90% of the time, this problem is caused by either a clogged gas orifice on the pilot light's gas line, or by dust/debris in the pilot air intake, as stated by tradesman1. Start by blowing compressed air through the pilot air intake, both directions. If that doesn't solve the problem, remove the pilot assembly, then the pilot orifice, and blow compressed air backwards through the small orifice. The bottom line is that anything that causes the pilot flame to reduce in size will trigger the oxygen depletion system and that will result in the unit shutting itself off. This is a safety measure. Other possible causes: insufficient gas pressure to the unit, high altitude, defective thermocouple.
I had this same problem and the only thing that I found was a small spider web in the pilot air intake which had traped a small piece of lint I blew this out and the heater worked great
Answers & Comments
90% of the time, this problem is caused by either a clogged gas orifice on the pilot light's gas line, or by dust/debris in the pilot air intake, as stated by tradesman1. Start by blowing compressed air through the pilot air intake, both directions. If that doesn't solve the problem, remove the pilot assembly, then the pilot orifice, and blow compressed air backwards through the small orifice. The bottom line is that anything that causes the pilot flame to reduce in size will trigger the oxygen depletion system and that will result in the unit shutting itself off. This is a safety measure. Other possible causes: insufficient gas pressure to the unit, high altitude, defective thermocouple.
I had this same problem and the only thing that I found was a small spider web in the pilot air intake which had traped a small piece of lint I blew this out and the heater worked great