How to quite your espar heater

There is absolutely no back pressure on my home made muffler. It's the same size pipe as the rest of the exhaust, with many holes drilled in it. The holy part goes thru a larger pipe, which is capped and soldered around it's ends and the outside of the smaller pipe. I think I used the insulation that was stuffed inside the extra exhaust pipe insulation wrap. I can't remember who told me how to make it, but I believe they said it still made noise, but the tone was a little lower so not as loud.Colby
 
Mine is also a straight through 3/4 inch copper pipe with holes drilled in it. The fiberglass packing is just pink household insulation. In fact, mine came from peeling a little from my shop attic. It is stuffed between the inside tube and the outside tube before the modified copper cap (for 1.5 inch tube) is soldered on. Just make sure that your solders are good or you'll have the same issue as with the commercially available mufflers.

As to back pressure, the smooth walled copper pipe probably creates less back pressure than the corrugated SS flex tube that comes with the Espar.

Commercially available glass pack auto mufflers actually have a design that creates a tiny amount of back pressure in order to improve the silencing. The holes in the interior pipe are modified to face the incoming exhaust sort of like a cheese grater. Think of inserting an ice pick in each hole and pushing it back in the same direction of the exhaust. This creates a tiny "clam shell" shape on the inside of the tube that faces the oncoming exhaust. It "scoops" some of the exhaust pulses into the holes and reduces noise.

I tore apart some "cherry bomb" type of auto mufflers way back when and saw how they worked.

Mark
 
Ron on Meander":1i3qtjvx said:
Doing it again, and without the DU95 to add additional heat. I'd go with the bigger Wallas 30 for heating a 25 in the PNW.

Cheers
Ron
Click to expand...

Another plug for the Wallas furnace, don’t mean to hijack the thread.

I’ve had the Wallas 30 DT furnace now for 5 seasons, has performed admirably. On mid-range to high you can hear the fan, on low it’s whisper quiet; and anything above low will cook you out of a 25 unless it’s in the 30s. It’s mounted under the forward passenger seat with two vents, one blowing aft the other-directed starboard
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Pictures of install in my album.

Wallas has two new furnaces: 30GB and 22GB https://www.scanmarineusa.com/online-store

The 22GB appears to be a good fit for a 25. $2680.00 with install kit. $$$ for sure.

You generally get what you pay for.
 
No noise issues with our little Wallas 1300 heater. We never loved the cooktop/heater in our 25 but it was better than nothing.

We do love the little 1300 on our current boat and cast friendly remarks in it's general direction with some regularity. Especially after adding a switch to the birth so we could start it without getting out of bed.

We really having a warm/dry boat on the cold, wet morning and when using the boat over the winter, we have even run it for an hour or so during the night to take the chill away. Being able to run it completely independent of shore power is also a favorite feature.

If you install the bigger 10L tank, don't bother carrying extra fuel for any trip under a month. One tank lasts us a year averaging over 25 nights per year we have had the boat.

The smaller of those new units look like a better fit for a 25. They look like bigger siblings to our little 1300 but with thermostats.

Greg
 
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