Hydro Hot issues

[Bob Disney]

It was time to service the Hydro Hot so I replaced the fuel filter and the spray orifice
No big deal except now the filter will not fill with fuel so no burn
According to the instructions it does not to be prefilled with fuel, supposed to prime on its own   
I have hit the inside switch a few time to turn it on but to no avail there is just no fuel in the separator on the bottom of the filter
According to the alladin I have only burned 52 gallons of fuel so there should be plenty of fuel in the tank to supply the system

Any Ideas?

[David T. Richelderfer]

I recently changed the diesel filter and spray nozzle on our Aquahot.  I did not fill the new filter before screwing it on.  The instructions said filling the filter is not necessary but advisable because then the Aquahot would not require turning on several times to get the filter and lines to the nozzle primed.  Okay, after a few times turning on the Aquahot, the filter was full of diesel and I could smell unburned diesel at the end of the exhaust pipe... so I knew the diesel got through the nozzle.  If I remember correctly, if the fuel pump is not working properly, then it will not fill the filter and prime the lines to the nozzle.

The reason our Aquahot would not fire up was a bad control box... which I had replaced with a newer, black control box only several years ago.  Well... now it has been replaced again and all is well.  The Aquahot tech told me the older, original, silver control boxes are more "mechanical" while the newer style, black control boxes are more solid state... but the new style black control boxes are made with cheap components and have gained a reputation for being unreliable.  I paid $150 for the service call plus $650 for the rebuilt silver control box.

I don't know what your device's problem is... could be the fuel pump, could be the control box, could be something else, but that is my recent experience.

[Bob Disney]

 As a sidebar to my first post
If the tank is full enough would the fuel pour out of the filter base plate if no hose crimping pliers are in use?
I crimped the fuel lines when I installed the filter as I was afraid fuel may come gushing out if the fuel level was higher then the filter.
I later pulled the filter off without the line crimping pliers to check if I had somehow kinked the filter gasket and allowed a leak and the pump was sucking air. No fuel came out

[Eric Maclean]

Bob
The first thing to check is your fuel filter if it is the Raycor type R12 with the brown priming pump knob on the top if it check the "O" ring
On the priming pump shaft as they dry out and will allow the system to suck air the. Next thing to check would be the seal on your new filter .
There is a possibility that the fuel line between the filter and the tank has dry rotted and is sucking air
Either way I'd remove the new filter and fill it with clean fuel or fill it using the manual priming pump and try it again .
If you are concerned that the pump is the problem you can try  removing the fuel line from the filter the fuel feed line into a can of diesel fuel to see if the pump will lift fuel from the can and run the burner.

Hope this helps
Eric

[David T. Richelderfer]

It seems logical that the fuel line is crimped to stop fuel from running while the filter is being swapped out.  Also, the fuel line coming from your RV's diesel tank should be pulling fuel from about the 1/4th full point of the tank.  If your tank's fuel level is below 1/4th full, then your Hydro Hot won't get fuel.  It's done that way so that you cannot run your fuel tank dry while parked.
 

[Bob Disney]

I found the problem
First the filter was sitting higher than the fuel in the tank
I had a defective bowl on the new filter that was not air tight. The black screw petcock allowed air into the system stopping the pump from pulling a vacuum to fill the filter.
Found this by filling the tank which of course allowed fuel to run onto the ground at the station where I was filling.
I only spilled about a quart of fuel on the concrete at the station
Fortunately I had a pair of needle nose vise grips in my tools allowing me to pinch off the fuel line.
I replaced the filter bowl with the one that was on the old filter then pulled off the pliers. No leak
I ran the water hose into the bay where the hydro hot resides to get the excess diesel out and let it drain for a while.
After it was reasonably dry I turned on the system allowing it to prime once then turned it back on.
Seems to be working like new.
It appears my biggest problem was assuming the new filter and bowl was defect free.

Now back to the rest of the list prior to our winter trip

[Eric Maclean]

Bob good to hear your up and running again

[David T. Richelderfer]

I remember when I was examining my new filter before installing it that the black screw petcock was not tight.  I twisted it by hand to tighten it.  I wonder if yours was missing an O-ring or something to seal it.  Anyways, I too am glad your equipment is fixed and you're up and running again.