Suburban Water Heater

[lappir]

I thought I had posted this before, but cannot find it. 

Over the years I've had issues with my water heater. First the switch placed in a kitchen cabinet went bad (I think) I replaced it and all was good for a while. Next the 12 volt switch went bad (again I think). Changed it out for a timer switch and all was good. I thought the heating element failed so I changed it, nope still not electric heated water. Survived on gas for a while. Asked a service person to come out to evaluate and he said "Here, take this switch and change it and see what happens." Hey it worked, and I was good for a while again. Recently it stopped working again (after a move) and I changed out the switch but it was a no go. Started looking around and found a wire burnt out behind the "Reset Buttons" at the top left. Vern said it's a safety device which I just changed out and it blew immediately when I reenergized the circuit.  I have a photo, but it won't load into this computer so I might have to fire up the other one and attach it later.  Sure was a nice spark and cute little pop when i blew. 

 

Rod

[Kirk W]

Have you taken any voltage of resistance readings with your meter? It is actually quite easy to check a switch with an ohm meter. Does yours look like the one in this picture?

[lappir]

Here are the parts. Thermostat I think is what the package said. One on the left was burnt out, replaced it and it immediately failed too. 

I've used my multi meter to check voltages, but not resistances. 

Rod

[Wrknrvr]

   I sent you a email. I just seen this post.

 

  I did explain how to check for a direct short somewhere. As probably a bad element.

   Will follow what you find.

 

[Wrknrvr]

   I am thinking about a different thought on this subject.

 

   On Suburban water heaters, that on and off switch that is shown in the picture above, can have a contact problem internally. And cause a water heater to not function. The switch can be stuck, as in it will not switch on and off.

   Also I have seen the terminal ends that connect to the switch go bad. They leave just enough wire to replace the end.

 

    So is it possible that the switch area problems could raise resistance, lower the voltage enough to raise the amperage going through that wire, to go up and cause a failure?

  That is a question?

[lappir]

Thanks Vern, 

The connectors to that switch do seem a bit discolored. As far as enough length to cut off the connectors and attach new ones, I'm not sure. May try it. 

Have sent a message to a RV repair place in Small Town Iowa. He helped me with the switch in the past so I think I will use him for the parts (if he calls me back). Otherwise I might just have to stop at another RV joint on the way. 

I'm sure it would be easier to order them on line and have them delivered, but then the few places that are left will just go out of business and we won't have anything except the dreaded "PRIME". 

Broke down and asked my daughter to order a part  for my dishwasher for me from them  and then I found one at a "Sears" in TX. Are there still Sears stores down there? Anyway figured having two wasn't a bad idea since I lost one so easily and quickly. It still hasn't appeared BTW. Nor have the thermostats. 

Unfortunately when I went to pick the envelopes up they both had "Prime" written all over them. False advertising anyone? 

When I get back from my trip I'm sure "Winter" will have arrived and I won't want to do anything on the North side of the house, where the Water Heater is. 

Wish me luck. 

 

Rod

 

[Kirk W]

6 hours ago, Wrknrvr said:

So is it possible that the switch area problems could raise resistance, lower the voltage enough to raise the amperage going through that wire, to go up and cause a failure?

If the resistance of the switch should increase that would cause part of the voltage be lost there and so lower the voltage seen by the heating element. Two resistances in series add and with higher total resistance the current flow will decrease. Ohm's law applies here so voltage divided by resistance will give you the amps in the circuit. If voltage drops or resistance increases, either one will cause current flow to decrease. 

22 hours ago, lappir said:

I've used my multi meter to check voltages, but not resista

It would help if you would tell us what model Suburban water heater you have as there are differences. Also, is your water heater a propane only model or does it also heat from 120V shore power? What voltages have you read and where did you read them? Here is a link to download a copy of the current Suburban service manual that I believe applies to your water heater. If I'm right the schematic you need is on page 10.

Edited December 2, 2023 by Kirk W

[lappir]

1 hour ago, Kirk W said:

If the resistance of the switch should increase that would cause part of the voltage be lost there and so lower the voltage seen by the heating element. Two resistances in series add and with higher total resistance the current flow will decrease. Ohm's law applies here so voltage divided by resistance will give you the amps in the circuit. If voltage drops or resistance increases, either one will cause current flow to decrease. 

It would help if you would tell us what model Suburban water heater you have as there are differences. Also, is your water heater a propane only model or does it also heat from 120V shore power? What voltages have you read and where did you read them? Here is a link to download a copy of the current Suburban service manual that I believe applies to your water heater. If I'm right the schematic you need is on page 10.

Thanks Kirk, 

 

It's a 10 gallon electric/propane. I will look at the diagrams when I get ready to work on it again. 

It does heat on 120 volt and that's the voltage I have tested for. Haven't tried any of the 12 volt, which it uses I'm pretty sure for the ignition of the flame. There was one other thing I just thought of writing this reply. I almost said it wouldn't ignite with the 120 volt breaker turned off, but I had dropped the fastener to the piece I replaced behind the propane valve housing and to retrieve it I had to loosen the housing. There was a "Ground" wire attached to one of the screws and when it didn't light I realized it. Maybe that's what caused the safety device on the tank to blow. The missing grounding wire. Dumb mistake. 

 

Rod

[Wrknrvr]

   I am thinking we should start a new discussion.

 

   Three lines left blank for blank words.

 

   So you say it operates fine on 110 volts alternating current.

 

   Yep new thread needs started.   This one needs buried.

 

    Ok, ok I have done such. Stuff.   

 

 

[Wrknrvr]

Let’s focus on this post, not the one I posted before

If I remember correctly, the black wires are for 110 ac current. I just looked at the service documents, black is for 110 vac electrical operation.

 

 The red is for 12vdc gas operations.   

•    I am wondering if it is heating on gas. But you thought it was heating on electric.

ok now I have black dots appearing.     I must have pushed something wrong. Told you I do stupid stuff also.

 Black dot is gone.

  You need to look at the service documents.

[Kirk W]

1 hour ago, lappir said:

It's a 10 gallon electric/propane.

That means that the model probably is SW10DE.  It has two sets of thermostat & ECO, one for 120V and the other for propane operation.  (see page 18 of the manual)

 

1 hour ago, lappir said:

It does heat on 120 volt and that's the voltage I have tested for. Haven't tried any of the 12 volt, which it uses I'm pretty sure for the ignition of the flame.

You are correct in that the 120V heating element is controlled separately, via it's own thermostat and ECO. If you look at the schematic on the left side of page 10 of the manual you will see that it is a very simple circuit, with a black wire bringing in power to the on/off switch, then black to the thermostat & ECO, black to the heating element, and then a white wire for neutral or the return side.

To the right of that schematic is the 12V/propane schematic and 12V supply is red wires with a yellow negative or return. Since there is no connection of any kind between the 120V heating and the 12V/propane side, either one should work just fine with the other turned off. The 120V circuit breaker would have no effect at all on the operation on propane so long as you have a good battery to supply 12V for the propane controls. That circuit board not only supplies the spark but it has a flame sensor to shut the propane supply valve that it also controls, if the flame should ever fail. As you can easily see from the two drawings on page 10, the two systems are completely independent of each other. 

Since you have had two 120V thermostats fail, I strongly suggest that before you do anything else you need to remove 120V power and then using your ohm meter, measure from either side of the heating element to ground (any metal part of the water heater) and also read across the heating element to see what resistance it has. The heating elements can short out or shore to ground (the metal tank) and either one could cause the problems that you have described. If you lift one lead from the heating element and measure through it, the resistance should be 10 ohms, give or take 1 or 2 ohms. From either terminal to the tank of the water heater should read very close to infinity ohms.