Suburban Water Heater - Doesn't on Electric...

In2b8r · 10-03-2016, 06:40 PM

I did what many have done before me... left the Electric Switch in the on position and the water tank empty. I replaced the heating element and confirmed that I do have 110 at the element yet it won't heat. The propane side works fine, no issues. Thoughts? How do I move forward with troubleshooting the issue so that I don't have to start replacing parts until I find the culprit?

donniedu · 10-03-2016, 06:53 PM

One side of the electric element goes thru the temp sensor pack. On Dometic water heaters there are two packs. One for 120VAC which is on the left and one for 12VDC which is on the right.

youroo · 10-03-2016, 06:57 PM

Did you also push the "Rubber Resets"? Youroo!!

In2b8r · 10-03-2016, 07:01 PM

I did check the resets, both are good. In addition, I checked and I do have 120 on the left side limit switch (blue electrical connectors). Could it be the circuit board? How would I know?

**Bama Rambler** · 10-04-2016, 09:22 AM

If there is 120 volts to the element, and the neutral is intact, the only way the element isn't heating is if it's bad. It won't be a circuit board issue. The 120 volt side only runs through the hi limit --- thermostat --- element --- neutral.

Having said that, if the winterizing valve(s) are in the winterize position it will be heating the water, but you won't get any out of the faucets? Also, if the water is already hot from the gas side, it may not turn on because the thermostat is already satisfied.

In2b8r · 10-04-2016, 09:30 AM

Thanks Rambler - that is why I am so puzzled. Valves are in correct position, I have checked multiple times... I left it on Electric all night and nothing - still cold this morning. The element continuity is good - 2nd element that I have tried - possible that the neutral has an issue although it is difficult to understand how but again possible. Not certain how I can determine the continuity of the neutral... any thoughts?

5picker · 10-04-2016, 09:41 AM

The 110v goes through the switch first, then the hi limit/ thermostat and finally to the element. if you have 110v in the black wire at the element, you can rule out all the circuitry before the element.

If you have 110v in the white wire terminal at the element, you can rule out the element and start looking at the neutral wiring from the element back to the electrical box connection and/or 110v plug/outlet.

5picker · 10-04-2016, 09:46 AM

Is the water heater hard wired or plugs into a receptacle?

If plugged in, unplug the heater and plug a lamp or something into the receptacle.
It's possible the wiring connection inside the receptacle is bad.
Most of the inexpensive receptacles/outlets just 'pinch' onto the romex wires.
Could be a bad connection on the neutral side.

If the outlet is good, start looking at the neutral between the element and the outlet. Sometimes there is a small electrical box on the water heater where the 110v pigtail attaches. Check the wire nuts and connections there.

If hard wired, remove and check connections at wire nuts at the connection at the water heater.

**wmtire** · 10-04-2016, 10:15 AM

Quote:

Originally Posted by 5picker

The 110v goes through the switch first, then the hi limit/ thermostat and finally to the element. if you have 110v in the black wire at the element, you can rule out all the circuitry before the element.

If you have 110v in the white wire terminal at the element, you can rule out the element and start looking at the neutral wiring from the element back to the electrical box connection and/or 110v plug/outlet.

5picker, not understanding this comment in red. Voltage at the element comes from the power supply. Just having voltage at the black (hot) and white wire (neutral) connecting to the element, will not indicate if the element is good or bad.....just that there is voltage. You don't even have to have the wires connected to the element to test them for 120 volts.

Testing for voltage is different than resistance.

Did you perhaps mean to state Ohm(or resistance) at the element is indicative?

rockfordroo · 10-04-2016, 10:24 AM

For a quick and dirty check:

Pull the plug from the receptacle. Turn on the electric switch. Check resistance (ohms) from one blade of the plug to the other. If you have some resistance, the switch, thermostat and element are all good.

If you don't get any resistance, then either the switch is bad, the thermostats are bad, or the element is bad. You can then start working your way through those components.

5picker · 10-04-2016, 10:48 AM

Quote:

Originally Posted by wmtire

5picker, not understanding this comment in red. Voltage at the element comes from the power supply. Just having voltage at the black (hot) and white wire (neutral) connecting to the element, will not indicate if the element is good or bad.....just that there is voltage. You don't even have to have the wires connected to the element to test them for 120 volts.

Testing for voltage is different than resistance.

Did you perhaps mean to state Ohm(or resistance) at the element is indicative?

The OP seems to have a neutral wiring problem.
Having voltage on BOTH sides of the element DOES tell you if the element is good or bad... in this case.

Meaning... if they check voltage on the hot/black side of the element and have 110v... then move the probe to the neutral/white side of the element and have 110v... that would mean the element is OK (continuity because if the element is burned out you wouldn't see 110v on the white side) and there is a problem with the neutral wiring back to the source.

You'll likely only see this voltage if there is an open in the neutral after the element. Under normal circumstances, if the element is good and the wiring is good, you wouldn't see 110v on the neutral side but would not verify the element.

Yes there is a big difference between checking voltage and resistance.

I believe OP is chasing a voltage current path problem on the neutral side. This test would verify current all the way through the load, verifying there is a neutral problem.

EDIT: and possibly where your confusion exists... this is holding one end of the meter probe to a known good /neutral/ground and the red lead to the test points. Basic electrical.

If the two meter probes are placed at the element, it would verify a good/complete circuit as you wouldn't read 110v across the two terminals of the element unless both sides of the electrical path were intact but wold NOT verify the element in this case..

**Bama Rambler** · 10-04-2016, 10:56 AM

I took 5picker's comment "If you have 110v in the white wire terminal at the element, you can rule out the element" to mean touching the minus lead of the meter to ground and then the positive lead to each side of the element. In that situation you should read ~120 volts on both sides if the element is good, but the neutral is open. In that scenario, if the element is bad you'll read 120 volts on one side and zero volts on the other.

5picker · 10-04-2016, 11:01 AM

Quote:

Originally Posted by Bama Rambler

I took 5picker's comment "If you have 110v in the white wire terminal at the element, you can rule out the element" to mean touching the minus lead of the meter to ground and then the positive lead to each side of the element. In that situation you should read ~120 volts on both sides if the element is good, but the neutral is open. In that scenario, if the element is bad you'll read 120 volts on one side and zero volts on the other.

Roger that.

In2b8r · 10-04-2016, 12:01 PM

I truly appreciate everyone's input on this... I double checked and I have 110 volts showing on both the black and white wires to the heating element (with the switch in the on position) The heating element has 9.8 ohms of resistance which I believe is good (?)(120v, 1440watt 2.0 amp element) so it certainly should be heating... but it is not... everything about the tank is cold, I even carefully opened the pressure relief and that discharge is cold as well... sigh

5picker · 10-04-2016, 12:14 PM

Quote:

Originally Posted by In2b8r

I truly appreciate everyone's input on this... I double checked and I have 110 volts showing on both the black and white wires to the heating element (with the switch in the on position) The heating element has 9.8 ohms of resistance which I believe is good (?)(120v, 1440watt 2.0 amp element) so it certainly should be heating... but it is not... everything about the tank is cold, I even carefully opened the pressure relief and that discharge is cold as well... sigh

OK... well now you are going to have to do some other tests.

Did you check for proper power where the water heater plugs in?
You need to do that first.
Plug in a lamp or something or stick your meter probes into each of the flat blade slots.
Do you have 110v?

Also check the neutral wiring path back to where the water heater plugs in to a receptacle or is hard wired.

Pull the plug at the receptacle... set your meter to read ohms... remove the white wire at the element... touch one probe to the white wire and the other probe to the wider of the two blades on the pigtail to the water heater. You should read continuity. If you don't, start tracing wires.

If your water heater is hard wired... same process, just eliminate the pigtail/outlet from the equation.

In2b8r · 10-04-2016, 01:44 PM

well it is hard wired and I can't get to the connection from the back I will have to pull the water heater out from the outside of the RV. Just for grins and giggles I checked all surrounding outlets in the event that the feed ties into one of them and they are all good... I see a hard wire connection box on the top front of the heater - but can't reach it from inside, there is also what looks to be a three or four wire coupling connection on a piece of romex which runs to the box on top of the heater and then the connector then another piece of romex which runs up behind the refrigerator... they wouldn't tie the frig and the heater together... would they? nah... that would be crazy right!?

5picker · 10-04-2016, 02:51 PM

Before you pull the WH... unhook main power, (or throw breaker for WH) then UNHOOK the wires from the element. Plug in main power (or reset breaker) and take your meter and check for voltage. (make sure WH switch is on, tank full of water and cold)
Red probe to black wire, black probe to white.
Do you have 110v? If you do, all your wiring and controls are good.

You won't read 110v at that place if any of the hot side voltage line (wires/switch/thermostat/hi limit) is open nor will you read voltage there if the neutral wiring back to the breaker box is open.

If you have 110v... I'm going to say you have several bad elements.

**wmtire** · 10-05-2016, 08:38 AM

Quote:

Originally Posted by Bama Rambler

I took 5picker's comment "If you have 110v in the white wire terminal at the element, you can rule out the element" to mean touching the minus lead of the meter to ground and then the positive lead to each side of the element. In that situation you should read ~120 volts on both sides if the element is good, but the neutral is open. In that scenario, if the element is bad you'll read 120 volts on one side and zero volts on the other.

Ok Guys, I'm still having a problem with this. Maybe we can get it figured out together. My understanding of measuring voltage is the difference in "potential" between two points.

So when you measure voltage, say on the black hot line...you have to use a difference from either the negative or ground (which are actually tied together back at the power source feeding the RV).

When you measure voltage just using the two points on the hot line, you get a zero volts reading (since you didn't use the negative or a ground with zero volts as a difference)

Now, if I am understanding correctly what you are saying, is that with all switches on, there is going to be 120 volts pushing thru the heating element and "thru the neutral wire"........so you are going to be able to check for 120 volts on the neutral side of the heating element.

For you to be able to read 120 volts ONLY on the 'Neutral" wire, what are you going to use as a difference in potential? If you say a ground, then doesn't that mean that there is 120 volts on the neutral wire but zero on the ground.

If there is 120 volts on the Neutral wire, then how are you able to measure voltage at the element using the hot and neutral sides...since the premise is dictating that the hot 120 volts black wire and the white neutral wire are one and the same now being that the voltage is going thru the element to the neutral side. It would be akin to trying to measure voltage from two points on the same wire again...which you cannot do.

donniedu · 10-05-2016, 09:00 AM

Lets make this really simple. Turn off the 120VAC. Open the element cover and remove one of the wires. Measure resistence across the element. Open means the element is burned out. A resistence measurement means element is good. Reconnect everything. If you have voltage reading at every point then all is good. Have you checked the positions of the winterizing valves to be sure one is not closed?

bubbles · 10-05-2016, 09:41 AM

Quote:

Originally Posted by In2b8r

well it is hard wired and I can't get to the connection from the back I will have to pull the water heater out from the outside of the RV. Just for grins and giggles I checked all surrounding outlets in the event that the feed ties into one of them and they are all good... I see a hard wire connection box on the top front of the heater - but can't reach it from inside, there is also what looks to be a three or four wire coupling connection on a piece of romex which runs to the box on top of the heater and then the connector then another piece of romex which runs up behind the refrigerator... they wouldn't tie the frig and the heater together... would they? nah... that would be crazy right!?

If you want to check the neutral wire interconnect you can check for continuity at any (nearest) AC wall socket in your unit to the white wire.

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