Outdoor Wood Furnace Info
All-Purpose OWF Discussions => Plumbing => Topic started by: AirForcePOL on March 17, 2014, 10:14:27 AM
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I posted this earlier but it didn't show up...
I recently purchased a Heatmaster 5000e to replace my Hardy H2. I will be working on my install here and there over this spring and summer. I want to make sure that I have a system that is done right this time. I don't heat my DHW with my current setup but I will be adding it with the new one. I really don't know what the best way to do it would be so I'm hoping you guys could help me out. I would rather try to have a setup that would allow me to turn my water heater off completely durring the heating months if it is possible.
What is the easiest and cheapest way to achieve that goal? I'm looking for advice on what my best options would be and what all of you use for your DHW. Thanks!
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I think the most effective method is with a good quality electric hot water tank and a sidearm heater,( some guys like the plate exchangers but we never run out of hot water with the sidearm and in the summer we automatically revert back to electric
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Uh-oh, I hate to buck Slim, but here I go!! I will start with a disclaimer. I do not, nor have not run a sidearm. I run a 20-plate plumbed in before my water heater. My breaker has been off since October 13. I have a family of 4, 2 adults, two small children. My wife takes 45 minute showers, I take 5. Kids get 3 baths a week-ish.
I like the plate over the sidearm if you have normal to above normal usage. Sidearms work for low use situations. There have been many guys on here that have had to add small circulators to their sidearms to achieve the volume of hot what they really need. This isn't necessary with a plate exchanger. The more you use, the hotter it gets! Sidearms need downtime to regenerate. I've been gone for 4 days before, and yes, when I get home the water is luke-warm. But, I turn on the tub, let it run for less than 5 minutes, and I'm back to full power!
My final illustration is this: I filled a 400 gallon hot tub with 110 degree water. I hooked up a hose to my hot side of my washing machine supply and let her rip for 2 hours. Bada-bing. You can't do that with a sidearm.
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Thanks for your input guys. No a question for both of you: When you run the exchanger on the supply side of the water heater, you are basically counting on the insulation of the water heater to keep the storage tank warm right? Is there much difference in head pressure between the two?
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Yes on the insulation and not sure what you are asking about head pressure, are you asking if there is a difference with head between the 20 plate and the sidearm
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Ok thanks. Yea basically which one has the least amount of head. I'm assuming it depends on which one I choose to go with. It would probably be a 20 plate. I haven't researched side arms at all so I don't know what size I would need.
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The answer to your first question for me is...yes. It works by heating water as you use it. As you draw hot water from the tank, new stove-heated water dumps in. The side arm heats the water while it is not being used. It is entirely possible to drain your tank of hot water and have to wait for it to regenerate. If you are low-usage, that would be fine. But, filling a hot tub, having 4 people take a shower in a row, running the washing machine AND dish washer AND taking a shower are no problem for my setup!
I believe the pressure head for both units are about the same. A 10-plate would be a restriction. But, a 20-plate would be fine.
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Air Force, I am assuming you have electric DHW? Do you have a back up boiler? There are many different ways to do DHW, what you have as an indoor system will make a difference in which way you want to heat your water assuming you do not want to get into changing your indoor loop also.
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Figure the btu load for each. Will the boiler circ be running all the time to be able to do the supply side FP method. Or how will you control the boiler supply for the heater. I like the output of the flat plate especially if you have it on a zone valve to control demand. This is if your boiler is not running 24/7. There are some sidearms with big output also but not many build them that way. Instead of one tube down the middle of 2"" pipe we put in several 1/2" or 3/8" inside the 2" pipe for more surface area. But you are still relying on thermosyphoning to get the job done. A sidearm has the least head loss, but the flat plate is also low when flow is within specs. It would be safe to size a sidearm on the high side for on demand like mentioned above.
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Yes I have a electric water heater. I have forced air for my heating system. I plan on leaving the circulator on 24/7. My furnace is only about 10 ft. from my water heater.
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I initially installed a side arm. It didnt keep up with two showers back to back and would run out on my kids baths. Now I have to admit that my hardy didnt always supply 180 degree water when my radiant heat was on so that could make a difference. I installed a 20 plate before my water heater and havent ran out of hot water since. Easy decision for me if I had to do it over.
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Thanks for your advice guys. I've got some time to think about it but I think I have a good start.
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Go with the 20 plate, I think you'll be very happy with it
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Country boy john, I would not call that bucking, lots of folks use the plate exchangers and they work great, I do get concerned however about the plates plugging up and putting more restriction on the loop, I have done sidearm units as many as 6 on one manifold with temp gauges and balancing valves that will give you continuous very hot water out of a 3/4 inch line at 40 pounds of pressure, this was for a Dairy barns rinse lines, it worked great but in hindsight a plate exchanger would more than likely have been better suited, I guess my only vice there is that I love the look of all that $copper
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That was another concern of mine slim. I have very hard well water. Will that cause problems? I thought about just making it easy to disconnect so that I can clean it every year.
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I normally will put a purge port on each port from the heat exchanger and follow that with a ball valve for easy cleaning without removing the HE
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I do similar, use hose bibs with valves on S&R end of HX, a person can use them to flush both ways and also fill the boiler with garden hoses using house pressure from inside the house.
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I am blessed with abnormally clear and pristine water in this part of the state. If I had very hard water, I'd look at purchasing water that has been treated or purified. You're going to have the same clogging problem with your water-air exchangers as you would with a plate exchanger. (I guess I'm assuming you are on forced air) I think it would be worth it to start with good water.
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I agree with Countryboy. Just fill the boiler with storebought water to start with. I probably only ad one gallon per year.
As far as DHW heating. I have both a sidearm and a plate exchanger. Started with a plate exchanger and never had a problem, just added a sidearm because I could and wanted that water to be hot all the time.
Another thing that was bothering me was that here on the thread people in the know are always saying that you don't want the return water to going back to boiler very cold. If you just use a plate exchanger, when you run your hot water at the faucet, you are seriously cooling the water returning to your boiler. I put my plate exchanger after my water heater so the domestic water running through the plate exchanger is preheated by the sidearm on the water heater. Less shock to the boiler.
Just skinning the cat my way.
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The DHW is only flowing a few GPM, most faucets are 2.0-2.5gpm limited now, so the occasional 5gpm laundry faucet or old style three handle bathtub faucet. That's not enough flow to pull down even 160 degree water. It would have to be seriously undersized FP, and then it would not be enough to heat up the water to 120. The boiler side is flowing double or more.
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Sorry I should have clarified, I will be using city water to fill the boiler but I was worried about my domestic water being hard.
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Oh, thanks sprinter, I was probably worried about nothing then. I didn't have a return temp monitor when I added the sidearm.
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unless i am doing math wrong (quite possable) if your domestic water was entering the plate exchanger at 2 gpm at 55 degrees...and your OWB was sending water through at 8 gpm you would lose about 17.5 degrees to heat that 2gpm at 6 gpm from the owb you would lose 23.3 and at 4 gpm 32 degrees ..these are close guesses at using water at 8 pounds per american gallon (i think)
this is figured at 2 gpm (16 pounds) raising water is 1 btu per pound per degree so for every degree raise you need 16 btu ...heating from 55 degrees to 120 is 70 degrees rise so 70 x 16 pounds would be 1120 btu per minute or 67,200 btu per hour or about 7 gpm to keep your 20 degree delta?
perhaps the real btu figuring guys can straighten this out if it is wrong
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I agree with Countryboy. Just fill the boiler with storebought water to start with. I probably only ad one gallon per year.
As far as DHW heating. I have both a sidearm and a plate exchanger. Started with a plate exchanger and never had a problem, just added a sidearm because I could and wanted that water to be hot all the time.
Another thing that was bothering me was that here on the thread people in the know are always saying that you don't want the return water to going back to boiler very cold. If you just use a plate exchanger, when you run your hot water at the faucet, you are seriously cooling the water returning to your boiler. I put my plate exchanger after my water heater so the domestic water running through the plate exchanger is preheated by the sidearm on the water heater. Less shock to the boiler.
Just skinning the cat my way.
Great mind think alike ;)
I'm thinking of doing the same. Normally the sidearm keeps up fine but once in awhile the wife has a damn near fatal brain fart and decides to do all the laundry in a afternoon, run the dishwasher a couple of times then she'll get a hot shower in. This always seems to happen if we have to be somewhere like a meeting or meeting another couple for dinner then I end up with the cold shower and um... shrinkage problems.
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WOW!!!!
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WOW!!!!
Well it's really cold water.
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Not sure how much you were joking about, but how do you run out of hot water? We've done all that in our house and the water in the tank just gets hotter the more you use it. Are you serious that you run out of hot water?
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Not sure how much you were joking about, but how do you run out of hot water? We've done all that in our house and the water in the tank just gets hotter the more you use it. Are you serious that you run out of hot water?
Serious as a heart attack.
Using a side arm, power vented 40 gallon water heater, couldn't get the top of the sidearm low enough. Seen no higher than 4 inches maybe? I ended up almost six. It does work, just not as well as it could I suppose. You also haven't met my wife, she looks like a damn lobster when she gets out of the shower, how she can stand it that hot is beyond me.
I also use a LOT of hot water in the winter. We use glycerin, jam and even maple syrup in the rations for the beef cows. It gets cold enough and the solids in all of those will settle out, only way to get em mixed back up is to add a lot of HOT water and agitate, I usually run out of hot water before I'm done. The hose is hooked right to the pop off valve at the top of the water heater.
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lol I like my showers really hot too.
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Let's work on that hot water shall we? You said your sidearm is 4 -6 inches above the relief valve, can we raise the tank and drop the sidearm down so the top of the sidearm comes directly horizontal to the relief valve.
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I thought you said you were using a side arm AND a 20-plate?? Something is NOT hooked up right of you're running out of hot water with a plate exchanger!! Did I read that wrong?
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Let's work on that hot water shall we? You said your sidearm is 4 -6 inches above the relief valve, can we raise the tank and drop the sidearm down so the top of the sidearm comes directly horizontal to the relief valve.
More of a problem of the power vent. I've been looking at redoing it and coming off with a ninety to the west, then another 90 to the south so I can pick pup the side arm. Side arm is on the south side of the water heater by the way. I can't go straight south from where the anode rod was because of the power vent.
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I thought you said you were using a side arm AND a 20-plate?? Something is NOT hooked up right of you're running out of hot water with a plate exchanger!! Did I read that wrong?
Most entirely my fault, I meant I'm thinking of running a hybrid as in adding a plate exchanger. Other than cost I think you would have the best of both, sidearm would have 40 gallons of hot water ready in the off peak times and when you weren't using that much hot water the plate exchanger wouldn't be dropping the water temp from the boiler and when we're using an excessive amount of hot water the plate would take over.
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I see, 90's will not effect the flow but being above the relief valve will as there will always be a problem with an air pocket at the high point.
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Ok, I see. Mr. Yoder runs both. I have enough usage that it's not worth it for me. I've been gone as much as 3 days and still have to add cold water to my shower when I get back. Like I said earlier, if I am gone for more than 3 days, I just run my tub for 3 or 4 minutes and I'm back in business.
If you already have a sidearm, I'd go ahead and add the plate. If I was starting out, I would do the plate and not worry about the sidearm.
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I see, 90's will not effect the flow but being above the relief valve will as there will always be a problem with an air pocket at the high point.
One of the nineties' has an auto vent in it. Have never had airlock issues.
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Have used the HX when installing new to me boiler,unreal never ran out of hot water. When new boiler was installed also installed an 80 gal. water store have never ran out of hot water ever. In winter with OWB running all hot anyone could use always. In summer I can get 3 sometime 4 days of hot water depending on usage like someone said several loads of whatever,when water gets cooler just flip switch and in 5 min water temp is up from boiler,this worked for me all last summer very little oil and good to run oil boiler some.
Whitepine2 P&M 250 best investment ever as well. :thumbup: