GlennWest Posted May 19, 2019 Report Share Posted May 19, 2019 (edited) Got to looking at my Teton brochure.T Joist rafters every 16". Well my purposed Mini Split Cassette is 22.5" square. So I will have to cut thru a rafter. Any suggestions from the carpenters here. If it was steel I would know what to do. lol My thoughts are cutting a rough 2' square opening and box it in with 1X12 board. I will need to trim it down some but 1X10 will come up short. Roof is 6", unit is 10.5" tall. Do not have a unit in hand but instructions I have read it seems the unit protrudes down 1/2". So I need an 1X11" board. I can attach box to one rafter and cut thru next and attach rafter to box. Do you think 2X be better? Or you have better suggestion. Planning on screwing it all, no nails. Edited May 19, 2019 by GlennWest Quote 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
whj469 Posted May 19, 2019 Report Share Posted May 19, 2019 What is a mini split cassette? Quote Link to comment Share on other sites More sharing options...
GlennWest Posted May 19, 2019 Author Report Share Posted May 19, 2019 (edited) 1 hour ago, whj469 said: What is a mini split cassette? Goggle them. Instead of wall mount, ceiling mounthttps://www.highseer.com/collections/multi-zones/products/12-000btu-multi-zone-dc-inverter-multi-split-system-heat-pump-230v-22-seer-ceiling-cassette-type-indoor-section-model-cb012gmfilcfhd?variant=24482022916160 Edited May 19, 2019 by GlennWest Quote 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
Daveh Posted May 20, 2019 Report Share Posted May 20, 2019 Hmmmm I thought someone would know. Maybe try you tube or other info for regular home construction. I would think the technique is transferable. Quote Dave and Lana Hasper Link to comment Share on other sites More sharing options...
Lance A Lott Posted May 20, 2019 Report Share Posted May 20, 2019 Are your rafters arched? Could you get a plywood rafter screwed and glued to the side of the uncut rafter? 3/4 cdx plywood would probably be my Choice both screwed and glued to make your box. Your biggest problem is that the two adjoining Rafters will have to carry the load of the one you cut. So any extra support you can give them is good. Are the rafters them selves 6 inches or does it have a dropped sealing? Quote Link to comment Share on other sites More sharing options...
GlennWest Posted May 20, 2019 Author Report Share Posted May 20, 2019 No dropped ceiling. From looking at the brochure on my Teton, they are solid board cut at an arc, flat on bottom. I will be able to attach the box to both outside rafters of the box. Had not considered plywood. Thinking about it, is better choice. Lots of campers has 24" spread on rafters. Only way to double the rafter is to tear roof up so I can. Don't want to do that if I can accomplish this without it. I can put it in two pieces. Will have a 2' opening in center of roof. Quote 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
Ray,IN Posted May 21, 2019 Report Share Posted May 21, 2019 As Lance said, how are you going to re-distribute the load from the cut rafter? You've also got to calculate in, the weight of the people on the roof installing, and eventually working on, the mini-split. Remember, it's not only the actual weight, but the kinetic energy of that actual weight bouncing on the roof while traveling the wonderfully smooth highways. Cutting the hole and constructing the box is easy, compensating for the kinetic energy is not so simple. That might require the services of a structural engineer. Quote 2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG retired;Good Sam Life member,FMCA ." And so, my fellow Americans: ask not what your country can do for you--ask what you can do for your country. John F. Kennedy 20 Jan 1961 Link to comment Share on other sites More sharing options...
theeyres Posted May 21, 2019 Report Share Posted May 21, 2019 As others are saying, I don't see anyway of doing this short of tearing into the roof or ceiling to put cross joists from the joists on both sides of the one your cutting. There is no other way I know of to support the load. Quote 2007 Arctic Fox 32.5 rls for full-timing, now sold. 2014 Sunnybrook Sunset Creek 267rl for the local campgrounds now that we are off the road2007 Silverado 2500 diesel Loving Green Valley, AZ (just South of Tucson) Link to comment Share on other sites More sharing options...
GlennWest Posted May 21, 2019 Author Report Share Posted May 21, 2019 Well, the box will connect the cut rafter making it rigid again. Yes, it is weaker. The rafters on each side connect to box. So 3 rafters connected together with a box. The box needs to be built strong. Teton put some fairly strong rafters up there. Quote 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
GlennWest Posted May 21, 2019 Author Report Share Posted May 21, 2019 Stronger??? I think it will be weaker but not enough to hurt. But that box is going to be ridged. I think all will be fine. Just wanted others opinions. I haven't done a lot of wood work. Quote 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
GlennWest Posted May 21, 2019 Author Report Share Posted May 21, 2019 Ok. We on same page now. Agree. Quote 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
Ray,IN Posted May 22, 2019 Report Share Posted May 22, 2019 (edited) How do you plan to address the kinetic energy weight problem? That link has the equation necessary to calculate this factor, but the speed of vertical movement is an unknown. You will note kinetic energy increases by a factor of four for a specific vertical speed. This is required to insure you do not stop for the night to find the minisplit on the floor, along with some of the roof. An EWAG will not suffice. Edited May 22, 2019 by Ray,IN Quote 2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG retired;Good Sam Life member,FMCA ." And so, my fellow Americans: ask not what your country can do for you--ask what you can do for your country. John F. Kennedy 20 Jan 1961 Link to comment Share on other sites More sharing options...
GlennWest Posted May 22, 2019 Author Report Share Posted May 22, 2019 I not able to address the kinetics. Beyond my education. But I also don't believe the sinerio you described will play out either. That unit weighs roughly 10#. My ceiling fan weighs close to that. My existing mini split rides on a wall which is nothing strength wise. Horizontal studs. Had to put plywood on back just to have something to screw too. Actually look for it to bounce off but it stays put. That rafter won't be weak. Maybe not as strong. Got me curious though. Might study up on kinetics this weekend. Thanks everyone. Gave me some good pointers. Quote 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
hamrs_62 Posted May 22, 2019 Report Share Posted May 22, 2019 what about the power for the unit, it says 208- 230 single phase power, most RV's take only two 110 volt circuits at any power panel that is what you will get I believe, not sure what your generator puts out, but I thought usually there is never 208 to the RV, just asking a question Quote Mark & Annette Link to comment Share on other sites More sharing options...
GlennWest Posted May 22, 2019 Author Report Share Posted May 22, 2019 It runs on two 110v circuits. I have plenty of space in my box for the breaker. Quote 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
Lance A Lott Posted May 22, 2019 Report Share Posted May 22, 2019 Gleen please educate me all of the mine splits I have looked into only neaded a small hole for the pipes to go through and had a power unit on the outside and the cooling unit on the inside. What kind is yours? Quote Link to comment Share on other sites More sharing options...
GlennWest Posted May 22, 2019 Author Report Share Posted May 22, 2019 The wall mount unit is just like you said. Hole for the freon lines, signal wires, drain tube. That is what I have now. I would add another to bedroom if a had a place to put one. The wall unit blows air one direction. The casette unit blows air in 4 directons. It mounts in the ceiling.Also it has a pump for the drain. One outside unit will have 2 sets of ports for freon lines and signal wires. Quote 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
DesertMiner Posted May 22, 2019 Report Share Posted May 22, 2019 (edited) Here's a picture of a sample "cassette" style mounting of a mini-split.... Edited May 22, 2019 by DesertMiner Quote Link to comment Share on other sites More sharing options...
Lance A Lott Posted May 23, 2019 Report Share Posted May 23, 2019 Thank you, the picture helps to visualize the hole you will need as well. Quote Link to comment Share on other sites More sharing options...
GlennWest Posted May 23, 2019 Author Report Share Posted May 23, 2019 Just go to Highseer.com. Quote 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
hamrs_62 Posted May 23, 2019 Report Share Posted May 23, 2019 19 hours ago, GlennWest said: It runs on two 110v circuits. I have plenty of space in my box for the breaker. I realize that, but that, but you will have to add a box to capture the circuits off of a breaker to feed it, bacause there is no place to have 208 in my motorhome, yours might be different in your rv, anyway it sounds good, Quote Mark & Annette Link to comment Share on other sites More sharing options...
Randyretired Posted May 23, 2019 Report Share Posted May 23, 2019 (edited) 1 hour ago, hamrs_62 said: I realize that, but that, but you will have to add a box to capture the circuits off of a breaker to feed it, bacause there is no place to have 208 in my motorhome, yours might be different in your rv, anyway it sounds good, 50 amp RV service has two 120 volt leads. This is identical to most residential systems and there is nominally 240 volts supplied when both leads are used. The breaker box is setup so that a double breaker can capture and supply this 240 volts. Most RV's don't use the 240 volts but properly wired 50 amp service does provide it. 30 amp RV service only supplies 120 volts. In most cases the correct breaker is all that is needed for 50 amp service. Edited May 23, 2019 by Randyretired Quote Randy 2001 Volvo VNL 42 Cummins ISX Autoshift Link to comment Share on other sites More sharing options...
Ray,IN Posted May 23, 2019 Report Share Posted May 23, 2019 On 5/22/2019 at 5:19 AM, GlennWest said: I not able to address the kinetics. Beyond my education. But I also don't believe the sinerio you described will play out either. That unit weighs roughly 10#. My ceiling fan weighs close to that. My existing mini split rides on a wall which is nothing strength wise. Horizontal studs. Had to put plywood on back just to have something to screw too. Actually look for it to bounce off but it stays put. That rafter won't be weak. Maybe not as strong. Got me curious though. Might study up on kinetics this weekend. Thanks everyone. Gave me some good pointers. My bad Glenn, I thought I read in your initial post this thing weight 100#, I'm not dyslectic only old. Randy I think the 50A main breaker panel in older RV's have redesigned bus bars that prevent the application of a 240VAC breaker. Of course a new panel may be installed whenever desired. Perhaps one of the sparkys can supply correct information. Quote 2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG retired;Good Sam Life member,FMCA ." And so, my fellow Americans: ask not what your country can do for you--ask what you can do for your country. John F. Kennedy 20 Jan 1961 Link to comment Share on other sites More sharing options...
GlennWest Posted May 23, 2019 Author Report Share Posted May 23, 2019 Mine is a square D box. Two 120 loads. All I need is a breaker. Actually it's already in there but not wired. And I know, 30 amp, no ac. That won't be true later though. Solar up will take care of that. Quote 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
Randyretired Posted May 23, 2019 Report Share Posted May 23, 2019 Glenn I think you can cut a rafter and span the outside with a box as you described and it would work. Another thought is depending on how tall the unit is you may be able to build a box under the ceiling to house it. The Teton ceilings are pretty tall at least in the living area. Quote Randy 2001 Volvo VNL 42 Cummins ISX Autoshift Link to comment Share on other sites More sharing options...
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