cheap dhw solution?

[feelingasi]

hi guys,
recently purchased an ahs e180, new from the factory, just before the "wait one year" backorder. Special thanks to jeff and patrick for taking the time to answer all my questions prior to the sale! I was actually so impressed with the answers and advice i was given i was addiment to purchase my boiler from jeff, as i did not want to slight him the commission, upon ordering the boiler i learned he was the owner. What a treat to deal with someone who has a vested interest in what they're selling!!

I fully expect the unit to function as advertised. the install is nearly complete.
IN THE HOUSE
120k water to air HX installed at FAO furnace
Kick space for that cold room in the house
IN THE BARN
Hanging modine for the workshop (recovered from school renovation)
Cabinet heater for the "man cave"/"bar above workshop"(also a recovered item)

Question is how to provide DHW to house as cheaply as possible. I had budgeted in an indirect hot water heater, but quite frankly i'm about out of money. i currently have elec HW and i'm sick of giving money to "national greed". I saw nofo's hot tub heater and was thinking of something along those lines, or a sidearm. I just dont know how to control either one, while leaving my existing unit in place to serve as a secondary unit in the winter, or the primary unit during the summer or when the boiler is shut down. does anyone have a "piping" skematic, combined with an "electrical control diagram" to help in this matter?

 

[barnartist]

Not sure if this will help you or not. I use a flat plate exchanger on my electric hot water tank. It is plumbed into the cold inlet side of the heater. So the water is hot going into the heater, and thus the electric wont kick on. This eliminates a mixing valve that would be needed if you were to do a side arm. BUT- you would need to be circulating that water continuously, or else figure out a way to turn that loops pump on when the water in the heater tank gets below a certian temp. I plan on using a maual timer as a pump control. I am going to put the timer in our bathroom, and get in the habit of turning it on before a shower. Probably a 15 min timer. This too will give me the option of how I wish to heat my water. Maybe if and when it really gets cold out, I can cheat some and pay for a few showers by not turning on this timer. Or if I get behind on the fire.
While this will cost a few bucks, it might be an option. I cant remember what size this flat plate is, I think it is a 20 plate. Last season I had the breaker to my hot water heater off all winter, and we had all the hot water we needed.

 

[feelingasi]

couldn't you use the stat that tells the elec hw heater to turn on to pull a relay and start the circ pump for the plate exchanger, wouldn't this "maintain temp" in the HW heater.

I have a pump ready to go for my DHW. i,m thinking of building a dom HX similiar to nofossils hot tub heater (see screwed up my plumbing) only a little smaller and all out of copper. should i run a "coil" of domestic immersed in "boiler" water or vise versa?I believe this is the principle that most gas/oil boilers with dom. coils work off. my thought is to place a strap on aquastat on the outgoing line of the homebru hx that feeds my elec hw heater and rely on it to supply my elec tank with "preheated" water. am I way off?

side note: I,m a commercial electrician with alot of knowledge of controls and relay operation. I try to rely on the KISS method whenever possible. I can pretty much make whatever i want, do whatever i need it to do, electrically. however, it helps to know what the subject wants to do, in this case water: specifically boiler heated water, which is something i'm struggling with.

 

[barnartist]

I've seen pics of Nofo's exchanger. Seems to work well for him. I wonder what a long single pipe would do-like an 8' schedule 40, and an 8' copper pipe inside. Mounted horizontal, and so the copper piece inside would be at the inner top portion.

Stupid of me not to think of something so simple on the water heater. Since your the electric man, tell me how to wire up my pump with the water heater, as long as I still have the electric option, maybe a manual toggle switch. I feel I've gotton good at the plumbing part, but struggle with the electric part.

 

[feelingasi]

sorry about the lengthy response time, i've been busy at work (mostly scavenging parts) , and at home, wiring my boiler.

if you can tell me how and why water flows, specifically, to heat DHW, i may be able to help! I know from all the reading i've done, alot of people have struggled with running boiler produced DHW while trying to rely on elec as backup.

I'm not sure how you have your system set up: after reading I think I'm gonna set mine up in a manner that would prohibit any and all circ pumps from running unless the boiler is at temp (wherever i set the primary loop aquastat). I haven't , nor do i plan on purchasing, a " controller".

I'm now rethinking my DHW needs, as recently, 2 appx 40 gal expansion tanks have "come available", I'm thinking of turning one of them into an indirect HW heater for DHW. I think maybe i'll cut the top off, install a coil, reweld and hope for the best. or i just run a sidearm and install a selonoid valve in my return line that opens with the circ pump and closes when my boiler isn't making heat . This should allow me to leave my elec tank on.