[pairodice]

So I had issues with the heater core at the front of the coach about a month ago.  I closed off the two valves that seemed to stop the flow of antifreeze to the front of the coach (the two valves closest to the front of the coach - BACK of the engine since it is mounted backwards as opposed to a truck…???).  
I drained, filled with water, drained, filled with water and ran the engine until the thermostat kicked in and drained the water then put in Final Charge RED Extended Life Antifreeze.  
I had an unexpected result today.  We traveled about 5 hours to Mississippi and settled into an RV park.  Went to take a shower and no hot water. Since I had turned off the heat loop to the front of the coach maybe this affected the engine heat to the Aquahot…??? 
So this started me thinking, which always gets me in trouble but NOT hot water this time, that I could just crank up the diesel or 240-volt electric AH and we could take nice hot showers as always. I went outside and everything looked fine BUT there was no juice in the AH tank that I could feel with my finger. The overflow jug was a little over the COLD mark.  
I didn’t want to start the AH with no juice but what was really ODD was that the juice in the overflow was now RED not the old green stuff that I had in it… I’m confused as to whether I should top off the tank with the old green or use the new hotness RED… what do you guys think and how on earth is this system connected to the engine now? Did I turn off the wrong valves??? 
The engine/radiator ran perfectly (after burping) and it even sucked antifreeze out of the overflow bottle which I’ve never noticed it doing before… 
BTW, the 12 to 24-volt conversion on the SCS air conditioners is working GREAT!  Ran for 3 hours on the genset in 80f and performed great front and rear! It’s almost cold in here now! Thanks to Gino/Jeff, Tom and others for their help! Now I have to get the heater system working with it and I’m golden (or time to sell!) …

[encantotom]

there were 2 sets of valves on mine. i have the ones to the front dash heater core off and the aquahot still works fine

tom

[pairodice]

Tom, thanks for the quick response. Haven’t chatted in a while and hope you are doing well. What you think about the red fluid in the AH overflow bottle? Should I fill the AH tank with the RED extended life?

[Jack Houpe]

Adrian you got my head spinning. What color is the fluid in the aquahot tank, green or red? There is a heat exchanger that goes into the aquahot tank that isolates the engine coolant from the aquahot coolant so it's not possible for the two to mix unless your heat exchanger has busted. If the aquahot tank is full of anything water or any type of antifreeze then you can turn on 220v heater or diesel heater.

[pairodice]

Thanks Jack - I’ll put some of the red stuff in it 50/50 since a gallon probably won’t make a difference… so now it should be purple - red and green… just had a brain fart, if I put water in the AH and it drains onto the ground then that means my AH is part of the heater core loop to the front of the coach - I’m still figuring all this heated water stuff out so sorry for the dumb questions…

[Richard]

See #22 https://newellgurus.com/showthread.php?t...2#pid71012

Jack is right. Something is amiss or your engine coolant should not be in the AH boiler.

I have to ask "how did you determine the two valves you shut off were the supply and return to the heater core up front? "

[pairodice]

Hi Richard, I put a water hose onto the fitting for each of the valves to verify they would stop the flow to the front heater core. I’m fairly sure they are correct… on the bright side I only needed about 1/4 gallon of juice in the AquaHot so I used some distilled water to fill the AH tank and it all worked fine for nice hot showers this morning. Now I just have to figure out why my 110-water pump is not giving very much pressure but I think that is a sediment filter issue…

[pairodice]

I just reread my original post and my question still remains: why would I not have engine heat from the aquahot for hot water after driving all day? Is the engine/AH hose part of the ‘loop’ that also supplies the front heater core? I need to draw a picture…

[[email protected]]

I just reread my original post and my question still remains: why would I not have engine heat from the aquahot for hot water after driving all day?  Is the engine/AH hose part of the ‘loop’ that also supplies the front heater core? I need to draw a picture…

I cannot tell you for sure how they did the lines, but from Richard was saying there is a loop for the dash heat and a loop for the aquahot. I think you need to verify what valves you turned off, you may have turned off the valve for the aquahot. 

There should be 4 valves. I just went out and located mine because to be honest I had no idea where they were located. 

Here is what I found on my engine all on the driver side of the engine, 2 valves just above the oil filter housing, 1 valve just behind the water pump, and 1 valve on the top of the engine next to the valve cover/thermostat housing. I believe the valve at the water heater should be a return line, and I would think that possibly the valve on the top of the engine is the other return line. The two just above the oil filter I would think are the supply to the aqua hot and to the heater core. Maybe one of the other guys can confirm this.

[Richard]

There are independent loops. One goes to the heater core up front. The other circulates through the AH boiler.

Great idea on figuring out the valves. I hope you remembered or labeled correctly.

So I can imagine one of two things. The first, and let’s do simple first. Is there any chance you used pink coolant in the Aquahot? Like Camco boiler fluid? Or even the pink Propylene Glycol normally used as ‘safe
‘ antifreeze. I do not recommend you tasting it, although a micro drop on your finger will not kill you. Ethylene glycol, the engine coolant is a sickly sweet taste. Propylene glycol, the Camco and safe antifreeze stuff, is slightly bitter.

The second is more insidious, and far fetched. The piping that the engine coolant circulates inside the AH boiler has failed. That allows the red coolant from the engine to enter the boiler. This would be no bueno.

What I don’t understand is if you closed the correct valves why the AH was not hot from the days drive. Keep an eye on the AH temp next time you drive.


Here is a bass ackwards way of checking the coolant loop between the AH and the engine. With the AH hot, electric or diesel, flip on the engine preheat switch and wait about an hour. Now go back and see if the manifold with the valves has hot pipes.