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Topic: AquaHot Flame Detector (Read 1316 times) previous topic - next topic

AquaHot Flame Detector

I have had trouble with interment running of the diesel  side of my AquaHot. It well start sometimes on the start command.  Sometimes it takes 3 times to start it. After it starts it runs well.

Things that I have done.
.New filter
.New nozzle
.Re-gaped the electrodes.
.New ignition coil
.Sent the Basco burner out to a professional shop they could not find any thing wrong.
.Sent out controller for testing they could not find any thing wrong.
.Changed out fuel hoses
Have any of you fine folks had any trouble with the flame detector??? I am about at the end my things to try. I can't trust it.
Any help would be appreciated.  Cheers  Karl

Re: AquaHot Flame Detector

Reply #1 –
Howdy Karl,
  Are you aware of Roger Berke's great website?  http://forum.rvhydronicheaterrepair.com/forum.php
Lots of good advice on his blog. 
I'm sure Rudy will log in with some good advice.
Good Luck, Dave A
Dave and Nancy Abel
'00 U320 36' WTFE  Build #5669
'10 Jeep Wrangler Unlimited Rubicon
Livingston, TX  SKP's Fulltiming

Re: AquaHot Flame Detector

Reply #2 –
I had the privilege of talking with Karl.  The problem is intermittent which ups the challenge a bunch.

So I suggested that he access the troubleshooting guides on the Aqua Hot Forum and go through the steps for "Failure to Fire".

We discussed some of these steps so he will have more info on what to expect as he performs the tests.  I believe he has the expertise to do a very good job on the tests.

So good luck.
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: AquaHot Flame Detector

Reply #3 –
Thank You Rudy,
.
Thank You for all your help.  I well do the tests that we had talked about on the phone today. We well see. Thanks again Karl

Re: AquaHot Flame Detector

Reply #4 –
Yes, I've had intermittent A-H failure to fire episodes that ended up being caused by a failing flame detector.  As I recall, it changes color when it deteriorates, but I don't remember if it's from purple to white or visa versa but Rudy surely knows.  You clean the flame detector at each service, but if it changes color it's a bad sign.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: AquaHot Flame Detector

Reply #5 –
I had the same issues with my 02 AH. I did the same replacement/testing actions as you. I finally took my burner assembly to Roger for bench testing. It turned out to be the fuel pump; it was putting out way too much pressure. Using a pressure gauge, Roger set it correctly and now it fires every time. He told me the fuel pressure can change with age and often need re-adjusting. Also the igniter has to be wired correctly. If you took these wires loose, make sure they are hooked up correctly or you will not get a spark. Don't ask me how I know this.
good luck.
OH
Rick & Deborah Webster
2002 3610 U320 #5964
2014 Jeep Wrangler Sahara JKU- 'Copperhead'
Richland Chambers Lake, East Texas

Re: AquaHot Flame Detector

Reply #6 –
The flame sensor turns from white to purple if it is overheated.  Color does not automatically indicate that it needs to be replaced.  Many times the flame sensor will look bad, but will work just fine.

There is a way to do a 'static' test on the flame sensor by covering it with shop towel to see if it will it will see light (flame).  I find this test to be very difficult to do and can easily give you erratic results.

I find the definitive test is to do voltage testing if you can get burner to light.  This procedure is outlined in the Aqua-Hot shop manual that is available online.  Basically, you test voltage going to the motor, then voltage being returned from flame sensor (to box).  Voltage should drop 1 volt or less.  A brand new flame sensor will drop around .6 of a volt.  Monitor voltage for several minutes.  As the flame sensor heats up, sometimes voltage return will drop off and cause control box to 'fault'.

This test can be misleading sometimes.  If the nozzle or fuel pump is not operating to specifications, then you will get erratic flame and erratic reading from flame sensor.

Intermittent problems can be caused by many, many things and it can be very tough to identify exactly what is going on.

- Roger Berke -

Re: AquaHot Flame Detector

Reply #7 –
Roger,

If the flame sensor merely changes resistance with light (flame) shining upon it, Â shouldn't you be able to determine a bad sensor with an ohm meter. Â Possibly showing <50 ohms one way and almost infinity the other?
Jim Frerichs
2002 U320 42'

Re: AquaHot Flame Detector

Reply #8 –
Jim

You can use ohm meter to test flame sensor.  Again, I find it to be difficult to get accurate readings.

Another fine point is that the flame sensor needs to be open circuit or box will not allow coil to fire.  As soon as flame sensor sees light (flame), it shuts off the ignition coil and goes into 'run' mode.

- Roger -
 

Re: AquaHot Flame Detector

Reply #9 –
Roger,

So the flame sensor probably is greater than 100,000 ohms in the dark adn less than 100 ohms in the light. A new one should test that way and hopefully a bad one will not.
Jim Frerichs
2002 U320 42'