Sanyo fridge repair? Manual?

[HikeSticks]

In an earlier post I asked about buying a replacement fridge. A parts vendor asked "What's wrong with the one you have?" Darn good question.
When I bought my '72 Trillium 13' last summer the previous owners advised me the fridge didn't work pre purchase. The trim around the door is non-stock so it had been a replacement itself. It is a Sanyo SRA 02 3-way. There is a sticker on a back panel visible through the outside access door but the printing is so small my old eyes can't read it. I tried plugging in the AC and turning the dial but nothing happened. If anyone has one of the fridges, or can offer any guidance, it would be greatly appreciated. My earlier post was prompted by my assumption that given RV service shop labour rates and part costs it is probably just as economical to replace it. (unless I can get a manual and tinker with it myself.)
Thanks,
Barrie

[Bill K]

Barrie,
When you turned on the AC how long did you wait before deciding it wasn't working ?

Bill K

[HikeSticks]

Originally Posted by Bill K

Barrie,
When you turned on the AC how long did you wait before deciding it wasn't working ?

Bill K

Hi Bill,
I only waited a few seconds really. I didn't hear anything so I assumed it wasn't working. Should I hear it working and, if so, how long should I wait to hear it?
Thanks,
Barrie

[Rick G]

Originally Posted by Barrie Bochoff

Hi Bill,
I only waited a few seconds really. I didn't hear anything so I assumed it wasn't working. Should I hear it working and, if so, how long should I wait to hear it?
Thanks,
Barrie

With an absorption fridge, you won't hear anything (yet another advantage of this type if you wake up easily at night). It is also really slow to cool. To test it, you can turn your fridge on to the AC setting, set your thermostat to a fairly low temperature or all the way on, and wait at least 4 - 6 hours (sometimes longer) to be able to tell whether it is working. Put a thermometer or a glass of water in the fridge when you start, so you can tell later, because when you open the door you may not be able to tell just from putting your hand in the fridge with the door open.

You can also put your hand near the heater unit (accessible from the main vent on the outside of the trailer) after an hour or more, to see if it is getting warm. Of course, it may get very hot, so be careful. The heater unit should be covered by insulation and probably a metal housing of some kind, but often the housing still gets warm to the touch. The heater unit can be found immediately above the propane burner flame, which makes sense since the flame heats up the heater unit, and you likely can get to it from the same place that you light the burner.

Rick G

[HikeSticks]

Thanks Rick. I had no idea... I have a digital laser heat gun; point it and pull the trigger and it will tell you the temperature of whatever the laser dot is hitting. I use it to check wheel bearing temperatures but it will work great for this application also.
I'll give it another try. If it works on AC it might be worth salvaging and trying to get the propane working.
Cheers,
Barrie

[Rick G]

Originally Posted by Barrie Bochoff

Thanks Rick. I had no idea... I have a digital laser heat gun; point it and pull the trigger and it will tell you the temperature of whatever the laser dot is hitting. I use it to check wheel bearing temperatures but it will work great for this application also.
I give it another try. If it works on AC it might be worth salvaging and trying to get the propane working.
Cheers,
Barrie

A good thought, but won't you have to open the fridge to get the laser heat gun to focus on anything? It might be simpler just to use a dollar store thermometer and leave it inside the fridge. When you open the door you would have several seconds to read the temperature before the outside air started warming it up. In fact, I always leave a thermometer inside the fridge so I can monitor temperature as I camp. The outside conditions have an effect on how well the fridge works on a given day. I am going to install a remote digital thermometer this spring so that I can read the temperature without having to open the door, but have not done so yet.

By the way, are you certain about the model number of the fridge? I couldn't find anything on Google about it, which is unusual.

Good luck,
Rick G

[HikeSticks]

Oh... I thought some part of the visible from the outside access door would heat up. The heat gun is very accurate; split second accurate. I opened the door and took a reading from the back wall of the fridge. It is reading the same as the outside ambient temperature per a digital thermometer. If the fridge is working, after a while, the inside back wall of the fridge should be colder than ambient. I live in the boonies and no dollar store is handy so I'll use what I have for now. Thanks for your advice.
Cheers,
Barrie

[Bill K]

Rick answered for me. Thanks Rick.

Bill K

Originally Posted by Barrie Bochoff

Hi Bill,
I only waited a few seconds really. I didn't hear anything so I assumed it wasn't working. Should I hear it working and, if so, how long should I wait to hear it?
Thanks,
Barrie

[Donna D.]

Or get an inexpensive indoor outdoor thermometer. Like this one: http://www.fiberglassrv.com/forums/f...ter-44983.html

Don't have to open the door!

[Visionsbydarrah]

Has anyone tried one of those 12V coolers? In place of the small refrigerator.

Just a thought, but if you have tried let me know how well it worked or not?

[Greg H]

Originally Posted by Visionsbydarrah

Has anyone tried one of those 12V coolers? In place of the small refrigerator.

Just a thought, but if you have tried let me know how well it worked or not?

The big 40qt 12 volt coolers suck. I used them in the semi and they only cool so far below the ambient temp. If you are in Phoenix and it's 100 outside and 110 in the vehicle the lunch meat aint going to be too cold.

[Visionsbydarrah]

Originally Posted by Greg H

The big 40qt 12 volt coolers suck. I used them in the semi and they only cool so far below the ambient temp. If you are in Phoenix and it's 100 outside and 110 in the vehicle the lunch meat aint going to be too cold.

Thanks for the info Greg.
I've been playing with the idea of getting one. Maybe I'll rethink this idea.

[HikeSticks]

I picked up a thermometer and plugged in the fridge. Left it for 4 hours. No change. I guess the fridge is dead. It will probably better to pick up another fridge than to pay to diagnose and fix an (very) old one.
Thanks,
Barrie

[Bill K]

did you check for 120v going to the fridge ?

They say that changing the heater element is not hard, I have not done it.

Bill K

Originally Posted by Barrie Bochoff

I picked up a thermometer and plugged in the fridge. Left it for 4 hours. No change. I guess the fridge is dead. It will probably better to pick up another fridge than to pay to diagnose and fix an (very) old one.
Thanks,
Barrie

[HikeSticks]

Originally Posted by Bill K

did you check for 120v going to the fridge ?

They say that changing the heater element is not hard, I have not done it.

Bill K

Hi Bill,
It was the 120v that I tried. I never use 120 service myself. I usually stay in the boonies and when I stay in a campground I never get a serviced site. I thought if it worked on 120v there may be some hope og getting it to work on propane.
I may just take it out and make space for a cooler/ice box. I'll save a lot of weight.
Thanks,
Barrie

[Rick G]

Originally Posted by Barrie Bochoff

Hi Bill,
It was the 120v that I tried. I never use 120 service myself. I usually stay in the boonies and when I stay in a campground I never get a serviced site. I thought if it worked on 120v there may be some hope og getting it to work on propane.
I may just take it out and make space for a cooler/ice box. I'll save a lot of weight.
Thanks,
Barrie

It's too bad you are 4000 miles away, I would love to have a look at it before you dump the fridge. Oh well, you know your capabilities/desire to engage in troubleshooting better than anyone. Good luck with your next step.

Rick G

[HikeSticks]

Hi Rick,
I'm removing the fridge but I'm not throwing it away. If I find anyone who tinkers with these things it will be easier for me to drop it on they're work bench than trying to convince them to work on it in my trailer. I am willing to try anything myself to get it going but I don't have any sort of manual for it and no experience with fridges. I have tools and ambition and if I had guidance or suggestions I would take a stab at it.
Cheers,
Barrie

[Visionsbydarrah]

So what's a new frig cost these days?

[Rick G]

Originally Posted by Barrie Bochoff

Hi Rick,
I'm removing the fridge but I'm not throwing it away. If I find anyone who tinkers with these things it will be easier for me to drop it on they're work bench than trying to convince them to work on it in my trailer. I am willing to try anything myself to get it going but I don't have any sort of manual for it and no experience with fridges. I have tools and ambition and if I had guidance or suggestions I would take a stab at it.
Cheers,
Barrie

Hi Barrie,

If you are handy, you do not need a manual, although it can be helpful. Fridges are very simple in concept, and you can probably find out what is the problem yourself.

But before you start troubleshooting the electrical, run the fridge for several hours on propane at the coldest thermostat setting. If the fridge works at all, then you know the cooling tube is probably OK and it is probably worth while fixing the electrical.

The electrical and propane systems are completely separate up to the point where they heat up the heater. If neither works, there is a good chance that your cooling tubes are blocked or the coolant has leaked away. If so, the only possible remedy is to remove the fridge and turn it upside down for a couple of days, which might free a blockage, or take it to a pro for repair, which might cost as much as a new fridge.

There is an excellent resource at : http://www.rvmobile.com/tech/Trouble/Index.htm which has tons of information (possibly too much). I also went through a troubleshooting process on my old Escort fridge (also no manual or internet help) at this post here a couple of years ago: http://www.fiberglassrv.com/forums/f55/3way-fridge-not-working-on-12v-39358.html

I also did a summary of fridge troubleshooting after I removed the fridge from the Boler: http://www.fiberglassrv.com/forums/f54/trailer-fridge-now-working-properly-42642.html

Here is the basic principle: Your fridge is run by one cooling tube filled with chemicals that is heated by any one of three possible sources: propane, 110V, or 12V. If your cooling tube is bad, it will likely cost more to fix than it is worth. If the electric heater element is bad, you might be able to get a replacement, but not likely since yours is an odd brand (although email to Sanyo to see). You would not need an exact replacement, any heater element that would fit into the space would work. Anything else, you can fix or replace.

On my fridge, the thermostat seemed to be working but the electrical connection had shorted over the years, meaning that my fridge ran all the time and froze everything. I was able to replace it with a different model new thermostat that fit into the space and worked fine.

Although you do not have a manual, you should have a faceplate on the fridge itself that tells you the rated power to the electrical heater in watts, and maybe even has a circuit diagram. Assuming that you are handy but don’t have much background in electronics, here is my suggestion to find out what is the problem. I presume that you have a standard digital multimeter that can measure volts, resistance in ohms, and amps. They are available at Canadian Tire for about 10 bucks.

The heater element is a resistance heater, the same as a standard house stove burner, and works the same way. Current passes through and the resistance in the element makes it heat up.

Check to see whether you have a connection in your whole circuit through the heater element. This can be done without using any power or removing anything. If your fridge has an actual plug that plugs into a 110V receptacle (most do), unplug it. Also disconnect the battery positive wire, removing a fuse if you have one or disconnecting the positive battery terminal. Turn the fridge on to the 110V selector switch setting (as opposed to propane or 12V) and turn the thermostat all the way on to the coldest setting (although it should be on anyway since the fridge is warm). Measure the resistance across the hot and negative pins of the AC plug (not the ground pin). You will need the multimeter set on a low range, probably the 0 - 200 ohm range.

As an example, lets assume that your fridge is rated at 100 watts on electrical. This rating would be the same for either 110V or 12V. Your measurement of resistance should be Power = Voltage squared divided by Resistance. For the 110V setting, that would be about 121 ohms for a 100 watt heater. For the 12V setting that would be in the area of 1.5 ohms. These are approximate, since the actual voltage varies in real life.

So, if you get a resistance measurement in the right range for your rated power, you know the heater element is connected and working. By the way, if the whole-circuit measurement of the heater element is in the right range and your fridge is still not working, that points back to the cooling tube again as being the culprit.

If you get a 0 reading, then you have a short circuit somewhere. If you get a very high reading, then you have either a break in the circuit or a really dirty connection. Change the resistance range to higher settings to make sure it is really a break and not just a high resistance. If the short or the break are in the heater element, you would have to replace it, if a replacement can be found. If they are anywhere else, they can be fixed.


So, then I would go right to the heater element and measure the resistance across it the same way. This is because you want to know whether the heater element is toast or not. Your electrical heater element probably has 4 wires coming out of it, two for 110V and two for 12V. You may be able to trace the wires from the voltage selector switch to see which is which. Label the wires if they are not colour coded, or else write the identifying marks down on a piece of paper so that you can identify which wire is which.

In most electrical circuits, only the hot wire runs through the switch and thermostat. The negative (return) wire connects directly to the AC plug negative pin. So, to measure the resistance across the heater element, you only have to isolate the hot wire, and you can use the same connection on the negative pin that you did for the first measurement.

To measure across the heater element without disconnecting anything, turn the voltage selector switch to the 12V setting (disconnect the trailer battery from the fridge as you do not want power going to the fridge at all). This disconnects the 110V circuit from everything else. You can then find the 110V wire that goes to the heater from the selector switch, and measure it across the negative pin of the AC plug, which is the return wire. It does not matter whether you measure at the heater element or a wire that connects directly to it, electrically they are both the same.

If the heater element measures in the right range, but there was a 0 or very high reading in the previous test, then the intermediate wiring, switch or thermostat is the culprit. All can be replaced or repaired fairly easily, as they are components which are still used today and you do not need an exact replacement.

To find out which wire is connected to what, you can use the multimeter to measure resistance at the places you suspect are the same wire. The same wire will have 0 resistance, or very close to it, whereas if you are measuring two unconnected wires it will have infinite resistance. If you measure some value in between, then the wires are connected to each other through something else, either a component or a leak somewhere.

Complicated? Not really, once you get the hang of it. Let me know if you decide to undertake this, and what your results were, and we can take it from there.

Hope that helps,
Rick G

[HikeSticks]

Wow! Thanks Rick. You have provided a lot of information. It will be a lot easier for me to tinker with it when I'm warm and working in a warm shop. There is writing on the fridge but with my old eyes I'm having trouble reading it where it's located. I am going to take a stab at it; nothing to lose, right?
Thanks again very much. I enjoy learning and this is a piece of equipment I've never worked on.
Cheers,
Barrie