Heating Help

Furnace pump sputters when tank gets down to 10"

Hello,

I have an old furnace with a two line on the pump.  It used to be when the tank was about out of fuel, the pump would sputter for about a day and the house would smell a little bit as the furnace was choking on the last little bits of fuel in the tank. 

Recently, this has started to happen when the tank gets down to about 10" in the bottom.  If you add fuel, the sputtering goes away.  I pulled off the line that hooks to the nozzle and let it pump into a bucket, and sure enough, it sputters intermittently and is full of bubbles and foam.

When it is above 10" it seems to run steady and smooth.

Thanks for any help and advice.

sounds like

the copper supply has floated upward a bit. Short of digging up the tank to find out why, turn the return into your feed, drop the 2 pipe system for many reasons, remove the by-pass plug, fitting, and plug it of 1/4" plug. Both lines should have been installed same level.

There....

There could be a lot of things going on. When was the last time it was serviced by a contractor? You need to have someone come out and do an inspection and possible tune up. As Bill said change it to a one pipe system. It may require that a Tiger-loop needs to be installed. A good contractor will know what you need and how to correct it. Make sure you discuss having them to convert you to a one pipe system, before you have a disaster!