Dometic Ice Maker Water Line Update

[wil01]

The operation of the Dometic refrigerator ice maker heater for the supply line from the input solenoid valve has been little understood by many, including me.I have queried Dometic several times and have received seven different documents from Dometic in an effort to find out everything about the heater for the ice maker supply line.None of these had a straight forward answer to this question.I have received different answers from real people at Dometic about this issue.I finally got to speak directly to the “Go To” person who answers questions for the person you talk when you call, and that person doesn’t know the answer.I’ll try to provide some useful information about this issue.My research was about a NDR 1292, but I believe most Dometic ice makers work the same way.

First, here is a quote from a Dometic document:

D. WINTER OPERATION
1. Your refrigerator is equipped with a heater tape wrapped around the water solenoid valve and outlet water tube. During cold weather operation below 32 degrees F (0 degrees C) the automatic temperature switch will turn the heater tape on automatically. If the recreational vehicle is in storage and the DC power is turned "OFF" there will be no 12 V DC present to operate the heat tape; therefore, it will be necessary to drain the ice maker. If temperatures are expected to reach or exceed 0 degrees F (-18 degrees C) the ice maker must be drained.

Never mind the error in the last sentence, that statement is incorrect about late model units.There is no heat tape on the solenoid valve.

After a lot of searching, I believe the following:

The heating element on the ice maker water line is powered by 12 volts.

The heater draws 25 watts.

The heater is powered from the main refrigerator circuit board.

The heater operates when the temperature is below 32 degrees F, and there is 12 volt power supplied to the main circuit board.It doesn’t matter if the refrigerator is on or off or if the line has liquid in it or not.

That all leads to some conclusions and opinions:

1. Since the heater is operated by 12 V, it isn’t necessary to make any special steps to keep the heater operating while underway.

2. The heater output is 85.25 BTU.A BTU is defined as the amount of heat to raise one pound of water one degree F.A kitchen match produces about one BTU.Note that Dometic believes that the heater produces enough heat to be safe down to 0 degree F.

3. It is important to note that the specific heat of water is 1.0, and the specific heat of air is about 0.24.That means that the same volume of air as water will be heated about four times higher than water with the same BTU input.

4. Dometic believes that the heater will keep the water in the line from freezing with a temperature difference between the water in the line and air outside of 32 – 0 = 32 degrees F.If that is true, that heater will heat the air in the line when it is drained and only has air in it about 32 * 4 = 128 degrees F.

5. There are many reports of failure of that water line.The info above suggests that allowing the heater to operate when the line doesn’t have liquid may be the source of those water line failures.Heating that line to 128 F isn’t a good thing.

6. The only way to keep the heater from operating is to remove the 12V supply from the main circuit board.That is significant while the RV is in storage and/or while traveling in sub-freezing temperatures.

7. I think the most important thing to take from this is to be sure that the refrigerator main circuit board has no 12 V supply voltage when there is no liquid in that line while in sub-freezing temperatures.The most obvious ways are to disconnect the coach batteries while in storage or pull the refrigerator 12 V fuse from panel while underway.

This search has helped me, and I hope it helps you.
Good Luck!
Wil

[Playtime III]

I have the Dometic NDA 1402

From the Outside I: Shut off the refer water supply line, disconnect it from the solenoid. Turn on the Prevent-A-Freeze and water pump (pumps pink vice fresh water). Open the refer supply line until it flows pink. OBTW aim the line at something as the water/pink can shoot 15'. Turn off the shut off, reconnect to the solenoid and turn back on.

From the Inside I: remove the cover on the icemaker and use a flatblade screwdriver to turn the timing mechanism to cycle the icemaker until I get pink, topside. (Following Dometic's instructions).

The heat tape can heat the pink stuff in the solenoid to icemaker line and solve your concern of heating the empty line and causing premature failure.

NOTE: My Dometic 1402 only has ice in the door so I only have one solenoid (the 1402 comes in two versions, water and ice or just ice in the door).

[wil01]

There is a much easier way to get the pink stuff into the supply line and ice maker.


With the system under pressure with pink stuff in it, just connect a pigtail to the solenoid electrical connection and plug the pigtail to 120V. The valve will open and fill the line with the pink stuff as well as putting the pink stuff into the ice maker.


The valve doesn't need to be open long to get the pink stuff into the entire system. The valve should never be powered in this way for more than 20 seconds.


You miss the point of the original post. It had to do with the operation of the heater while underway and in storage, and the problem with an empty water supply line.


Good Luck!
Wil

[DJJ]

Wil,

Are you sure the solenoid is 110v not 12v? Not that I doubt you but I could not tell from the schematic that came with the unit as it looked like the power came from the circuit board. So not being 100%, I just let the ice maker cycle on its own several times to get the pink stuff through.

Jeff


Jeff

[wil01]

It is really hard to get a clear picture of this from Dometic , but I'm sure that the solenoid in a NDR 1292 and NDR 1062 are 120 V.


I've actually seen it work manually. When the water line to the icemaker from the solenoid broke, Dometic advised the technician to make up a 120 V pigtail by attaching female crimp spade fittings to an extension cord and then plugging the extension cord into the 120 V receptacle. That did, in fact, open the solenoid and verify the broken supply line.


Using this method is the easiest way to get antifreeze in the solenoid, the supply line and the ice maker. Doing it this way you don't need to disconnect and reconnect any fittings at all.


Make the pigtail by cutting the female end plug off of an extension cord. Observe the size of the connectors on the solenoid and crimp the same size female connectors onto the extension. You'll only have to do this once. The pigtail can be stored and used when needed.


Just pull the female electrical connectors from the solenoid. Connect your two female connectors from the pigtail you constructed to the solenoid. Plug the pigtail into the available hot 120 V receptacle. It doesn't matter which connector goes to which wire. It will work just fine any way hey are connected.


The only precaution is don't keep the solenoid powered in this way for mare than 20 seconds in any 5 minute time frame.


Good Luck!
Wil

[Solask]

You don't need to draw pink into the ice maker unit. If you double check your Dometic instructions, you will see that you are instructed to remove both input and output lines off the solenoid before activating the solenoid. The idea is to winterize the solenoid, not the ice maker in the freezer...

[wil01]

I don't think you understand this is NEW information I am trying to share. There is a potential problem with an air filled supply line to the ice maker.


The heater will come on at or below 32 degrees F if there is 12 V power to the main circuit board. If that line is filled with air, it can over heat and cause the input line to fail.


As far as I know, this is new information, and it is from Dometic. And the line from the solenoid to the ice maker does need to be protected. That means it needs to have liquid (water or antifreeze) in it in sub-freezing temperatures. Without that liquid, that line is subject to being damaged.


I thought that was clear, and I thought I could write, bur I'm beginning to think that any effort to share info with RVers is a aste of time.


Good Luck!
Wil

[Solask]

Originally Posted by wil01

I don't think you understand this is NEW information I am trying to share. There is a potential problem with an air filled supply line to the ice maker.


The heater will come on at or below 32 degrees F if there is 12 V power to the main circuit board. If that line is filled with air, it can over heat and cause the input line to fail.


As far as I know, this is new information, and it is from Dometic. And the line from the solenoid to the ice maker does need to be protected. That means it needs to have liquid (water or antifreeze) in it in sub-freezing temperatures. Without that liquid, that line is subject to being damaged.


I thought that was clear, and I thought I could write, bur I'm beginning to think that any effort to share info with RVers is a aste of time.


Good Luck!
Wil

You were very clear. Don't get so frustrated. Perhaps there will be less interest in the topic than you anticipated. But please keep contributing.
My comment was to the poster that was filling his ice maker with Pink. I probably shouldn't have posted this because it has nothing to do with your original point. It's called thread hijacking, and for that I apologize.

[wil01]

But the real problem is that you don't appreciate or believe that an air filled supply water line to the ice maker may lead to that line failing if 12 V is supplied to the main circuit board in sub freezing temperatures.


That is new information, and your advice would have the poster doing what is believed to cause the problem. Most of us have done that way for a long time and many of us have suffered the broken supply line problem. I do try to learn new things and not get caught in the "as usual" trap. Do it anyway you desire.


Good Luck!
Wil

[Solask]

I failed to mention that I don't have 12 volts supplied to the MH when stored. I shut it off. So, no exposure of the blanket heating up an empty solenoid. Also, since my solenoid is removed so easily, I simply take it out.

[DJJ]

Originally Posted by Rkh

You were very clear. Don't get so frustrated. Perhaps there will be less interest in the topic than you anticipated. But please keep contributing.
My comment was to the poster that was filling his ice maker with Pink. I probably shouldn't have posted this because it has nothing to do with your original point. It's called thread hijacking, and for that I apologize.

You are right that the instructions in the owners book tell you to disconnect the water lines and drain them and to take a screw driver to cycle the ice maker to empty it. I was in a bind as I was dropping the RV off at the factory for a month and it was 18 degrees the day we left it. I found the water supply line valve to be broken as it would not shut the water to the ice maker off. Never having had to winterize the RV before (live in south FLORIDA) just needed to get it done so I could get on the road back to warm weather. Newmar has full hook up sites so I just winterize night before I left the factory.

Wil, great info. I was assuming (now I know wrongly) that the heat tape around the water valve was turned on when you turn the switch for operating the refrigerator in colder climates. Also, won't turning off the refrigerator prevent 12v going to the heat tape?



Jeff

[wil01]

The heater operates when there is 12 V to the main circuit board and the temperature is 32 degrees or less. Turning the refrigerator off at the switch will not remove the 12 volts from the main circuit board, so the heater will continue to be operative.


The only way to prevent the heater from operating is to remove the 12 V supply to the main circuit board. You can do that by disconnecting the coach batteries or removing the refrigerator 12 V supply fuse to the refrigerator. That fuse is most likely in a 12 Volt panel.


Good Luck!
Wil

[96 Wideglide]

Wil, have you felt the solenoid in sub freezing weather, with the unit powered off, to confirm this to be true?
I would check mine, but its 38* right now.

[wil01]

96 Widwglide,
I’m glad you raised that question. As I have said before, getting the correct information from Dometic is very difficult. What I have said before about when and how the supply line heater works came directly from the “Go To” girl at Dometic. Now I have received the installation manual for the ice maker for the NDR 1292, NDR 1062 and others. Here is a quote from that document:

The ice maker heater kit will be functional when the
refrigerator and automatic temperature switch are in
the ON position. The automatic temperature switch
is turned on when the cavity temperature falls below
32° F (0° C).

Now, that does thicken the soup. Who are we to believe – the “Go to Girl” at Dometic or the installation manual for the ice maker? I think the only real solution is to make the test you suggest. I live in South Carolina so we don’t get many less than 32 degree nights.

I hope you, or I, or someone else in sub-freezing temperatures will make the test by turning the refrigerator off and testing either the voltage at the heater or, as you suggest, feel the heater to see if it does or doesn’t operate with the refrigerator turned off.

This new info doesn’t alter the fact that allowing the heater to run with only air in the line invites trouble. Getting the correct answer to this question will just give us better information so we can operate our refrigerators without trouble.

Thanks for bringing this up.

Good Luck!
Wil