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Topic: Engine recirc at Aqua-hot system leak (Read 334 times) previous topic - next topic

Engine recirc at Aqua-hot system leak

during my recent Aquahot burner service, I opened my enclosure to find a bit of coolant in the pan under my blower. First thoughts were winterization went wrong, but luckily found it instead to be an age or abuse related stress crack on the engine recirculation piping.

As what I found I feel could maybe happen to anyone, figured I would photo and share.

The coolant leak was emminating from the copper "L" just right of a copper union that is in place to facilitate the recirc pump replacement. I myself have never been a big fan of copper unions, as all it takes is one slip when loosening/tightening to stress the mated pipes. Is that maybe what happend here.....OR was it the weight of the pump assembly over time, it is quite heavy? only the tootsie pop owl will ever know.
You can clearly see the stress crack. I would add the copper used OE was the heavier type N thick wall. It takes quite a bit to create a stress in that stuff.


As I am not a fan of unions, I chose to use compression fittings in place. Local lowes only had one compression fitting in the size I needed, so I opted to use Sharkbite fittings for the rest. They are rates to 200psi and 200°F. I may upgrade them to comp type if I see any heat related issues. The hardest part about the job was getting the downpipe cut for the placement of the new fittings. With the compression fitting in the place I put it, it is also quite easier to remove the pump for service or replacement without extra stress on the piping system. I also added a piece of 3/8 polycarbonate under the pump so its weight does not affect the piping.


Mike in AL
2001 U295
8.3 ISC 350
Build 5918

Re: Engine recirc at Aqua-hot system leak

Reply #1 –
On the left upper corner of your first picture it looks like your zone pump seal might be leaking. I replaced all of the pump seals and had to drain the Aqua Hot to accomplish the project. I will have a close look at the copper tubing as I am pulling the burner for service and a new igniter coil next week.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Engine recirc at Aqua-hot system leak

Reply #2 –
Quote from: craneman –
On the left upper corner of your first picture it looks like your zone pump seal might be leaking. I replaced all of the pump seals and had to drain the Aqua Hot to accomplish the project. I will have a close look at the copper tubing as I am pulling the burner for service and a new igniter coil next week.

Good point did not notice that with all the attention on the problem I encountered while doing a basic burner service. Do you by chance have the part numbers for the seals? I'll go ahead and do all those while in here!

And if I am going to do that might as well replace that recirc pump that is also not working....gotta see can I spec that.
Mike in AL
2001 U295
8.3 ISC 350
Build 5918

Re: Engine recirc at Aqua-hot system leak

Reply #3 –
I will look for the post, I got the numbers from a member at the time.
Found the post. Look at reply #14 and #19

Aqua Hot Repair
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Engine recirc at Aqua-hot system leak

Reply #4 –
Quote from: craneman –
I will look for the post, I got the numbers from a member at the time.
Found the post. Look at reply #14 and #19

Aqua Hot Repair

Thank you. Need to be sure what type of Zone pumps I have....as for the engine recirc pump that I feel will be the entire pump, not to include the brass base....based on the parts manual, looks like all of those pumps are the same.
Mike in AL
2001 U295
8.3 ISC 350
Build 5918

Re: Engine recirc at Aqua-hot system leak

Reply #5 –
The seals were the same on all 4 pumps on mine.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Engine recirc at Aqua-hot system leak

Reply #6 –
In 2019 we traveled from CA via Nac then Blue Ox in NE to HWH in IA on our way to a RV Fantasy caravan to the Canadian maritimes. While in ME I discovered a similar leak, but on the other side of the AquaHot. The crack was on the outside of the elbow. Bought a piece of coolant hose to bypass the AH. Completed our caravan trip and stopped by FOT for maintenance on our way west. I had FOT replace the 90 degree fitting and all was well for about 6 months, then the elbow fitting shown in your post cracked on the outside bend. Found my old coolant hose part to yet again bypass the engine loop. The AH tech from AR said he would have to remove the unit to repair the pipe. Currently it still needs repair.  May take your approach when I get my transmission issues resolved.
David & Sherry Kendrick
"Gizmo" The Doggy Lama
USAF(Ret) 1971-75; 1979-95 (20 yrs)
2003 U320 F03 [6179] 38PBDS (3/2016)
2016 Chev Silverado Z71 LTZ
Motorcade 17738
--------------------------------------
New Horizons 5W 25' RKS (1/2004 - 3/2016)
2003 Chev Silverado 2500HD Duramax
Tent (5-person) White Stag (1972 - 2003)

Re: Engine recirc at Aqua-hot system leak

Reply #7 –

Seems to be a very common occurance on these AquaHots, especially the twenty+ year old ones. PO of my coach used some sort of putty to fix a leak on the rear engine line and then a few months into ownership, the front one started to leak. I ended up cutting out the elbows and used high temperature silicone coupler hose. I found this route from someone else either on foreforums or another site.. it's been about 9 months and they are still holding up just fine.

Amazon.com: HPS HTSEC90-062-BLUE Silicone High Temperature 4-ply Reinforced...

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
1999 U320 WTFE #5586
2014 Subaru Forester 6sp
4000 watts of solar
650 aH @ 24v

Re: Engine recirc at Aqua-hot system leak

Reply #8 –
You can purchase heater hose with a molded elbow from auto parts stores.  Cut the ends to the length yu need.  Remove the elbow and install the molded elbow and double clamp.  No need to remove heater from coach.
Rudy Legett
2003 U320 4010 ISM 450 hp
2001 U320 4220 ISM 450 hp
1995 U320 M11 400 hp
1990 Granvilla 300 hp 3208T
Aqua Hot Service Houston and Southeast Texas

Re: Engine recirc at Aqua-hot system leak

Reply #9 –
Like Rudy said. I had repaired several using compression fittings, but the last one I decided to use heater hose and found a 90 degree hose and double clamped it. Wish I had thought of that sooner. It was much easier and I feel like it will flex and take the stress off of the copper pipe.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins
 

Re: Engine recirc at Aqua-hot system leak

Reply #10 –
All good points, never even gave thought to using just heater hose.... :headwall:
Mike in AL
2001 U295
8.3 ISC 350
Build 5918