Want to add a dual water heater switch.

twinster2 · 03-15-2017, 11:46 PM

You can tell its winter and I'm bored, so I have ordered a Suburban Dual Gas/Electric water heater switch for the inside of the trailer. And yes, I am aware of the fact that turning on the electric with the tank empty is a bad thing. Anyway, I'm wondering if I should run a 120 volt 14 gauge line to the switch or a 12 volt line from the switch to a relay near the tank for the 120 volt.

**LJAZ** · 03-16-2017, 08:12 AM

I would think it would be somewhat easier to snake the 12V line up to where the switch is than the 14 gauge. The switch would also see less current that way. OTOH, relays do occasionally fail. I'm not sure it makes a huge difference, but if it were me I'd probably opt for the 12V with the relay.

twinster2 · 03-16-2017, 10:13 AM

The OEM switch that is already on the electric portion of the water heater is a toggle similar to the one on the dual switch plate. That OEM switch is directly wired to the 110-120 volt circuit so it "must be" rated for that voltage and amperage. If I want to Keep It Simple Stupid (KISS), I would run the 14/3 gauge wire from the water heater to the dual switch plate thus bypassing the OEM water heat switch. I could also probably pop the OEM switch out on the water heater and use it on the electric side on the dual switch plate. That OEM switch is red with a pin in it so that is a safety plus to prevent it from being turned on accidentally with a empty tank. The relay is a nice idea but I'm not sure I really trust them since they can fail in the closed position.

twinster2 · 03-16-2017, 03:56 PM

Decided to do the relay method after all. Order this Suburban relay, part # 232948, and will run 12 volt line from the switch panel to the relay that I will locate near the water heater.

APD · 03-16-2017, 06:09 PM

Using a relay and keeping the load carrying wiring short as possible would be safer. IMO.
The relay must be heavy duty and rated for the wattage/amps you will be asking it to carry.

PaintyLiz · 03-21-2017, 09:37 PM

Love this idea, wish I knew enough to understand how to implement it. There are times we hate realizing we forgot to flip the switch on and have to go outside and do it! We don't usually turn it off anymore til we get home.

Liz

twinster2 · 03-24-2017, 09:20 PM

Today I started running the wire for the dual switch. It took about an hour just to run two wires from the switch to below the sink. Did not expect the difficulty, but it is done. Only thing left to do is finish running the wire to the water heater and add the relay. Maybe in the next few days I will be able to finish it.

twinster2 · 03-25-2017, 05:46 PM

Well I have some pictures of the work I've done so far. The first one is the new switch mounted to the wall. The next picture is the electrical box on the hot water tank. In adding the relay, I discovered that two holes were already drilled onto the box that fit the relay perfectly (the holes are where the two nuts are that attach the relay on the back side). The third picture shows the attached relay in the electrical box (note the back and white wires coming from the external switch, thermostate and heating element).

APD · 03-25-2017, 09:05 PM

I like that switch and the ease of operation!
Our unit is a standing pilot, gas only that I have to light every so often when camped.
This makes me think about upgrading.

Alan

twinster2 · 03-25-2017, 09:49 PM

Quote:

Originally Posted by APD

I like that switch and the ease of operation!
Our unit is a standing pilot, gas only that I have to light every so often when camped.
This makes me think about upgrading.

Alan

Alan-
Upgrading will likely require quite a few modifications since your tank is a manual gas unit with no electric option. Probably the best thing to do is buy a new Suburban or Atwood water heater with those options already installed, than run the wiring to a internal switch. If you do it, put the switch in a accessible area that you can run wiring too it. Unfortunately for me, I had to use the hole where the original gas only switch was (I enlarged that hole to accommodate the dual switch) and it was difficult to get the new wiring thru the wall and below the sink. Don

APD · 03-25-2017, 10:04 PM

Thanks Don. I did look into installing a pilot re-igniter on our heater but, like you said, having a new unit would be better. We always camp with shore power so having the electric option would be good as well.

Alan

twinster2 · 04-03-2017, 06:46 PM

I thought I would be able to wrap up this project today, but I was wrong. Turned out that the AC thermostat/limit switch is burned out. I should have remembered that the AC heating element was not working at the end of last years camping trip. When I temporary bypassed the thermostat, the heating element works great with the indoor electric switch and relay. So I order a new thermostat today and once installed my dual switch will be alive and functioning. Oh happy days.

twinster2 · 04-09-2017, 07:46 PM

I got the new AC thermostat installed, filled the hot water tank and turned on the inside electric switch. Half hour later I got hot water! Oh happy days!!

This project is now finished. Now onto adding the solar panel.

MikeC · 06-27-2017, 07:57 AM

twinster2 - I saw your post from earlier this year on adding the dual switch wall plate for your Suburban water heater. I am trying to do this in my unit but can't find a clear wiring diagram for the relay. Your last picture showed the relay mounted but no wires connected. Do you have any info you can share on what wire (110v hot/neutral and 12v pos/neg) go on which connector. Based on the # of spades I don't see how it can pass both lines of the 110V. Thanks in advance !!!

twinster2 · 06-27-2017, 12:15 PM

Quote:

Originally Posted by MikeC

twinster2 - I saw your post from earlier this year on adding the dual switch wall plate for your Suburban water heater. I am trying to do this in my unit but can't find a clear wiring diagram for the relay. Your last picture showed the relay mounted but no wires connected. Do you have any info you can share on what wire (110v hot/neutral and 12v pos/neg) go on which connector. Based on the # of spades I don't see how it can pass both lines of the 110V. Thanks in advance !!!

The two vertical connectors on the left side are for your 12 volt switch. Doesn't matter which one you use for + from switch and - from ground.

The two tab connectors on the bottom are your 110 volt line. The horizontal tab that is marked COM is where you connect hot wire coming from your supply (i.e. black) and the other tab connector at the bottom right is connected to the back wire going to the heating element/manual switch. The white wire from supply is neutral and it is connected directly to the white wire from the heating element/manual switch. Make sure you turn off the circuit breaker when you wire it up.

MikeC · 06-27-2017, 12:51 PM

Quote:

Originally Posted by twinster2

The two vertical connectors on the left side are for your 12 volt switch. Doesn't matter which one you use for + from switch and - from ground.

The two tab connectors on the bottom are your 110 volt line. The horizontal tab that is marked COM is where you connect hot wire coming from your supply (i.e. black) and the other tab connector at the bottom right is connected to the back wire going to the heating element/manual switch. The white wire from supply is neutral and it is connected directly to the white wire from the heating element/manual switch. Make sure you turn off the circuit breaker when you wire it up.

Thanks for the insight. I was getting hung up thinking it was taking the main 110 line in from the circuit breaker and then passing it back to the water heater. Wasn't thinking about the current switch wiring. Makes perfect sense. Thanks for your help !!!

twinster2 · 06-27-2017, 01:53 PM

Yea, using the existing manual switch wiring offers some additional protection such as turning it off at the tank when you know the tank is not full of water. That way, if the switch gets accidentally turned on inside, at least you don't burn out the heating element.

Don

Hjabernathy · 11-27-2021, 10:49 AM

Here I am in November 2021 having to convert a Suburban SW6DE that I unknowingly purchased to replace a SW6D. I found this forum and postings, thankfully. I discovered that I should have purchased a SW6DEL, a fact I discovered in this forum. I was able to follow the detailed, well written and well illustrated posts herein to convert the SW6DE to a SW6DEL. Everything went perfectly with purchase and installation of the relay switch and double switch inside the coach. The double switch and water heater work wonderfully.

I should add though a description of the problem I ran into with respect to installing a check valve on the hot water port of the water heater. The valve wouldn’t open causing me a great amount of consternation. I did note that the SW6D that I was replacing did not have a check valve. The new valve seemed to function when I installed it. However, water would not flow through it. After I took it out, replacing it with a straight-through nipple, I found that I could not open it by blowing on the inlet side. Everything worked as it should after I removed the check valve.

I wonder if the check valve required a higher pressure than was generated by the water pump in the coach. I kind of doubt this since many people installed this check valve, a brass 1/2“x1/2” fitting purchased on Amazon, in RVs according to the reviews. I know I had it installed correctly, arrow on the valve indicating flow out of the water heater at the hot port. Just thought I’d throw this out.

APD · 11-27-2021, 12:30 PM

This thread (at the time) inspired me as well. I added a Hott Rodd kit to our water heater a few years ago. Haven't used propane for heating water ever since.
Our gas valve had began to give trouble and wouldn't maintain the standing pilot.
The electric has allowed us to get a few more years of camping out of our old water heater.