Preheating your DHW - OWB

[urhstry]

I am ready to hook up the DHW coil off my Shaver to my electric hot water heater. Like others have done on here, I am going to run the incoming cold water to the OWB and back into the water heater. The problem I am thinking is that if you go for roughly 10-12 hours without pushing water through the lines, the incoming lines will cool and so will the water in the electric hot water heater. Therefore, you will need to run the water heater as you normally would thus not saving you any money. Am I missing something here or for those of you that have this setup, is there something more I should be doing?

 

[trialanderror]

i had the problem of the recovery time taking too long with the side arm....sooooo

sidearm#1 is on the side of the DWH
sidearm#2 is preheating water going into DHW from wellhouse..


i made a super sized side arm, 10 foot long...
only i set it up to have the cold well water flow against the OWB's path of circulation, so as the cold well water inched it's way through sidearm#2, it gets a continuous surrounding of fresh hot water..

so water comes in from the OWB, hits the bottom of the sidearm#1, comes out the top, into sidearm#2, out, and to the HX for the forced air...

works good. you win twice, as preheated water is continuously kept hot...

not sure if it's what you were looking for, but it's an idea i came up with.

 

[hypothesis]

I ran the DHW coil in my 290 last season and didn't notice any problems. I set it up as described in Shaver's installation guide. I actually turn off the breaker for the hot water tank's electricity. If the water temp. drops in the tank, then the water in the tank circulates to the DHW coil in the furnace, gets heated, and then returnes to the hot water tank. That's my experience with it. Hope this helps.

 

[boyland]

I am curious, I have 2 teenage daughters and we never run out of hot water using side arms. We do have 2 water heaters perhaps this is why maybe adding and additional hot water heater or larger one. I have a 40 and an 80.


I never uderstood the shaver hot water deal unless you keep water ciculating it will cool off or you have to run out a lot of gallons of cold to get to the hot.

 

[trialanderror]

I am curious, I have 2 teenage daughters and we never run out of hot water using side arms. We do have 2 water heaters perhaps this is why maybe adding and additional hot water heater or larger one. I have a 40 and an 80.

on one zone with the 30 gallon DHW, i don't have a mixing valve....
so instead of pulling 20% hot water, 80% mixed cold water, the whole house gets the full 175+F water......very nice when washing dirty greasy clothes in the washer......very bad when it takes 30 gallons to fill the washer....
naturally after doing a batch like that gotta wait a hour or so to have a decent recovery to take a shower...so i got pissed and made that pre-heat sidearm, which turned out quite impressive. and didn't cost me $80 like a mixing valve is going to.

i'll eventually get around to installing one....

 

[boyland]

Another option is to add another water heater core, maybe on someone has junked prior to your water heater giving you another 40-50 gallons.

I would also recommend this if your OWB has a smal water jacket add additional water storage inline.

The preheater is an interesting idea. Never thought of that.

 

[jgoodhart]

I just run my well water to the hot water coil in the boiler then back to my DWH. I turn the water heater down or off and the only problem we have is the water gets too hot. It's normal to adjust the water temperature once or twice while taking a shower.

 

[urhstry]

I just run my well water to the hot water coil in the boiler then back to my DWH. I turn the water heater down or off and the only problem we have is the water gets too hot. It's normal to adjust the water temperature once or twice while taking a shower.

I can see the water getting too hot when you are calling for it during "awake" times of the day, but I can't see a hot water heater holding that same ~175 degree water with even a 50 degree loss overnight. The reason I asked this question is because guys have posted that this is what they are doing, with no problems.

 

[jgoodhart]

Just for you I checked my hot water temperature and it's 125 deg and it's been 10 hours since the hot water been used. The only issues we have with this set up is the hot water don't stay a consistant temperature and can get too hot. The piping run from the boiler to the hot water heater is about 60 feet.

 

[Windwalker7]

You need a seperate pump and thermostat for the DHW.


Just press the extra thermostat against the hot water tank next to the other thermostat already there.

Seal around it with silicone to hold it in place.

This new thermostat connects to the pump and will kick on/off the pump as needed to maintain the temp.


Look in here for a diagram and better explaination.


http://www.nextlevelsolutionz.com/outdoor-wood-furnace-install.htm