Solar Hot Water Heater

Back in April, 2019, I posted about finally getting hot water in the cabin using a coil in our wood stove.  This system has been great, and has worked reliably.  However, during the heat of the summer (especially this summer), it’s been just too hot to run the stove.  So, it’s back to having cold showers or good ol’ bird baths in the sink.  Even in very hot weather, I’m not a real fan of cold showers.

After nearly a year of planning and collecting bits and pieces, Ken built a solar hot water heater for the cabin back in June.  Prior to the heat wave, it operated quite well through thermal siphoning, just like the coil in our stove.  On a nice summer’s day, it generated enough warm water that we could both have a comfortable shower.  In fact, the system actually produced water that was almost too hot during our 40°+ weather.  Hard to imagine that!

Solar hot water heater deployed to catch the sunlight.

Then it stopped working.  We figured it was either an airlock or maybe a kink in one of the hoses.  Ken took the system apart, flushed it, reprimed it, and nothing.  No flow.  We couldn’t figure out what was up.  Finally, we bought a little 12V hot water pump from Amazon, hooked that into the system, and voila, hot water again.  We just need to run the pump, which draws very little amperage, for a minute or so to prime the system, and then it runs by convection until the temperature of the water in the pipes of the solar collector cools down to below the temperature in the tank.  The only down side is that we have to remember to run the pump if we want hot water in the tank.  I still don’t understand why it needs priming, but such as it is.  I’m happy to have hot water for summertime showers without having to fire up the stove, which would have been intolerable in the hot weather we’ve been having.

Thankfully, temperatures are finally starting to cool down in the last week or so, fall is in the air, and the last time it rained, we started the stove up to get the chill and dampness out of the cabin.  We’re expecting rain again in a couple of days, and I wouldn’t be surprised if we light the stove up before then, as it was cool in the cabin this morning.  So, we’ll soon be back to heating our water with the stove coil, which has always worked reliably.