wiring furnace and power ventor-need 2 circuits?


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Old 11-13-08, 02:47 PM
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wiring furnace and power ventor-need 2 circuits?

I am installing new furnace, a carrier with variable speed blower. I also will be using a field power ventor. the tag on the furnace states

115V
Load 15.7 amps
max breaker 20 amps
min circuit ampacity 18.1

the power ventor instructions state that it needs 15 amp circuit. I don't see where it says a separate circuit and it doesn't have anything else mentioned except on the ventor it states

115V
136 Watt
1.77 Amps

So, do I need to run 12/2 20amp circuit for the furnace and a separate 14/2 15amp for ventor? Or can I tap the 20 amp furnace circuit to use for ventor? Seems crazy to have to run a separate circuit for a 1.77amp motor. If I have to use separate circuit is there any reason that I couldn't use the ventor circuit for some outlets in this 10' x 15' utility room. I plan to just pull down overhead lighting wire from room above for overhead light in this room. Can't pull down outlet circuit since the room above is dining room and I am wiring outlets separately on own circuit-not part of kitchen small appliance circuits.

thanks
 
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Old 11-13-08, 03:09 PM
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another furnace related question. The furnace supply duct will be right under the floor joists and where the wires will enter the room will require that they go over top of the duct. The duct is insulated, but wanted to make sure it is OK to run wires so close to the furnace supply. They would be running right over top of furnace. The supply comes out of top of furnace and then turns to run under joists. The wire would be in the joist bay, which will be insulated.
 
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Old 11-13-08, 05:57 PM
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Your furnace requires its own 20 amp circuit. The ventor does not. You can put that on some other circuit (or its own) just not with the furnace.

As far as the cables above your air supplies, it is not an issue.
 
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Old 11-14-08, 04:43 PM
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shielding wires-conduit and AC /MC

thanks, I thought I would need 2 circuits. today realized that humidifier will also need power. It plugs in so I will put an outlet on side of furnace and then run wire from there to ventor and put an outlet in the room and in the crawlspace also on this circuit. All will be GFCI. I know I have to use conduit in this concrete unfinished room for the drops from floor joist above down to the outlet and down to a light switch. Does it matter what type I use-EMT vs IMT vs PVC?

I also thought that I had to shield the cables running from joists down to furnace- was thinking AC or MC? but HVAC said no-they run plain wires all the time. But he also said that I only needed one circuit! they also ran UF wire along my foundation outside to condensor units. I thought these had to be in conduit? I think I better start new thread with these questions.
 
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Old 11-14-08, 07:42 PM
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I prefer EMT myself. I find it easy to work with and is more sturdy than PVC. Then again, I work with the stuff almost every day. With the fittings out there I would think most people can use it even with out a bender.

BTW - Not sure what IMT is but I think your talking about IMC, which would be overkill.

NM-B (romex) and UF need to be protected form physical damage. Just running it on the outside of a concrete wall exposed does not meet code. Inside joist/stud spaces are considered protected. Your HVAC guys should not be wiring unless they have the proper licenses anyway. (If required in your state)

With the cable drops to the furnace, you could use AC, MC, Flex metal conduit or most times we use a stick of EMT with a bushing (fitting) on one end and a box on the other feeding into the furnace. Then we slip some Romex down the pipe to the box and into the furnace. Remember, you will also need a disconnect on the furnace. Most cases a switch is sufficient.
 
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Old 11-14-08, 10:17 PM
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sorry I meant IMC.

These HVAC guys just disconnected old equipment and hooked up new to the existing wires. My previous contractor had HVAC guys that moved my old equipment to the new location and they are the ones that used the unprotected UF. Although the new guys said that it was OK. I will probably run conduit in future to bring it up to code. I will have a total of 5 appliances (two condensing units, two pool pumps and a pool heater) so will likely have to run several conduits since I don't think could run all of these in one.

was planning on running down to box on furnace and put a switch in that box, and then go into furnace.

thanks
BTW-I did start new thread on conduits
 
 

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