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  1. #1
    Join Date
    Jan 2009
    Posts
    56

    Anyway to disable oil burner in dual-fuel HVAC?

    Hi,

    I've run into a small glitch with my dual fuel. I have a dual-energy HVAC system with a Carrier HP with an oil furnace. Standard run-of-the-mill Carrier thermostat that came with the HP and a dual-energy relay board.

    My problem is that my oil delivery company failed to deliver oil and my tank is on empty. I've put in a call to refill the tank, but it will take 24-48hours. Currently, the furnace runs (there is probably just enough left in the bottom of the tank), but I am afraid that it may dry out the tank and then I would be forced to purge the line, which requires an additional service call (extra costs). (Not sure how to purge it myself, nor do I want to mess with the dirty oil...).

    Current weather around here is roughly -7C to 2C. I figure that just the HP will be enough to heat the house.

    The question is if there is a way I can disable the oil burner until I get the tank filled without disabling the HP? I tried disconnecting the white wire from the relay-board to the furnace relay, and it does disable the burner from firing, but since the thermostat (and HP) don't know that the oil burner has been disconnected, they still try to fire up the burner every so often to defrost and/or to produce more heat to raise temp more quickly.

    Am I stuck? Is there anything I can do temporarily for the next couple of days to rescue the situation?

    Thanks!

    Eric

  2. #2
    Join Date
    Jan 2010
    Posts
    6,229
    Does your oil furnace have a on/off switch ?

  3. #3
    Join Date
    Jan 2009
    Posts
    56
    Quote Originally Posted by VTP99 View Post
    Does your oil furnace have a on/off switch ?
    If there is, unfortunately, I cannot seem to find one for the burner itself. There is a breaker for the furnace which is seperate from the HP, but shutting that down obviously shuts down the blower and the thermostat, so that doesn't really help.

    Otherwise, I have a Brock oil burner, with a Honeywell reset switch but nothing that would turn the burner on or off independently of the rest of the system.

    And since I disconnected the lead from the relay board, the HP doesn't seem to like it very much, and the house temp has dropped to 16C.

    Thanks,

    Eric

  4. #4
    Join Date
    Jan 2010
    Posts
    6,229
    What will cost you more a oil service call or the charge to purge the line ? A service tech can disable that with no problem. I am not at liberty to give you DIY advice per the site rules. Sorry

  5. #5
    Join Date
    Jan 2009
    Posts
    56
    Quote Originally Posted by VTP99 View Post
    What will cost you more a oil service call or the charge to purge the line ?
    Not sure what you mean by an "oil service call". Oil delivery is on its way, but they only promise 24-48 hours.

    I guess the biggest question I had is if it was even feasible to disable the burner in such a manner, given that the HP relies on the burner to do its defrost cycles, and if so, how it would affect the HP if the burner was not firing.

    Does a burner typically have an on/off switch that is separate from the rest of the system? Would that control only the burner itself, or the blower as well?

    Thanks,

    Eric

  6. #6
    Join Date
    Jan 2010
    Posts
    6,229
    [QUOTE=benze;9649492]Not sure what you mean by an "oil service call"
    .the HP relies on the burner to do its defrost cycles, and if so, how it would affect the HP if the burner was not firing.

    Does a burner typically have an on/off switch that is separate from the rest of the system? Thanks,

    Eric,
    "oil service call" Your HVAC service co.
    The HP defrosts itself by going into a/c mode with no condenser fan running.
    All electric HP's can run some backup heat strips to offset the cool air in defrost mode.
    Most systems will have only one switch @ unit and one breaker feeding such switch.

  7. #7
    Join Date
    Jan 2009
    Posts
    56
    Quote Originally Posted by VTP99 View Post
    The HP defrosts itself by going into a/c mode with no condenser fan running.
    All electric HP's can run some backup heat strips to offset the cool air in defrost mode.
    I don't understand what you mean by the backup heat strips. I don't see how they would help if they are located in the outdoor unit, unless the unit didn't go into a/c mode.

    Once in a/c mode, don't you need warm/hot air from the burner to compensate against hte cold coming off the expander head in the ductwork?

    Thanks,

    Eric

  8. #8
    Join Date
    Jan 2010
    Posts
    6,229
    Quote Originally Posted by benze View Post
    I don't understand what you mean by the backup heat strips. I don't see how they would help if they are located in the outdoor unit, unless the unit didn't go into a/c mode.

    Once in a/c mode, don't you need warm/hot air from the burner to compensate against hte cold coming off the expander head in the ductwork?

    Thanks,

    Eric
    "All electric" heat pumps w/electric furnace can run the HP with the heat strips @ the air handler or fan coil simultaneously. Your duel fuel will do this only in defrost mode.

  9. #9
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,903
    Get 15 gallons of kerosene and put it in your tank, and set the thermostat to 60(16C).
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  10. #10
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,837
    [QUOTE=VTP99;9649592]
    Quote Originally Posted by benze View Post
    Eric,
    The HP defrosts itself by going into a/c mode with no condenser fan running.
    All electric HP's can run some backup heat strips to offset the cool air in defrost mode.

    This isn't true. Many HPs use either gas or oil units as the aux heat source for defrost. The true answer is that yes, the HP will defrost using the AC cycle but you'll chill the house during the process. It shouldn't take too long but you will feel the ill wind while it's defrosting.
    Most systems will have only one switch @ unit and one breaker feeding such switch.
    This again is not accurate. On a hybrid heat system using oil or gas furnace as the aux/supplemental heat, there should be a serviceman's switch at the furnace, a circuit breaker for just the furnace, a circuit breaker for the heat pump and a disconnect at the outdoor unit for the heat pump.

    As Beenthere stated, go to your local service station and pick up 5 or 10-gallonsn of diesel fuel. Dump it through the fill pipe into your oil tank and you're all set. The diesel will burn the same as the #2 fuel oil. You won't be able to tell any difference at all.
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  11. #11
    Join Date
    Jan 2010
    Posts
    6,229
    [QUOTE=skippedover;9650562]
    Quote Originally Posted by VTP99 View Post

    This again is not accurate. On a hybrid heat system using oil or gas furnace as the aux/supplemental heat, there should be a serviceman's switch at the furnace, a circuit breaker for just the furnace, a circuit breaker for the heat pump and a disconnect at the outdoor unit for the heat pump.

    As Beenthere stated, go to your local service station and pick up 5 or 10-gallonsn of diesel fuel. Dump it through the fill pipe into your oil tank and you're all set. The diesel will burn the same as the #2 fuel oil. You won't be able to tell any difference at all.
    Try rereading the thread. We were talking about his furnace switch being able to seperate the burner from the blower. Read his last line of post #5. He knows he has a breaker for each unit in his post #3. Also read the last line of my post #8. I was explaning the operations of a "all electric" system. Do you understand ?

  12. #12
    Join Date
    May 2008
    Location
    OKLAHOMA
    Posts
    106
    Ditto on the kerosene, but, why not diesel?

  13. #13
    Join Date
    Jan 2009
    Posts
    56
    Quote Originally Posted by skippedover View Post
    On a hybrid heat system using oil or gas furnace as the aux/supplemental heat, there should be a serviceman's switch at the furnace, a circuit breaker for just the furnace, a circuit breaker for the heat pump and a disconnect at the outdoor unit for the heat pump.
    Have one circuit breaker for the furnace and another for the HP (as expected). Also have a disconnect at outdoor unit for heat pump (although hidden in such a hard-to-get-to-area burried place, not really all that useful).

    As for the furnace, though, no service man switch. The line from the breaker feeds directly into a White Rodgers transformer which then feeds into the furnace (haven't traced much further than that, but it looks like the output goes to to the burner and to a timer relay to activate the blower).

    Am assuming that the serviceman switch would be somewhere between the WR transfo and the furnace? What difference would that switch be vs me just unplugging the W terminal from the dual-fuel relay board output which feeds the burner relay? Am still unsure as to why unplugging the burner relay failed to work properly. I would have expected the HP to run its normal course, but just with the burner not firing.

    Thanks,

    Eric

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