Waste Oil Heater Forum - Your definitive source for burning waste oil for heat.

I would definitely redo the whole pump setup.

Pump on top of tank - 1/2" hex nipple screwed into pump - 3/4"male to 1/2" female swivel for Lenz outlet - 3/4" street L for Lenz inlet - 1 piece of 3/4" black pipe long enough for the p/u screen to be at roughly 3" off the bottom of tank - 3/4" check valve goes on pipe and p/u screen screws in to it.

Loctite #2 gasket sealer for threads and tighten everything tight plus another turn.

This way when it comes time to clean filters you only have to loosen the 1/2" swivel to remove with stand pipe so both filters get cleaned at the same time. 

The gauge on the burner should go up to set pressure and not bounce around at all. I have had suction side air leaks but no oil leaking out. It can be quite frustrating so I eliminate as many fitting as possible and plumb it the way I do. 

I would watch oil pressure and make sure it is not dropping. Did you get the Lenz filter with gauge that mounts before the pump with the heater ? Watch that gauge and if it starts dropping to 10" of vacuum you need to clean filters.

Another thing is compressed air. Is the compressor keeping up ok on the longer runs ? The air proving switch needs at least 30 psi to turn the pump on. I like to install an air filter regulator and set it at 50-60 psi.

That is kinda of a odd spot to get hot. The flame goes forward and the heat travels through the tubes.

Is it drafting good ? Have you checked over the firebox and heat exchanger tubes real good to make sure there are no holes ?

If there is any holes, when the fan kicks in it blows back through the inside of the firebox causing issues.

I would pick air flow issue first. That fan might never have been cleaned its whole life. 

When the dial hits 140 does the fan kick in and run ? After the fan is running does the temp continue to build ? It should maybe rise a little but level off.

Does the fan blow good and hard when it does kick in ?

Also has ash been cleaned recently, not at all, etc ? I just want to make sure and rule out plugged heat exchanger tubes.

While you are at it lets double check the wiring if you have not already.

Orange wire will go wiring junction on side of heater to fan.

Red wire will go to yellow power cord, once inside the burner it goes to the little preheat block temp switch, once block is warmed to 120* +/- the other wire on the switch sends power to the primary control.

Once again I apologize for thinking we are both thinking the same.

I visualize the fan limit switch in the upright position when I describe it. On your heater it is laying on its right side. So when I say ' bottom right ' I mean that while looking at it in the upright position with the dial on top.

With all the different brands I work on they have it mounted differently so to make it easy in my head I remember it in the upright position.

Does that make sense ?

Orange and red are in the correct spot.

 The black wire should be in the bottom right hole.