Highpointe Convection/Microwave Oven
Our 2009 Navion had a conventional microwave that worked just like you would expect. I had always thought it would be great to have the convection version and retro-fit. Now that we have a 2018 Navion...
Forum Discussion
I have found a permanent fix for this convection-microwave oven: remove the unit and use the space for a coffee maker or a display case for a collection of salt and pepper shakers. The second part of the fix is to always park the RV within walking distance of a Cracker Barrel and give up cooking altogether. I have come to this conclusion because I am unable to convince anyone that there is a problem.
I am convinced that I am on my own and will get no support either from the factory or the dealer on this matter. The darn thing does not work and I have nothing to lose, so I pulled out the whole thing out and took it completely apart. What I discovered is a possible design flaw that is the result of trying to take a conventional microwave and adding a grill and convection oven functions. In my opinion, you can not have those three functions in the same steel box without additional technology. Flying cars: they do neither well to be practical.
I will detail what I found so if you have one of these things, you can come to your own conclusions. The convection microwave is installed in an enclosed space in the RV. Above and below the unit are louvered facias. This is the only place any venting occurs. Removing the complete unit, I found that there are sheet metal shroud/ducting on the bottom, top and rear of the unit. This is a purpose built kit specific for installation in an enclosed area to facilitate venting. I removed all the attached kit parts and set the microwave in an open area for a test using a dish of water heated to boiling. The results were the same as in an enclosed area: the cavity of the microwave became dripping wet with condensation. Using the microwave in the home kitchen as a benchmark, there is an obvious problem.
Next step was to determine if there is a defect in the oven itself. For this, the outer cover needed to be removed. This description may describe features common to most all consumer microwave ovens. The interior is essentially a steel box. At the bottom is a glass tray that rotates using a synchronous motor for even cooking. On the right side is a covered window where the magnetron generates the microwaves. Nearby, is a window of perforations (round holes) where there is a light and in this case, translucent tape covers about 80% of this window preventing air flow. On the right side between the interior and exterior walls is located all the electronic components including a vent fan that draws fresh air in. On the top of the cavity is a heating element for the broiling function. At the rear of the cavity is a matrix of vent holes where the convection oven heat originates. There is an enclosed metal chamber attached to the rear of the cavity that contains a heating element and an air circulation fan. On the upper right side of the cavity is another series of vent holes and the assumption is that this is to vent excess moisture. From examining the microwave in the house, air is introduced from the right by the case fan and vented on the left. Not so in the microwave in the RV. There is a shallow steel box installed over the vent preventing any airflow. In fact the only place excess water vapor can go is through the unsealed holes on the left side where it on several occasions saturated the electronic control board and cause the oven to shut down. Removing the convection component from the rear of the oven revealed that in just a few months, significant amounts of condensation was trapped there and started to corrode the metal. The surface of the interior of the oven is also showing significant staining.
The modification was fairly simple. I am guessing that the steel box installed over the vent on the right side of the cavity was because of the heat generated by the convection oven or the grill. But, this compromises the function of the microwave by trapping moisture. I folded open the bottom of the box to allow air flow. Leaving it installed, it will serve as a baffle for heat generated during grilling and convection cooking.
I re-assembled all the parts and re-installed the unit in the RV. No screws left. I did remove about 3 1/2 feet of 12/2 wire that terminates on the electric outlet that serves the microwave. Still plenty of slack; but why so much extra wire crammed in the space behind the microwave? This is something I have found throughout the RV; way too much slack in the wire harness. Does the assembly process require that? Anyway, I ran some tests by boiling water in a serving dish. This generates more steam than usual cooking. Keep in mind that just two baked potatoes rendered the microwave inoperative for several hours. That is where this whole thing started. The results? There is no longer the huge buildup of condensation in the microwave. Some of course, but it seems to be about the same as the benchmark microwave in the house. I am assuming that the small amount of air flow from the fan is entering the cavity on the right and excess moisture is venting on the left. There is still a minor amount of condensation on the door, but the moisture that was intruding into the control panel has seemed to be stopped. Is this a fix? I will need a little more time to tell. I will keep the Cracker Barrel option open for the time being.
After spending more than six figures on an RV, why should I have to be doing this stuff on my own. Is there a minimum amount of money one has to spend before you can be guaranteed that it leaves the factory without design or build defects? This whole episode made me think back to something that has some parallel. Does anyone remember the Gemini space program? Two astronauts were already in orbit and a second space capsule was to be launched with the object to practice rendezvous and docking; a procedure necessary for subsequent Apollo missions to the Moon. While the first crew in orbit passing over Cape Kennedy, this is what they saw: The rocket motors of the Titan first stage igniting and then shutting down. Someone left a dust cover in the engine causing the failure to start. Fortunately, everything was recycled and refueled and the rocket motors were re-started without incident. The mission was a success. The rest is history. Failure can be introduced at every step of the process from inception to product on the shelf. Why could I not just cook two stupid potatoes? Maybe the answer is in the afore mentioned story about the space program or just look at the film of the original Tacoma Narrows Bridge (Galloping Gertie). Compared to this, my problem is, wait for it.... small potatoes.
I am convinced that I am on my own and will get no support either from the factory or the dealer on this matter. The darn thing does not work and I have nothing to lose, so I pulled out the whole thing out and took it completely apart. What I discovered is a possible design flaw that is the result of trying to take a conventional microwave and adding a grill and convection oven functions. In my opinion, you can not have those three functions in the same steel box without additional technology. Flying cars: they do neither well to be practical.
I will detail what I found so if you have one of these things, you can come to your own conclusions. The convection microwave is installed in an enclosed space in the RV. Above and below the unit are louvered facias. This is the only place any venting occurs. Removing the complete unit, I found that there are sheet metal shroud/ducting on the bottom, top and rear of the unit. This is a purpose built kit specific for installation in an enclosed area to facilitate venting. I removed all the attached kit parts and set the microwave in an open area for a test using a dish of water heated to boiling. The results were the same as in an enclosed area: the cavity of the microwave became dripping wet with condensation. Using the microwave in the home kitchen as a benchmark, there is an obvious problem.
Next step was to determine if there is a defect in the oven itself. For this, the outer cover needed to be removed. This description may describe features common to most all consumer microwave ovens. The interior is essentially a steel box. At the bottom is a glass tray that rotates using a synchronous motor for even cooking. On the right side is a covered window where the magnetron generates the microwaves. Nearby, is a window of perforations (round holes) where there is a light and in this case, translucent tape covers about 80% of this window preventing air flow. On the right side between the interior and exterior walls is located all the electronic components including a vent fan that draws fresh air in. On the top of the cavity is a heating element for the broiling function. At the rear of the cavity is a matrix of vent holes where the convection oven heat originates. There is an enclosed metal chamber attached to the rear of the cavity that contains a heating element and an air circulation fan. On the upper right side of the cavity is another series of vent holes and the assumption is that this is to vent excess moisture. From examining the microwave in the house, air is introduced from the right by the case fan and vented on the left. Not so in the microwave in the RV. There is a shallow steel box installed over the vent preventing any airflow. In fact the only place excess water vapor can go is through the unsealed holes on the left side where it on several occasions saturated the electronic control board and cause the oven to shut down. Removing the convection component from the rear of the oven revealed that in just a few months, significant amounts of condensation was trapped there and started to corrode the metal. The surface of the interior of the oven is also showing significant staining.
The modification was fairly simple. I am guessing that the steel box installed over the vent on the right side of the cavity was because of the heat generated by the convection oven or the grill. But, this compromises the function of the microwave by trapping moisture. I folded open the bottom of the box to allow air flow. Leaving it installed, it will serve as a baffle for heat generated during grilling and convection cooking.
I re-assembled all the parts and re-installed the unit in the RV. No screws left. I did remove about 3 1/2 feet of 12/2 wire that terminates on the electric outlet that serves the microwave. Still plenty of slack; but why so much extra wire crammed in the space behind the microwave? This is something I have found throughout the RV; way too much slack in the wire harness. Does the assembly process require that? Anyway, I ran some tests by boiling water in a serving dish. This generates more steam than usual cooking. Keep in mind that just two baked potatoes rendered the microwave inoperative for several hours. That is where this whole thing started. The results? There is no longer the huge buildup of condensation in the microwave. Some of course, but it seems to be about the same as the benchmark microwave in the house. I am assuming that the small amount of air flow from the fan is entering the cavity on the right and excess moisture is venting on the left. There is still a minor amount of condensation on the door, but the moisture that was intruding into the control panel has seemed to be stopped. Is this a fix? I will need a little more time to tell. I will keep the Cracker Barrel option open for the time being.
After spending more than six figures on an RV, why should I have to be doing this stuff on my own. Is there a minimum amount of money one has to spend before you can be guaranteed that it leaves the factory without design or build defects? This whole episode made me think back to something that has some parallel. Does anyone remember the Gemini space program? Two astronauts were already in orbit and a second space capsule was to be launched with the object to practice rendezvous and docking; a procedure necessary for subsequent Apollo missions to the Moon. While the first crew in orbit passing over Cape Kennedy, this is what they saw: The rocket motors of the Titan first stage igniting and then shutting down. Someone left a dust cover in the engine causing the failure to start. Fortunately, everything was recycled and refueled and the rocket motors were re-started without incident. The mission was a success. The rest is history. Failure can be introduced at every step of the process from inception to product on the shelf. Why could I not just cook two stupid potatoes? Maybe the answer is in the afore mentioned story about the space program or just look at the film of the original Tacoma Narrows Bridge (Galloping Gertie). Compared to this, my problem is, wait for it.... small potatoes.
