sarsnik

Recipes 

I have been looking into building a simple flash boiler to speed up AG brew days. I could do the standard copper coil in a chimney method, but I was somewhat inspired by the idea of a tankless hot water heater.

As far as I can tell, one of these heaters is just a burner under a 'finned' tube. Could I try to emulate this by using a auto oil cooler? Something like this:

http://www.amazon.com/Flex-lite-4118-TransLife-Transmission/dp/B00029J3WA/ref=pd_sbs_auto_4

Would there be any issues in regards to poison / off flavors with the welds or brazing done to this coil? (I know next to nothing about welding)

Thanks

bad67z

Recipes 

My first concern would be if there were any connections that would come into contact with the water/steam that are made with solder containing anything that would be hazardous to consume.

sarsnik

Recipes 

Yeah I just found a few posts mentioning that the flux could be toxic. Maybe you can buy replacement heat exchangers for the tankless water heaters?

Artemisag

Recipes 

I'm no expert, but I know lead is sometimes used to seal radiators. I would just contact the seller to confirm

JKoravos

Recipes 

Why don't you just buy a tankless water heater?

sarsnik

Recipes 

Unless I'm mistaken, to get the a decent flow rate it looks like I'd have to get a $500+ tankless unit. They are designed for 140ish water max, so if you modify them to go higher the flow rate has to drop to compensate.

kladue

Recipes 

The finned coil idea is a good one, the problem is the lower temp brazing material used may contain cadmium as an alloying metal, not a good thing for potable water.
What flow rate are you looking to achieve, and at what outlet temperature ?. Having built and used the tubing versions, 165 degrees at .75 gpm with a BG-10 firing it is possible. Temperature is controlled mostly by gas flow to the burner with water flow held steady, and when making superheated steam, outlet temperatures over 300 degrees have been seen.
With steam injection RIMS systems, you can go from strike to boil without changing boiler connections as all the brewing water is always headed for the mash tun. Wort boiling is not a worthwhile effort for a flash boiler, direct fire is faster and more efficient than a steam heated coil in the wort which has been tested.

paganknight

Recipes 

The other thing to think about is that is ment too cool i don't think the fins would hold up to direct fire too well. the ones in tankless water heaters are made of different materials
to take the heat of the burner

Just my 2 cents

Brewmoor

Recipes 

Have you looked into transmission coolers? Not sure the how they are welded together or price but I have seen them in stainless.

__________________
"What the mind can conceive and believe, the mind can achieve."

My build thread. Compact Single Tier!