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HELP ! Electric AC and Electric Heat on at same time (strange: but huge electric bills too).

InventPeace | Posted in Energy, Heating & Insulation on June 25, 2011 12:15pm

I have unit that has all electric heat and air (10kw ).  I keep getting complaints from renters that the bills and deposits are high?

Heres that data fact finding: Took panel off furnace ac unit inside house:

Using Voltmeter:

1. When thermostat is set on  AC  and AC  is actually on and cooling, the heater elements still show voltage on all 4 elements (heat strips ). very strange!     This explains huge electric bills.

2.  I thought maybe the thermostat was bad or wired wrong: I actually took the thermostat off (hunter brand ez clip on/off type)  ; but amazingly all 4 heater elements still showed 167 volts each ac voltage (approx ) with AC on (air conditioner on)  and with the thermostat completely disconnected and in my hand??

I am thinking their is either a bad part in the unit OR someone wired in the thermostat wires inside the unit wrong to start with.

 This is a newer unit installed perhaps 5 years ago new (the guy who installed it was upon reflection a bit off I think, he left a 4-6″ gap around the plenum leading to super heated atitic air ; i had to hire someone else to shore up the gap so that the unit wouldn’t suck in the hot attic air; super negligent, I would be red faced if I did that. ).

     .  In the winter the AC does not seem to run when heat is on;   but in summer when AC is on, all 4 heater elements are showing 167 volts approx .?? 

As a temp solution we disconnected all 4 elements at the elements themselves individually (after  carefully marking which wire goes to what element)  and insulated (taped their ends ).  This means that the heater will not work at all under any circumstances, but the Air Cond still works fine, means we have to either solve theproblem or get used to rehooking the 4 heater elements up every winter and disconnecting them in the spring.

 Has anyone had this problem in the past? 

  One person had a similar problem and replaced the sequencer, but that only seemed to solve part of the problem:    He also said he completely disconnected the thermostat from the wall and all thermostat (24v ) wires were not connected to anything, BUT  the heater STILL  came on, and heated his house in the “mornings” of  summer months??  He said it was always on AC setting in all warm summer months. 

He finally ended up diconnecting 2 of the heater elements and putting the other 2 on a separate circuit breaker to the fuse box, that way he can make sure that “Heater” breaker is off in the summertime!    (in other words he is heating his house with only half power and he says thats works fine since he is in florida and its not excessively cold anyway).      Truth is stranger than fiction !  Strange , Strange, strange !

   Any help would be appreciated, we’d like to work correctly.

We thought about putting a special 4 pole single throw switch in near the furnac/AC unit closet,  to allow the users to be sure the furnace was completely off,  in the summer, and allow ez heat back on in the winter, 

Again any insight into the $$$ expensive problem would be appreciated. As said we know its not the thermostat because we unhooked it completely uninstalled, thus we think it has to be the unit itself. 

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  1. DanH | Jun 25, 2011 04:09am | #1

    First off, how are you measuring the voltage on the heating coils?  Unless you're placing one voltmeter probe on one terminal of the coil and the other probe on the other terminal (vs measuring to ground or some other point) you're very possibly measuring "phantom voltage" of one sort or another.

    If that's not the problem, you need to hire someone who understands the controls. 

    1. InventPeace | Jun 25, 2011 08:02am | #2

      We did that already:

      We had an ac/heat guy out there to look for problems.. he missed the boat.   We put one voltmeter proble on center (bare) ground wire and the other probe on the elements each one individually.. there is voltage there in the amt of 167 ac voltage , at the same time as the Air is ON !  very strange..

      Before you answer thermostat , please read all the data collected and try to tell me in general what you think it might be.. this is the second one I've seen like this,, and the first one was not really solved but worked around.. makes me think that there is alot more out there bankrupting people (with the higher utility rates.).  

      We are wondering about electronic anything anymore with all the power surges, maybe a surge damaged the electronic board inside and is causing this problem.

      Sometimes! ;the Old Ways are the Best Ways.

      . IE FOR sure separate element breaker or manual switch to make sure the elements can never be on unless switch is on. 

       

      Any insight is appreciated!

      1. DanH | Jun 25, 2011 09:14am | #4

        If you measured to the bare ground wire, you measured wrong.

        I am wondering where you get 167V.  Is this building served by 3-phase power or some other setup that differs from the standard 120V/240V residential scheme??

        1. InventPeace | Jun 25, 2011 10:11am | #6

          3 questions

          I measured a regular outlet with the meter and got 125v just to check the voltmeter. 

          1.  Wondering if there were 110 one  terminal of element, and other 110v phase on other end of element,, how indeed do we get 167v to bare ground wire from one terminal of each element?  

            2.   Are the elements supposed to be 220v across both terminals of each element (110v to each end of each element to get 220v)

           3.  Or are the elements 110V, with one end of elements going to ground, (this was our thinking since it "looks" like one phase coming in feeds 2 elements,  and it 'looks' like  the other phase coming in feeds the other 2 elements .  Of course this is after first feeding into what looks like relays and a sequencer,  also there are light wire connections to electronic board inside.  In other words phase A goes to relay 1 and assoc wiring etc, while phase B goes to another relay and sequencer , it appears. 

          Would this then mean that each element is supposed to be 110v total across its own  terminals?  

          Any insight is appreciated.  

          1. DanH | Jun 25, 2011 10:21am | #7

            The elements are almost certainly 240V elements, with no center connection.  You would read 240V across the two terminals when the element is on, and zero volts when off.

            But look closely at the elements -- likely there is a sticker on them that gives the voltage rating.

            The only way I can think of offhand that you might get 167V is with an open neutral to the power line, but then you'd have light bulbs blowing right and left.

            (How many units in this apartment building?  How is the power fed in -- overhead or underground?  If overhead, how many individual wires are coming in?)

    2. InventPeace | Jun 25, 2011 08:43am | #3

      Again?

      Goodman Manufacturing  co. ELectric AIr/Heat inside unit upright unit,  with horiz fan on top of evaporator pyramid.   

      MODEL#  ARUF 3030 1BA    

      Ok. after re-reading your last post, you are saying there should be a 167vac 'phantom' voltage from ground to heater elements when AIr is on?  That we do not understand, we would think there should be zero voltage from ground to any part of the element. 

      FYI: There are 2 hot wires coming in from fuse box, one seems to run 2 elements the other runs the other 2 heat elements.  They tap off of these somewhere to run fan also. 

      The users manual (limited hookup diagrams) and no diagrams of actual heater element or sequencer or relay connections; 

         If you can help please do.    thanks.

      1. DanH | Jun 25, 2011 09:22am | #5

        Ok. after re-reading your last post, you are saying there should be a 167vac 'phantom' voltage from ground to heater elements when AIr is on?  That we do not understand, we would think there should be zero voltage from ground to any part of the element.

        It's entirely possible that only one leg of the 240V supply to the heater elements is switched, and the other leg is "hot" at all times (when the breaker is on).  Then, if you measure from either leg to ground (or neutral) you'll read a voltage (though how you'd get 167V under any circumstances is beyond me).  [How old is your meter, and is it digital or the type with a needle?  Does it require batteries?]

        There should be two obvious power terminals on the heating element (in addition to a possible ground connection).  You need to measure BETWEEN those two terminals.

        1. InventPeace | Jun 25, 2011 11:01am | #8

          yes we put in new battery and checked on reg 110v outlet.. but its possible we still could have a bad meter.. so we'll check that out.  

          The real PROBLEM is super high AIR COND bills in summer.. to the point ot insanity $500 month on only 1000 sq ft house?  Others have said $360,  deposit was $390 to turn it on last month,  Also you have to remember that the other example with the other guy (see first post), was getting his house heated in the mornings in the summer when he had the selector on Air Cond, and even still heated house when he also completely disconnected the thermostat (hate to think design flaws in HAC units but I was a witness to it as well)l.   In his case it went on for years and he only occasionally noticed it,.  (the ideal was that if its cool on a summer morning lets damn sure not heat the house for any reason, as it will be very hot weather as day progresses);  So he simply disconnected 2 elements, and replaced sequencer with new one, and also put the other 2 elements on a breaker all their own, to isolate them and be abe to turn them off "for sure".  He doesn't have the problem now and simply heats his home on 2 elements instead of 4, also AIr is working great!  THis all makes one think there "MAY" be a design flaw in the HAC business, and it may be more then one co, that is making some wrong assumption about how it will work in summer months.   I hate to say that, but I have seen so many errors, typos, etc in all kinds of equipment that is coming partially or completely out of china that I have to accept its possible.  (Chinese line workers don't read english and do things like put hot where cold is supposed to be on faucets, mislabling things, etc.. and if no one tells them its wrong, they don't fix it. )

                Maybe the circuit board has a problem?

           We'll go back over someday and recheck across both terminals with AIR on, and see what we read. 

            Thanks for your advice! 

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