MEP 803a back in business: Exhaust questions

[EFR]

Gentlemen:

A little over a year ago my new to me MEP 803a suffered a significant failure during a power outage.

MEP 803a failure

Greetings: I suffered a failure with my MEP 803a during storm Isiais. I bought the unit two years ago with 82 hrs. Changed all fluids when I bought it, replaced leaking fuel lines, and have been running generator under light loads every 3 months. I have the unit wired to the main panel via a...

www.steelsoldiers.com

I started taking it apart, but the repair was beyond my comfort level. I located a gentleman who was very knowledgeable with the 803a and brought it to him for repair. After several months and just shy of $3K later, she is running and back installed.

I put the generator in my wood shed and had the local wiring inspector help me wire it, properly and legally, to the house. That in itself was no small feat as I have solar, which created a whole other set of problems, but it is done now.

My question to the experts today is exhaust. I'd like to pipe the exhaust out of the shed for obvious reasons. I have run the unit with just a 90 degree elbow with the shed doors open which works fine, but usually when we lost power, it is during some type of rain or snow storm and I don't like the idea of leaving the doors open (mostly for fear of weather damage to the smartwood doors).

Two options I was considering is 1 1/4" to 2" NPT adapter at muffler, 8" flexible pipe (for vibration isolation) and solid 2" pipe to rafters, 90 degree elbow, out wall, sealed by selkirk high temp boot. The other option is similar, but using flexible exhaust. Flexible exhaust pipe seems like a half ass solution, but the advantage is it would be easier to slope down away from the bend to ensure any condensation runs outside, not back into the muffler.

Which do you think would be best? Any better option? How hot can I expect a 2" pipe 8'+ from the muffler?

FYI I spoke to both the fire chief and building inspector, and neither were helpful.

Thanks

 

[WWRD99]

I think I see a wood burning water heater in there now? I'd do the same exhaust set up it has...the double walled pipe going through the roof with a hood....how are you getting fresh air in this shed?

 

[EFR]

I think I see a wood burning water heater in there now? I'd do the same exhaust set up it has...the double walled pipe going through the roof with a hood....how are you getting fresh air in this shed?

There is 24' of soffit venting for the wood furnace which works fine. When I run the generator, all windows will be open to allow airflow. There is also a shutter exhaust fan on second floor.

I'm hoping not to go through roof for a couple of reasons;
1. I'd hate to cut a hole in a perfectly good roof
2. Exhaust piping to insulated stove pipe creates fitment issues-how to ensure a rigid, airtight seal between different materials?
3. I'd have to source some type of rain cap for the smaller stove pipe that would both be effective at keeping out rain, yet effective in allowing free flow exhaust

 

[Light in the Dark]

I would use a pellet stove wall passthrough adapter on whatever wall you want to exit. Run some 1.25" black iron pipe (same size as whats on the top of the muffler) out through it and seal as desired. Have that pipe hanging by threaded rod and brackets like you would a Modine heater, over to the genset. Just couple the two together with a flexible section of pipe. If you wanted to you could step up to a larger pipe if it made you feel better, but just make the exhaust end capped when not in use for rodents and bugs.

 

[Light in the Dark]

And if you have any angles, (2) 45s are preferable to a single 90.

 

[Mullaney]

There is 24' of soffit venting for the wood furnace which works fine. When I run the generator, all windows will be open to allow airflow. There is also a shutter exhaust fan on second floor.

I'm hoping not to go through roof for a couple of reasons;
1. I'd hate to cut a hole in a perfectly good roof
2. Exhaust piping to insulated stove pipe creates fitment issues-how to ensure a rigid, airtight seal between different materials?
3. I'd have to source some type of rain cap for the smaller stove pipe that would both be effective at keeping out rain, yet effective in allowing free flow exhaust

.
Very much like the other comments...

As close as you are to an outside wall, I would go straight out the wall behind the MEP. Use a section of double insulated stove pipe first, then insert the exhaust pipe into the double insulated stove pipe to protect the wall. Use lots of steel wool to pack the exhaust pipe into the stove pipe in the wall. I think you would be surprised how well it might fit

You could extend the exhaust pipe a little further out from the wall as well.

 

[WWRD99]

Well...having a second story to go through won't work...you'd want to keep the exhaust hot so it flows up without cooling and getting tons of condensation inside...going out the side should work with the pellet stove spacer in the wall and the pipe run through it...that's a great suggestion from LITD...this is my setup for my stove that you might be able to use on yours...there's adapters for the the exhaust pipe you could kneck up to a bigger size to fit a larger double walled pipe in...you could also use exhaust wrap on the pipe coming out from the genset to the new pipe to keep it hot so the flow is kept high and condensation low...an added plus would be not burning yourself if you accidentally touched it...you wouldn't need the outside rise since it'll all be inside the "shed"...that must be a big place! One note though, I'd try to fit a flexible pipe in it somewhere since the exhaust does move when running so having it not rigid would keep the muffler from fatigue cracking as well...a automotive one would do the trick nice and you can get them in a small diameter...I'd put it right after your first turn going towards the wall.

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