Multimeter Help - Suburban SW10DE Water Heater

[hittheroad]

The amount of knowledge on this forum is mind boggling. And your posts have helped innumerable times. So i'm going to ask for an assist again. Despite lots of experience and years doing this... I'm still an electrical novice. I did manage recently to trace electric power and identify a blown converter and replace it for a sucessful outcome - but that's the exception.

I HAVE gone through posts on my issue! And it's great information. But, not specific enough to guide me. Darn it!

My 110 side is gone. The propane side works fine.

So - could someone please show me EXACTLY where to place the red and black probes on my multimeter to identify voltage - or not - for the components of my water heater?

e.g. to confirm heating element voltage, put your red probe HERE and your black probe HERE. If you get X voltage it's good, if not its bad. Same with therostat and ON/OFF switch. To test it put this probe HERE and the other THERE. And heres what you should see - or not. And those results mean _______ .

It can't possibly be that tough to replace bad components. I can do that. It's how to identify which component is or is not functioning that's my difficulty.

I've attached a photo of the water heater. In hopes someone has some time on their hands and can put some arrows or something on it to show PUT THIS PROBE HERE AND THAT PROBE THERE to test THIS...

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The above is what I really really would like to get so I CAN deal with this in future.

Having said that, not knowing for sure if I was using the multimeter correctly, I eventually found that one of the wires to the on/off switch had fried for an inch or so from the connector. So I trimmed the wire, replaced the connector (those 90 degree connectors are hard to find!) and replaced the switch itself. If I'm using the probes on the multimeter correctly, it appears that I now have 110 volts on that fried wire - but only with the switch in the OFF position. Which, in my possibly deranged mind, seems to indicate that something else in the circuit has failed, be it an element or thermostat or something.

Any assist I can get - thank you !

[Joe_GA]

OK, first of all, please be careful! 120 Volts AC kills a lot of people. The circuit is a pretty simple one. The current goes to the switch first. Since you found the burned wire and repaired it, I assume you know how to shut off the power to the water heater.

So, when you measured power at the switch were you putting the meter probes on the two switch connections? If so, you will only read 120 volts when the switch is off.

Also assuming the heater has water (no water will fry the heater element) in it, turn on the power and the switch. Place one probe against the metal case of the heater. Now place the other probe on the heater element where the black wire is connected. If you have 120 volts there, place both probes on the 2 terminals on the heater element. Still have 120 volts? The heater element is bad. Place the other probe on the thermostat with the black wires. If no power at the element, measure from heater case to the thermostat connections. The thermostat is the one with the black wires. You should measure 120 volts on either of the connections. If you only measure voltage on one terminal, the thermostat is bad. It's late and I got to get some sleep. Let me know what you find.

[hittheroad]

THANK YOU for the prompt response. Attempted to follow instructions - photos attached. With the WH On/Off switch in the ON position... and with black probe on the WH casing:

WH Element Black Wire test - no voltage.
WH Element Both Wires test - again, no voltage.
WH 110 Thermostat test - no voltage on either upper or lower wire attachment.
WH Switch test, Switch in ON position - no voltage probing lower (On position wire) connection, which was the fried wire trimmed and connector replaced.
WH Switch test, Switch in OFF position -113v reading.

From the photos, did I place probes and measure voltage correctly? And if so, thoughts on what the above readings seem to indicate?

[bubbles]

Do the voltage checks with the switch OFF. Or reverse the wires on the switch. Sounds like maybe a bad switch. Typically on a switch the terminal for the corresponding position will be the opposite end terminal on the back of the switch. Do you know how to use the ohms meter function?

[donniedu]

Bad switch, shorted out wire can and often do take out the temp sensor pack. Start where the 120V side is plugged in. Verify voltage. Yes, move to the switch. My guess it will be dead. Common problem and frankly if it is I would bypass it usi g the breaker inside to kill power. Temp sensor packs are another common problem. You want to look at the one on the right side. Left side is 12VDC. Check voltage red to wire, black lead to ground. Folow voltage until you see zero. There is your problem. BTW did you reset the temp sensor pack? You can also disconnect one of the wires from the heating element and using the ohm function on your meter check the heating element.

[bubbles]

Whoa, how did that black wire on the switch get from black to red which is what is on the right thermostat.

[Brother Les]

Please be very very careful around the 110 voltage.... you can be hurt very badly or worse if you accidentally arch on something. Did you shut the main power off from the 'house' power when you pulled that switch out? Shut the main power off when you put it back in and also be careful that you do not arch anything.

With the main power off, unhook the electric heating element and take out and replace it. The switch wire was burn because of some heavy resistance, I would guess this came from the heating element shorting. If at any time the water heater ran low on water and the electric element was on, this would cause it to overheat way to much and begin to burn/short out. So, to go that extra step and change the element also.

[donniedu]

Originally Posted by Brother Les

With the main power off, unhook the electric heating element and take out and replace it. The switch wire was burn because of some heavy resistance, I would guess this came from the heating element

Not necessairly. If a wire shorts to ground, and believe me it is common the way Suburban stamps the sheet metal, it can take out the temp sensor pack first.

[bubbles]

Originally Posted by Brother Les

Please be very very careful around the 110 voltage.... you can be hurt very badly or worse if you accidentally arch on something. Did you shut the main power off from the 'house' power when you pulled that switch out? Shut the main power off when you put it back in and also be careful that you do not arch anything.

With the main power off, unhook the electric heating element and take out and replace it. The switch wire was burn because of some heavy resistance, I would guess this came from the heating element shorting. If at any time the water heater ran low on water and the electric element was on, this would cause it to overheat way to much and begin to burn/short out. So, to go that extra step and change the element also.

Actually it would burn because of no resistance. And what about that wrong thermostat callout by donniedu ?

[Joe_GA]

Sorry I didn't get back sooner. It sure seems like you have a bad switch. Don't replace the heating element. It draws a lot of current and the OEM switch is a piece of junk. If the element was shorted, it would trip a breaker. It's common for the switch to go bad.

Also, double check all advice you get. The 120 volt thermostat is on the left and has black wires on it. I replaced my switch with a heavier duty switch. It no longer fit in the cutout so I added wires to the originals and mounted my new switch on an angle bracket. If it wasn't cold and dark outside, I'd get you a pic.

[TGR]

You have received both good and incorrect advice and terminology in response to your refrigerator problem. I hope I can straighten out the confusion.

First, a few points. 1.) Be careful, 120 VAC can harm you. 2.) Make all your measurements between the indicated point and a good ground. 3.) 120 VAC can be anywhere from 110 to 125 VAC so don’t be confused by a slight deviation.

• The 120 VAC first goes to your ON/OFF switch. You should read a nominal 120 VAC between ground and both connections on the switch if the switch is on. If you have ~120 VAC on only one side of the switch when it is in the on position, your switch is bad.
• If you have ~120 VAC on both sides of the switch, the power then goes to the combination AC thermostat/high-limit switch. This thermostat/high-limit switch has a reset button. Both wires connected to this unit are black, while the ones for the gas thermostat/high-limit switch are red. Both black wires on the AC thermostat should have ~120 VAC. If only the side coming from the power switch has 120 VAC, try the reset button but don’t touch the power leads with your fingers. Removing the 120 VAC power before resetting the switch would be safest. If you don’t have 120 AC on both black wires and the reset doesn’t work, you need a new thermostat/high-limit switch.
• If you have ~120 VAC on both of the thermostat’s black wires, the power then goes to the heating element. The side of the heating element that comes from the thermostat should have ~120 VAC but the other side will be near 0 VAC. If you have 120 VAC on one side and no hot water, then the heating element is bad.

The original burnt wire on the power switch was caused by overheating because of a bad connection at the switch or perhaps the switch itself. Also, a shorting heating element could have caused a poor connection to fail. A bad heating element can either be open or shorted.

Bad heating elements are often caused by using the water heater in the AC mode without filling the tank first. This will cause the heating element to overheat and short out or burn open. The surge of power caused by the short may also cause other parts of the circuit to burn up.

[5picker]

Originally Posted by TGR

You have received both good and incorrect advice and terminology in response to your refrigerator problem. I hope I can straighten out the confusion.

First, a few points. 1.) Be careful, 120 VAC can harm you. 2.) Make all your measurements between the indicated point and a good ground. 3.) 120 VAC can be anywhere from 110 to 125 VAC so don’t be confused by a slight deviation.

• The 120 VAC first goes to your ON/OFF switch. You should read a nominal 120 VAC between ground and both connections on the switch if the switch is on. If you have ~120 VAC on only one side of the switch when it is in the on position, your switch is bad.
• If you have ~120 VAC on both sides of the switch, the power then goes to the combination AC thermostat/high-limit switch. This thermostat/high-limit switch has a reset button. Both wires connected to this unit are black, while the ones for the gas thermostat/high-limit switch are red. Both black wires on the AC thermostat should have ~120 VAC. If only the side coming from the power switch has 120 VAC, try the reset button but don’t touch the power leads with your fingers. Removing the 120 VAC power before resetting the switch would be safest. If you don’t have 120 AC on both black wires and the reset doesn’t work, you need a new thermostat/high-limit switch.
• If you have ~120 VAC on both of the thermostat’s black wires, the power then goes to the heating element. The side of the heating element that comes from the thermostat should have ~120 VAC but the other side will be near 0 VAC. If you have 120 VAC on one side and no hot water, then the heating element is bad.

The original burnt wire on the power switch was caused by overheating because of a bad connection at the switch or perhaps the switch itself. Also, a shorting heating element could have caused a poor connection to fail. A bad heating element can either be open or shorted.

Bad heating elements are often caused by using the water heater in the AC mode without filling the tank first. This will cause the heating element to overheat and short out or burn open. The surge of power caused by the short may also cause other parts of the circuit to burn up.

TGR gives some very thorough advice here although I suspect he meant this advice is for the water heater and not the refrigerator.

I'll simply add to his 3rd bullet point...
If you have 120v on BOTH sides of the element, you'll need to trace the wire from the element to the power connection box. (usually near the water heater itself) The one element wire continues on and connects to the neutral side of the power feed. If the connection in the box is no good or the wire itself is burned/broken, you have an open circuit and you will have no hot water.

[TryingToLearn]

Just another slight clarification. When testing the switch terminals, do not put probes on both terminals. One probe on the ground, the other probe on one of the terminals. With the probe still on the ground, then check the other terminal.

[hittheroad]

Ok. First THANK YOU ALL. Your input is why this forum is so valuable!

Let me clarify a couple-three things.

Been RVing for years with multiple rigs. Now on our 5th year of full-timing. Learned a LOT about these beasts over the years. And managed innumerable fixes during that time as we all eventually have to do.

I'm not a rookie to RVing, but still consider myself a novice on the electrical side of things.

And YES I DO value my life. And YES you bet that the power is off and CONFIRMED off when forced to deal with things like this. Even the 12v is disconnected at the battery in a case like this. Overkill perhaps, but I am darn well going to make things as safe as I can. And I've done my research to the extent I can. So I know the 110 thermostat/high-limit is on the left with black wires while the 12v is on the right with red wires. And yes, my first action was to depress the reset on the thermostat 110v side. No change. And god forbid I ever not ensure the WH is FULL of water before kicking on power to it. Although, getting older, anything's possible! You do the best you can with the brains you have. With a lot of help from any source you can obtain!

But... power has to be ON to measure it. It's the aspect of HOW to measure it (and what those results indicate) i.e. the specific placement of the meter probes to obtain those measurements, that drove me to post my query. I think of the multimeter probes as RED=Hot and BLACK=Ground - so I use them in that fashion... use the black to some sort of ground (trailer frame etc.) and the red to the connection I'm attempting to read voltage on...

As I mentioned in the initial post - I did replace the ON/OFF switch with a new one. After repairing the fired wire going to the ON connector to the switch. So - it's new, but possibly still a problem. The "flow" of power sequence is definitely helpful. And made me realize - I have NOT tested for voltage on the wire running to the OFF side of the switch! It was the wire running to the ON side that fried. And I do know via multimeter that there -IS- 110v on THAT "ON" side wire/connection of the switch... but only when the switch has been flipped to the OFF position.

So I guess that's my next check. I'd expect that if, with the switch in the ON position, I'd have 110v on both sides/connectors/wires. While if it's in the OFF position, only 110v to the ON connector/wire. Correct?

Then, presumably, I can go on to see if the (left side 110v) thermostat/high-limit switch is getting voltage. ( Specifically WHERE to place the multimeter probes to do so is still a question in my mind... )

And then, if IT has voltage, on to the heating element.

Tell me if I'm off base anywhere in this, please!

(I just kind of feel I have to add one more comment... I get it, trying to learn from a distance, via the internet, is definitely NOT the best approach. Absolutely true. But I don't have the luxury or possibility of someone HERE, standing over my shoulder, showing me how it's done. If I did, I'd go that route in a heartbeat. But I do have at least some level of common sense, and some level of ability. And I do think - I can learn this. And I can fix this problem in the future if I CAN learn this. So again, thanks to all of you for your input - I'll do my best with what you're willing to share!)

[Mr. Dan]

Keep at it! Try your best to ignore the unhelpful comments.

[bubbles]

This may or may not help at this point.

[D W]

X2 (especially on a live circuit unknown to the tester)

[rockfordroo]

If you are not familiar with using a multi-meter, and want to do it "more safely," I would suggest you use check for continuity instead of voltage.

1. Remove all 110VAC power from the rig.
2. See circuit drawing in post #17.
3. Remove the downstream wire from the heating element (the wire that goes back to the rig).
4. Set the meter for reading resistance (ohms).
5. Put one probe on each side of the switch. You should read 0 ohms with the switch ON and infinite ohms with the switch off.
6. Put one probe on each side of the thermostat. If it's closed as it should be, you'll read 0 ohms. If it's not closed, it will read infinite ohms.
7. Put one probe on each side of the element . If it's good, it will read 14.5-17 ohms. If it's bad, it will read 0 ohms (shorted) or infinite ohms (open). (If your water heater breaker hasn't been tripping, your element is probably NOT shorted.)
8. Replace whichever component shows as bad.
9. Re-attach the downstream wire to the heating element.

Actually, at this point, I'd check the element first, as it's most likely the bad actor.

[jeff64]

Might I suggest a suburban WH service manual .pdf file and

https://www.youtube.com/watch?v=TdUK6RPdIrA

YouTube video on multimeter use

[wmtire]

Originally Posted by rockfordroo

7. Put one probe on each side of the element . If it's good, it will read 14.5-17 ohms.
Actually, at this point, I'd check the element first, as it's most likely the bad actor.

I do agree with checking the element, which you do check by resistance(ohms) and not voltage. You can get voltage thru a bad element, but it's the resistance that makes the heat, and why you check an element for that.

However, the Suburban 1440 watt heating element should read at 10 ohms.

This is confirmed by the Suburban training and service manual (which may help the OP), pages 18 and 19 below:

http://docs.renegaderv.com/Suburban/...2005-18-11.pdf

and also this link that let's you input the wattage (1440 watts) and voltage (120 volts).... to get the amps (12) and ohms (10)

https://www.rapidtables.com/calc/ele...alculator.html