Solar wood hotwater backup.

gomango

I need a bit of advise here.

My dad has a heat exchanger in the back of his wood stove, and a single hot water solar panel collecting water in a 60 gallon tank on his roof. He backs up the system with an aquastar 1600PS. The system works great and I have followed suit in my home. The problem I have run into is that bosch has discontinued the 1600PS and their tech support tells me that the new models will not except preheated water.

I have four 3'x8' solar panels to work with and an 80 gallon tank stuffed up in the rafters. The wood stove will heat the tank in the winter, but in the summer we will rely on the solar. I am looking for a good backup on demand LP water heater that will not take to much power. I have been eyeballing two models that for some reason I cannot find any documentation about weather or not they except preheated water. Does anyone have any experience with these?

The Takagi T-Kjr2 http://www.takagi.com/index.php?product_id=101&page_id=2
The Rinnai V53i http://www.rinnai.us/tankless-water-heater/v53i/
It should be noted that I am on a gravity feed system, and the pressure is not the best. I get about 2.5 gal/minute. This summer, one of the projects I plan is to install a booster pump, but that is another post.

Thanks in advance.
Dave

BB.

Re: Solar wood hotwater backup.

One warning (we want everyone to be safe--take it as love:-))...

Is your stove heat exchanger well protected by T&P (temperature and pressure) valves? Good circulation, no hot spots, no valves that can be turned off and isolate the T&P from the "boiler"?

-Bill

Ralph Day

Re: Solar wood hotwater backup.

I have a TKjr and Enerworks sdhw system. They work well together.

A friend has a TKjr on a gravity feed system (tank on a hill), and it works well with only 22psi on the system. A shower doesn't plaster you to the back of the stall at that pressure:D


Ralph

See this link for wood heat and water together...in a bad way.

http://www.woodheat.org/heating-water-with-a-wood-stove.html

gomango

Re: Solar wood hotwater backup.

Nothing is installed yet. I am still in the planning stage. I have the components. Im looking for the on demand heater at this point.

Blackcherry04

Re: Solar wood hotwater backup.

BB. wrote: »

One warning (we want everyone to be safe--take it as love:-))...

Is your stove heat exchanger well protected by T&P (temperature and pressure) valves? Good circulation, no hot spots, no valves that can be turned off and isolate the T&P from the "boiler"?

-Bill

Please take this to heart. I had a pump failure and a misplaced pop off valve that allowed steam to build up in a heat exchanger and it blew the doors off the firebox and dumped the hot coals right out on the floor. It was 2:00 in the morning and lucky I even heard it, I really felt the vibration more than a sound. I had cut the oxygen off, but I guess it flared back up. I had a thermo disk as a fail safe that should have circulated the water, but it didn't work because the steam closed a check valve in the system with back pressure.

mike95490

Re: Solar wood hotwater backup.

Ralph Day wrote: »

See this link for wood heat and water together...in a bad way.

http://www.woodheat.org/heating-water-with-a-wood-stove.html

Thanks ! Just getting plans going, and I will be double checking what the contractor is doing.

peterako

Re: Solar wood hotwater backup.

Hi there,

i have installed dec. 2009 a wood hotwater stove ( italian manufactor )
It works perfect and came with all safetys installed.

one month ago i am working on a project in Dubai UAE and the house is in Greece. I was talking using skype with my wife. When suddenly the steam release valve started blowing. :grr

My kids played with the fuse board in the basement ( yes i made it kid safe )
And switched of the power to the circulation pump.
Because i build the sysytem and learned my wife what to do in case off.......
see managed fast by switching on power again and adding extra water to have the system in a 20 min. to be normal again.

only the kids after that had a painfull buttom and a week without TV...;)

Why i am telling you this safety is all wood stoves realing are great to connect to your water heating system but you must remove the heat.

It is not a japan nuck. reactor but it gives in a smaller scale the same overheating effects.

and allways the person that is present must know also what to do if it is going wrong.

greetings from Greece

See this link from my stove http://www.jolly-mec.it/index.php/en/fireplaces-and-stove-range/water-heating-fireplaces/fireplace-combi-idro-system.html

Dave Angelini

Re: Solar wood hotwater backup.

T & P valves inside and outside and a second one inside if you are even close to excessive BTU production.

gomango

Re: Solar wood hotwater backup.

OK guys... It appears that this thread has been hijacked by wood stove safety lectures. Thanks Ralph for answering my question.

I purchased the TKjr yesterday.

Ralph Day

Re: Solar wood hotwater backup.

Did you purchase the remote too? Dip switches inside the TKjr work, but if you want more temperature setpoints and want to know the input and output temps get the remote too.

I have a master switch beside the remote in the bathroom cupboard. You run the shower, see if the unit is cycling on and off (an led shows burn/not burn). If it cycles I up the target temp. I can tell by the inlet temp if it's going to be a problem and will up the target temp before starting.

For about $100 (probably less) you can't beat the control the remote gives you.

Ralph