| Author | Message | ||
| Steve Zona (Highwayrunner)
Rating: N/A |
Hi guys, do any of you know if the over the road factory ac ductwork is always open fron the compartment where it starts in the evaporater bay, where the blowers are to the ducts? or is there a flapper or valve or any other type of obstruction to airflow. if i hook up a shop blower to the ductwork, should I not get air through all the floor duct openings? thanks as always. this group is truly great, Steve and Cindi | ||
| John Jewett (Jayjay)
Rating: N/A |
Well, it does on my GMC 4905, but I don't know about your, uh... whatch-a-mah-call-it. ...JJ | ||
| john w. roan (Chessie4905)
Rating: N/A |
I always wondered what MCI meant  | ||
| Jtng Rating: N/A |
It blows the air out of that evaporator bay and into the ducts (2) that vent at each side. The cold (or heated) air then is ducted via that stainless steel ductwork along the outside wall, next to the seats. To use the return vents (6, + center isle ramp) and ductwork as part of your forced air system, you'll have to force the air into the return air ductwork. After taking apart the S/S ducting and seeing the accumulation of crap..... and then after reworking the ramp... and seeing the mess in that nest of ducting.... Well... All the ductwork in your bus will look the same. All the years and years of passengers, and every ounce of crud they've discharged, will be someplace in that ductwork. EeeeeeuuuuuuuIeee. You really wanna' use it? It changed my mind! | ||
| ChuckMC9 (Chucks)
Rating: N/A |
Mine wasn't that bad at all, nothing like Gumpy's ratsnest, and it wasn't that hard to clean up. I would have seriously considered trying to make that work except couldn't figure out how to make it work with the windowsill and coverings. I bagged the idea. | ||
| Jim Ashworth (Jimnh)
Rating: N/A |
Steve-- short answer, yes it's open. The shop blower may not be powerful enough to make any significant air flow through the ductwork however. The standard blower is very powerful, moving 2500cfm of air in heating and 2750 cfm in air conditioning. This is with a 1-1/2hp motor. The bus volume is 1900 cubic feet so it can move a heck of a lot of air in a short amount of time, just to put it into perspective. Jim | ||
| Michael Lewis (Puffbus)
Rating: N/A |
We tried attaching a forced air propane furnace to the ducts on our MC9. It was not worth the trouble for the ducting issues and the space that it took in the bays. There is no restrictor or flapper in the ducts themselves. We also found the furnace noisy and decided to bag it. Recently, Reddot corporation had some 24v hot water type heaters on ebay. These are discontinued, as far as I could tell, but seem to be a good choice for getting heat in specific areas. If one used three or four of these, I think they would heat the bus well. I would much rather tie into the bus hot water and run 3/4" heater hose from the existing full length channel than run 4" ducts. I would also like to get rid of the existing drivers heater in favor of a smaller unit, allowing some additional storage in that area. We just removed the drivers evaporator and that opened up some great space. Abandoning the factory fresh air system would also open up a large area in the center front for storage. We are thinking of a hatch type arrangement, since we already have hardwood flooring there. My concerns around this are not moving enough air in the front and taking the large factory fan off the alternator circuit. The other aspect to using the existing ducts is that once the floor ducting is gone, the only place these would blow is in the front, living area, leaving the bedroom and bath. Hope all this makes sense... Michael | ||
| Steve Zona (Highwayrunner)
Rating: N/A |
Well I guess the real question is. would there be enough air flow "cfm" to use the existing ducts with a basement type ac heat pump.if for instance we used a coleman 27.500 btu heat pump, would the blower in that unit haave enough cfm output to actually get air all the way through to the ducts that are at the end of the run? Steve and Cindi | ||
| Jim Ashworth (Jimnh)
Rating: N/A |
Check "da book". It may be available on-line. Jim | ||
| Rob King Rating: N/A |
Hi Steve The coleman website is http://www.rvcomfort.com. You could look at the specs online to see if it would work for you. Rob | ||
| John Jewett (Jayjay)
Rating: N/A |
Steve and Sindi, the blower on the 27.5K unit is 650CFM. It's a squirrel cage unit that can be changed from horizontal to vertical discharge with little trouble. ...JJ | ||
| Jtng Rating: N/A |
There's nothing that can't be done. ... of course! But good old common sense should be screaming: Both air conditioning and heat lose it's effectiveness based on the method of delivery. Direct injection into the room, and the losses are the least. Add ductwork, and the losses rise. Add great lengths of un-insulated ductwork of a cubic foot capacity that exceeds the cubic foot effectiveness of the heater/air conditioner, and it becomes impractical to use the ductwork...... unless all you want to do is cool or heat the ductwork. That big, un-insulated ductwork that runs under the plywood floors (and through the un-insulated bay ceilings) of the MCI, were designed for the OE equipment that heated and cooled the bus. If you plan to use a system that is not designed with at least as much capacity as that OE system, you -will- be disappointed. | ||
| Tim Strommen (Tim_strommen)
Rating: N/A |
To add a variance to JTNG's post, one could use the OEM ducts, but you'd have to take very serious insulating measures to prevent the heat loss on the exterior surface. There are companies who make duct liner panels that could be placed in the original duct, at the expense of duct volume (air speed would increase though which would also reduce the exposure time to the exterior surface, thus reducing the heat loss more). It isn't such a bad thing if the heat loss is in a direction it was headed anyway (ie., if you lost heat into the duct just before the outlet vent into the same room), but what may happen is you could have some condensation issues which may lead to mold, etc. I'd recommend tearing out the OEM system and going with a pre-insulated duct (like the flexible 4-12" stuff they use in homes). You can mash that stuff into roughly the same space as the original duct work at the expense of air volume but also at the reduction of heat loss (remember though, for every doubling of air speed through a duct, the sound of the air multiplies by 5-7 times). Cheers! Tim |