How To Repair Rv Refrigerator Cooling Unit

Your RV Refrigerator Role seven-Replacing Dometic or Norcold Units

By Paul Unmack, PE-CSE, ME #116483, www.arprv.com

In my 2022 series of manufactures, I discussed how RV refrigerators work and how to better their reliability, efficiency and safety, by controlling the cooling unit boiler temperature with the patented ARP Control. This article volition embrace cooling unit replacement.

Why Cooling Units Fail
The cooling unit of measurement on your refrigerator is dependable as long as the boiler temperature is limited to a level where the water within it is not allowed to boil. The ARP Control (see ad on folio 69) will proceed this from happening; however, this device has only been available for a short menses of time when compared to the age of virtually RV refrigerators. Therefore, harm to the cooling unit may take occurred before installation of the ARP. The ARP volition prevent further damage, simply the cumulative damage cannot be reversed.

When failure occurs, the replacement of the cooling unit often is nigh economical, particularly if you are handy and tin can perform the task yourself. Even if you decide to hire a technician, information technology'due south best to understand the procedure.

Has My Cooling Unit Failed?
Failure of the cooling unit will result in the boiler overheating. If your refrigerator has an ARP Control, it volition turn off your fridge. Without the ARP, the cooling unit heats rather than cools your refrigerator.

Possible indications that the cooling unit has failed:
• The heat source is on and the refrigerator is non cooling.
Please see commodity Nov/Dec 2022, "Test Refrigerator Using Both Rut Modes."
• Unit emits a strong ammonia odor.
If either of the above is true, turn off the refrigerator and perform a visual inspection. The ammonia scent, or xanthous remainder, seen in the photo on the side by side page is a telltale sign that the cooling unit has failed.
• Cooling unit of measurement boiler temperature is higher than normal.
The only fashion to know if the boiler is overheating is to have the ARP Control or use some other type of temperature sensor connected to the proper place on the boiler tube.
• Cooling unit of measurement rut source is on, simply absorber coil is cool to the touch.
This indicates that the ammonia is not circulating in the system. Please run into article Oct/Sep 2022, "Cooling Bicycle and the Absorber Curl."
• A gurgling sound, when the heat source is on, indicates that there is a hole in the cooling unit of measurement. Gurgling is due to the water in the system boiling, because of low force per unit area in the organisation, reducing the temperature at which the water will boil.

CAUTION: If you lot are unsure how to make up one's mind if the cooling unit has failed, I strongly advise turning off your refrigerator and consulting a qualified RV technician.

Cooling Unit Replacement
Steps In one case you make up one's mind the cooling unit has failed, and you've decided to replace the cooling unit of measurement, the following steps demand to exist taken:

1. Use the make and model of your refrigerator to find a manufacturer of that cooling unit. This information is usually on a tag in the door cell of the refrigerator. Here are some questions to ask when ordering, so that y'all have everything needed to get the task done:
• Does the cooling unit come up with the necessary thermal-mastic?
• Is there a core charge, or practice you need to render the cooling unit to get a deposit back?
• Are there any special requirements for installation of the cooling unit for your make and model of refrigerator?

2. Other than typical handtools, yous may need:
• Caulking gun for the thermal-mastic
• High-quality aluminum HVAC tape (available at hardware stores)
• If the cooling unit does not come with depression-expansion spray-foam insulation and information technology is required for the chore, yous will need to buy insulation foam.

3. Once the cooling unit is ordered and you lot have the needed supplies, remove the refrigerator. I recommend making a table, or using blocks and some plywood, on which to slide it. This makes the job much easier.
• With refrigerator removed, next remove the cooling unit of measurement controls.
• Remove the old cooling unit.
• Install the new cooling unit of measurement.
• Test and reinstall the refrigerator.

Refrigerator Removal 1.
Remove mounting screws.
• On the front side of the refrigerator, the mounting screws can be seen by removing the decorative molding that hide the screw heads.
• The rear of the fridge can be accessed through the vent door on the side of the RV. At that place could be screws holding the unit of measurement in, at this location, and they can be seen at the lesser of the refrigerator. On Dometic refrigerators, there are frame rails that sometimes have screws belongings it to the RV. On Norcold units, there is a sheet-metal pan, and often screws pass through this pan into the RV.

ii. Disconnect electricity, gas and plumbing to fridge:
• Shut off/disconnect 120VAC (shore ability) and disconnect 12VDC at the battery bank, or remove the 12V fuse that supplies 12VDC to the refrigerator. Disconnect both ability lines to the refrigerator.
• If the unit has an ice maker, turn off the h2o and disconnect the water line. Remove the 120VAC to ice maker.
• Plow off LP gas at tank. Employ a stove-meridian burner to burn off residue LP gas. Disconnect the gas line at the back of the refrigerator and plug the piping so clay cannot arrive.

Tip: Use your digital camera to take photos of wire position, and place all wires and/or plumbing with masking tape labels. This makes reinstallation much easier by avoiding guess work.

Remove Fridge from Cabinetry
Once all connections and mounting screws have been removed, one person giving a difficult shove from the dorsum of the fridge while another pulls from the inside, volition start moving it out of its cabinetry. Move the refrigerator into the RV slowly, while checking to brand sure nothing is however attached to the unit.

Removing the Cooling Unit
With the refrigerator still upright, the screws that concur the cooling unit into the refrigerated cabinet need to be removed. The bluish ovals (in the photo above) show which screws concur the cooling unit evaporator to the freezer and refrigerated portions of the refrigerator. As these screws are removed, use a piece of cardboard and shove the screws into the cardboard to maintain the location that it came from in the fridge. Some refrigerators have unlike length screws in different locations; each spiral needs to go dorsum into the aforementioned location of the cooling unit if the threads and/or length of the screws differ.

Place padding on the floor of the RV and carefully place the refrigerator face-down. Remove the control board, which will have the following items plugged into it:
• Fridge temperature sensor (thermistor)
• Electric heating elements
• LP gas valve
• LP burner igniter
• Some controls have other accessories, such as fans. If yous tin become a service-manual wiring diagram, it will be helpful. Otherwise, take a lot of photos and marker all connections carefully.

Remove the burner associates and transfer information technology to the new cooling unit. The burner assembly will exist attached with screws. It is important that the screws be inserted back into the new cooling unit the same way they came out of the old i. On some Dometic cooling units, if a screw is put into the wrong hole, it tin cause impairment by puncturing the tubing. Also, be careful with the igniter electrode. The porcelain insulation cracks easily, and once it'southward cracked, the igniter may not function properly. Be sure to adapt the igniter electrode upon reinstallation of the burner assembly. (www.ARPrv.com/dometic-refrigerator-flame.php.)

Important: At the top of the flue tube on the sometime cooling unit of measurement, in that location is a canvas-metallic wind baffle. Remove it to admission the flue baffle. The flue baffle is a screw diffuser on a wire that drops into the flue tube. If this flue bamboozle is not installed onto the new cooling unit of measurement, information technology won't work properly on LP gas. Transfer the flue baffle and wind baffle to the new cooling unit of measurement.

The boiler housing and electric heaters demand to exist transferred to the new cooling unit if these parts are not included with the replacement cooling unit. This is the best time to install the ARP boiler temperature sensor according to instructions.

Removing the Cooling Unit
The cooling unit volition have screws securing information technology to the dorsum side of the refrigerator. The purple arrows on the image on the adjacent page, show the judge locations of the rear mounting screws for this particular cooling unit. These screws tin loosen and fall out of the evaporator, so we recommend using Blue Loctite Threadlocker when reinstalling these screws.

Once the rear mounting screws are removed, remove the tape that is around the evaporator cream pack. Commonly the cooling unit tin can be jiggled and lifted to remove at this point. Sometimes the cooling unit tin become stuck inside the evaporator cream pack pocket (see the Evaporator Foam Pack Pocket image on page 68). The manufacturers of cooling units recommend using a section of 2×4 as a lever past placing it into the absorber coils and lifting. Check with the manufacturer of your cooling unit of measurement to see how they recommend prying the cooling unit out of the evaporator foam pack pocket if it is stuck. Each cooling unit is slightly different, so the installer needs to practice discretion when prying on it to avoid causing it to rupture.

Training for Installation
Upward until now, not much skill was needed other than basic mechanical knowledge. Now nosotros share the truthful secrets that carve up the adept cooling unit install from the bad one.

Kickoff and foremost, cracking care needs to be taken to seal the evaporator cream pack into its pocket. Second, do not follow an educational activity given by some manufacturers! This instruction includes using thermal mastic around the sealing articulation between the evaporator foam pack and the pocket. Why would one want to put a thermal conductor where an insulator should be? Therefore, if yous have a cooling unit that has Thermo-Mastic in the sealing joint, take fourth dimension to scrape it all out. Likewise, remove all the Thermo-Mastic on the back side of the cooling fins. This part of the procedure is highly of import. We cannot emphasize plenty how important it is to utilize the Thermo-Mastic properly, in addition to sealing the evaporator pocket and so that condensation does not ruin your handiwork.

Saturation of Insulation and Sealing Tape
After the cooling unit has been removed, care needs to be taken to remove all the old tape and make clean the surface where the new tape will attach effectually the evaporator pocket joint. Be sure to employ high-quality aluminum HVAC tape, non the material duct tape that some manufacturers utilize. Too, at this indicate information technology is imperative to inspect the insulation effectually the evaporator pocket for moisture. If the evaporator pocket was not sealed properly, let'south say the tape was deteriorated, allowing moisture to condense on the evaporator, the water volition saturate the refrigerator chiffonier insulation. Advisedly check the bottom of the evaporator pocket insulation for signs of water saturation. Expect for stains where water ran downward the dorsum side of the fridge from the evaporator. Too, push button on the insulation to run into if water comes out or if the insulation feels damp. If there is water in the insulation, allow it to dry for a few days earlier installing the new cooling unit of measurement. This is the reason we recommend removing the refrigerator as before long as possible and letting it sit without the cooling unit in the cabinet. Oestrus from a calorie-free seedling inside the refrigerator cabinet space can help speed upwards the drying process.

Cooling Unit Installation Dry Run
Once the refrigerated chiffonier has been cleaned, we recommend a dry run installation of the cooling unit into the refrigerator.

Lay the cooling unit down into the cabinet to brand sure that the evaporator cream pack fits into the pocket properly. The foam pack should seat all the way into the pocket. If information technology doesn't, trim any foam from the evaporator foam pack that may be interfering with a proper fit. Another advantage to this dry run is that you and your helper have a take a chance to coordinate setting the cooling unit of measurement into the cabinet for optimum alignment.

The evaporator should be set into its pocket evenly. Things go messy and sticky in the next step, so let the dry run be where any potential problems get worked out. The refrigerator needs to be set upright speedily in the next step to insert the screws into the evaporator from the refrigerator side. The dry run sees to it that the next phase goes equally fast as possible.

Seal Evaporator on Refrigerator Side
When all the old thermal mastic has been cleaned out, the insulation in the fridge cabinet is dry and the surface around the evaporator pocket has been cleaned with something like 409 (my favorite), information technology is time to utilise the Thermo-Mastic. The refrigerator shown in these photos is a Norcold, and the cooling fins in the refrigerated compartment are fabricated piano accordion-manner. This method of manufacture allows moisture to enter through the slits in the cooling fins. Nosotros at ARP have found a way to seal the cooling fins and increment efficiency. Every bit seen in photo above, the cooling fins accept been sealed with a sparse layer of Thermo-Mastic, using a putty knife. No matter if y'all have a Dometic or Norcold fridge, the objective is to continue air out of the evaporator. Air can get to the evaporator either from the back side through the gap between the foam pack and the refrigerator, or from within the fridge itself. Air infiltration brings water vapor; water vapor condenses on the evaporator coils then drips down, destroying the insulation and rotting the evaporator tubing.

Awarding of Record and Thermo-Mastic to Evaporator
The new cooling unit needs to be prepared for installation by application of the sealing tape and Thermo-Mastic. On Dometic cooling units where the cooling unit has a frame fellow member blocking the installation of the evaporator sealing tape, information technology is a good idea to put the tape on before installation. Run record around the outer periphery of the evaporator foam pack, so that the tape is half way on the evaporator foam pack and halfway off the foam pack so that, when the foam pack in inserted into the fridge, the one-half of the record will stick to the refrigerator cabinet. Here's the fox: Remove the backing for the tape to stick it to the foam pack, and then put the backing back on the half of the tape that is going to adhere to the refrigerator cabinet. This prevents the tape from sticking to anything before it should. Once the evaporator has been put into place, pull the record backing off to make a perfect seal.

Seal Evaporator—Insert Cooling Unit
At present that the evaporator foam pack has tape, and the tubes have a thick layer of Thermo-Mastic on them, the final stride before inserting the cooling unit into the refrigerated chiffonier is to use low-expansion spray foam to seal the outside joint of the evaporator pocket. Before applying the spray foam, make sure you are ready to insert the cooling unit of measurement into the refrigerator.

Spray the foam effectually the outside edges of the pocket. Referencing photograph higher up: Note the blue arrows indicate to a bead of spray foam about one-inch thick effectually the circumference of the evaporator pocket on the sealing surface. Once the spray foam is in place, set the cooling unit of measurement carefully, and evenly, into the refrigerated chiffonier. Insert at least two of the cooling unit rear-mounting screws, and then, placing the evaporator foam pack inside information technology, press as hard as you tin, while the refrigerator is still on its confront.

Immediately, elevator the refrigerator to the upright position and start inserting the screws from the within of the refrigerator, into the evaporator.

Tip: Silicone sealant can exist used to seal nether the head of the screw to prevent water from wicking into the evaporator. Start with the center screws and work your way out to the outer screws with a screw blueprint of insertion and barely tightening them. The idea is to spike downward the evaporator from the center before the edges. Tighten the screws in nigh three passes. The starting time pass snugs up the screws, the second pass tightens a little tighter and squeezes the Thermo-Mastic. The 3rd pass fully tightens each screw.

Lay Refrigerator Dorsum Down and Finish Installation
At present that the evaporator screws are inserted from inside the refrigerator, lay the refrigerator dorsum down and finish taping the evaporator articulation and reinstalling all of the accessories onto the cooling unit. Three areas of care need to be taken; the first is that the flue bamboozle needs to be put dorsum in. The second is getting the LP gas igniter adjusted properly. Finally, before putting the refrigerator back into its cabinet, let's get the the fluids where they belong in the cooling unit of measurement tubing. This step is important because the weak solution cavity in the boiler gather can get drained with all the twisting and turning of the cooling unit during transit and installation. Merely roll the refrigerator onto the boiler side. This allows the fluid in the cooling unit belongings tank to run down into the boiler. When the refrigerator is tipped upright once again, the fluids will encounter the weak solution crenel. Repeat laying down the refrigerator so that the cooling unit boiler is closest to the ground and the property tank is to a higher place; repeat this step a number of times to send the fluids where they belong in the cooling unit of measurement.

Now you are set to reinstall the refrigerator and run it. If you have installed an ARP Control, we recommend running the new cooling unit for nearly a week before turning information technology on. This allows time for the fluids to fully mix in the cooling unit. The ARP is highly sensitive and will turn off the cooling unit unnecessarily during this break-in period if not turned off.

Fridge for Life—Conclusion
With a properly installed cooling unit, and an ARP Control protecting it from the kickoff of the refrigerator'south life, your cooling unit should last as long as your RV. As long as the boiler of your refrigerator is not overheated, and no mechanical or electrical parts fail inside the cooling unit of measurement, we tin can say with confidence your fridge could last as long as your RV, given that at that place are not any cooling unit of measurement manufacturing defects.

Our first refrigerator outlasted three RVs and had nearly 300,000 miles on it when I killed information technology past operating it off-level. We likewise take a Servel fridge that has run faithfully for 81 years without any cooling unit replacement.

Paul and Mao Unmack are mechanical engineers. Paul ran an automotive repair business in Blood-red Guild, Montana, for 20 years before receiving his engineering degree. He has proficient nuclear, fire suppression and industrial process command systems design. Mao designed pressure vessels for ammonia plants in Communist china for 12 years, so came to the U.South. to get a master's of welding engineering. She designed biodiesel plants and worked for a government-funded research and development system. Paul and Mao run the entire ARP command business organization while taking on engineering consulting gigs.

How To Repair Rv Refrigerator Cooling Unit,

Source: https://escapees.com/your-rv-refrigerator-part-7-replacing-dometic-or-norcold-units/

Posted by: craigdumbet.blogspot.com

Share this post