Registered: 1440223530 Posts: 72
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This may be covered somewhere else in the Forum but I'll add my $0.02 anyway.
When I wire a snap switch I like to add two more simple 120 volt AC switches. One is in series with the snap switch and when 'off' disables the switch and in line fan. The other is across the snap switch wires, and ergo in parallel. When this switch is 'on' the in line fan runs regardless of the state of the snap switch. I've found this to be helpful in harvesting the early morning and late afternoon heat that is still very welcome when ol' Sol is not yet high and warm enough to activate the snapper. I find I get from one to two hours of nice 70 to 80 plus heat for 1.5 or more hours in the morning before Sol really gets his behind out of bed, and the same in the evening before he sets. I've also found this will provide some useful heat on those partially or thinly clouded days when Sol is still providing some warmth through the clouds but not enough to activate the system. Yeah, I know, I could wire in a thermostat or two instead of the switch but what the heck? I'm up and around feeding animals and I'm as good of a judge as any dumb thermostat or at least I like to think so....? BTW, I still don't like electrical windows in vehicles. I guess that's why I use GOM as my Forum nickname, short for grumpy old man. The outboard switches are also handy to turn on/off the outside solar heat panel on summer nights when I use the solar panel to help cool the house. I saved a mint this past year just flipping a switch from time to time for both heating and cooling.
Registered: 1388591029 Posts: 2,748
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Always wondered what GOM stood for!
I've done about the same thing with a 3-position toggle. It does come in handy. __________________ Solar is like the wind. It may be free, but putting it to work isn't! Willie, Tampa Bay
Registered: 1352981942 Posts: 2,251
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Due to low sun, haze and lots of trees, it takes a LONG time for the sun to finally warm up my collectors this time of year. The collectors are in full sun about 8:30(through the trees), but only begin to cycle on and off a couple of hours later. Having an independent switch so I can blow some basement temperature air through the collectors for a few minutes would help thaw things out much faster. It's also nice to have if you are working on the ducting or checking air flow. I was looking to purchase a couple of on-off-on switches a couple of days ago for the very reason GOM stated. Does anyone have a wiring diagram?
Greg in MN
Registered: 1388591029 Posts: 2,748
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Cut the hot wire going to the snap switch. If there's an existing switch simply remove it. Connect the "hot" end to the CENTER pole of your SPDT center-off switch. Connect the other end to one side of the switch. Connect a new wire from the other side of the switch to the fan, bypassing the snap switch. That's all there is to it. Throw the switch one way and it's ON, the other way and it's AUTO. Center is off. __________________ Solar is like the wind. It may be free, but putting it to work isn't! Willie, Tampa Bay
Registered: 1378212127 Posts: 554
Reply with quote #5
One other suggestion... Add an indicator light to show when the fan is on, especially if the fan can run in a quiet low speed mode. The first season on my original collector I had a snap disc bypass switch plus a second switch to turn off one of the two fans (turned out that was not needed). At the end of the day I could turn the fan speed down, bypass the snap disc, and run the collector a little longer. The light is a reminder it is still running. If you forget, the collector will turn into an air conditioner.
After that initial season I took out the snap disc bypass. It wasn't worth the bother to get a little more run time. Although, having the bypass there for testing is nice. Kevin H MN