Outdoor Wood Furnace Info

All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: hrc200x on December 25, 2014, 03:55:20 PM

Title: side arm exchanger sucks heat out of water heater in the summer
Post by: hrc200x on December 25, 2014, 03:55:20 PM
When I was getting the OWB with side arm on the water heater up and running this fall (fresh install) I was circulating the water through it before a fire was going, to check for leeks, during this time the water heater was still being heated with propane. I noticed that within probably 5 mintues of turning on the OWB circulating pump the propane would turn on for the water heater. It was probably working the opposite way as its designed, it sucked the heat out of water in the water heater. The dealer for the OWB said to let the circulating pump run all summer long, there won't be a fire going in the summer, so if i do this it will suck all the heat out of the water heater. Should a bypass loop before the side arm with valves be installed so it won't circulate through the side arm, or will shut offs on the domestic side of the side arm stop the thermo siphon action? I'd guess the second way there would still be heat loss through the steel of the valves though.

I know summer is a long way off, but I believe the water heater sprung a leek, if i was going to add shut off valves now would be the time to do it.
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: slimjim on December 25, 2014, 04:21:25 PM
Definately use the ball valves
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: CornFarmer416 on December 25, 2014, 06:34:42 PM
I didn't relize we have to run the water pumps year round? I just figured you shut them off after winter and just let them circulate one day in the month?
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: juddspaintballs on December 25, 2014, 07:52:54 PM
First of all, every zone or circuit should be on brass ball valves so you can isolate it for repairs or shut it down if you don't want to use it.  Keep the water heater isolated out all summer regardless of whether you're running the circulator so it doesn't thermosiphon backwards. 

Secondly, I only ran the circulator for my system about once a month during the summer and never had any issues. 
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: slimjim on December 26, 2014, 02:53:11 AM
Agreed, and in the past I have always shut my circs off in the warmer months, however after cutting open the tank on the 9 year old Wood Doctor that I am repairing and seeing the settled sludge and corrosion in the bottom of the tank, I think I will now let my Wood boiler loop circulate constantly all year.
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: ijon on December 26, 2014, 05:21:43 AM
Would that  make condensation ?
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: mlappin on December 26, 2014, 05:31:26 AM
I have gate valves in the bottom and top of my sidearm, come spring when I let the boiler go out and I turn the water heater back on those valves get shut.
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: yotehunter66 on December 26, 2014, 06:14:09 AM
Agreed, and in the past I have always shut my circs off in the warmer months, however after cutting open the tank on the 9 year old Wood Doctor that I am repairing and seeing the settled sludge and corrosion in the bottom of the tank, I think I will now let my Wood boiler loop circulate constantly all year.
I completely drain and flush my system every year. I would think that would keep the build up down and fresh boiler treatment in the system.
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: aries9245 on December 26, 2014, 06:27:36 AM
So just by continuously circulating the pump it will not sludge up? Is it because the water moves and doesn't give it a chance to settle or does it just build up inside the tank by not moving .. I would think being an open system that Oxegen is the key killer regardless..
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: slimjim on December 26, 2014, 06:37:23 AM
Well the moving water certainly would keep the crap in suspension better and that particular boiler has about 1/3 of the bottom as dead space that water does not circulate in at the moment but when I put it back together it will as I will be putting a return port at the lowest point.
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: aries9245 on December 26, 2014, 11:52:33 AM
Ok Slim what do you feel is the cause of most sludge is impurities in the water breaking down when heating or the steel realesing impurities as part of its breaking down be the cause ?
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: mlappin on December 26, 2014, 01:11:08 PM
Ok Slim what do you feel is the cause of most sludge is impurities in the water breaking down when heating or the steel realesing impurities as part of its breaking down be the cause ?

Even "soft" water still has crud in it, just let a faucet drip here and you'll still have rust stains even though the "Culligan" man has been out to test our water and said they can't get it any softer than the 3rd party softener we have is.

Can also be dust, mill scale, oil, etc on the steel when the boiler is built. Add in any residue from your fittings, pump, HX, lines, etc and you end up with crud in your water.
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: juddspaintballs on December 26, 2014, 02:25:38 PM
What about a coolant filter like on big trucks?
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: Jwood on December 26, 2014, 02:29:34 PM
Now for us Bl owners that have piped our returns to the top as suggested by this site I now feel that may have been the wrong move and should have the return on the bottom?
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: slimjim on December 27, 2014, 03:34:58 AM
I'm not sure why you would think that Jwood?  As long as the water is moving, it should keep any sediment in the boiler suspended and allow a filter to remove it regardless of which direction it is moving, this particular unit that I am working on had no ports on the bottom 1/3 of the unit so all the debris settled to the bottom of the tank, your boiler is a dry base boiler, it has ports at the top as well as the very bottom of the tank.
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: Jwood on December 27, 2014, 03:52:51 AM
I was probably just over thinking Slim not implying anything just want what's best for the boiler. If you think I'm safe that's good enough for me bud!
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: slimjim on December 27, 2014, 03:56:24 AM
You are fine, all is good. Did you have a nice Christmas?
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: aries9245 on December 27, 2014, 04:15:04 AM
Mlappin.. It's amazing how much crap is in the water so I guess ur right  between the two there's no chance of being sludge free.
Title: Re: side arm exchanger sucks heat out of water heater in the summer
Post by: Jwood on December 27, 2014, 05:09:21 AM
Christmas was ok Slim thanks how about yourself?