pump & dhw HELP

[maplewoodshelby]

I got my dhw system hooked up but having issues. Here is my layout.
I have a boiler with a 1/2 copper coil in the water jacket. My piping is this:

I leave one side of the boiler coil and travel 50 feet using pex to the hot water out side of my 62 gallon water heater (on top). I tee in here. Above this i have a mixing valve installed. I know mixing valve works correctly as i have been using it for the past 3 days while electric water heaters were on electric. I leave this water heater out the bottom drain and travel 40 feet to the top of a 20 gallon tank and go in the cold side here (on top) I leave this tank from the hot side (on top) and travel 10 feet to my pump Taco 006 stainless that is pulling water right before water goes back in the other side of boiler coil to be reheated.

I got it hooked up last night and I think I got all the air out. I turned the pump on and it sounded like it was pumping. However no hot water was moving thru the coil. I let it run a little and went in and turned on the spigots in the house. I came back to the boiler and the pump was really hot. I turned it off and let it cool down. I took the pump motor off and plugged it in for a second and it still works.

Any suggestions. My thoughts are that there is too much pressure with 2 water heaters. When i took the motor off it almost blew my head off with pressure. However teh pump is rated for 125 psi so I'm puzzled why it wont pump.

 

[webie]

I experimented with heating up DHW 20 years ago using a 1/2 coil like you are using . I can tell you what works good and what works great because I plumbed and re-plumbed many different ways , my goal was to try to get it to gravity feed . ( never did work right )
What is wrong with yours is chances are in the top of your current water heater chances are there is a check valve in there so as to keep hot water from thermosiphoning back thru your cold water . On my water heater if you turn a hot tap on really slow you can actually here it ( sounds and is actually a little ball in there bounceing up and down ) . I do believe you can remove it , if you want to go that route , I suggest not .
The very best way to heat I found was to draw out from your DHW drain and return HOT water to a T in your COLD side . There is a dip tube that goes to the bottom and after an amount of time (really not that long ) your home brew hot water will rise up and fill the tank .
The easiest way to think about how this works is you are making it work just like it did. It heated the water from the bottom up .
The only major problem you have heating it from the top down like you are trying to do is you have a higher degree of stratification , normally you wouldn't see this because your mixer fixes things for you until you get near the end of depletion or are depleted of DHW and then you only get small burps of hot water then ice cold until it reheats the whole thing again .
If you set it up like I explained here you will never know you are heating it with wood .
I hope I explained this good enough.
Webie

 

[maplewoodshelby]

thanks for the info. I will look for this check valve. Anyone else have any thoughts. I'm gonna try webie solution and if that dont work I'm quitting the dhw thing. Putting too much into it and its not worth it

 

[maplewoodshelby]

Thanks everyone for answering my questions. I got my dhw up and running. The only problem is that I was airlocked. I put in a drain after the pump and let it run for about a minute. It purged the line and now everything is working great. I have two seperate water heaters running off my boiler and more hot water tahn i know what to do with. Webie my tank did not have a check valve but I do realize that some do. Glad I didnt start cutting before making sure it was purged.