Anyone use a tankles hotwater heater?

[cj8scrambler]

I'm thinking about building an AG system and have been looking around at people's setups. I haven't seen any tankless hotwater heaters used for RIMS (or would that be HERMS) systems, but it seems like an obvious use to me. For $200 you can get some small 3kw heaters designed for bathroom sinks:

http://www.houseneeds.com/shop/HeatingProducts/WaterHeating/Powerstream/PowerStreamIndex.htm
http://www.airdelights.com/instant_flow_sr.html
http://www.homeclick.com/showpage.asp?itemid=170593

Seems like with some modifications to the controller this could make a good mash heater. Someone else must have tried this already. Are there some obvious pitfalls I'm missing?

-Doug

 

[Mikey]

The spec. says max. output temp is 135F, not quite high enough for AG.

 

[Genghis77]

I had an RV that used a propane fired tankless water heater. It was great for getting hot water fast. It got up in about 2 seconds and the water was plenty hot enough for making instant coffee from the tap. Had to be careful not to get scalded in the shower. They're great as add ons and where space is limited. But I believe they fell out of favor for being less efficient than tank type heaters. Electric element RV heaters might do well. The element is encased in a sacrificial annode and will bring my 10 gallons to 135 degrees in about 20 minutes. Still not sufficient for brewing. I believe the draw is about 8 amps, The gas gets to temp in about 5 minutes, but is hard on eroding the aluminum tank. A tankless hot water might be a good way to instantly get your water up to 135 before heating to brew temp. A preheater of sorts.

 

[cj8scrambler]

The spec. says max. output temp is 135F, not quite high enough for AG.

I saw that, but I figured that was based on 50F (or colder) input water. Some of the heaters specify the maximum delta instead of the maximum output temp. Since the mash will already be fairly warm coming in, I figured it might be able to handle the smaller delta even at the higher temp. However this is a BIG assumption on my part. I guess maybe that's why I haven't seen any being used for this purpose.

 

[AiredAle]

I have one I installed to heat water before it goes into my keggle, to save heat up time. I brew in my utility room, and use a medium size propane burner (with good ventilation, etc.). I didn't want to get a bigger burner to heat faster since I don't want to overwhelm the ventilation I have.

I'm an extract brewer, and wanted to shorten the heat to boil time. It works well, will raise my 55 degree cold tap water to 125 easily. The drawback is that to get the highest temp water you need to throttle down the flow. It seems that just as you get the flow down and the temp up, the heater kicks out because it has as low flow sensor. so, you get a burst of cold water until you turn up the flow, then it takes a few seconds to get back to temp. I haven't wanted to tinker with the controls so I put up with it.

I suspect if you could overcome that, you might be able to use it as a RIMS heater, but might be easier to just make one. And more entertaining.

 

[bummerkit]

you can get small taps that will put out near boiling water for making coffee and such, but I have no idea what the flow would be. it might take you all day to get 5+ gallons. try googling for instant near boiling water...

 

[Scalliwag]

I would guess that this would differ between brands and models but my gut tells me these have a thermostat controlled system that does not allow the water to get hotter than 135F for safety reasons. Some systems *may* be able to handle producing hotter water if the thermostat was bypassed.
There are a lot of factors such as if it may damage the element quickly. But *if* it could withstand being maxxed out long enough to do 5 or 10 gallons of water that would be really nice.
Technically a person could jumper across the terminals for the thermostat and any safety sensor that kicks off in the event it senses the thermostat has failed and see what happens.
I know people that would do that and if it did bite the dust they would pull the jumpers and take the dead unit back if it did fail. the bastages!!!!

 

[kladue]

Here is a DIY water heater system using 1/4" stainless steel tubing in a 6" tube, fired with a 30K 6" burner. This unit will bring 47 deg water to a boil at a quart a minute flow rate. Last picture is of a max output test using 300 deg superheated steam to raise water from 139 deg to 188 deg at .8gpm flow.
http://picasaweb.google.com/kevin.ladue/InstantWaterHeater