Wabasto Heater is eating Fuel Pumps...

[SCarns]

Help!

I have an old Wabasto AirTop 5000. It was in the boat when I bought it. I has performed flawlessly for months.

Then, the fuel pump died on it. Called Sure Marine in Seattle, and they were surprised, but were also happy to send me a new one - they are $193... I paid for express shipping because it was cold - about $280 out the door.

Pump worked well, but the heater began giving me issues. Sent it in and Sure replaced the atomizer and made sure everything else was good... Another $550 with shipping.

Installed it and everything was great. Next morning, woke up cold as the new $300 pump had failed. Got a Chinese one off Amazon Prime ($40). Installed it and it ran great. Next morning, woke up cold again... New pump was dead.

Fuel is fresh and I have a polishing system, so it should be in pretty good shape. Just coincidence that I am getting a bad batch of pumps? Or is there something I'm missing?

[Pete7]

They work on a pulse of electricity from the heater. What happens if you take a live feed from the battery and dab the positive wire on the pump terminal?

It should just go "clunk" each dab and pump a very small amount of fuel along the line which is how you prime them.

Pete

[SCarns]

Originally Posted by Pete7

They work on a pulse of electricity from the heater. What happens if you take a live feed from the battery and dab the positive wire on the pump terminal?

It should just go "clunk" each dab and pump a very small amount of fuel along the line which is how you prime them.

Pete

That's not it. The "spring" mechanism inside isn't returning the plunger. The Chinese one, I can make "click" once if I knock it a few times on the table, then if it's stuck again. The wabasto one is dead-dead, completely unresponsive.

At least the Chinese one I got on Amazon Prime, so I already have a replacement coming. However, I'm very hesitant to install it, as there are already three strikes against this heater.

[Pete7]

They are pretty much a sealed unit aren't they? can't say I looked too closely as ours just works going clunk. However, I would be tempted to cut the first one open and see if the spring is rusty and if there is any water in the little filter which the heaters come with. Something not right here.

Pete

[SCarns]

Originally Posted by Pete7

They are pretty much a sealed unit aren't they? can't say I looked too closely as ours just works going clunk. However, I would be tempted to cut the first one open and see if the spring is rusty and if there is any water in the little filter which the heaters come with. Something not right here.

Pete

Unfortunately, I have to send it back for warrantee replacement, otherwise I would hack it open.

I did cut open the filter and it's clean. Sure Marine guy said water would need to sit in it for a month before it would be an issue. I've dealt with the fuel issues I did have, and it all looks good, so I have a hard time believing it's fuel related. What I will do when the next one comes is pump it out of my jerry jug full of fuel for a while and see it the same thing happens before switching back to the main tank. I'm wondering if this is somehow logic board related... I do know if they aren't operated correctly, the will eventually burn up. They are tough, but not infallible.

[Smokeys Kitchen]

We have an airtop 3500. It came on the boat and has worked great for the most part.

The only time it has not is when we got some water in the fuel and the heater would try to start but wouldn’t fire. Then the control unit would stop sending signals to the pump and it would quit. After the tank was emptied, fuel cleaned and replaced I tried to get the Airtop to work again.

It took about 2 hours to get all the air/bad fuel to pump out of the line. I disconnected the line at the heating unit and then had my wife turn the heater control on. Fuel would come out for a bit then shut off. This went on for quite a while until it seemed like I was just getting good fuel to the heating unit. Then I would hook the fuel line back to the heater and try to fire the unit. It took about 3 cycles of this before the heater fired. Once it fired the pump worked fine.

[macrae]

You could have bought a complete furnace (Chinese) system for $125.00 includes the fuel pump and ignitor. Same system as Wabasto.

[rphdiego]

Is your heater 12v or 24v?

[SCarns]

Originally Posted by macrae

You could have bought a complete furnace (Chinese) system for $125.00 includes the fuel pump and ignitor. Same system as Wabasto.

I have one more thing to rule out, but yes, that is the next step...

[SCarns]

Originally Posted by rphdiego

Is your heater 12v or 24v?

12 volt.

[rphdiego]

Was just thinking you were using 12v pump with a 24v heater. Also the pump should be mounted closer to the tank as they work better pumping rather than sucking.

[Boatwright]

"Fuel is fresh and I have a polishing system, so it should be in pretty good shape. Just coincidence that I am getting a bad batch of pumps? Or is there something I'm missing?"

Parts suppliers are always willing to throw parts at a problem as long as you keep paying. Back to basics:

1) I'm OK with the first pump failure as a cause, however with multiple "failures" of a very simple piece of gear, I'd be looking at the "something missing".

2) We have an Espar. Works great. Use it rarely during the cruising season, but often on the hard during the winter and spring.

3) When it has symptoms as you describe, it is always due to air in the 12' of fuel line between the pump and the unit, after disconnecting the line for service. The pump is close to the fuel tank. It has a simple metal can in-line filter available at any autoparts. Trouble starts when I replace the filter every two or three years, and introduce a slug of air.

4) After multiple start failures, the Espar seems to enter a lockdown mode.

5) Simple fix is to kill all power to the heater for a couple of minutes. Meanwhile disconnect the fuel line at the heater, put the line in a suitable can, hot-wire the pump as others have suggested and run the pump until all the little bubbles are out. Make sure you don't have an air leak upstream of the pump. Our Espar has plastic fuel line that lets one see the bubbles.

6) You have a fuel polishing system, however our Espar draws unfiltered fuel direct from the tank. There is a good chance you are either introducing air when you change pumps, have an air leak upstream, or the fuel (as happens) isn't as clean as you hope.

Good luck and stay warm.

[SCarns]

Traverse City? I've spent many a day of there, as I am a Michigan native myself. While not as cold, central coast of California was pretty chilly last night. Replacement pump arrives today.

Originally Posted by Boatwright

There is a good chance you are either introducing air when you change pumps, have an air leak upstream, or the fuel (as happens) isn't as clean as you hope.
Good luck and stay warm.

These are my conclusions also. I have replaced the fuel line all the way from the tank to the heater. The pump is at the tank. I am replacing the filter and will double prime everything (if there is such a thing) to make sure all air is evacuated prior to operation. Plus, I plan to draw from a temporary tank with brand new fuel, as to either eliminate the potential fuel issue, or know all the fuel in the tank needs replacement - I can "polish" pump it into my other tank. I will probably leave the filter off at this point, rather than introduce another point of failure.

[Boatwright]

Small world. I have visited Ojai and Ventura many times to see and old friend who was a retired prof at Ventura College.

Back to your problem:

1) The pump works like an old fashioned door bell. It will oscillate against the spring as long as it has power. If it were on all the time it would pump way too much fuel for the unit's needs. Instead the control circuit sends measured on/off pulses to the pump. If you listen to the pump you will hear click, click every second or so. This is normal.

2) Shutting the unit off resets the control circuit after a no ignition shutdown.

3) IMO you are introducing air into your fuel line when you change pumps, or you have an air leak between the fuel pick-up and the pump, or both. You may also have an ongoing clog in your fuel pick-up which causes the pump to pull enough vacuum to start sucking in air. These are common problems with diesel fuel systems.

4) The unit fires for awhile, you think all is OK, go to bed, and then the air makes its way to the burner and the unit goes into safety shutdown. You believe the problem is another bad pump, you reset the circuit when you shut the power off to replace the pump, rinse and repeat.........

5) The fuel filter I am referring to can be found at any autoparts for about $10. I recommend the metal, not plastic, type -- about the size of a tomato paste can. These are throwaway -- I always buy two. Keeps the bugs and diesel goo out of the heater pump. Also, be sure and remove the fuel pick-up to check it for clogs, it may be sucking diesel goo lurking at the bottom of your tank.

I think you are on the right track, but don't rule anything out and throw more money at your system until you are 100% sure that the basic problem of air in the fuel is eliminated.

Good luck.

[skipperpete]

My cabin heater installation instructions insisted on the little pump being fitted at a 45° angle and it works fine at that.... but not if its horizontal.