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heating -airconditioning

> The problem is that the fan is interlocked with <BR>
> the fan circuit on the furnace so when the range <BR>
> hood comes on the furnace blower and A/C also <BR>
> will come on. You must isolate the fan circuit <BR>
> with a relay so that the "G" circuit being <BR>
> energised will not back feed right back thru the <BR>
> T-stat and energise the cooling circuit. The <BR>
> same thing would happen if you were to use your <BR>
> jumper and jump R to G. the cooling will come <BR>
> on. <BR>
> <BR>
> Install a Double pole/Double throw relay <BR>
> at the furnace. The wire coming from the stat to <BR>
> "G" must go thru the n-c set of contacts. The n-o <BR>
> set of contacts will be used to also energise <BR>
> "G", but only if the Range hood is turned on. The <BR>
> relay will now be energised from what ever <BR>
> actuates the Range hood. Do you <BR>
> understand?<BR>
> <BR>
> Mike T. <BR>
<BR>

Comments

  • Bill_74Bill_74 Member Posts: 1
    low voltage wiring-heating-a/c

    home has gas heating and a/c --
    problem is that when the range hood fan is turned on the furnace blower comes on for makeup air --
    thats ok .. but it also brings on the a/c unit..
    i am uderstanding that it's with the low voltage wiring.
    can you help resolve this ,and if it has to due with wiring is there a site that has diagrams available.

    thank you
    Bill
  • Empire_2Empire_2 Member Posts: 2,343
    \"G\" circuit

    The problem is that the fan is interlocked with the fan circuit on the furnace so when the range hood comes on the furnace blower and A/C also will come on. You must isolate the fan circuit with a relay so that the "G" circuit being energised will not back feed right back thru the T-stat and energise the cooling circuit. The same thing would happen if you were to use your jumper and jump R to G. the cooling will come on.

    Install a Double pole/Double throw relay at the furnace. The wire coming from the stat to "G" must go thru the n-c set of contacts. The n-o set of contacts will be used to also energise "G", but only if the Range hood is turned on. The relay will now be energised from what ever actuates the Range hood. Do you understand?


    Mike T.
  • TechmanTechman Member Posts: 2,144
    LoVolt Wiring

    Hi! I was wondering how/why the furnace blower is providing "make-up air" for the range hood x-fan?Enjoy!
  • jim lockardjim lockard Member Posts: 1,059
    Me too

    Where is the furnace getting the make up air from? If the furnace is getting this air from outside, then do you condition and filter the air? J.lockard
  • LarryCLarryC Member Posts: 331
    Make up air

    Is this a Canadian requirement? I have heard of bathroom exhaust fans also having to meet this requirement.

    Mike T: The schematic posted is not using a Double Pole Double Throw relay.

    Larry C

    Here is a link to ECN discusion web site. http://electrical-contractor.net/ubb/Forum3/HTML/000335.html

    Edit to add link
  • Empire_2Empire_2 Member Posts: 2,343
    Hi Larry

    Although I did not show it, it is the Honeywell relay that is used for a fan center, which is DPDT. You could use the SPDT, but the only reason I stated that is the fan relay has a higher amp ratting. I knew someone would catch that.... Good job.;-) The DPDT has more terminals in which I want him to connect R to one set and G to the other off the T-stat. In fact it has to be a DPDT relay. Sorry I didn't make that clear.

    Mike T.
  • Empire_2Empire_2 Member Posts: 2,343
    Bill, Did this help????????

    I was wondering if you could make heads or tails of what I was trying to explain??? A reply would be great so that we know that we helped or if you have any more Q:.....

    I let him out into traffic and he don't even wave Carol...;-)

    Mike T.
  • Eugene SilbersteinEugene Silberstein Member Posts: 1,380
    Furnace blower for make-up air?

    Something sounds fishy here...
  • Empire_2Empire_2 Member Posts: 2,343
    We'll never know

    Bill will not write back on this topic.

    Mike T.
  • Bill, that should not be wired in that manner

    as the range hood is an independent circuit from any heating or cooling equipment. Someone has gotten some wires crossed.

    If you are bringing make up air into the area of the range hood it must be interlocked with the range hood not the heating/cooling system.
  • Darin(in Michigan)Darin(in Michigan) Member Posts: 90
    Tstat wiring

    I followed the correction measures but shouldn't some one mention that the reason the A/C is coming on is because on a non programmable single stage heat/ cool stat, the G and Y terminals are internally jumpered unless the subase is in a fan on position. My .02

    Thanks
    Darin
  • Empire_2Empire_2 Member Posts: 2,343
    It was mentioned.......

    Also, just a thought...Since Bill is not replying and we know nothing of what he has as far as MUA, All I can think is that this a r larger house and that exhaust fan must be particularly large. The furnace may incorporate a MUA actuator and damper...Who knows. Opening up MUA on a call from this range hood should require MUA to the envelope not just the area in which the exhaust is located. Like I said, Who knows since Bill asked a question and basically vanished. I hate that!!! ;-)

    Mike T.
  • Eugene SilbersteinEugene Silberstein Member Posts: 1,380
    Hmph!

    Was it something we said?
  • Empire_2Empire_2 Member Posts: 2,343
    Humming

    The theme from Jeopardy........Tap along if you can.....:-)

    Mike T.
This discussion has been closed.

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