120VAC relay or switch on Suburban SW6DE WT

[Mtn Mike]

Okay, so I upgraded my old pilot light water heater to a DSI ignition/1400 watt/120VAC model (SW6DE). The online retailer was very helpful with most of my questions before my purchase. They sent me a dual switch that controls the 12v DSI ignition AND apparently the 120VAC element. It's an Atwood switch, not Suburban, so obviously it's incorrect part. But I'm thinking I might be able to use it anyway as I'll explain in a second. Suburban does not seem to make a comparable switch.  The SW6DE does have a small on/off switch by the valve outside the coach, which I think controls the 1400 W/120VAC element.  But I definitely want an on/off switch for the 1400 element in the coach. So, I guess I either need a 120VAC household switch, or I can use the supplied Atwood switch with a 12VDC - 120VAC relay. Nowhere is this explained in the instructions provided by Suburban or anywhere else online. Can someone else with this model explain how you have it wired? TIA!

 

[Mtn Mike]

This is the schematic for an Atwood tank, and there's a relay included: http://www.panther-rvproducts.com/media/Combo%209E-10E%20Conversion(1).pdf

This is the schematic for the suburban, with no reference to a relay or 120VAC switch:
http://www.livinlite.com/pdf/service/wh/SW6D-SW6DE-SW6DM-SW6DEM-Installation.pdf

 

[Alfa38User]

For my Suburban HWH, I have the standard Gas control switch and an ordinary 120V household switch for the electric side of the water heater. They are simply mounted side by side on the wall. I leave the outside switch ON all the time. Using the Atwood switch for gas and an ordinary switch or the 120V side will work but I would not attempt to use the 120V side of the Atwood switch you have as the relay is not furnished with a Suburban AFIK.

Either that, or ask your supplier to exchange the switch for the correct part!! Keep in mind you, or he, will have to supply a single 120V switch along with the gas side switch assembly  and, IMHO, if the existing Atwood switch will work, it is hardly worth the trouble.

 

[Mtn Mike]

For my Suburban HWH, I have the standard Gas control switch and an ordinary 120V household switch for the electric side of the water heater. They are simply mounted side by side on the wall. I leave the outside switch ON all the time. Using the Atwood switch for gas and an ordinary switch or the 120V side will work but I would not attempt to use the 120V side of the Atwood switch you have as the relay is not furnished with a Suburban AFIK.

Either that, or ask your supplier to exchange the switch for the correct part!! Keep in mind you, or he, will have to supply a single 120V switch along with the gas side switch assembly  and, IMHO, if the existing Atwood switch will work, it is hardly worth the trouble.

Thank you very much! That's exactly what I needed to know. I guess one could just use the provided external 120VAC switch and forgo the internal switch, but that's not desirable to me considering the LPG switch is conveniently in the coach.

Regards and happy RVing.

 

[Alfa38User]

Look around, you may be able to find a similar 120V switch (2 or 3 terminals) that can simply replace the supplied switch, 120V side. They simply clip into the frame and are easily removed. Remove the 12V jumper between the two sides though. (Check the designation on the switch itself first but I suspect it will refer to a 12V, x amp  capacity and be unsuitable.)

 

[Mtn Mike]

Look around, you may be able to find a similar 120V switch (2 or 3 terminals) that can simply replace the supplied switch, 120V side. They simply clip into the frame and are easily removed. Remove the 12V jumper between the two sides though. (Check the designation on the switch itself first but I suspect it will refer to a 12V, x amp  capacity and be unsuitable.)

I don't think a 120VAC switch will fit in the Atwood switch holder. There's no way it could meet code, or be safe. I'm not totally opposed to using the switch with a 12-120 volt relay but I haven't seen one available. I'll probably configure mine exactly like yours is.

 

[Gary RV_Wizard]

The Atwood switch is not rated to directly switch the 120v power. Atwoods since about 2004 have a 120v relay as part of the heater and the external switch merely tells the Atwood circuit board to turn on the 120v power source.  The 120v power goes direct to the heater, not through the remote switch. The switch itself is 12v, I believe.

As far as I can determine, the Suburban requires a second 120v switch in the 120vac power source if you want an inside remote on/off. You could use the Atwood switch if you add a simple relay near the heater. Might be easier than running 120v/12A capable wire to an inside switch and back to the heater.

 

[Mtn Mike]

The Atwood switch is not rated to directly switch the 120v power. Atwoods since about 2004 have a 120v relay as part of the heater and the external switch merely tells the Atwood circuit board to turn on the 120v power source.  The 120v power goes direct to the heater, not through the remote switch. The switch itself is 12v, I believe.

As far as I can determine, the Suburban requires a second 120v switch in the 120vac power source if you want an inside remote on/off. You could use the Atwood switch if you add a simple relay near the heater. Might be easier than running 120v/12A capable wire to an inside switch and back to the heater.

Thank you very much Gary. Thats exactly what I was starting to realize and I'm glad you confirmed it.

Im not yet sure whether I'll go the route of a 120vac switch or a 12v -120v relay.  It sounds like the Atwood relay is integrated into the unit internally and therefore not something I could just buy and use with the Suburban. Any idea on the specifications I would need for a relay? Alternatively it may not be worth the trouble when I could just wire in another 120vac branch with a switch...

Luckily today I got the new water tank installed and its roaring away quite well on propane. The 120 circuit will come eventually.

 

[Gary RV_Wizard]

Yes, the Atwood relay is part of its control circuit board.

You need a Single Pole/Single throw (SPST) relay that can switch at least 15A (the heater element draws about 12A @ 120v), but you want one that uses 12v for the trigger, so that the wall switch is wired for 12vdc instead of 120vac. A double pole relay works too, but you only need to switch the 120v hot wire.

Note that the relay and the switch on the heater itself will be in series, so both must be on the heat water electrically.

 

[kjansen]

My Suburban WH is wired to a separate circuit breaker in the panel with the switch mounted on the WH outside.  I could just run the wire from the breaker to a switch by the panel and that would give me control inside by leaving the switch on WH on at all times. 

Is this something you could Mtn Mike?  For me it would only require a light switch, box and a few feet of wire, maybe $5 total.

 

[Rene T]

My Suburban WH is wired to a separate circuit breaker in the panel with the switch mounted on the WH outside.  I could just run the wire from the breaker to a switch by the panel and that would give me control inside by leaving the switch on WH on at all times. 

Is this something you could Mtn Mike?  For me it would only require a light switch, box and a few feet of wire, maybe $5 total.

I  did the exact same thing on my last 5vr. Put it in a place that was easy to get to but still out of the way. Very easy to do.

 

[Mtn Mike]

My Suburban WH is wired to a separate circuit breaker in the panel with the switch mounted on the WH outside.  I could just run the wire from the breaker to a switch by the panel and that would give me control inside by leaving the switch on WH on at all times. 

Is this something you could Mtn Mike?  For me it would only require a light switch, box and a few feet of wire, maybe $5 total.

Thank you for that description. I don't have a separate WH circuit, but there is a 20 amp circuit nearby that I could branch off of.  I'm still debating between this and a relay.

 

[Mtn Mike]

Yes, the Atwood relay is part of its control circuit board.

You need a Single Pole/Single throw (SPST) relay that can switch at least 15A (the heater element draws about 12A @ 120v), but you want one that uses 12v for the trigger, so that the wall switch is wired for 12vdc instead of 120vac. A double pole relay works too, but you only need to switch the 120v hot wire.

Note that the relay and the switch on the heater itself will be in series, so both must be on the heat water electrically.

hmm, trying to remember how a relay works...Does that mean I will draw 12 volt current to keep the 120VAC circuit in the closed/"WH on" position? 

 

[Gary RV_Wizard]

Relays are either "normally open" or "normally closed".  The trigger current must be on to keep the relay energized, and "energized" puts it in the opposite of the "normal"state. If you chose a normally open relay, then yes you would apply 12v voltage/current to keep it closed (circuit active). Vice versa if normally closed.

But there are also "latching relays" that use little or no current to keep them energized.

 

[Mtn Mike]

Got it, thanks again for the information Gary and everyone else who responded.