high costs for hot water?  I think I spend like $5/mo and it's mostly for the pilot light.

[Pointedstick]

Seems like a lot of work vs. slapping some electric panels up there and calling it a day.  Do you have really high costs for hot water?  I think I spend like $5/mo and it's mostly for the pilot light.

Astute observations. My costs are similar, in fact. However $5 per month requires roughly $1,500 to permanently offset with investments, so any system that neutralizes that cost for less than $1,500 is cost-effective. Even more so if it lets you get rid of your gas bill entirely, which has the effect of eliminating the $10-30 base charge (another $3-9k reduction in investment needs). Furthermore, it makes you immune to inflation and price volatility in the natural gas market. Another advantage of a solar water heating system vs a solar photovoltaic system is grid independence. Grid-tied solar systems don't give you any power or heat your water if the power goes out.

Finally, I want to test the idea to get a sense of how simply, feasibly, reliably, and inexpensively a freeze-proof solar hot water system can be implemented en masse.