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Marathon air leak ? toilet flush alternative ?
After being parked a while, noticed auxilary compressor running too long. Pressure guage in drivers bay showed no pressure in compressor tank. Filled it with Prevost air – decompressed in about 1 minute after turning off. Thought the culprit was Furnas compressor switch attached to Grainger tank- replaced that – same thing. When I pressurize it with Prevost air it sounds like something close to tank, but I cannot locate it. Tried soapy water, etc. Mostly have given up on finding it myself. I’m 700 miles from anyone I’d trust to work on it, so we’re going home without Marathon auxillary air – which brings me to the question – is there any way of getting the toilet to flush without air pressure? 2002 XLII single slide.
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30 Replies
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Mike
If you have a Microphor toilet it is air operated to flush. No way around it I know of.
If you open your yellow valve in the front run box to join Prevost aux air and Marathon aux air will your belt driven engine compressor keep up with the leak?
Have you checked your air lines on the aux tank? Maybe you have a whole in the bottom of the tank?
Later
bv
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With engine on and yellow valve open it holds only at about 40 psi. Need about 60 psi to flush toilet. Plus, I don’t think other campers would appreciate starting up the engine for every flush.
I’ve decided I’m not a fan of things being run with compressed air that can just as easily be done another way. I have a small class B with a toilet that works with a foot pedal. I’m also not looking forward to discovering whether or not I can get the drop door to close and latch so I can drive off. I can prop windows open. I can live without the air slide floor covering the entry steps. I can live without the oh geez silent door closing on the washroom. I can’t live with a toilet that won’t flusbh, or a drop door dragging on the ground.
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Most all of us heve been there with the Microphor, you need a Tecma but for right now if you don’t find the leak I believe your hose door will close at 40 psi.
Have you put your hand around the aux tank and felt any air?
It has to be a huge leak if the engine compressor can’t keep up.
If you can’t find the leak I just thought of a way to get your air up. It would involve buying a small air compressor with about a 5 or 6 gallon tank and hook it to your aux air connection in the front run bay and that would get you enough to flush the toilet. You need about 150 psi to 165 psi comp to make it work.
Later
bv
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I don’t think Bernie meant 150 – 165 lbs.
With a leak that big, surely you can hear it when the aux pump is running.
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150 psi
Don’t know why I had lbs on the brain
Later
bv
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If you are going to buy a compressor you can get a very small one with a tank and plumb it directly to the tubing exiting the toilet regulator. Set the new compressor regulator to 70 lbs and turn the toilet regulator all the way down so it won’t feed. It seems like time and money would be better spent locating the leak if you can though. Hopefully Jon or others will jump in. Good luck with your diesel toilet.
Jeff and Lindsay
91 Marathon XL -
Thats what the guts of a microphor looks like, it’s behind the wall if you want to try and hook an air line to that.
Good luck with that.
Later
bv
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I was referring to the regulator that is likely in the steering bay that feeds the toilet.
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On my ’01 Marathon, my Micrhophor toilet is “DC” operated, not air. I have model “LF-220, DC Operated.”
I know they had all kind of problems with the air operated Microphor Toilets, but the DC one’s don’t seem to have many issues, at least from folks posting on this forum, and talking with the folks who sell Micrhophor parts.
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I would not recommend pressurizing anything on the coach in excess of about 120 PSI.
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It would be a major undertaking to change to a Microphor electric. The electric is direct drop, you can actually see into the holding tank when flushed. The air Microphor is rear discharge, same as the Tecma.
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If you have a bus that can only generate 40 psi off the engine compressor with the Marathon aux joined to Prevost aux hooking a 150 psi comp to it will not hurt to flush a toilet A1.
Later
bv
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Did someone suggest hooking the toilet into the chassis air system temporarily? You’d want to hook into the toilet air line before the toilet air pressure regulator. Shouldn’t be hard to tee in somewhere. Surprised you can’t find that major a leak.
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Unfortunately, the Microphor Air toilet was used because, unlike the 12v Microphor, or regular RV toilets that are a direct drop into the tank, the compressed air actually propels the toilet hopper contents horizontally over the the waste tank. There are two decent or good alternatives to the air toilet. 1) an electric macerator toilet like Marathon uses currently. The macerating pump in the bottom of the toilet pumps the toilet contents horizontally over to the waste tank, or 2) a water jet toilet. It operates off of the venturi principle to pump the toilet contents horizontally to the tank.
A not so good alternative that is relatively new is the vacu-flush toilet like airplanes. Has an extra tank for a vacuum reservoir, and vacuum leaks are much more difficult to find/get all taken care of than is the case with a pressurized fluid system like water or air.
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Believe me, I can’t believe I can’t find it either. Part of the problem is I can’t keep the system pressurized. If I run the engine, it’s way too noisy to locate anything. If I just run the auxillary compressor, it won’t pressurize beyond zero; I hear air flow noise in/near the tank, but can’t localize it; which is why I replaced the pressure switch at first as I thought the piston/diaphragm must be the source. Brand new switch and no change. Also changed the safety valve on the pressure tank. No difference. Everything has soap residue on it from being sprayed repeatedly looking for a leak.
I could in theory plumb the toilet air either to Prevost Air or a small compressor, but I’m seriously understocked on various sizes of PP tubing and pneumatic connectors, elbows, splicers, Tee’s etc. As in nearly none. Mom and pop hardware shops in the mountains are useless, and I’m 200 miles from Denver, a city I avoid driving in/through no matter what anyway.
I’ve ordered every connector I could find online and a few hundred feet of 3/8″ and 1/4″ tubing. We’ll see when anything shows up. A shop with a compressed air source (and infinite connectors and tubing) could just start disconnecting things and pressurizing and see where the drop is. Annoying as all heck, this is. First time I’ve had a (significant) problem on the road that I couldn’t solve or work around.
1984 96" with 8V92TA
(remodeled Liberty Coach)
Greenwood, MO
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