Diesel heater fuel supply issue

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DLETF

DLETF

Veteran Member
Joined
Sep 28, 2017
Messages
48
Location
USA
Vessel Name
Buster
Vessel Make
North Sea Cape Classic 30
A Wallas 30GB diesel heater was installed on my trawler 18 months ago. I have been more than satisfied with the unit until 3 days ago when it shut down about 10 minutes into the startup process. Inspection of the fuel line revealed just air in the line. After tightening all the fuel line fittings, the heater ran normally for 30” with the fuel line disconnected from the pickup tube in the port fuel tank and the end of the line placed into a gallon jug of diesel fuel. The metal fuel pickup tube was removed, inspected and reinstalled. The tube was not plugged and I could easily blow air through the tube. The in-line fuel filter (90 micron) had a slight amount of debris and no apparent damage. After reconnecting the pickup tube and the filter, the heater was powered up but no fuel filled the line. The fuel filter was removed and the heater again powered up with the same result; no fuel in the line.
The Wallas heater appears to be functioning properly but it is not receiving fuel to the burner. The port fuel tank is nearly full and the bottom of the pickup tube is 4” above the bottom of the 24” heigh tank. The duel Racor filter bowls have clear diesel fuel and no apparent water.
What am I missing here?
What is the next step?
Thanks :banghead::banghead::banghead:
 
Does the heater have a fuel delivery pump?
 
DLETF said:
A Wallas 30GB diesel heater was installed on my trawler 18 months ago. I have been more than satisfied with the unit until 3 days ago when it shut down about 10 minutes into the startup process. Inspection of the fuel line revealed just air in the line. After tightening all the fuel line fittings, the heater ran normally for 30” with the fuel line disconnected from the pickup tube in the port fuel tank and the end of the line placed into a gallon jug of diesel fuel. The metal fuel pickup tube was removed, inspected and reinstalled. The tube was not plugged and I could easily blow air through the tube. The in-line fuel filter (90 micron) had a slight amount of debris and no apparent damage. After reconnecting the pickup tube and the filter, the heater was powered up but no fuel filled the line. The fuel filter was removed and the heater again powered up with the same result; no fuel in the line.
The Wallas heater appears to be functioning properly but it is not receiving fuel to the burner. The port fuel tank is nearly full and the bottom of the pickup tube is 4” above the bottom of the 24” heigh tank. The duel Racor filter bowls have clear diesel fuel and no apparent water.
What am I missing here?
What is the next step?
Thanks :banghead::banghead::banghead:
Click to expand...

It's normal for the Wallas to go thru several startup cycles with a dry fuel system. If it's pulling fuel from the gallon jug (I assume the jug is set below the heater, yes?), then it'll pull fuel from the main tank. If the jug is above the heater, it may be gravity feeding the heater.

Did you run the heater for longer than 30 seconds or 30 minutes? Is the exhaust blocked in any way? What codes are you receiving on the remote control? The codes can pinpoint the problem area.

At this point, I'd replace all rubber hosing to eliminate it as an area of air leakage.
 
As Pete indicated the Wallas heater may take several tries to get fuel up into the heater.

Your troubleshooting sounds spot on.

When you were troubleshooting Iam assuming here that you took your fuel hose off of the fuel tank pickup and took that very same hose and dipped it in a gallon jug of diesel? How was the fuel level of the gallon jug compared to the fuel level of the tank you are drawing from?
 
Pau Hana said:
It's normal for the Wallas to go thru several startup cycles with a dry fuel system. If it's pulling fuel from the gallon jug (I assume the jug is set below the heater, yes?), then it'll pull fuel from the main tank. If the jug is above the heater, it may be gravity feeding the heater.

Did you run the heater for longer than 30 seconds or 30 minutes? Is the exhaust blocked in any way? What codes are you receiving on the remote control? The codes can pinpoint the problem area.

At this point, I'd replace all rubber hosing to eliminate it as an area of air leakage.
Click to expand...

Peter:
The gallon jug of diesel fuel was located below the Wallas fuel pump; at the same level as the port fuel tank.
The heater fired up on the first attempt after removing the fuel line from the tank pickup tube and placed in the jug. The heater ran for 30 minutes. The entire fuel line was dry before that startup. The Wallas fuel pump on my trawler pulls the fuel column about 1 inch with each pump cycle.
I have no evidence that the exhaust line is blocked.
The fault code when the heater shut down during startup 4 days ago was “Flame out” with the red burner icon and the yellow fan icon blinking before complete shutdown. The same fault code appeared during the 2 failed startup experiments after the successful startup experiment using the gallon fuel jug.
I, also, assumed that the heater would startup normally after determining that the metal fuel pickup tube was not blocked but that was not what happened.
I will replace the rubber fuel line hose tomorrow and repeat the experiment.
Thanks for the suggestions.
 
ksanders said:
As Pete indicated the Wallas heater may take several tries to get fuel up into the heater.

Your troubleshooting sounds spot on.

When you were troubleshooting Iam assuming here that you took your fuel hose off of the fuel tank pickup and took that very same hose and dipped it in a gallon jug of diesel? How was the fuel level of the gallon jug compared to the fuel level of the tank you are drawing from?
Click to expand...
Kevin:
You are correct to assume the fuel line was disconnected from the fuel tank pickup tube and that end placed into the gallon jug of diesel fuel without the in-line fuel filter and the the 2 short sections of rubber hose that connect the filter to the pickup tube and then to the fuel supply line.
The gallon jug was placed next to the fuel tank at the same level as the fuel tank. Both are located below the Wallas fuel pump.
Thanks for your interest.
 
DLETF said:
Peter:
The gallon jug of diesel fuel was located below the Wallas fuel pump; at the same level as the port fuel tank.
The heater fired up on the first attempt after removing the fuel line from the tank pickup tube and placed in the jug. The heater ran for 30 minutes. The entire fuel line was dry before that startup. The Wallas fuel pump on my trawler pulls the fuel column about 1 inch with each pump cycle.
I have no evidence that the exhaust line is blocked.
The fault code when the heater shut down during startup 4 days ago was “Flame out” with the red burner icon and the yellow fan icon blinking before complete shutdown. The same fault code appeared during the 2 failed startup experiments after the successful startup experiment using the gallon fuel jug.
I, also, assumed that the heater would startup normally after determining that the metal fuel pickup tube was not blocked but that was not what happened.
I will replace the rubber fuel line hose tomorrow and repeat the experiment.
Thanks for the suggestions.
Click to expand...

I’m mystified. If the heater ran fine on the gallon jug and short rubber hose, logic says it would pull fuel fine from the port tank it had been feeding from earlier.

You can blow thru the pickup tube, and tried running with and without the filter. Is it possible that the tube itself is compromised (perhaps at the 90 degree bend) and allowing air to enter the system?

A quick test would be to take a length of hose and run it into the the port tank- if the heater fires normally with that length of hose, I’d lean strongly towards a compromised fuel tube.
 
When we had a Wallas unit on our boat, I had to call Scan Marine in Seattle for help. They were incredibly generous with their time on the phone, and they sold me what I needed to fix the problem. We were able to thank them at the Seattle Boat Show some years later, and found them to be refreshingly straightforward and professional. We will be checking with them about a diesel stove this boat show season.

No affiliation, usual disclaimer applies. Good Luck.
 
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