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Smart Valve

JUGHNE
JUGHNE Member Posts: 9,009
Anything to replace these?  This is the third "smart" valve on one furnace.  Other furnaces have had a variety of failures......Just dead.....or open main valve only, (skipping pilot lighting).......gas valve pressure regulator failing and allowing full gas pressure to burner.  But yes the HSI does have longevity.  Any advice for these valves?  Or do they just have this history everywhere??

Comments

  • Tim McElwain
    Tim McElwain Member Posts: 4,482
    Which generation of Smart Valve

    are these, if Generation I they have been replaced by Generation II. Generation III are a separate system using either Silicon Carbide Igniters on some, Silicon Nitride on others and some are using the 24 volt igniter for the pilot. For the most part it may be the volume of these that are out there on equipment as they were a big seller for Honeywell. It has been my experience that they are pretty reliable as a percentage of failure to the volume that are on equipment.



    It might be a good idea if you are seeing a particular version (model numbers of the SmartValve would help) to contact Honeywell.
  • JUGHNE
    JUGHNE Member Posts: 9,009
    Thanks for the reply Tim,

    This particular furnace is a Heil NUG5075 of 1995 vintage.  The original valve was replaced in about 1998 with a SV9501m2718 date code 9805d3c7.  The replacement for #2 will be SV9501M2528/U .  This still has the original 24 Volt HSI. There was a temp fix to jam a match stick next to the 4 wire molex plug.  It is just a connection issue that will require complete valve replacement.  Do you recommend a different HSI?  Thanks again.
  • Tim McElwain
    Tim McElwain Member Posts: 4,482
    SV9501 is a

    Generation II control. The new valves should have solved the connection problem as they were changed due to that and a couple other problems on early valves. Generation I came out in 1993 and Generation II came in 1997 so anything today should be okay. The 24 volt HSI /pilot actually has a the same igniter sensor which has not changed and should be okay. The igniter/sensor portion of the pilot is field replaceable
  • JUGHNE
    JUGHNE Member Posts: 9,009
    SV Replacement

    Thanks Tim, this replacement included a 4" long extension for the 4 pin control cable.  I added that to the existing cable and it takes the strain off the molex connector in the new gas valve.  There was no explanation for it's use included in the I&O paper.  The Heil furnace cable had just about no slack in it so this seemed like it could help.
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