Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84 exptools; site ihuxn.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!ihnp4!ihuxn!res From: res@ihuxn.UUCP (Rich Strebendt) Newsgroups: net.consumers Subject: Re: pilot light out? Message-ID: <986@ihuxn.UUCP> Date: Wed, 6-Mar-85 18:43:33 EST Article-I.D.: ihuxn.986 Posted: Wed Mar 6 18:43:33 1985 Date-Received: Fri, 8-Mar-85 03:12:42 EST References: <767@amdcad.UUCP> <298@mtxinu.UUCP> Distribution: net Organization: AT&T Bell Laboratories Lines: 27 > > My heater hasn't been working all week. I finally looked at it > > and discovered the pilot light was out. Lighting it restored > > normal function. > > > 2) How did it know the pilot was out? > > There's a valve operated by the heat of the pilot. If there's no > pilot, then the valve closes and cuts off the entire gas supply. > So far as I know, this is an entirely mechanical setup. No. There is an electrical solinoid that is operated by the electricity generated by a thermocouple upon which the pilot light impinges. No pilot light => no heat on end of thermocouple => no electricity being generated => solinoid drops out closing gas supply valve. The need to heat up the thermocouple to get enough current to hold the solinoid in is the reason that you have to hold the valve to the pilot light open for a while (typically about a minute) after lighting the pilot light. If you find the pilot light out repeatedly with no good explanation (like a contractor ripped out a gas main), then look at the possibility that the thermocouple is dying. It should be fairly inexpensive to replace, and on an old unit may be the cause of the kind of problem you may be having. Rich Strebendt ...!ihnp4!ihuxn!res