Exterior Diesel Heater Silencer Question

SkinnyBuddah

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Jul 12, 2015
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Morning All,

Yet another one for the brains trust. Got the diesel heater installed over the weekend and loving the speed at which it brings my tent on wheels *cough* sorry expanda up to a nice cosy temp.

As a seperate package the seller sent me two muffler type silencers... for testing purposes I simply plugged one into the end of the exhaust pipe and it made no noticable difference in the noise coming from the exhaust what so ever. Now i'd expect there to be the possibility of some of the air escaping before the muffler as I didn't clamp it on or anything like that was just a friction fit into the pipe.

So the question I have is, should the muffler be positioned at some kind of mid point before the end of the exhaust pipe? or shouldn't matter (Clearly I'm an Electronics Geek and not a mechanical genious).

Also, I've already got the intake silencer (Plastic filter) installed on the intake which to be honest doesn't seem to make much noise at all, so should I run two mufflers on the exhaust? Or go the extra effort and run the muffler on intake again at a midpoint with the silencer installed as well.

Hope that made sense to someone as the noise outside the van is consierable. I'm not expecting run silent covert type van heater, but I'd like to not annoy everyone around me running what sounds like a jet engine taking off all night.
 

Drover

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Certainly makes sense to me @SkinnyBuddah , I also didn't really notice any great change in the noise from either muffler when fitted or removed what I did eventually do was I extended the air intake with a 40mm PVC pipe capped one end and drilled a 25mm hole in it and shortened the original air intake pipe and fed it into the PVC pipe and modded the filter to fit on the other end of the pipe this made the intake much quieter by reducing the suction noise while the exhaust I added 1.5m of 45mm exhaust pipe with a reducer to 25mm on one end, reduced the original exhaust in length to allow it to bend away from the unit then fitted it to the larger exhaust pipe, again much quieter and with better flow for the exhaust to escape , I didn't fit the silencer as I didn't want any restriction to exhaust flow with it now being about 2m in length, once the unit is up and running its a lot quieter than a roof mounted AC all you hear is a sort of rumbling i suppose you could call it.
It is important to have a filter on the air intake to stop bugs and stuff, I worked out the intake pipe only being 25mm dia does do the vacuum cleaner bit and the suction is all the noise, increase the dia of that pipe and the noise from suction decreases.

Internally if your unit draws air via a pipe from a vent in a cupboard you may find it will be quieter if the pipe is removed and it draws air from inside the cupboard which inturn draws air thru the vent, no suction sound then from vent, not a good idea if it shares the space with other stuff that could get sucked in though.
 
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SkinnyBuddah

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Thanks @Drover. Thinking I might move the air intake to the awning side of the van as at the moment it doesn't appear I can hear any noise from the intake. Its just the damn exhaust. That said It seems to be noisest during that initial heat up. I guess whats worrying me (haven't taken the van out since fitting the heater) is that if say its 2am and i've left the heater on, how low the temp in the van will be allowed to drop before it kicks in again. If it maintains with a low fan so very little noise then i'm happy. But if its going to ramp up to full bore again I'm pretty sure i'll annoy people. That said, inside the van all I can hear is the noise from the fan.. lol

Actually the noise from the exhaust sounds about the same as that of the water heater on gas but about twice as loud.
 
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Drover

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I was told if its that cold you need the heater on, if some idiot is wandering around outside freezing their whatsit's off then its their problem.................makes sense so I don't worry anymore................yapping flamin dogs are far worse.
Yep they sound like a jets APU starting up then once all up to temp the noise drops back, mine is under a seat near the door so had to put an extension to exhaust so it dumps over on the RH side behind the wheel and the intake was just behind the step so I could hear it sort of a low howl as it sucked so the bigger pipe extended it towards the back of van and no noise now from it......door is behind the wheels so all the noise is down the back while bed is up the front and inside it's no noiser than a normal fan heater but while in Canberra the other month ours ran all night, actually it would run from about 1700 to 0800, tried the shut down at bed time only to fire it up again at 0200, so it stayed runnning at about 3/4 throttle, our is a manual switch thing not an auto job, nothing like winter in Canberra to test a heater............

Mine now sounds about the same as the HWS cooking away.
 

SkinnyBuddah

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Ended up just chucking it on the end of the exhaust - Haven't mounted it yet as it seems to make no difference really.. lol
Gave it a run tonight - And once it reaches temp it calms down enough that the muffler does make a difference and it becomes whisper quiet before the addition it would be quit but not so quiet as to be like a tyre with a slow air leak.

Overall for $250 and some time and patience, recon its one of the best investments yet. And I got to get my geek on and use the 3D printer to make a cap for the fuel tank that runs the fuel line through. If only I knew how to make a non spill breather line I wouldn't have to take the bloody thing off and swap with the orignal sealed one. Guess thats mk2 if i can be bothered.

Now working with another bloke to create a touch screen interface for the thing that gives bluetooth and wifi access to the heater. Annoys the crap out of me that the LCD doesn't dim after a few seconds.. So thats going out the window when I get a chance.. lol