Light fan heater combo unit for bath

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jcole

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Lawrenceburg, Kentucky
Hello guys and gals.

I have seen but never wired a light fan heater combo unit for a bath. I am assuming I just install a switch for the heater separate from the fan and light switches? Is there a built in stat for temp control on these units? I am also assuming there is a high limit temp shutoff built in? Any advice or suggestions for wiring one of these up?

Thanks for any replies.
 
jcole said:
Hello guys and gals.

I have seen but never wired a light fan heater combo unit for a bath. I am assuming I just install a switch for the heater separate from the fan and light switches? Is there a built in stat for temp control on these units? I am also assuming there is a high limit temp shutoff built in? Any advice or suggestions for wiring one of these up?

Thanks for any replies.
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Typically three switches: light, heat and fan. I'd feed with a dedicated or light circuit as the heaters draw somewhere around 500-1000 watts if I remember correctly. There is a usually high limit built in, but not a built in stat typically. If you want it stat controlled, you'd have to wire a separate stat in. There's a couple different types of heaters available, heat lamp and fan forced resistive.
 
Thanks for reply sparky.

Is there only one motor? If so, I am assuming that there is two fans mounted on the same shaft and one blows for heater and the other sucks for the fan? Or is there two motors?
 
jcole said:
Thanks for reply sparky.

Is there only one motor? If so, I am assuming that there is two fans mounted on the same shaft and one blows for heater and the other sucks for the fan? Or is there two motors?
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If the heater is forced air there will be two fans, two motors.
If it is infrared there may not be a second fan and motor.

Newer combos may also have a built-in humidistat that runs the fan on low speed automatically whenever the humidity is above the factory set point.
 
jcole said:
Hello guys and gals.

I have seen but never wired a light fan heater combo unit for a bath. I am assuming I just install a switch for the heater separate from the fan and light switches? Is there a built in stat for temp control on these units? I am also assuming there is a high limit temp shutoff built in? Any advice or suggestions for wiring one of these up?

Thanks for any replies.
Click to expand...

They will most likely require a 20A individual branch/dedicated circuit. 12/4 NM (if they have a nightlight, you'll have to use 2 cables, MC, or conduit since no one makes 12/5 NM). 3 rocker fan/light/heater switch (another 30-50$) in a single gang box, you'll want a deep one, two gang box if it has a nightlight.

Advice? The existing ductwork is probably undersized, you can either have the HO get a mechanical contractor to change it or buy a reducing hub. Dont plan on using the existing wire to the existing fan; you can, ofc, but you'll still need a dedicated circuit for the heater, and a dollar says the existing cable or ductwork isnt oriented correctly for the new fan. Plan on cutting drywall. Bring good metal backed super sticky duct tape, and a good assortment of different length drill bits. Check the ceiling joists to see if they are deep enough to accommodate the fan, and spray foam will be tricky unless there is access above - speaking of which, ask if there is access above, and that any attic boards arent nailed down or there isnt a ton of junk blocking the way.

One of these fans can take 1 guy most of a day. Bringing a helper for fishing wire and the crawlspace/basement work goes much faster. There will be a fair amount of cleanup from drywall cutting and blown in insulation going everywhere. Ask the HO to clear out/put away as much stuff in the bathroom as possible.

If it's new construction, wiring up a 12/4 whip to the fan in the shop/on the truck is a lot faster than doing it in the ceiling.
 
Thanks for the reply fletcher.

I was planning on just using regular toggle switch in a 4 gang box (light, fan, heater, vanity light)? Not a good idea? This is a remodel. There was already a 20A circuit for a wall mount heater and a 15A circuit for the lighting in the existing bath. Drywall has already been removed. Just curious - why would I need good metal backed super sticky duct tape, assortment of drill bits, and spray foam?

Thanks again.
 
Check the fan unit itself to see if any switches/controls are included. (I know I;m dating myself as it's been a lot of years but some units I installed came with a "despard" type switch assembly)
 
"despard"
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That is a term I have not heard in many a year! :D

I think I still have some laying around... Tiny two prong receptacles and pilot lights also.

The last fan/light and another light I installed only had room for a single gang box, so I used the triple switch from Broan/Nutone to do all three. Tight, but worked. I like the separate switches better, but needs more wall space!
 
jcole said:
Thanks for the reply fletcher.

I was planning on just using regular toggle switch in a 4 gang box (light, fan, heater, vanity light)? Not a good idea? This is a remodel. There was already a 20A circuit for a wall mount heater and a 15A circuit for the lighting in the existing bath. Drywall has already been removed. Just curious - why would I need good metal backed super sticky duct tape, assortment of drill bits, and spray foam?

Thanks again.
Click to expand...

He's assuming that you are making the connection to the duct work. When you remove the old fan, your are going to probably pull down some insulation. You may need to pre-drill the holes in the fan collar to make the attachment to the duct work. The tape is the final seal once everything is right and tight.
 
Forget those switches.. Wire it in a 3 or 4 gang box. I have seen those switches and it is a bear to wire them and fit into a box. I throw them out... I don't believe Nutone or panasonic supplies them anymore but I am not certain.

Separate circuit for sure. If there is no nite lite then use 12/4 or run a 12/3 and a 12/2.....Nite lights makes for 2- 12/3 cables. Make sure to separate the neutrals at the unit for each cable

Some guys run carflex with the correct number of wires.
 
Dennis Alwon said:
Forget those switches.. Wire it in a 3 or 4 gang box. I have seen those switches and it is a bear to wire them and fit into a box. I throw them out... I don't believe Nutone or panasonic supplies them anymore but I am not certain.
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I believe some of those switches have one common terminal for all three switches. If you are going to put everything on one circuit anyway (night light, light and fan, for example) that can simplify the wiring a lot.
 
jcole said:
Thanks for the reply fletcher.

I was planning on just using regular toggle switch in a 4 gang box (light, fan, heater, vanity light)? Not a good idea? This is a remodel. There was already a 20A circuit for a wall mount heater and a 15A circuit for the lighting in the existing bath. Drywall has already been removed. Just curious - why would I need good metal backed super sticky duct tape, assortment of drill bits, and spray foam?

Thanks again.
Click to expand...

The metal backed tape is for connecting the existing ductwork to the fan outlet or reducer hub; regular "duct tape" is pretty worthless for doing that.

The asst. drill bits is because you never know how far apart the joists are, or where one may fall in regard to the wall where you are putting the switchbox. You may wind up with a blind corner in a ceiling; it has helped me in the past to have shorty paddle bits and the occasional holesaw bit to help get wire thru tight quarters.

You dont need spray foam*; I mentioned that because if there is existing spray foam in that ceiling, you'll have to hack it up to get the fan body and new wiring in place. *If you do hack it up, then a can or two to replace the insulation you removed is good to have.
 
JFletcher said:
The metal backed tape is for connecting the existing ductwork to the fan outlet or reducer hub; regular "duct tape" is pretty worthless for doing that.

The asst. drill bits is because you never know how far apart the joists are, or where one may fall in regard to the wall where you are putting the switchbox. You may wind up with a blind corner in a ceiling; it has helped me in the past to have shorty paddle bits and the occasional holesaw bit to help get wire thru tight quarters.

You dont need spray foam*; I mentioned that because if there is existing spray foam in that ceiling, you'll have to hack it up to get the fan body and new wiring in place. *If you do hack it up, then a can or two to replace the insulation you removed is good to have.
Click to expand...

Sorta like post #9? :cool:
 
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