Believe nothing, no matter where you read it, or who said it – no matter if I have said it! – except it agree with your own reason and your own common sense.” – Siddhartha Gautama, a.k.a. the Buddha

hot water update.

The pump works great, actually, a little too well.   I need to install a restriction on the heating coils to slow the water down so it absorb more of the heat.  
I set up the system just shy of full last night and started a fire in the stove.(didn’t need one, but hey, ) 30 gallons of water in the tank with the system primed up, the water level just below the outlet pipes as I don’t have the rest of the plumbing in place yet.  I ran into one problem early on and that was an air pocket in the heating coils.   The steam built up enough pressure that the pump was not able to force it through.  A little suction on the outlet pulled that through and the whole shebang started running smoothly.   This leaves me with some trepidation on how well this is going to work. 
But to finish where I started, the system ran all night but the water temps never rose above 80 degrees in the tank.   Part of that is the long run to the stove (needs insulated as does the tank itself) and I feel that the heating coils are just flowing too fast to pick up the heat efficiently.  It would likely work better pumping up to a solar collector as the head would slow the flow down quite a bit. 
Any other ideas?   Thinking I can make a better set of coils with smaller diameter pipe embedded in an aluminum casting.   Add in a restriction on the inlet side of the coil, with full flow out, and it would effectively become a one way valve of sorts.(and I am likely wrong and make my vapor lock issue worse  LOL)  Another point to alleviate the vapor lock is to re-run all the plumbing so that it all runs on an even plain instead of traversing this big  “U” shape between points.  This is the joy of getting completely off grid, all the experimenting and learning curves involved.   Yeah, I make mistakes, but I never forget them.

4 responses

  1. wonderdawg

    Might be as simple as a valve on outlet side of pump to adjust restriction till its tweaked to correct flow….curious how pump will handle 110% water temp…your coils probably too small to do any fast rise in water temp….be tempted to try …a pot on back of stove with a low inlet and high outlet, maybe even without lid, could really slow water flow significantly…. SOURCE found local Ace hardware sells water heaters and stacks returned or replaced warranty tanks till get enough to take to salvage…have picked up 2 electrics for 10 bucks each and both had bad t-stats.. other than that like new..replaced for 14 bucks, been working fine since….mention in your case because of 30gal insulated tanks with fittings…

    December 13, 2015 at 9:30 am

    • I put one of those valves for a water hose on the inlet side of the coils. It worked but disclosed another problem I didn’t know I had. Apparently I cracked the housing on the pump and the restriction raised the pressure enough to leak. Looks like I need to order another one. Two is one, one is none will getcha every time.

      December 14, 2015 at 12:27 pm

  2. Robert Dudley

    You would have been better off using 3/8 od tubing in a long loop. Not much surface area on 1/2 inch pipe.
    Take a 25′ length of 3/8″ copper and put a tight bend 180° ,then coil the parallel tubes on a flat surface. Hook up the water and set that on top the stove, it’s all about contact area, with this type set up. Even better, would be a double boiler set up that has a tank fixed directly to the stove with the coil inside the tank.

    December 13, 2015 at 12:02 pm

    • I had thought about that, and one thought was to flatten the long sections to improve contact and act as a restriction to flow. I also looked into a stainless coil (look for wort coolers in home brewer supplies) for around the flue. Still considering casting something with the coils inside. Lots of surface area with that if’n I use my head instead of my wallet to think with. ;-p

      December 13, 2015 at 12:51 pm

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