Outdoor Wood Furnace Info

All-Purpose OWF Discussions => Plumbing => Topic started by: tippy on January 19, 2012, 02:33:19 PM

Title: instant hot water
Post by: tippy on January 19, 2012, 02:33:19 PM

Hi all!
just installed a homemade OWB, with internal DHW coil that I have yet to connect.

I'm thinking of plumbing the DHW (OUT) to the gas water heater (IN).
Then use a pump (with clip-on thermostat)  to push it through the house supply before returning to the boiler.
this will keep constant hot water at all the fixtures in the house. anyone else setup like this?

 thanks for the kick-ass site! :thumbup:

Title: Re: recirculating DHW
Post by: Bull on January 19, 2012, 08:41:26 PM

Welcome to the site Tippy

Title: Re: recirculating DHW
Post by: mikenc on January 20, 2012, 07:06:36 AM

I have a pump on mine. I put a tee at relief  valve and one on drain to circulate mine. I would think You will need a circulating line in order to keep constant hot water at fixtures in house.

Title: Re: recirculating DHW
Post by: tippy on January 20, 2012, 08:58:15 AM

I have a Tee behind the hwh pressure relief for the supply(in) from the OWB(out).
I'll use the hwh(out) to feed the house supply as normal.

the kitchen sink is farthest from the hwh, so I plan on extending
just past the lateral to the sink and use it to return to the boiler(in)....
essentially putting the house line in the loop.
not too worried about heat-loss in the pipe as it's in a basement area.

do I need an expansion tank? check valve?
should I use the hwh drain or cold inlet as the (in) from the boiler to better circulate the tank?
lot's of questions, but thanks for the hospitality!

Title: Re: recirculating DHW
Post by: Ridgekid on January 20, 2012, 09:45:17 AM

Tippy-

Your not going to use the OWF water for domestic use are you? You want to run your Domestic water through a HX to heat your hot water.

Does that make sense, or did I read your post wrong?

Title: Re: recirculating DHW
Post by: tippy on January 20, 2012, 10:24:10 AM

no...
there is a copper coil exchanger built into the boiler tank for dhw.

Title: Re: recirculating DHW
Post by: mikenc on January 20, 2012, 10:01:39 PM

Sounds like it will work to me. Free hot water sure beats paying utility company dosen't it. :thumbup:

Title: Re: recirculating DHW
Post by: jerkash on January 21, 2012, 04:32:27 AM

My setup is basically like yours except I don't circulate hot water continously.
I have a cold water line run from my house to my OWF, thru the coil, into my hot water heater.  It works just like it did before I hooked it up.  I have a bypass valve that I use when I'm using my OWF to sent the cold water to the OWF and then back.  My hot water heater stores the hot water till I need it.  I think you will lose a lot of BTU's by running in continously.

Title: Re: recirculating DHW
Post by: jerkash on January 21, 2012, 04:35:07 AM

Also, you're hot water will be 180 degrees if you have your OWF set at that temp.  Way to hot!!

Title: Re: recirculating DHW
Post by: tippy on January 21, 2012, 10:11:14 AM

clip on aquastat for the pump.
might put it on a timer too now that I think about it. ???

*edit
Revised Plan.... thanks for the responses so far!

Title: Re: recirculating DHW
Post by: tbone on January 26, 2012, 10:14:34 AM

I have the same set up as jerkash....works great.  I have used up all the hot water on occassion (if the coil can't keep up with the demand and you empty the holding tank (hot water heater).....but that's alot of water and rarely an issue.

Title: Re: recirculating DHW
Post by: RSI on January 26, 2012, 10:31:52 AM

I did pretty much the same thing at my brother's house except I put a side arm in series with the cold water line into the tank and put a tee before it and ran a line to the farthest fixture in his house. As far as I know it is working fine.

If you get a pump with a built in check valve it saves a few fittings.