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Topic: Propane smell at water heater in 1996 U280 (Read 677 times) previous topic - next topic

Propane smell at water heater in 1996 U280

When we start our water heater in our 1996 U280, it makes a loud whoosh sound when it ignites and you can smell propane outside and in the coach.
Any ideas on what might need replaced?
Thanks
Susan and Bob
1995 U320CSE
40'
Cummins M11
Coach build #4730
Previous Foretravel's 1996 U280, 1995 U300

Motorcade # 17974

Re: Propane smell at water heater in 1996 U280

Reply #1 –
First check with a manometer to make sue you do not have a gas leak. then if no leak could be the burner and flue need to be cleaned. Also could have a bad board, misadjusted air gap on the igniter.
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: Propane smell at water heater in 1996 U280

Reply #2 –
Agree it sounds like some kind of delayed ignition problem allowing excess propane buildup before burner finally lights?

But, trying to figure out how the propane smell (whatever the cause) in the water heater compartment could get up inside the coach.

Two separate propane leaks?  One inside and one outside?
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Surely, no age has been more fraught with insecurity than our own present time."

Re: Propane smell at water heater in 1996 U280

Reply #3 –
Quote from: red tractor –
First check with a manometer to make sure you do not have a gas leak.
Correct me if I'm wrong, but doesn't a manometer measure the gas pressure?  If so, proper gas pressure would be a good thing to verify.

For detecting a propane gas leak, seems like a device similar to those in the links below would be more appropriate:

HOME-FLEX Electronic Gas Leak Detector-11-810-001 - The Home Depot

Techamor Y201 Portable Methane Propane Combustible Natural Gas Leak Sniffer...

You can also use a simple soap bubble solution to check the gas line connections (anywhere on the coach) for leaks.
As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Surely, no age has been more fraught with insecurity than our own present time."

Re: Propane smell at water heater in 1996 U280

Reply #4 –
Quote from: Chuck & Jeannie –
Agree it sounds like some kind of delayed ignition problem allowing excess propane buildup before burner finally lights?

But, trying to figure out how the propane smell (whatever the cause) in the water heater compartment could get up inside the coach.

Two separate propane leaks?  One inside and one outside?

I had a similar problem and it turned out to be a faulty gas valve leaking even when turned off.  It doesn't take much poorly burned gas to get the smell up inside the coach.  When the burner would shut off there would still be a tiny flame at the orafice.  Also the burner tube can get clogged up with soot and needs to be cleaned of all the carbon buildup for a better flame.  I believe you have a 10 gallon model and there should be a tune-up kit and new gas valve available.

Jerry
The selected media item is not currently available.
Jerry and Cindy Maddux
1993 U300/36WTBI DD6v92TA
build 4271  "Miss Lou"
1995 suzuki sidekick 4x4 toad
Gulfport, Ms

"Pride of Ownership"

Re: Propane smell at water heater in 1996 U280

Reply #5 –
I'd go along with Red Tractor and check the air supply adjustment first.  Sounds like its a bit "rich" upon ignition.  If so, its an easy fix.

jk
Jack and Cathy
1992 U280 Unihome 36' Build #4034
Cummins 8.3 /  Allison MT647/ PacBrake
Apopka, FL / Barre Center, NY

Re: Propane smell at water heater in 1996 U280

Reply #6 –
Quote from: Chuck & Jeannie –
Correct me if I'm wrong, but doesn't a manometer measure the gas pressure?  If so, proper gas pressure would be a good thing to verify.
You can use one to see if you have a leak also

1. Turn OFF all appliances or devices that use Propane. This
includes ALL pilot lights. There must not be any Propane
gas flow.
2. Turn OFF the Propane at the DOT cylinder of ASME tank.
3. Lift up the cover of the cook stove top exposing the
burner assemblies.
4. Remove one of the burner assemblies. Typically a screw
will secure the assembly base to the stove top pan. By
removing this screw the burner assembly can be pulled
away from the burner manifold exposing a small stub out
with a small orifice hole in it. This stub is called the
"burner spud fitting".
5. Attach the Manometer hose over the spud fitting.
6. Turn ON the Propane at the DOT Cylinder or ASME Tank
and fill the Propane system. Wait about 5 seconds and
TURN OFF the Propane.
7. Go to the burner assembly that the Manometer is
hooked to and turn ON the burner knob allowing gas to
flow into the burner spud and the Manometer.
Note: You should be reading approximately 10 to 11
inches of Water Column on the manometer with the
burner knob turned on.
8. Turn ON one of the other burner knobs and "bleed
down" the Propane gas pressure in the gas line to
approximately 8 inches of water column (+ or – ½ inch).
Once the pressure has been bled down, then turn off the
2nd burner.
    (With out big LP hoses I prefer to light a burner to lower the pressure)
9. Let the manometer sit for 3 to 5 minutes at the 8 inches
of water column.
Note: You are looking to see if the Propane in the system
bleeds off through a leak which would indicate a problem
with the integrity of the Propane system.
If the 8 inches of water column pressure drops during the
3 to 5 minute test...there is a LEAK!
Note: if there is a leak it MUST be repaired by an
authorized service technician for the safety of the RV
occupants. Many states require that you have a license
or certification to perform repairs on RV Propane
Systems. Please check with a dealer or service center to
have safe repairs performed.
10. Once the Propane system has been tested, the system
must be restored to its original condition. Burner must be
reinstalled over the burner spud.
Note: For Safety Reasons – Only if there is NO LEAK found
can the DOT Cylinder or ASME tank be turned on!!!
Steve

1997 U270 36' build 5179
Motorcade #18147
1980 CJ5

Re: Propane smell at water heater in 1996 U280

Reply #7 –
If the manometer test is OK your spark igniter (DSI) may not be aligned right or something might be blocking it.  this could let gas accumulate for ignition.
Steve

1997 U270 36' build 5179
Motorcade #18147
1980 CJ5

Re: Propane smell at water heater in 1996 U280

Reply #8 –
Quote from: Super8mm –
You can use one to see if you have a leak also...
Steve,

Very interesting post.  I have read many times "Use a manometer to test your propane system pressure" but never have I seen the exact procedure for actually doing the test.

I do have one question (just curious).  Why do you bleed the pressure in the lines down to 8" before checking for leakage?  Why not just do the test at "normal" system pressure (11")?
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Surely, no age has been more fraught with insecurity than our own present time."

Re: Propane smell at water heater in 1996 U280

Reply #9 –
Quote from: Chuck & Jeannie –
Steve,

Very interesting post.  I have read many times "Use a manometer to test your propane system pressure" but never have I seen the exact procedure for actually doing the test.

I do have one question (just curious).  Why do you bleed the pressure in the lines down to 8" before checking for leakage?  Why not just do the test at "normal" system pressure (11")?
That is just above where bottom of usable gas feed is so it is easier for it to drop quickly,  at 11" it might take longer to start dropping but at 8" it will be quicker.
Steve

1997 U270 36' build 5179
Motorcade #18147
1980 CJ5

Re: Propane smell at water heater in 1996 U280

Reply #10 –
Got it - Thanx!  :thumbsup:
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Surely, no age has been more fraught with insecurity than our own present time."

Re: Propane smell at water heater in 1996 U280

Reply #11 –
Thanks for all the info. We bought the coach two years ago. It was part of an estate sale so had been sitting in storage for 10 years.
It was at an RV Dealer in Florida and they basically just handed us the keys without telling us anything.
I think they were just in a hurry to get it off their lot.
I appreciate being able to get advice on this site.
Susan and Bob
1995 U320CSE
40'
Cummins M11
Coach build #4730
Previous Foretravel's 1996 U280, 1995 U300

Motorcade # 17974

Re: Propane smell at water heater in 1996 U280

Reply #12 –
If you go to the link below you will find a wealth of info about many types of RV appliances.  They have service manuals, trouble shooting guides, and parts manuals.  You can probably find some helpful advice there about cleaning and adjusting your water heater burner assembly.  If the coach sat for a long time it's possible something like mud dauber wasps may have got in there and plugged something up.  It's a very good web site and worth a look!

Bryant R.V. Services
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Surely, no age has been more fraught with insecurity than our own present time."

Re: Propane smell at water heater in 1996 U280

Reply #13 –
Quote from: coastprt –
I had a similar problem and it turned out to be a faulty gas valve leaking even when turned off.  It doesn't take much poorly burned gas to get the smell up inside the coach.  When the burner would shut off there would still be a tiny flame at the orafice.  Also the burner tube can get clogged up with soot and needs to be cleaned of all the carbon buildup for a better flame.  I believe you have a 10 gallon model and there should be a tune-up kit and new gas valve available.

Jerry

I got the new gas valve and changed it today on the Atwood 6 gallon model for my coach.  The new Dometic Valve #92078 replaces the Atwood #93844.  It is an easy swap with only two screws to remove.  The new valve also comes with a new orifice and elbow to make hookup easy.  I cleaned out the burner tube which can get clogged with soot and cause problems.  After the air adjustment on the tube I'm now getting a nice quiet blue flame. 

Jerry
The selected media item is not currently available.
Jerry and Cindy Maddux
1993 U300/36WTBI DD6v92TA
build 4271  "Miss Lou"
1995 suzuki sidekick 4x4 toad
Gulfport, Ms

"Pride of Ownership"