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Old 11-11-13, 06:09 PM   #24
Helper EcoRenovator
Join Date: Mar 2012
Location: Warwick, Rhode Island
Posts: 82
Thanks: 21
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Thumbs up solar hot water collector steam..

Hi, thank you Sir,

Yes there may be a little steam in the pipe when the colder water begins entering the collectors however the pressure in the piping is relieved by an 'air vent' and 'vacum release' valve I've installed.

The vacum relief valve is at the highest point on the collectors outside 'right where the water exits the collectors'

The air vent is installed in the 3/4 copper pipe going into the top of my drainback tank.

I T'd off that 3/4 pipe just before it enters the drainback tank and installed a 1/2 inch 6 inch pipe straight up in the air off the 3/4 pipe.

On that 1/2 inch pipe I installed a ball valve which I leave cracked open at all times.

If I had no air release pipe the pressure would kick in during 'pump on' and 'stop' the water flo dead.

so the air vent solves that problem during pressure situations and the vacum release allows all the water to quickly drain back the second the pump shuts down.

Feel free to ask me as many questions as you want cuz I love talking about this solar stuff...

I'm not an expert on solar hot water systems by no means but did do one heck of a lot of research prior to putting my drainback system together.

so far.. everything is working like a clock.. no leaks (which was amazing) and I create hot water daily.

I installed a site glass on the side of the small 6 gallon electric hot water tank that I use for my drainback tank so I can keep an eye on water volume in the tank.

I have to remove the site glass to clean the ugly brown water out of it now and then but ya hardly 'ever' have to add water.

Just one circulator pump is used to heat up 2 tanks of water.
1 for domestic hot water use. (which is tied directly into my tankless hot water heater)

the other tank of hot water is used for heat distribution which I pump over to a radiator I installed in my family room. That's an independent variable speed Taco circulator pump that I use for that.

I stuck a thermostat in my family room dedicated to the heat distribution pump. All the thermostat does is send 24v to the little controller on the side of the pump which connects the 2 wire terminals together as it's calling for heat.

TIP: Ground water temp coming into your house from the street/well is normally 55 degrees at all times. SUMMER AND WINTER

It's cold ground water that 'replaces' the water in your solar hot water storage tank when water is removed for showers, etc.

That's not good cuz the water coming IN to your tank is cooling down that water big time.

If you run your cold water (ground water from street or well) thru a preheat tank located upstairs in a conditioned air space (68 to 71 degrees) PRIOR to running it to your solar hot water (COLD IN) pipe.. your solar hot water system doesn't have to work as hard to bring the water temps up to 120 degrees.

55 to 120 = not good - solar hot water system needs more hours to heat the water up.
68 to 120 = much better.. less hours needed to heat the water up..

Preheat tank does not need to be insulated.
The room air around it keeps it at room temp so actually 'no insulation' is even better.
Tank size = anything from 10 gallons to 20 gallons is all you need cuz most showers use only 8 to 10 gallons of water for each shower.

Once the shower is over and the preheated room temp water is now in your solar tank the water in your preheat tank immediately starts to warm again via the room temp air.
Pat from Warwick, RI

Please Note:
Comments and/or suggestions I make here at the forums on 'your' projects as well as my own have all been carefully and scientifically calculated by 'the seat of my pants'
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Last edited by solarhotairpanels; 11-11-13 at 06:20 PM..
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