RV Doctor – How do I clear my propane lines?

Dear RV Doc,
Recently while on a trip my hot water heater wouldn’t ignite. The technician at the dealer examined it and says there is oil in the propane lines and that I should break the line at the lowest point and at the heater and blow the oil out from the appliance towards the tanks. I am hesitant to open the line for fear of leaks in the future. Is there a better way to clear the lines? What can be done to prevent oil buildup in the future? – Russell Adams, (Mariposa, CA)

Answer:

Russell, I take it your dealer is not in the business of repairing RVs; your request should have prompted an estimate instead of a proclamation and invitation for you to do the work yourself. That said, usually any indication of an oily substance in an LP line means the LP container(s) have been overfilled, and quite possibly, often.

It simply depends on how far into the LP piping system the oily substance has migrated. It will be necessary to replace the regulator if any oil is found anywhere in the system.

First, disconnect the rubber hose from the outlet of the regulator. If evidence of the oily goo is there, keep removing the piping/tubing until no further evidence is found. It’s not practical to re-use any piping/tubing affected; doing so could cause damage to the appliances. Flushing and cleaning completely is virtually impossible. But I seriously doubt the oily residue has progressed too far into the system (hopefully).

When installing or reassembling LP piping and tubing joints, be sure to use an LP rated sealant like Rect-O-Seal, yellow Teflon sealing tape or something similar. As long as you leak test each joint you should have little to worry about as far as leaks.

Daub each fitting/joint with some children’s blowing bubbles to determine if a leak exists. Tighten each fitting until no bubbles are evident. To be 100% sure, have your service tech perform a manometer leak test after all the pipes and tubing have been replaced. LP is to be respected, but certainly not feared.

The foremost effective method of avoiding this in the future is to never fill the LP container more than 80% full and have the LP pressure checked/adjusted a couple of times per camping season. The capacity of the container is found on the data plate or collar (depending on type of container). The LP container(s) should also be drained and purged with LP vapor before filling again. Chances are, moisture also exists in the container. Any LP retailer should be able to provide this service.

(Please feel free to comment, however, please also note that due to the volume of communications I receive from multiple channels I cannot guarantee a personal response in every instance. However, questions of an overall general interest may be considered and published in an upcoming RV Doctor column.)