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  1. #1

    Angry Normal life for Robert Shaw HS-780?

    I have apparently blown the fourth ignition control unit on a forced air furnace. This means about one every two to three years. Before I shell out again, I hope some insight as to what might be wrong or what I am doing wrong. I notice that the HS780 has been replaced by other models. Build issues? Is one of the replacements more robust? This is in San Francisco, so it doesn't get run into the ground.

  2. #2
    Join Date
    May 2006
    east central indiana
    I don't care for them that much myself. Don't know that there's an issue with those though, I just usually replace them with something else when I find one bad. Now in your case I'd wonder what is it about your furnace or power supply that keeps burning them out. Perhaps a service call is in order.

  3. #3


    Thanks. The last three replacements have been with service calls, and they have checked the furnace and replaced the same unit. The last time PG&E came out (one of their good sides) and checked it for safety, giving it a clean bill of health/safety and saying it was the board. The last technician replaced the board, found the one he had brought was blown, and then went for another (I paid by the hour, I think).

    So, can I ask what you like better? Maybe an indication why? Information is power and I feel pretty impotent right now in this matter. I'd like a little more info before I hand over several hundred dollars again.

    I was thinking about checking out the option or just replacing the furnace early (there must be better models out there) but I can't get any indication of what prices would be without visits, so until I have some clue as to ballpark of that, I would really appreciate a bit more information on the question of ignition controls.

  4. #4
    Join Date
    Jul 2002
    St Paul, Minnesota


    If information is power, what did you do with the information you got from these guys?

    I like the part about the location of the control modules> where is yours mounted? Some techs don't use the mounting brackets that come with controls and mount them right on the metal frame where temps are hottest.

    And, have you always had another RS control for a replacement?
    Last edited by jrbenny; 02-08-2007 at 08:41 AM. Reason: hvac forum link

  5. #5
    Join Date
    Jan 2007
    N.E. KS
    Anyone can change one of those controls, but it sounds like you need to find a service person who will figure out why it keeps failing.
    Some people know the cost of everything but the value of nothing.

  6. #6
    Join Date
    Dec 2004
    Grand Rapids, MI
    Our company uses the Honeywell brand and have no problems. Do you have any elec. problems at your house or low voltage issues ? luck dan

  7. #7
    Thank you all.
    "If information is power, what did you do with the information you got from these guys? "

    What information? I hired a professional, and he made the repairs without explaining much. Wiser now, I am here.

    It is definitely mounted directly on the metal. As for low voltage, I wouldn't know, but I have an electrician coming to check it out.

    I spoke with one repair company about an alternative model, and was told they would only replace withthe original unit. (New unit, but original identity.)

  8. #8
    Join Date
    Mar 2005
    Suppy NC
    RS controls seem to be reliable as compared to any other
    is it mounted in the proper fashion

    is your unit short cycling causing the control to work harder
    do you have a lot of power failures

    is the unit grounded properly

    there is a reason for this many failures and you need to find a tech that is willing to look for it and not be just a part changer

  9. #9
    Join Date
    Aug 2002
    manitowoc wisconsin
    I live in wisconsin now & ohio before that.Ignition modules do get used alot in these climates.I have always used honeywell hot surface ignition modules.If the module is mounted on a warm surface if can cause it to fail.not all furnace manufacturers put stand offs in thier furnaces for mounting them.I have taken equal lengths of tubing & slipped them over the screws to leave an air gap behind modules that have been heat damaged over the years.I did not have call backs on those units.Some of those boards are just mounted in poor locations by the manufacturers.If your contractor does not want to change out a simple ignition module to another brand then call someone else that will if that's what you want.universal modules are used every day by thousands of contractors.I think in the last five years I have had only one honeywell module not working new out of the box.not to bad considering the number of them I have replaced in that time.I replace fewer honeywells than other manufacturers modules.It could be that you have a venting problem or setup problem if this is an overheating issue too.Have a full clean & check done to the unit when the control is replaced.
    Take your time & do it right!

  10. #10
    Thanks. It is not mounted directly. I have ordered a technician (other work on the house made it impossible to do the heater..electric power off and on.)


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