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Sound- absorption or reflection - Printable Version

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Sound- absorption or reflection - david brady - 02-22-2009 02:39


I pulled this out of the Powertech manual: (for what it's worth),



"Each engine is equipped with a high water temperature shutdown

switch, which will automatically shut down the set if the operating

temperature climbs too high. To prevent the generator set from

shutting down make sure the compartment openings are large enough

to allow adequate circulation of cooling air. The minimum free air

opening in the compartment door is 400 sq. in. or 2580 sq. cm.

Remember that louvers, screens and protective grills will restrict
airflow.

A relatively open mesh screen will restrict airflow as much as 45%.

The intake opening must be increased to compensate for

such restrictions."



David

'02 LXi, NC





Kurt Horvath wrote:


I would say that careful inspections are the order of the day to
keep

your coach in top form and you safe.



I'm not up to snuff on this post but in my case the new exhaust,

exhaust blankets on the new Stainless pipes (18ga.) and a soon to be

installed thermal and acoustic insulation in the engine compartment

she'll be cool, quite and efficient The blankets and the SS pipes are

rated at over 2000 degrees continuous duty. So the hottest parts are

insulated and the hottest gasses are directed out and away from the

motor. I did install 2 - 1650 cfm electric fans in the engine

compartment, to take care of any other residual heating problems.

I don't see how insulating any Bird compartment would be detrimental.

I can't imagine any engineer using the coach in any calculation as a

heat sink, to dissipate any heat from the engine or generator



Isn't that what radiators and exhausts are for.?



I'll redo the insulation in the genny compartment when I do the main

engine area.



Look at any Prevost conversion the generators are mostly in enclosed

compartments, Birds , at least the PT series are completely open

underneath. I would not worry about maximum insulation in the genny

box. When driving you get air flow, when parked the blower is sucking

air in from some where, some is air is flowing through the genny

box , along with the manifold, exhaust and valve cover blankets it's

already retaining/containing a lot of heat internally that can
only

be removed through the exhaust and radiator. If after insulating you

see higher temps. Install a lower temp. thermostat.



After my near miss at burning up my coach I'd like to ask the forum a

question.



Has anybody ever checked the condition of the Generator exhaust stack

that goes up through the body? And how would we go about checking it?

It has the potential to be a serious issue should it be leaking

exhaust fumes into the coach.



In my coach the Genny Stack is located next to the Fridge. How well

insulated is it? Maybe that's why my Fridge works great when parked

but doesn't when I'm driving. I almost always run the generator when

driving, and yes it's running while parked if not at a place it can

be plugged in to. So is it part of my Fridge cooling problem? Maybe,

any thoughts?



Kurt Horvath

95 PT 42

10AC



--- In "WanderlodgeForum%40yahoogroups.com",
"timvasqz" ..>

wrote:

>

> Not too far fetched. My cummins engine computer is cooled with

> diesel fuel. I am just curious where you were transfering heat to

> with your 'insulation heat dissipation remanufacture redesign'

>

> heat is transfered and lost to other objects. for one thing to

lose

> heat somthing else must take it. its a calorie calc. when you

> insulate to keep heat from the interior of the bus where does that


> heat now go?

>

> some times when an interior gets hot and calls for modification it


> is an overlooked sign that the heat producer has other issues

causing

> excessive heat. KurtH can atest. in a genset the genhead may be

> cooking or engine exhaust is screwed up.

>

> Greg ofTim&Greg

> 94ptca

>

>

>

> "WanderlodgeForum%40yahoogroups.com",
"Stephen Birtles"

> wrote:

> >

> > why thank you for the mindless dribble another useless
comment

> >

> > Stephen 77fc35

> >

> >

> > --- In "WanderlodgeForum%40yahoogroups.com",
"timvasqz"
> wrote:

> > >

> > > To disipate heat, is to transfer it. Steve maybe you can


disapate

> it

> > > thru a dupree valve back to the tank? Call it Hot$$$$ ?

> > >

> > > I understand that the vault gets up to +250 degrees(USA).
I

> guess

> > > that is a factor for Ernie to consider once he removed
the

> disipation

> > > path of the vault heat to the bus interior. where does
that

> heat

> > > now go.

> > >

> > > Insulation keeps environments from disapating heat. heat
is

> removed

> > > so the method to remove the heat in the compartment
would now

be

> the

> > > radiator system and the diesel engine is the heat sink,
but

the

> > > diesel engine caused most of the heat. If the origional
design

> was

> > > not intended to do that it would have to be beefed up

> > >

> > > If you insulate the exhaust the otherwise exposed metal
does

not

> > > radiate heat in the compartment. heat goes out the stack
with

the

> > > exhast air. But is the stack able to take all the extra
heat.

> > >

> > > If someone complains to me about the noise my genset is
making

I

> > > say "What? can't hear you, my genset is too loud".

> > > GregofTim&Greg

> > > 94ptCa

> > >

> > >

> > >

> > > In "WanderlodgeForum%40yahoogroups.com",
"Stephen Birtles"

>

> > > wrote:

> > > >

> > > > We will look into re manufacturing or redesigning a
similar

> product

> > > > that will work as sound absorption as well as heat

dissipation

> > > > It will take some time to get a satisfactory
product.

> > > > Stephen 77fc35

> > > >

> > > >

> > > > --- In "WanderlodgeForum%40yahoogroups.com",
"Ernest Ekberg"

> > > > wrote:

> > > > >

> > > > > After installing many generator compartments
with the new

> > > insulation, I

> > > > > was wondering if there is a manufacturer that
offers both.

> > > > > I insulated Bob Lawrences' generator
compartment last

> December.

> > > He

> > > > > measured the db levels before and after and
found that

while

> the

> > > heat

> > > > > was reflected from the interior of the coach,
the sound was

> also

> > > > > deflected to the outside. thus his db levels
INCREASED to

> over

> > > 90.

> > > > > I know my with my coach, that I have been
asked to park way

> > > downwind as

> > > > > my generator is really loud. Maybe its the
dogs I carry

with

> me???

> > > > > But, if there is a product that will absorb
that sound

while

> > > reflecting

> > > > > the heat, let's talk about it.

> > > > > Ernie-83PT40 in Texas, buying earplugs by the
case~

> > > > >

> > > >

> > >

> >

>





No virus found in this incoming message.

Checked by AVG. Version: 7.5.552 / Virus Database: 270.11.2/1965 - Release Date: 2/21/2009 3:36 PM


Sound- absorption or reflection - david brady - 02-22-2009 02:48


That's right Ernie, the Powertech manual covers required enclosure

volume too, and they caution that the volume is reduced by the
insulation.

In other words, after the insulation is in place, then the remaining
volume

must still be to spec.



http://www.powertech-gen.com/images/PTSMH%2015%20through%2020.pdf



David Brady

'02 LXi, NC



Ernie Ekberg wrote:



David, I would also assume that if the new insulation is
too thick and takes up too much room, that it would restrict air flow?



Ernie Ekberg
83PT40
Wanderlodge
Weatherford, Tx



Sound- absorption or reflection - Ernie Ekberg - 02-22-2009 03:02

I wonder if a thinner- less then 2" of convoluted foam would do the trick?


Ernie Ekberg
83PT40
Wanderlodge
Weatherford, Tx

--- On Sun, 2/22/09, david brady wrote:

From: david brady
Subject: Re: [WanderlodgeForum] Re: Sound- absorption or reflection
To: WanderlodgeForum@yahoogroups.com
Date: Sunday, February 22, 2009, 8:48 AM


That's right Ernie, the Powertech manual covers required enclosure
volume too, and they caution that the volume is reduced by the insulation.
In other words, after the insulation is in place, then the remaining volume
must still be to spec.

http://www.powertec h-gen.com/ images/PTSMH% 2015%20through% 2020.pdf

David Brady
'02 LXi, NC

Ernie Ekberg wrote:
David, I would also assume that if the new insulation is too thick and takes up too much room, that it would restrict air flow?


Ernie Ekberg
83PT40
Wanderlodge
Weatherford, Tx


Sound- absorption or reflection - David Brady - 02-22-2009 03:10

As long as it's fire resistant/retardent, installed with fire retardent
adhesives, maintains the required volume (after insulation), doesn't
restrict the incoming airflow, etc. The Powertech folks are pretty
specific. It might be worth a call to them to see what materials they
recommend.

David
'02 LXi, NC


-----Original Message-----

From: Ernie Ekberg

Sent: Feb 22, 2009 10:02 AM

To: WanderlodgeForum@yahoogroups.com

Subject: Re: [WanderlodgeForum] Re: Sound- absorption or reflection











I wonder if a thinner- less then 2" of convoluted foam would do the trick?


Ernie Ekberg
83PT40
Wanderlodge
Weatherford, Tx

--- On Sun, 2/22/09, david brady net> wrote:

From: david brady net>
Subject: Re: [WanderlodgeForum] Re: Sound- absorption or reflection
To: WanderlodgeForum@yahoogroups.com
Date: Sunday, February 22, 2009, 8:48 AM


That's right Ernie, the Powertech manual covers required enclosure
volume too, and they caution that the volume is reduced by the insulation.
In other words, after the insulation is in place, then the remaining volume
must still be to spec.

http://www.powertec h-gen.com/ images/PTSMH% 2015%20through% 2020.pdf

David Brady
'02 LXi, NC

Ernie Ekberg wrote:
David, I would also assume that if the new insulation is too thick and takes up too much room, that it would restrict air flow?


Ernie Ekberg
83PT40
Wanderlodge
Weatherford, Tx















Sound- absorption or reflection - Ralph L. Fullenwider - 02-22-2009 04:31

Hi Kurt:

I am assuming that you have the Dometic side by side and it is a 2 way,
LP/AC. Of course when the gen set runs or your on shore power, the 120 VAC
heater is keeping your unit cool. With the gen off or no shore, you should
be running on LP, and that is not cooling if I read the post right. There
are several things to cause this: Bad board,, blown fuse,, rust flakes
laying on top of the burner,, thermistor bad,, bad lp valve,, high voltage
ignite/reignite module. To be honest, I should imagine the LP side may just
need a little PM done to it.

If the LP works when parked, the flu needs cleaning and there is a baffle
in side the boiler tube that needs to be cleaned and on top of the boiler
tube there should be an anti blow out plate installed and the gap should be
about 1/2 inch.

There is insulation located in the enclosed up exhaust pipe for the gen
set. That compartment it is in is completely enclosed as to shut out any
CO2, that may leak. I have never removed the exhaust pipe from there however.

Safe Travels,

Ralph Fullenwider
'84FC35 " Ruff Diamond"
Oklahoma


At 08:06 AM 2/22/2009 +0000, you wrote:
>I would say that careful inspections are the order of the day to keep
>your coach in top form and you safe.
>
>I'm not up to snuff on this post but in my case the new exhaust,
>exhaust blankets on the new Stainless pipes (18ga.) and a soon to be
>installed thermal and acoustic insulation in the engine compartment
>she'll be cool, quite and efficient The blankets and the SS pipes are
>rated at over 2000 degrees continuous duty. So the hottest parts are
>insulated and the hottest gasses are directed out and away from the
>motor. I did install 2 - 1650 cfm electric fans in the engine
>compartment, to take care of any other residual heating problems.
>I don't see how insulating any Bird compartment would be detrimental.
>I can't imagine any engineer using the coach in any calculation as a
>heat sink, to dissipate any heat from the engine or generator
>
>Isn't that what radiators and exhausts are for.?
>
>I'll redo the insulation in the genny compartment when I do the main
>engine area.
>
>Look at any Prevost conversion the generators are mostly in enclosed
>compartments, Birds , at least the PT series are completely open
>underneath. I would not worry about maximum insulation in the genny
>box. When driving you get air flow, when parked the blower is sucking
>air in from some where, some is air is flowing through the genny
>box , along with the manifold, exhaust and valve cover blankets it's
>already retaining/containing a lot of heat internally that can only
>be removed through the exhaust and radiator. If after insulating you
>see higher temps. Install a lower temp. thermostat.
>
>After my near miss at burning up my coach I'd like to ask the forum a
>question.
>
>Has anybody ever checked the condition of the Generator exhaust stack
>that goes up through the body? And how would we go about checking it?
>It has the potential to be a serious issue should it be leaking
>exhaust fumes into the coach.
>
>In my coach the Genny Stack is located next to the Fridge. How well
>insulated is it? Maybe that's why my Fridge works great when parked
>but doesn't when I'm driving. I almost always run the generator when
>driving, and yes it's running while parked if not at a place it can
>be plugged in to. So is it part of my Fridge cooling problem? Maybe,
>any thoughts?
>
>Kurt Horvath
>95 PT 42
>10AC
>

Sound- absorption or reflection - timvasqz - 02-22-2009 04:37

David some of the gensets have the engine driven fan and open bottom
vault. Location of intake and exhaust are as important a variable as
maf. If the oil pan was insulated more of the engine heat would make
its way to the radiator. Many of the N14's put in Ford city tractors
(they dont have sleepers) have the oilpan insulated? my only guess is
to keep the heat from under the hood at low speeds???

'88 I picked up a longblock diesel Ford1900 (30hp)farm tractor engine
to prepare a tractor for remote use. after install I found temps ran
dangerously high. When I called the ford dealer for guidence the
first thing the parts man said is "Did you reinstall the hood?". I
had not and never considered the hood anything more than ornimental
as it was a thin sheetmetal 1/3 cover atop the engine. Once installed
the engine ran great and still serves us in Guam. My point here is
more calcs go into cooling and modifications should consider mfgs
origional methods. Or when making mods realize the related variable
to monitor.

One mod I never understand is the "Make it run cooler" add ons folks
do. when you make something run cooler than engineered you afford the
opertunity to add more stress with a lost 'heat caused by excessive
stress warning'. You hear it at rallys when someone brags 'I climbed
the XXXPass at 60 and temps never got above 165f'. These are the same
types who drop dead shoveling snow because they never break a
sweat. Most engines are from the factory designed to run safe while
within their abilities.

Greg of Tim&Greg
94ptca

--- In WanderlodgeForum@yahoogroups.com, david brady
wrote:
>
> I pulled this out of the Powertech manual: (for what it's worth),
>
> "Each engine is equipped with a high water temperature shutdown
> switch, which will automatically shut down the set if the operating
> temperature climbs too high. To prevent the generator set from
> shutting down make sure the compartment openings are large enough
> to allow adequate circulation of cooling air. The minimum free air
> opening in the compartment door is 400 sq. in. or 2580 sq. cm.
> Remember that louvers, screens and protective grills will restrict
airflow.
> A relatively open mesh screen will restrict airflow as much as 45%.
> The intake opening must be increased to compensate for
> such restrictions."
>
> David
> '02 LXi, NC
>
>
> Kurt Horvath wrote:
> >
> > I would say that careful inspections are the order of the day to
keep
> > your coach in top form and you safe.
> >
> > I'm not up to snuff on this post but in my case the new exhaust,
> > exhaust blankets on the new Stainless pipes (18ga.) and a soon to
be
> > installed thermal and acoustic insulation in the engine
compartment
> > she'll be cool, quite and efficient The blankets and the SS pipes
are
> > rated at over 2000 degrees continuous duty. So the hottest parts
are
> > insulated and the hottest gasses are directed out and away from
the
> > motor. I did install 2 - 1650 cfm electric fans in the engine
> > compartment, to take care of any other residual heating problems.
> > I don't see how insulating any Bird compartment would be
detrimental.
> > I can't imagine any engineer using the coach in any calculation
as a
> > heat sink, to dissipate any heat from the engine or generator
> >
> > Isn't that what radiators and exhausts are for.?
> >
> > I'll redo the insulation in the genny compartment when I do the
main
> > engine area.
> >
> > Look at any Prevost conversion the generators are mostly in
enclosed
> > compartments, Birds , at least the PT series are completely open
> > underneath. I would not worry about maximum insulation in the
genny
> > box. When driving you get air flow, when parked the blower is
sucking
> > air in from some where, some is air is flowing through the genny
> > box , along with the manifold, exhaust and valve cover blankets
it's
> > already retaining/containing a lot of heat internally that can
only
> > be removed through the exhaust and radiator. If after insulating
you
> > see higher temps. Install a lower temp. thermostat.
> >
> > After my near miss at burning up my coach I'd like to ask the
forum a
> > question.
> >
> > Has anybody ever checked the condition of the Generator exhaust
stack
> > that goes up through the body? And how would we go about checking
it?
> > It has the potential to be a serious issue should it be leaking
> > exhaust fumes into the coach.
> >
> > In my coach the Genny Stack is located next to the Fridge. How
well
> > insulated is it? Maybe that's why my Fridge works great when
parked
> > but doesn't when I'm driving. I almost always run the generator
when
> > driving, and yes it's running while parked if not at a place it
can
> > be plugged in to. So is it part of my Fridge cooling problem?
Maybe,
> > any thoughts?
> >
> > Kurt Horvath
> > 95 PT 42
> > 10AC
> >
> > --- In WanderlodgeForum@yahoogroups.com
> > , "timvasqz"
> > wrote:
> > >
> > > Not too far fetched. My cummins engine computer is cooled with
> > > diesel fuel. I am just curious where you were transfering heat
to
> > > with your 'insulation heat dissipation remanufacture redesign'
> > >
> > > heat is transfered and lost to other objects. for one thing to
> > lose
> > > heat somthing else must take it. its a calorie calc. when you
> > > insulate to keep heat from the interior of the bus where does
that
> > > heat now go?
> > >
> > > some times when an interior gets hot and calls for modification
it
> > > is an overlooked sign that the heat producer has other issues
> > causing
> > > excessive heat. KurtH can atest. in a genset the genhead may be
> > > cooking or engine exhaust is screwed up.
> > >
> > > Greg ofTim&Greg
> > > 94ptca
> > >
> > >
> > >
> > > WanderlodgeForum@yahoogroups.com
> > , "Stephen Birtles"
> >
> > > wrote:
> > > >
> > > > why thank you for the mindless dribble another useless comment
> > > >
> > > > Stephen 77fc35
> > > >
> > > >
> > > > --- In WanderlodgeForum@yahoogroups.com
> > , "timvasqz"
> > > wrote:
> > > > >
> > > > > To disipate heat, is to transfer it. Steve maybe you can
> > disapate
> > > it
> > > > > thru a dupree valve back to the tank? Call it Hot$$$$ ?
> > > > >
> > > > > I understand that the vault gets up to +250 degrees(USA). I
> > > guess
> > > > > that is a factor for Ernie to consider once he removed the
> > > disipation
> > > > > path of the vault heat to the bus interior. where does that
> > > heat
> > > > > now go.
> > > > >
> > > > > Insulation keeps environments from disapating heat. heat is
> > > removed
> > > > > so the method to remove the heat in the compartment would
now
> > be
> > > the
> > > > > radiator system and the diesel engine is the heat sink, but
> > the
> > > > > diesel engine caused most of the heat. If the origional
design
> > > was
> > > > > not intended to do that it would have to be beefed up
> > > > >
> > > > > If you insulate the exhaust the otherwise exposed metal does
> > not
> > > > > radiate heat in the compartment. heat goes out the stack
with
> > the
> > > > > exhast air. But is the stack able to take all the extra
heat.
> > > > >
> > > > > If someone complains to me about the noise my genset is
making
> > I
> > > > > say "What? can't hear you, my genset is too loud".
> > > > > GregofTim&Greg
> > > > > 94ptCa
> > > > >
> > > > >
> > > > >
> > > > > In WanderlodgeForum@yahoogroups.com
> > , "Stephen Birtles"
> > >
> > > > > wrote:
> > > > > >
> > > > > > We will look into re manufacturing or redesigning a
similar
> > > product
> > > > > > that will work as sound absorption as well as heat
> > dissipation
> > > > > > It will take some time to get a satisfactory product.
> > > > > > Stephen 77fc35
> > > > > >
> > > > > >
> > > > > > --- In WanderlodgeForum@yahoogroups.com
> > , "Ernest Ekberg"
> > > > > > wrote:
> > > > > > >
> > > > > > > After installing many generator compartments with the
new
> > > > > insulation, I
> > > > > > > was wondering if there is a manufacturer that offers
both.
> > > > > > > I insulated Bob Lawrences' generator compartment last
> > > December.
> > > > > He
> > > > > > > measured the db levels before and after and found that
> > while
> > > the
> > > > > heat
> > > > > > > was reflected from the interior of the coach, the sound
was
> > > also
> > > > > > > deflected to the outside. thus his db levels INCREASED
to
> > > over
> > > > > 90.
> > > > > > > I know my with my coach, that I have been asked to park
way
> > > > > downwind as
> > > > > > > my generator is really loud. Maybe its the dogs I carry
> > with
> > > me???
> > > > > > > But, if there is a product that will absorb that sound
> > while
> > > > > reflecting
> > > > > > > the heat, let's talk about it.
> > > > > > > Ernie-83PT40 in Texas, buying earplugs by the case~
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> >
> > ------------------------------------------------------------------
------
> >
> > No virus found in this incoming message.
> > Checked by AVG.
> > Version: 7.5.552 / Virus Database: 270.11.2/1965 - Release Date:
2/21/2009 3:36 PM
> >
>

Sound- absorption or reflection - timvasqz - 02-22-2009 04:41

Should be easy to check the stack. Cap it or shove a potato in it
and crank the engine over powertec may have a height spec
Greg

--- In WanderlodgeForum@yahoogroups.com, "Ralph L. Fullenwider"
wrote:
>
> Hi Kurt:
>
> I am assuming that you have the Dometic side by side and it is a 2
way,
> LP/AC. Of course when the gen set runs or your on shore power, the
120 VAC
> heater is keeping your unit cool. With the gen off or no shore, you
should
> be running on LP, and that is not cooling if I read the post right.
There
> are several things to cause this: Bad board,, blown fuse,, rust
flakes
> laying on top of the burner,, thermistor bad,, bad lp valve,, high
voltage
> ignite/reignite module. To be honest, I should imagine the LP side
may just
> need a little PM done to it.
>
> If the LP works when parked, the flu needs cleaning and there is a
baffle
> in side the boiler tube that needs to be cleaned and on top of the
boiler
> tube there should be an anti blow out plate installed and the gap
should be
> about 1/2 inch.
>
> There is insulation located in the enclosed up exhaust pipe for the
gen
> set. That compartment it is in is completely enclosed as to shut
out any
> CO2, that may leak. I have never removed the exhaust pipe from
there however.
>
> Safe Travels,
>
> Ralph Fullenwider
> '84FC35 " Ruff Diamond"
> Oklahoma
>
>
> At 08:06 AM 2/22/2009 +0000, you wrote:
> >I would say that careful inspections are the order of the day to
keep
> >your coach in top form and you safe.
> >
> >I'm not up to snuff on this post but in my case the new exhaust,
> >exhaust blankets on the new Stainless pipes (18ga.) and a soon to
be
> >installed thermal and acoustic insulation in the engine compartment
> >she'll be cool, quite and efficient The blankets and the SS pipes
are
> >rated at over 2000 degrees continuous duty. So the hottest parts
are
> >insulated and the hottest gasses are directed out and away from the
> >motor. I did install 2 - 1650 cfm electric fans in the engine
> >compartment, to take care of any other residual heating problems.
> >I don't see how insulating any Bird compartment would be
detrimental.
> >I can't imagine any engineer using the coach in any calculation as
a
> >heat sink, to dissipate any heat from the engine or generator
> >
> >Isn't that what radiators and exhausts are for.?
> >
> >I'll redo the insulation in the genny compartment when I do the
main
> >engine area.
> >
> >Look at any Prevost conversion the generators are mostly in
enclosed
> >compartments, Birds , at least the PT series are completely open
> >underneath. I would not worry about maximum insulation in the genny
> >box. When driving you get air flow, when parked the blower is
sucking
> >air in from some where, some is air is flowing through the genny
> >box , along with the manifold, exhaust and valve cover blankets
it's
> >already retaining/containing a lot of heat internally that can
only
> >be removed through the exhaust and radiator. If after insulating
you
> >see higher temps. Install a lower temp. thermostat.
> >
> >After my near miss at burning up my coach I'd like to ask the
forum a
> >question.
> >
> >Has anybody ever checked the condition of the Generator exhaust
stack
> >that goes up through the body? And how would we go about checking
it?
> >It has the potential to be a serious issue should it be leaking
> >exhaust fumes into the coach.
> >
> >In my coach the Genny Stack is located next to the Fridge. How well
> >insulated is it? Maybe that's why my Fridge works great when parked
> >but doesn't when I'm driving. I almost always run the generator
when
> >driving, and yes it's running while parked if not at a place it can
> >be plugged in to. So is it part of my Fridge cooling problem?
Maybe,
> >any thoughts?
> >
> >Kurt Horvath
> >95 PT 42
> >10AC
> >
>

Sound- absorption or reflection - Pete Masterson - 02-22-2009 06:12

On Feb 22, 2009, at 12:06 AM, Kurt Horvath wrote:

<snip>

Look at any Prevost conversion the generators are mostly in enclosed
compartments, Birds , at least the PT series are completely open
underneath. I would not worry about maximum insulation in the genny
box. When driving you get air flow, when parked the blower is sucking
air in from some where, some is air is flowing through the genny
box , along with the manifold, exhaust and valve cover blankets it's
already retaining/containing a lot of heat internally that can only
be removed through the exhaust and radiator. If after insulating you
see higher temps. Install a lower temp. thermostat.
Dunno about earlier 'birds, but the PowerTech generator is in a sealed box, except when extended, it's open underneath. The top and sides of the box are covered by a soft foam stuff that has an egg crate finish. (Similar to what you might see in a high-end camera shipping case.) I don't recall what, if any insulation is on the bottom of the box, but the obvious choice was to not have the foam as it would absorb oil drips from the engine and become a serious fire hazard.
The radiator and fan are completely external to the sound cabinet -- and located on the street side, front (just below where the driver sits) fan noise is not much of an issue on my coach. Indeed, from inside, the generator is not especially noisy -- from the bedroom, it's difficult to hear, but (back there) I do sense the vibration that travels through the coach frame.
After my near miss at burning up my coach I'd like to ask the forum a
question.

Has anybody ever checked the condition of the Generator exhaust stack
that goes up through the body? And how would we go about checking it?
It has the potential to be a serious issue should it be leaking
exhaust fumes into the coach.
In my coach, the bottom 1/3 of the roof exit genny stack is visible in the storage bay by the AquaHot. I don't see any ready access to inspect the portion inside the coach. Due to the differences in my floor plan to the more common walk-through bath arrangement, the stack runs up past the shower (to the rear) and behind a 'curio cabinet' near the dining table on the front side. It appears that a generous amount of space is allowed for the passage of the stack. Looking at what I see in the storage bay, it may be a double-wall design.
In my coach the Genny Stack is located next to the Fridge. How well
insulated is it? Maybe that's why my Fridge works great when parked
but doesn't when I'm driving. I almost always run the generator when
driving, and yes it's running while parked if not at a place it can
be plugged in to. So is it part of my Fridge cooling problem? Maybe,
any thoughts?

Kurt Horvath
95 PT 42
10AC
I note that the owner's manual in my blue box suggests that the cap on the lower generator exhaust outlet (under the edge of the coach just below the roof-exit pipe) be removed when traveling on the road. I also discovered that it's probably just as well to operate with the lower exhaust port open in all situations where it is practical.
I was going through air filters quite rapidly (the engine breather tube exits about a foot from the air filter intake -- inside the engine box). I subsequently installed a longer breather tube and routed it past the seal where the generator box opens. (The "seal" is basically the same foam sound insulation used elsewhere in the generator box. It makes a fairly soft closure -- probably to allow sufficient air to enter the box to let the engine run (as I didn't observe any other openings in the box -- but that doesn't mean that some other opening isn't present). Once I rerouted the breather tube, the air filter changes were significantly reduced.
Anyway, the first sign that the air filter needs replacement is seeing excess soot in the genny exhaust. Not realizing that air filters were the heart of the problem, I had let the soot condition continue for some time while I did a number of other troubleshooting efforts. (I ruled out the air filter because I'd "just replaced it.") Ultimately, I realized it was the air filter -- replaced it -- and the generator ran a lot better -- but it still seemed to be running short of ideal. I then removed the lower genny exhaust port cap (for the first time since buying the coach more than a year earlier) -- and a TON of soot blasted out -- it was causing some back pressure in the exhaust system making the engine not run quite right.
The soot made a huge mess, but I've subsequently operated the generator with the cap off most of the time -- only switching to the roof exit parked where I'll need to use the genny regularly.
So, Kurt, to eliminate the worry while going over the road, take the exhaust cap off. Be prepared to be impressed by the amount of soot that's collected -- soot that is also a potential fire hazard. Note: stand clear of the exhaust exit when you start the generator -- and choose a location where a LOT of soot will not present a problem. Leave the cap off while operating the generator over the road. Use the cap when boondocking where routing the exhaust out the roof is a wise practice. Hint: put the cap on or take it off while the generator is not operating and the pipes are cool to the touch (so you don't get burned).
As for the impact (if any) on the operation of your 'frige, have you tried looking in from the exterior access panel that most LP gas refrigerators have? (I've noticed them on older 'birds -- I assume the '95 has one but my all-electric coach doesn't.) Perhaps, using a mirror if necessary, you can see a portion of the exhaust stack from that access point. If excess heat in the vent area behind the refrigerator is a problem, perhaps a small fan might assist in improving the air flow.
Pete Masterson
'95 Blue Bird Wanderlodge WBDA 42 (For Sale)
El Sobrante CA
"aeonix1@mac.com"