Flash Boiler with Used Tankless Heater Build - Home Brew Forums
Register Now For Free!

Home Brew Forums > Home Brewing Beer > DIY Projects > Kettles, Mash Tuns & Hot Liquor Tanks > Flash Boiler with Used Tankless Heater Build

Reply
 
Thread Tools
Old 09-23-2010, 11:21 AM   #1
PaulHilgeman
Recipes 
 
Mar 2008
Posts: 268
Liked 6 Times on 6 Posts



I got a free 10 year old tankless heater, old for sure, but very little use.

So far, I have disassembled everything and have the burner solenoids controllable and the ignition system working.

I have a few questions. As far as the burner goes, it was origianlly a NG burner, will LP work the same as long as I keep the PSI real low, at least for testing? I suppose I can always throw a regular burner in there if it doesnt work.

Second, the heat exchanger is 10 passes, about 6" long of 1/2 inch copper pipe through a series of about 75 1/32" thick copper plates. I guess time will tell if this is enough.

Has anyone else done this? Would seem to be an easy way to get some parts to find one on Craigslist.

-Paul

 
Reply With Quote
Old 09-26-2010, 01:24 PM   #2
PaulHilgeman
Recipes 
 
Mar 2008
Posts: 268
Liked 6 Times on 6 Posts


well, This doesnt just work well, it works perfectly.

I set-up the system at 1/2 gal per minute and fired the burner up, after about 10 seconds, I was getting just steam out of the outlet and I got scared and shut it all down.

After some tweaking to get to the magic 170 degree mark at the output, I measured the flow rate at 2 gal per minute, maybe a hair over.

This was with 68 degree input water.

I will post some pictures of the build shortly, but I think the key is to have as much surface are in contact with the flame as possible, and the forced-air blower provides a ton of O2 for the burn.

The only problem with the propane is that I am getting a little soot in the exchanger, but I probably ran about 50 gal through it yesterday when i was testing, equivalent to probably 6 5 gal batches.

 
Reply With Quote
Old 09-26-2010, 04:45 PM   #3
kladue
Senior Member
HBT_LIFETIMESUPPORTER.png
Recipes 
 
Dec 2006
Turner, Oregon, Oregon most of the time now
Posts: 2,305
Liked 53 Times on 47 Posts


How much control of the fuel flow do you have?, enough to reduce the flame to a point you can do fly sparge water heating at a low flow rate?. IMHO the flash boiler is the only way to go, makes it possible to get started in minutes from a cold start, and with flame level control you can do fly sparging and steam injection RIMS.

 
Reply With Quote
Old 09-26-2010, 05:20 PM   #4
cascadia
 
cascadia's Avatar
Recipes 
 
Nov 2009
Seattle
Posts: 92

Very intriguing. Can you post some pictures? Thanks

 
Reply With Quote
Old 09-26-2010, 11:28 PM   #5
PaulHilgeman
Recipes 
 
Mar 2008
Posts: 268
Liked 6 Times on 6 Posts


I'll post some pictures tomorrow.

Sure, I am sure all it would take is some regulator on the gas input, The one I have is from a propane heater that had a regulator piped in on the equipment, so I wasnt able to salvage it. Eventually, I will upgrade to a regulator on the propane side, but for now, I am a batch sparger, and this is perfect, I can just adjust flow rate to get everything right.

 
Reply With Quote
Old 09-26-2010, 11:36 PM   #6
MacBruver
 
MacBruver's Avatar
Recipes 
 
Feb 2009
Orange County, CA
Posts: 616
Liked 7 Times on 7 Posts


Wow... 100F delta at 2gpm... that rocks! Very interested to see more pics of it.
__________________
Primary:
Secondary: Bee Cave Robust Porter (with coconut)
Kegged: Cascade/Citra Amber Ale

 
Reply With Quote
Old 09-27-2010, 12:52 PM   #7
PaulHilgeman
Recipes 
 
Mar 2008
Posts: 268
Liked 6 Times on 6 Posts


Ok, so here we go:



Here is a shot of the very dangerous test run, you cant see the thermometer, but that is 170° water coming out, 68ish° coming in. This is a good example of mixing, Fire, Water and Electricity. The GFCI tripped right after I took the photos, which closes the solenoid valves for the gas.



This is a basic shot of the front of the unit. I sprayed it all white, the left switch is a 25A DPST switch, flipping it up sends rectified and smoothed AC to the solenoids to open them up, and sends unrectified AC to the motor to get the blower running. Assuming gas is hooked up, it starts flowing. Next to the right is a simple push button switch that feeds 120V to the ignite (generates a spark above the burner) to ignite the LP.



This is the guts of the unit, you can see my wiring in the lower left, from the bottom to the top, you can see the blower housing with the solenoids, above that, the burner chamber, followed by the heat exchanger.

It has 3/4" NPT inlets and outlets, I plan on reducing these down and putting quick-disconnects on them, that way if I ever want to use it after the sparge, I can really bring things to a boil quickly by pumping my sparge through it.

 
Reply With Quote
Old 09-27-2010, 02:14 PM   #8
weathejx
Recipes 
 
Aug 2010
Washington, DC
Posts: 65
Liked 1 Times on 1 Posts


very cool

 
Reply With Quote
Old 09-27-2010, 03:39 PM   #9
Jawbox0
HBT_SUPPORTER.png
Recipes 
 
Dec 2009
Debary, Florida
Posts: 464
Liked 26 Times on 22 Posts


How sensitive do you think it will be to the Input water temperature? I'm not totally clear on the specifics of temp control in these things?

 
Reply With Quote
Old 09-27-2010, 03:49 PM   #10
skinydipper
Recipes 
 
Sep 2010
Northern VA
Posts: 32

Quote:
Originally Posted by PaulHilgeman View Post
I have a few questions. As far as the burner goes, it was origianlly a NG burner, will LP work the same as long as I keep the PSI real low, at least for testing? I suppose I can always throw a regular burner in there if it doesnt work.
You need to change the orfice from NG to LP, the orfice sizes are different. I don't remember which way, but I believe the NG orfice is smaller than the LP orfice so you may be able to reem the hole to the correct size.

 
Reply With Quote
Reply
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tankless water heater for fly sparging? WoweeZowee DIY Projects 38 12-07-2012 12:13 AM
Flash boiler GreenMonti Brew Stands 309 04-24-2011 04:29 AM
Simple Flash Boiler BeerCanuck Brew Stands 13 02-18-2010 02:21 AM
copper and flash boiler build question Ranger9913 Brew Stands 4 01-19-2010 12:21 AM
Flash boiler safety? bobdobalob Brew Stands 9 05-28-2009 04:06 AM


Forum Jump