On board shower using exhaust heat?

What hose did you tap into on the heater core? If you are on the input, by turning your ball valve, you will eliminate hot water from entering your heater core (ie zero heat).

I did prime my hoses/exchanger with coolant before running engine.

I need to idle around 1050+ rpm for the exchanger to get really hot.

 

I tapped into the supply side of the core. In bypass it works great & I know when diverted to hit the heater first it'll return to the cabin heater much cooler but for the "return" lines from the heat exchange to be cool makes me think it's not circulating through the exchange correctly.
I'll try pulling a hose out & filling it up today.

Can't wait for this thing to work!!!

 

Interesting. I hope you get it solved quickly!

 

Hmmm....
Went out & checked it this morning & noticed the coolant reservoir was 3" lower than I left it last night.... So there's a start.
Let it run & same thing- return line from heat exchange is still cold. Didn't have time to pull hoses or really mess with it so I'll see if there's anything in the heat exchange when I get home :0

 

Pulled the lines, primed with coolant, idled to regular temp on bypass mode- cab heater again works fine. Switched to shower mode-

20 min idling at 190 degrees & under 1,000 rpm, nothing. No cab heat no hot water through exchange.

Took a hot lap around the neighbourhood keeping it above 2,500 rpm and suddenly perfect cab heat and HOT heat exchange & hot water flowed through shower head once I pulled in the driveway.

Hot shower slowed to cold after 30 seconds or so while idling- again under 1,000 rpm.


Seems to me the check valve on the return (set at 5 PSI) is too high under idle conditions.

The point of this check valve: I can turn the 3 way valve in one direction (bypass) and have truck operate like a stock vehicle.
The other way, this check valve forces the hot water to go through my heat exchanger & heat the shower. In case of failure- broken exchanger or cut hose ETC
I turn ONE valve and it bypasses the exchange, making an idiot proof system that should function even in a failure.

Seems the only drawback is this system works only above 2,500 rpm.

So.... Now a hard decision. Keep it & accept the idle must be high to shower comfortably?
Or ditch it in place of a second ball valve and risk having a less than optimal not-so-idiot-proof system?

 

IITTSSS ALIVE!!!!!

I deleted the check valve in place of a regular ball valve and it now works PERFECTLY!
I hooked up just the hot side with a hose & the water came through so hot that the thermostatic valve shut itself off.
Tee'd in to flow hot and cold from test hose and PERFECT water temp came out of the shower head.

I'm so damn excited. Now just to mount the pump / hoses & clean up install

 

Great news!! I have been following along and really happy to hear you reached the result you wanted.

 

pump bracket



Mounted and plumbed



These two items are all I need to carry now!
RV shower head and a length of double female garden hose fittings- they stow easily in the cab and are just as easily replaced at a walmart if lost or broken.

The shower head screws onto the mixing valve up front and the double male goes into the pump



Throw it in a 5 gallon bucket & good to go!
Five gallons lasts just under 10 minutes- no pressure or temp drop. Kept the engine around 180 degrees as well.



Im proud of this one.

If you're stalking this thread, try it! It's not too difficult.

 

[QUOTE="OldManTan";8894970]Great news!! I have been following along and really happy to hear you reached the result you wanted.[/QUOTE]


Thank you!

I'm kinda shocked it works so well. I expected it to find issues with the design but it works better than expected.
I really hope others will try this one id love to help out

 

Yeah, most of the thermostatic mixing valves max out at 170f, the temp of the thermostat. Our trucks hit the higher operating temp at idle pretty quick, but stay cool at cruising on the freeway due to the increased airflow.

It's challenging to keep the setup simple but at the same time mix in enough cold water to keep the hot water from bypassing the mixing valve.

Most of these mixing valves use wax as the medium and it has a specific temperature where it works and where it fails. IIRC Honeywell has some UK models that work with a max inlet temp of 90C, which is about 194F. The Standard USA Models rate them at 212F max temperature (boiling water), but they generally state operating temps of 70-120F or 70-145F. So it might be that it can sustain 212f and not break.

They supposedly have a fail safe temp, so maybe if it gets too hot, it turns to cold water.

The specific model you want to get is the Honeywell AMX300/U, these are hot water heater mixing valves that handle up to 212F.


-----Just FYI regarding the wort cooler heat exchanger you're using. Some people have experienced cracking which ended up causing the water to mix with the coolant, so there's really not a way to prevent this except for allowing it to heat up gently, but the due to the specific use case, there's really no way to do this. Just something to watch out for. Failures may happen, but you seem to prepared with the ball valve to shut off the entire system.

 

Interesting!

So far the mixing valve works incredibly well- even temp water comes through from cold start through 193 degree engine heat.

My model says 190 max inlet and may fail if it hits that, but given the energy loss in the hoses, fittings etc I doubt it'll ever actually hit the mixing valve that hot.

I know it does work correctly though- I hooked up only the hot side and tried to pull hot water through & it started to allow some water then suddenly stopped all flow until I attached the split cold side in and then it let water out cool enough to touch. That's a good enough safety check for me!

As far as cracking, I thought about that & it would have been a big risk with my check valve setup, but the way I have one ball valve open at all times, the heat exchange will always be exposed to warm engine heat.

Now what happens if I try to suck icy cooler water through it on a super hot day.... Has yet to be determined.

 

I've been researching Duda Diesel heat exchangers and I've read nothing but positive comments from a variety of sources. Your remark is the first negative I've seen. Do you have any links to sources of such failures?

 

•

 

Would anyone be interested in buying a complete unit of this?
I could put it all together so all you'd have to do is run hoses and mount in your engine bay.

Once you've got all the parts it's really not too difficult to install.

 

Cost?

 

I think parts alone will run 400 or so. I might be able to get them cheaper, however.

A quick search pulled up a couple that cost 600+ in AUS dollar which I believe is worth more than ours.

I could probably undercut what's out there by 100$ + not including shipping by packaging the simplest method I've made here. I'll dig up some pricing from one of my vendors to get an actual price if enough people are interested!