A/C fan comes on when heater is on

Discussion in 'RV Tips & Tricks' started by Capcuba, Dec 7, 2004.

  1. Capcuba

    Capcuba New Member

    I have a 98 Bounder and if I have the generator on and the heater operating the A/C fan comes on after a miniute. And it stays on. If I turn off the generator the heater heats as normal and blows air as advertised. Has anyone run into this where the roof top A/C fan comes on when the heater and gen are on? I have an intelltec A/c,/heater control.
     
  2. Poppa

    Poppa Member

    A/C fan comes on when heater is on

    Hey guy, I don't know but Roof top AC has heat strips and when it come on so does the fan in the ac to circulate the air.
     
  3. C Nash

    C Nash Senior Member

    A/C fan comes on when heater is on

    Capcuba, never heard of that one. Has it always did this? Might be that if only the ac fan and not the compressor is on it is designed this way to help circulate the heat. Let us know what you find. Might try emaling Bounder and asking their tech dept.
     
  4. Ed H.

    Ed H. New Member

    A/C fan comes on when heater is on

    The question I have to ask is does it do this on shore power or just the generator?
    There was some discussion here a while back about the Intellitec systems doing weird things. The voltage or frequency output of the generator may be off just enough to confuse the electronics. I have seen it happen where the "brain" looks for a specific voltage and if that is not there, the thing gets all confused and does some pretty odd stuff.
    If it is a generator only oddity, you may want to have both the voltage and frequency outputs checked before doing much else.
     
  5. Capcuba

    Capcuba New Member

    A/C fan comes on when heater is on

    Well, It does do it with shore power also. I e-mailed Intellitec who made the system and they seem to think its the thermostat. The heater is gas, and you can hear the furnace come on and start blowing. Then in about 3 or 4 min all of the sudden the front a/c blower comes on. I thought at first it was for air circulation also, but after a bit it seemed weird. I can turn off shore power and or the gen and it works as advertised. Like I said the tec says its the thermostat, and I'm sure he knows a lot more than me, but I have my doubts and will play with it a little more, before secuming to a thermostat. I live at south padre island, so its not like I use the heater a lot.
     
  6. Capcuba

    Capcuba New Member

    A/C fan comes on when heater is on

    Oh and thanks everyone.
     
  7. Kirk

    Kirk Senior Member

    A/C fan comes on when heater is on

    Does your a/c have heat strips installed? It must if it blows heat. I would tend to agree with the tech that you talked with that the problem is the thermostat. The reason that it only does that with 120V-AC power available is the fact that your a/c unit only operates on that power source. I suspect that it actually is truning on at any time that you select heat on your thermostat, but if you don't have any 120V power it can't run. Have you looked at the a/c unit to see if there are controls for installed heat strips?

    Are we correct to guess that you recently purchase this RV?
     
  8. Capcuba

    Capcuba New Member

    A/C fan comes on when heater is on

    Yes, bought it used 3 or 4 months ago. Don't know about heat strips. As the heaters are gas and can hear them come on and then heat.
     
  9. Kirk

    Kirk Senior Member

    A/C fan comes on when heater is on

    Have you checked the air conditioner controls, if you have any? Yours may not have seperate ones other than on the thermostat, as many now do not. But if it does have, make sure that they are turned off. If you don't have any controls but the thermostat, check to see if the a/c is blowing cold air, at the same time as the furnace is operating. If it is, there is no doubt that the thermostat is the problem.

    You don't say what make of a/c you have, but if it is a Dometic the actual controls for the furnace and the a/c are both located in the a/c unit. With mine where we have only the thermostat to control either the furnace or the a/c, there are three switches on the thermostat. One selects (top to bottom) cool, off, and furnace. The second is labeled Fan and has positions on & Auto. The last switch has no label but has positions high & low and it controls the fan speed for the a/c unit. Now if you have the same as mine, or another make but with the same type of control, there are two things that could cause the heat and the a/c to come on together. The most likely is the thermostat, but the control board in the a/c unit could also do the same thing, as it is where either the a/c or the furnace seems to be controled. With the furnace in operation, there is an audible click at the a/c unit when the heat comes on and again when it goes off. I'm not sure why, as I have never traced out the controls, but I can assure you that it happens. I guess that I should look into that before I have some problem as I just looked and the third addition RV Repair manual from TL books doesn't have this type of control in it either.

    Hmmmmmmmm?
     
  10. Capcuba

    Capcuba New Member

    A/C fan comes on when heater is on

    Mine is an Intelltec that
     
  11. Capcuba

    Capcuba New Member

    A/C fan comes on when heater is on

    Mine is an Intelltec that Fleetwood put in some of their units. Mine is a Bounder, and its all-in-one. Climate control to operate the A/C and heater. Like I said all works fine without shore power or Gen. It's only when I have Gen or shore power does the fan in the overhead A/C units come on. The blower in the heater is in the panels by the entry way and in hall.
     
  12. Kirk

    Kirk Senior Member

    A/C fan comes on when heater is on

    I'm not familiar with the Intelatec climate control, but from reading your post it sounds as though you also have a thermostat? Do you select heating or cooling via the climate control pannel? Have you checked the air temperature into and out of the air conditioner to see if it is warmer to indicate a heating strip, or cooler to indicate taht it is air conditioning at the same time as the furnace operates? That will tell you a great deal as you will then know if you are getting only the blower, or both?

    Let us know what is happening as we could all learn somethin as well as possibly help out.
     
  13. Capcuba

    Capcuba New Member

    A/C fan comes on when heater is on

    I don't have heat strips
     
  14. Capcuba

    Capcuba New Member

    A/C fan comes on when heater is on

    Kirk, I'm sure your right. Without 120 or so volts, it just doesn't come on. I recently installed a bypass that allows my A/C fan to cycle when the compressor does. As without it the system is designed to keep the fan on while the compressor shuts off. Intellitec approved this bypass module, so we'll se how it effects the heater too.
     

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