Aqua Hot problem

[Fred Cook]

Well it got down to -10 here the other night and the aqua hot is not working right. I switched in on a few nights ago just before the deep freeze. Now upon checking it out this morning, it was not working. So I turned the switch off and turned it back on and it started working again and heat was coming out of the furnace. After a short while the aqua hot stopped as it normally cycles…. but it will not come back on. However if I turn it off and then flip the switch back to the ON position, it will come on but again will not cycle as it should. Any suggestions?

[Bryan Beamon]

Are you using a fuel additive to stop your fuel from gelling?

[Fred Brooks]

 Fred, Did you put any additive to the fuel tank for freezing? The trouble shooting guide is available under coach assist. I believe your model is an AHE-100-02 Fred

[Fred Cook]

No I did not use an additive to the fuel. But the fuel should’ve been OK because the aqua hot was actually running and exhaust was being produced. So how can the fuel be a problem if the aqua hot starts and runs for awhile?

[Norm Vernon]

The fuel tank and lines are not heated, so in real cold weather the diesel will/can gel and stop flowing in the lines and filter to the aqua hot - no fuel = no flame , Aqua Hot shuts down. If you add anti gel like Power Service 911 to the tank before the cold sets in it usually prevents this depending on how cold it gets. Once the lines and filter are frozen the only solution is to warm it all up until the fuel flows again and then add anti gel.

[Fred Cook]

The fuel tank and lines are not heated, so in real cold weather the diesel will/can gel and stop flowing in the lines and filter to the aqua hot - no fuel = no flame , Aqua Hot shuts down. If you add anti gel like Power Service 911 to the tank before the cold sets in it usually prevents this depending on how cold it gets. Once the lines and filter are frozen the only solution is to warm it all up until the fuel flows again and then add anti gel.

Well I certainly hope this is what happened and there is no damage to the coach. We’re supposed to have a warming trend this week so hopefully it will start working right again.

[Fred Brooks]

   Norm raises a good point. Also consider the fuel tank is exposed on 5 sides cooling the contents let alone the fuel lines that are suppling the aqua-hot, engine and the generator. The fuel lines inside the coach compartments are warmer than the supply lines which are external. You may have other issues on a 22 year old aqua-hot. It could be a dirty nozzle, a combustion chamber that has never been replaced or cleaned, a partially plugged fuel filter suppling the diesel to the aqua hot. If the electric side is working, that may be enough to save the unit from damage but not enough to warm the interior. Hopefully you are plugged into 50amps shore power and have electric space heaters plugged in. Fred

[Fred Cook]

Thanks Fred. Yes I am plugged into 50 amp service at my home and I have an infrared heater in the basement and also inside the coach. I have both of the electric and diesel switches on for the aqua hot.  Also, I had the Aqua hot serviced last year by a qualified technician. He replaced some of those parts you mentioned.  It was cold like this last year too and never had a problem but the wind was blowing much harder this year.

[Eric Maclean]

Fred
When did you last fill the fuel tank?
Most consumers don't understand or know that the fuel supplier change the formulation of the diesel fuel from summer to winter
The summer fuel has more parafin in it than does winter fuel. If you still have a load of summer fuel in the tank it will thicken and wax at or around zero degrees .the only cure or should I say bandaid is to add a diesel fuel additive to the tank and wait till you can get warmer weather and the unit running to mix the additive through the whole system.
Don't forget to run your engine Aquahot and gen set to get the additive through everything or they will still has problems in the next co!d snap.
The waxing usually creates a problem as the fuel filters will pick it up and plug restricting fuel flow sometimes you an get away with putting in your additive in the fuel tank and taking a pail of hot/ warm water add place it under the fuel filter so that the fuel filter is heated this will help keep the fuel from waxing in the fuel filter and allow the unit to work until the additive can get through the system.

Ps:
the same hold true with Propane as the suppliers of propane have a different formula for warmer climates than for cold climates , in the warm climates they mix Butane in to their Propane as it is some what cheaper . The same problems develop as the temperature gets colder as butane does not have the same boiling point as propane so when the temp drops below zero the butane will not gasafy in the tank and the propane system will have no pressure.

I'm from Eastern Ontario Canada where these are not uncommon problems
Hope this helps
Eric

[Fred Cook]

Thanks Eric. Hopefully all is well when temp gets into the 50’s later this week.

[Mike Grevers]

You would think that the compartment that the aqua hot is in would be sufficiently warm to keep the fuel from gelling. The filter housing and everything is in this compartment and since the unit is cycling it should be warm enough to keep the fuel liquid. Typically gelling occurs in the filter itself and not in the line.

When you say it does not restart; do you hear the injection pump/fan unit try to start? If not, it may not be shutting down because it has satisfied the demand for heat but rather in a fault state that is not cleared until you reset it from inside the coach.

[David T. Richelderfer]

Plain old #2 diesel (with no anti-gel formulation) will start gelling at temperatures in the 20s F.  With biodiesel, depending upon the percentage of bio, the gelling may start in the 30s F.  -10 F, as you listed in your opening post, certainly will cause gelling even in diesel formulations with low percentage mixtures of #1 diesel or kerosene additives.  Once the diesel in the fuel tank, lines, or filters has gelled, you have little recourse other than warming the fuel.  The gelling is caused by paraffin wax found in diesel fuel.  Pure paraffin wax is solid at room temperature, so once gelled, it will require lots of heat to reliquify.

The AquaHot compartment warmth with the electric ON should keep the fuel inside the compartment from gelling.  But the fuel entering the compartment in the lines from the tank could be gelled and would shut down the AquaHot's diesel burner as soon as it plugs the filter.  So, the AquaHot's burner could operate for a while until the gelled fuel slowly clogs the filter.

Your best choice at this point is to wait for warmer weather or place several heating lights under the fuel tank, lines leading to the AquaHot compartment, and under/inside the AquaHot compartment.  After a day or two, you may be successful in starting the diesel burner.  In the meantime, get some anti-gel additives, such as #1 diesel, kerosene, or commercial anti-gel additives in a bottle and add it/them to the fuel tank.

[Fred Cook]

Well…. All is well now. It has warmed up into the low 60s and now everything works properly. So I’m guessing that the fuel lines had gelled as stated above. Also none of the waterlines froze up to the point of breaking.  I will text steps to prevent us in the future.