i do have the studs installed for the coil. Just no coil yet. I wanted to see what my monthly cost to run our natural gas water heater and if it was worth adding a tempering tank and so on…. We’re paying roughly $25/month for NG and that also runs the dryer, and stove. At that rate, it wasn’t worth it for me.The only issue is if yours did not come set up for it, you have take the air jacket off (at least at the back) enough to weld the mounting studs on the back of the firebox...not that bad to get to once the blower housing is off...
Well. I’m just looking for the best way to extract heat out if my vf100. I have no problem overheating my house by filling the firebox to 3/4 full even with the damper dial set to the lowest setting and the thermostat set to 50 degrees. So yes, if I can dump some heat off the plenum, the better.Brother firefighter, I'm going to just generally advise you not to go this route. You MIGHT be able to make it work, but I think you'll probably be disappointed. I think your biggest problem is in temperature differentials. It's going to be difficult to transfer the heat to move a lot of BTUs, and in your situation, you're trying to transfer twice, once to the water, and then back to the garage air. And, I'm guessing that in WI, your garage is going to need a lot of heat. I've seen it get to -25 in my attached garage, and that is going to take a lot to overcome. You might be able to keep it above freezing if you ran it all of the time, but I wouldn't expect to be able to bump the temperature to comfortable unless you start a day ahead of time, or had a lot of stored hot water, and even then, I'm not sure.
Because of the temp differentials, it would be a lot easier to do this if your goal is to keep the garage at 40. If you're looking for 70, ever, I think you'll be disappointed.
I'll respectfully disagree with Brenndatomu on the issue of the factory hot water coil. I ordered one with my stove, and. just can't see that doing this job. I returned mine. From what I've seen and done, if you want to move a lot of the heat from your VF to some other use, the duct heat exchanger is the way to go, as long as you have cold water going through it - which is why 40 is going to be so much more doable in the garage than 70.
I guess I'd throw out that a VF100 doesn't make a lot more heat than the average woodstove. If you consider that a lot of people heat their average home with an average woodstove, that makes sense. The VF is sized to do the same job as the average woodstove . Most folks heating a garage, also have an average house woodstove in there doing that job. So, depending on the heat needs of your house, and your garage, you're still roughly one woodstove short on a cold day.
That said, if you're finding that your VF is a little big for your house needs, it could be an advantage to be able to move some of that heat to some other use, like the garage, while keeping the easy full reload program going without cooking you out of the house. I do find that option useful with my setup, and, while it would never work for anybody where it actually gets warm, I get a side benefit of being able to have a hint of air conditioning on hot days by using my system to cool the house by running my incoming water through the heat exchanger system before it gets used for irrigation or whatever.
If you were using this to heat or preheat your DHW, and dump excess heat to the garage when desired, it might make sense, but I think you should plan on having some additional source of heat for your garage.
If you think you want to do this, and would like to talk to me, I'd be happy to talk to you about it FWIW. I don't know if you can PM here. If not, post again and I'll get you my business number. There's a lot of little things like size of heat exchanger depending on the water temp you're shooting for, that I've learned. There's a lot to tweak depending on your specific situation.
And, now I have to go do something about the Type 3 engine with the two inside dual tires that didn't survive the last forest fire. Never Forget!
I’m not really looking for a constant 70 in the garage either. 40-50 would be nice. I can get it up to “working temp” with my portable propane heater. As far as outside temps, I’m in south east wi about an hour north of Milwaukee. So our average temp don’t go below 0 that often. We stay in the teens to twenty most winter.