[Wood Fired Pool Heater]

Just wanted to add an update on this.

I still like the heater despite the fact that I think the honeymoon is ending. We swam today in 90°+ water and I really enjoy water that warm.

I still don't mind - even enjoy - splitting the wood, and I still don't mind tending the fire or cleaning out the ashes after a few days burn.

I do wish it had better smoke control. While that may be in large part due to the wood I have and possibly because that wood is not fully cured yet, I just feel uncomfortable having the smoke float around the neighborhood while I'm starting up or putting in large amounts of wood. Nothing horrible or even irritating, just a bit distracting.

Another thing that keeps staying in my face is the inefficiency of the setup. I can get really great temperatures out of it, and the water does warm up fairly fast but every time I stand near it I feel how much heat is being wasted, and I see how hot the chimney gets, and I start thinking about ways to supercharge it;

- add insulation on the sides,

- add baffles on the inside so the chimney gasses have to travel farther and over more heat exchanger before they escape out the top,

- add a blower and some air intake piping so the air input can be accelerated on startup and better controlled for restriction

- add a stovepipe damper so I can reduce the amount of chimney flow to a) slow down the fire and keep more heat around the heat exchanger for longer

- Insulate the door or make it a glass door

- Enlarge and lengthen the heat exchanger so it not only covers the top but also the sides and back.

The last thing to mention is the lack of automatic control. There is no way to quickly disconnect the PVC if the pump should fail for some reason. I already had to replace a bunch of PVC when the power failed and I didn't remember to put out the fire soon enough, and since then I had another incident where the water was hotter than I expected and it made one section of PVC sag a bit. No leaks or failures but still irritating. Even forgetting to switch the pump to constant on when the fire is burning is an easy mistake to make that will cause big problems.

I've given it a lot of thought and there is no easy or cheap solution to the dilemma. Anything that covers all possibilities - pump failure, power outage, leaking, would require a lot of engineering (some combination of battery back-ups, electric 2" valves, breakaway piping, fire extinguishers, etc.) This is a point where any other kind of heat except possibly solar wins by a huge margin.

Still, having said all that it's great to swim in May in such a warm pool which gets so much shade but to still pay nothing for the heat. I can still recommend it in many situations.

More later

I just installed basically the same pool heater a few days ago which I bought used (two years old) off a local pool installer. I was lucky to find your post, it's been very helpful since I never got any information or literature when I bought the heater. I fired it up just yesterday and so far so good, but I am experimenting on how to get the most efficient burn. Have you tried different position on the lower damper door to get more heat? Also, wondering if your burning seasoned wood or green? Any insight would be appreciated.