Aqua Hot Non Start

[Keith Moffett]

The computer was replaced three years ago. 
The burn chamber, nozzle and filter has just been replaced.
The igniters are adjusted.

The motor spins up and what sounds like the fuel selenoid is clicking but no start.  The air in the fuel has been purged multiple times since the filter change.
The electric side works fine.

Any suggestions?
Keith

[Edward Buker]

Keith,

When it does start do you get some darker smoke (assumes this is intermittent)? That would mean that fuel is being sprayed but not ignited. I would pull the burner after a non start and see if there is fuel in the burn chamber. If there is I would change the nozzle again and recheck the alignment. The nozzle spray pattern to the igniter electrodes is critical in that the edge of the fuel spray pattern has to overlap them just right for an ignitable fuel air ratio. That pattern is not always achieved by a new nozzle due to the tolerances involved. I would use the brand Armond or Roger Berke recommends and sells.

I think it is unlikely that the ignition transformer and driver circuit contained in it is bad but you never know. I pulled mine when I had an intermittent start issue and used a Makita 12V battery and fired it 100 times on the bench and sure enough several times it did not fire. Replaced the transformer and have not had the problem since. Some small chance the electrode ceramic or high voltage path is firing elsewhere then the electrode tips due to a defect. Small chance the flame sensor could be defective, visually inspect for cracks and you can do a resistance check with and without light on it. Spec is in the manual if I remember right. My bet would be the nozzle given it was changed...

Later Ed

[David T. Richelderfer]

Was the ignition coil replaced?  Two years ago my Aquahot became intermittent at firing up.  When cold outside it would ignite the diesel once in ten or fifteen tries, or worse.  When warm outside it would ignite almost every time.  But who needs heat when it's already warm outside?  FYI - We had to show the warranty guy that the igniter coil was intermittent before the warranty company would cover its replacement.  By the time the warranty guy arrived onsite it was mid afternoon and warm outside.  We had to cycle the ignition coil about thirty times before it finally missed igniting and he authorized replacement.  Earlier that day when in the cool of the morning the Aquahot would hardly fire up.

[Keith Moffett]

Keith,

When it does start do you get some darker smoke (assumes this is intermittent)? That would mean that fuel is being sprayed but not ignited. I would pull the burner after a non start and see if there is fuel in the burn chamber. I would use the brand Armond or Roger Berke recommends and sells.

I think it is unlikely that the ignition transformer and driver circuit contained in it is bad but you never know. I pulled mine when I had an intermittent start issue and used a Makita 12V battery and fired it 100 times on the bench and sure enough several times it did not fire.
Later Ed

I replaced the nozzle last spring because non start.  I was more careful that time about air in the line and it fired right up but smoked (white smoke) all summer.  Last fall I had the coach winterized so the AH didnt run.  I replaced the filter and nozzle again with no luck a few days ago.  I did notice that there was about 1/4 of the filter glass with air in it due to spilling.
All my parts come from Roger.

Thanks ED
Keith

[Keith Moffett]

Thanks David and Ed
Seems there ought to be a better test for the coil etc. tha just throwing parts at it.

I am persuing the trouble shooting in the shop manual and will report back.

[Keith Moffett]

Seems I found the answer thank God!  Never hurts to follow instructions I guess. 
The trouble shooting guide lists check the thermostats (aquastats) only if the burner motor doesnt run at all.  On ours the motor ran fine but there was no spark.  I checked the VDC high limit thermostat and while there was continuity across the unit there was none to the output connection. 
Gave the connector a good cleaning and the AH fired off first try.
Last summer when the AH ran it belched white smoke.  When we got it started this time it smoked heavily but cleared up fairly soon. 
No smoke now and it runs great!     
Thanks again

[Richard LaLande]

maybe you can help me? our AH was serviced and repaired at BSC new pumps , board , motor burner and a few other parts.. it has no (red) lights and no faults showing.. now this is the funny thing only in the morning when i want to take a shower does the AH not fire the Diesel Burner even tho the green light is on.. i  hear it (spinning or humming) but nothing else.  I have to go inside and power down, wait a few seconds then power up and then it will run normal... now i hear the heat running thru the night and note i turned off the elect. switch to rule at least one thing out.. so i'd like to clean off those connectors but a little "green" in this MH thing.. any way any help appreciated.

[Edward Buker]

Keith,

Good trouble shooting, you had low voltage due to a poor connection that made the ignition transformer/circuit board marginal for repeatable start up and operation. I have run into bad thermostat units but not seen that root cause you had found. Put that one in the memory banks.

Later Ed

[Edward Buker]

Richard,

There can be a multitude of causes for intermittent firing with the burner. With the motor spinning up, I assume that it shuts itself down after a short period which is the flame sensor safety system stopping the fuel supply and burner motor due to lack of flame. As far as being in the morning the only variable that could be involved is lower DC voltage if you are not plugged into a power source. That could cause a weaker spark or a little less fuel pressure and or air flow with your burner motor slowing. The other possibility is that the air and fuel being a bit cooler may be a little harder to ignite with a marginal spark or air fuel mixture.

I would check the voltage going to the burner in the morning and several times during the day. If you are plugged into a power source it should be the same and you could rule that possibility out. You have to do this with the burner motor spinning or firing. Lower voltage at the burner in the morning for some reason like boondocking could cause this  issue.

The most likely cause of this issue is that the electrodes and the nozzle pattern are marginally overlapped. You cannot assume that just because the nozzle has been changed that all is well. A spec of dirt or the original nozzle machining could be an issue. That is why particular brands of nozzles get recommended by the experts as less problematic.

I would check the electrode spacing and gap, clean the tips and the ceramic insulators, clean the face of the flame sensor, and change the nozzle to one that is the brand recommended by Roger Berke.

If the nozzle change and electrode setting does not solve the issue, beyond this the next step would be a testing of the ignition coil on a bench and a fuel pressure measurement at the nozzle to see if all is well with those items.

Later Ed

[Bill Sprague]

maybe you can help me? our AH was serviced and repaired at BSC new pumps , board , motor burner and a few other parts.. it has no (red) lights and no faults showing.. now this is the funny thing only in the morning when i want to take a shower does the AH not fire the Diesel Burner even tho the green light is on.. i  hear it (spinning or humming) but nothing else.  I have to go inside and power down, wait a few seconds then power up and then it will run normal... now i hear the heat running thru the night and note i turned off the elect. switch to rule at least one thing out.. so i'd like to clean off those connectors but a little "green" in this MH thing.. any way any help appreciated.

This is Rick's first post.  Welcome to the BAC forum and to the BAC itself. 

For those reading, Rick and his wife, are the current owners or our beloved Monterey that BJ and I owned for 12 years.   We've exchanged a few emails, but have not yet met. 

It hurts that Rick is having trouble with the HydroHot.  It had it's fair share of maintenance for our twelve years and was functioning normally on our last trip.  About a year before we gave it up it had a extra thorough service performed by John Carrillo at a rally in Bend.   After that service, it was running as good, or even better, than it ever had.  It puzzles me why BCS had to do so much work on it. 

One ugly thought is that it could be the Webasto computer with the mechanical relays.  At about year two the HydroHot had a similar pattern.  It was intermittent.  We took it to two Florida shops without immediate success.  At the second shop I had to make a deal with the owner that I would pay the shop rate for his best tech to patiently watch and listen.   When it finally did what I was complaining about, a light tap on the "brain box" caused one of the tiny internal relays to do it's thing.  The fix was to replace the box.  After replacing the box, I tore the old one apart.  The four or five mechanical relays are tiny and looked delicate. 

Rick, the box I'm talking about is about twice the size of a deck of cards, is metal, his held in a bracket to the left of the burner and has wires plugged in.   It is easy to replace but very expensive.   I sincerely hope you don't need one and there is another explanation such as suggested by Ed or others.

Bill

[Richard LaLande]

Hi Bill!!
I think the reason BCS had to replace a bunch of stuff is maybe the last place I went might have shorted stuff out..

Today and yes we are plugged into shore power, we ran elect. thru the night as it wasn't cold..for me my wife is hot blooded
then when we were ready to shower we turned on diesel ( 30 mins before ready) and had no all the hot waster we wanted.. hip hip hooray!

Like Bill said we are new and want to learn and we are and yes its using every bit of extra cash we have but we sort of knew this might happen.
We will make it work Lord willing and enjoy this season we are in. Looking forward to meeting a few of you as our paths cross. Bill you took very good care of the Beaver Coach and we think you for a developing friendship if only by e-mail 

Bill since I have your eyes how often did you replace the fuel/water separator filters..I noticed you changed them 7/2014 at 114k miles
I have read a bunch of forms and reviews but I'd like to keep up your service regiment if possible. I will be getting the trans. serviced this july as you
said that was next on your list. Thanks Bill and to all who chime in

[Keith Moffett]

Hi Rick and welcome to the Beaver family.
Bill and wife BJ are realy good folks and that coach was special to them but dont tell Bill I said that.
BCS are good at their job and trustworthy.  A good relationship to maintain in my opinion.
I havent met anyone in the club that hasent had the bad shop experience.  One such well intentioned fella cost us 5K before repairs.  It happens.

I am a big fan of trying the simple solution first so when it comes to your HH I would eliminate simple things first.  Make sure all relays are fully seated, all fuses and contacts are good with no wires damaged by contact with an elbow.  My #3 relay was out just enough to have intermittant contact but looked ok.  Now last thing I do is check these before reassembly.
The themostats / aquastats different name same thing,in our AH are just behind a square metal plate above the burner and this has only 2 screws.  The top left one is our high limit DC unit and this had the bad contact.  Might get lucky and find it a bit corroded and intermittant.  Not making contact in the AM but good once it has been tried several times.
Just a heads up, that wire is on a spade connector and both it and the wire get hot so look for a broken wire above the connector.

[Bill Sprague]

...... but dont tell Bill I said that.....

Grinning here in the motorcabin parked on the Columbia River at Maryhill!

[Bill Sprague]

.....Bill since I have your eyes how often did you replace the fuel/water separator filters..I noticed you changed them 7/2014 at 114k miles
I have read a bunch of forms and reviews but I'd like to keep up your service regiment if possible. I will be getting the trans. serviced this july as you said that was next on your list. Thanks Bill and to all who chime in

In the spirit of on line forums everywhere, I'll answer by starting a new topic so that this one can stay on the Aqua Hot subject.

[Richard LaLande]

Keith,
Thanks, I will check with those first