Sol-Aire Heater Noise

[john bush]

In testing house systems in our newly acquired 75 PB, I
find the OEM Sol-Aire 30,000 BTU heater exhibits an
unexpected (by me) characteristic. When cold, it creates
a clear acoustic resonant sound in the exhaust tube.
As it warms up, the pitch rises slightly and the volume
created eventually drops to nothing (mercifully). I would
WAG the pitch is somewhere in the 600-800 Hz range
and loud enough to be heard from a couple hundred feet
away with the real potential to annoy neighbors, to say
nothing of the would-be sleepers in the coach.

Q1: Is this at all normal?

Q2: Is it symptomatic of jet mis-adjustment or other such
problem? ( I have tweaked the air mixture slightly but to
no avail. At first blush, the flame seems reasonably
close to the objective described in the adjustment
procedure).

Q3: Were there supposed to be some baffles or something
in the exhaust line to suppress acoustic resonances in that
pipe?

Q4: Any suggestions?

TIA
John Bush
75 PB, Sunol CA (where its getting a bit cool at night
and it would be nice to use the furnace while tinkering
in the GMC but without disturbing the neighborhood
dogs with the howling furnace!)

 

[gene]

sometimes this is caused by a fan. The booster fan behind the oven
sometimes is the problem, (I disconnected mine) and I also oiled the main
fan and that helped.

There was supposed to be an adjustment (maybe is that mixture ajd you
talked of) that is somewhere on the front. But I cannot remember where I
read about that.
gene

>In testing house systems in our newly acquired 75 PB, I
>find the OEM Sol-Aire 30,000 BTU heater exhibits an
>unexpected (by me) characteristic. When cold, it creates
>a clear acoustic resonant sound in the exhaust tube.
>As it warms up, the pitch rises slightly and the volume
>created eventually drops to nothing (mercifully). I would
>WAG the pitch is somewhere in the 600-800 Hz range
>and loud enough to be heard from a couple hundred feet
>away with the real potential to annoy neighbors, to say
>nothing of the would-be sleepers in the coach.
>
>Q1: Is this at all normal?
>
>Q2: Is it symptomatic of jet mis-adjustment or other such
>problem? ( I have tweaked the air mixture slightly but to
>no avail. At first blush, the flame seems reasonably
>close to the objective described in the adjustment
>procedure).
>
>Q3: Were there supposed to be some baffles or something
>in the exhaust line to suppress acoustic resonances in that
>pipe?
>
>Q4: Any suggestions?
>
>TIA
>John Bush
>75 PB, Sunol CA (where its getting a bit cool at night
>and it would be nice to use the furnace while tinkering
>in the GMC but without disturbing the neighborhood
>dogs with the howling furnace!)
>
>
>
>
>
>
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/

 

[david l greenberg]

Someone correct me if I am wrong-a distinct possibility- but wasn't it
decided Sol-Aire's were dangerous and had been recalled?

They do indeed whistle. At the New Hampshire Int'l rally a couple of
Septembers ago l could hear every coach that still had one installed.

Dave Greenberg
GMC MOTORHOME REGISTRY

 

[richard bachert]

The word on this network is that the Sol-Aire's combustion chambers will
rust through, allowing CO to enter the coach and/or allow flames to reach
nearby areas, burning the coach down to the rims. Not good things.
Dick 75 PB in Atlanta

>Someone correct me if I am wrong-a distinct possibility- but wasn't it
>decided Sol-Aire's were dangerous and had been recalled?
>
>They do indeed whistle. At the New Hampshire Int'l rally a couple of
>Septembers ago l could hear every coach that still had one installed.
>
>
> Dave Greenberg
>GMC MOTORHOME REGISTRY
>

 

[al chernoff]

To add what Emery said, Wes Caughlin says to replace the sol-aire. I have no
intention of doing so. It was/is working great and I plan to keep it. However,
Gene and I took out both of our units and then did a lub on the motor, bearings
etc. His was making a squeal and mine was not. So after taking them out,
cleaning all the junk out, and butting oil in, everything is great with the
solaire. However, I did buy from camping world a new c02 detector, just for the
sake of being certain. After all, they are 20+ years old and I want to make
sure I don't cause any problems. I do think that that is a good thing to have
anyway. I wired mine up next to the thermostat and put in a small switch that
turns it off. I don't need it on all the time, so when it is parked, I turn it
off. No sense running down the batttery over the winter when it is parked.
that's my .02c
al

>
> >
>
> Dave - OK -- you are wrong. Please don't start any rumors and tell my
> Solaire that its dangerous and has been recalled. Not true.
>
> The only RECALL that GMC did for a furnace was for the Type II Suburban
> Furnace. 22,000 BTU and 30,000 BTU on certain 1973 and 1974 ZE05000
> motorhomes. These had leaks in some brass fittings and involved NT-22 and
> NT-32 furnaces manufactured between 1/4/73 and 8/31/73. Serial numbers
> ranged between 0282292 and 0364780 however, not all of them between those
> numbers had the problem.
>
> There was a Dealer Service Information Bulletin dated April 1975 for the
> SolAire furnace to provide dealers with trouble diagnosis charts, diagram of
> the furnace and a description of the proper method for removing the furnace
> from the vehicle. Not at all for any safety problems.
>
> The was a Dealer Service Information Bulletin dated July 1977 for the
> DuoTherm furnaces installed starting sometime in 1977. Again it was to
> advise dealers of the service of the furnace and not for any safety problems.
>
> There was a Dealer Service Technical Bulletin dated Nov. 26, 1973 regarding
> the proper pilot adjustment on the earlier model Suburban furnaces put into
> TZE033 and TZE063 models (1973).
>
> There was a Dealer Service Technical Bulletin dated March 1978 regarding the
> Ignition Pak Replacement for Sol-Aire Furnaces that replaced the procedure in
> Maintenance Manual X-7525, Page 24G-13. They said it simplified the
> procedure.
>
> This is the total of all recalls, Dealer Service Technical Bulletins and
> Dealer Service Information Bulletins pertaining to furnaces.
>
> Many of us are still using the SolAire. Mine has been extremely reliable
> over the years. It does not make the noise that some have posted to this
> site indicating that their furnaces do. I would guess that the noise could
> be caused by improper gas pressure or flow at the burner, a partially stuck
> gas valve (12v.) causing a restriction in the line, a bend in the gas tubing
> or possibly a dry bearing in the fan motor. If not a bearing, the type of
> noise described is usually a restriction in either a gas line or in the path
> of the air flow. With the age of the unit everyone should lubricate the
> bearings anyway.
>
> The only problem that I have read about other than the noise was that someone
> had it pull away from the outside wall so that the exhaust pipe was spilling
> into the motorhome. That could be bad! Carbon monoxide. Suggest that
> owners unscrew the outside vent covers and check to see that the tubes are
> sealed at the wall. Also a good time to replace the screws with stainless
> steel ones to get rid of the rust. If anyone is really concerned there are
> some good propane/carbon monoxide detectors that can be put in the motorhome.
>
> As for rusting of the combustion chambers, this can be a problem with any 20+
> year old furnace -- no matter what your manufacturer is. One should check
> your furnace periodically. I do this at least once per year when it starts
> to get cool out. I have no plans to replace my SolAire furnace unless it
> dies of old age.
>
> Emery Stora
> 77 Kingsley
> Santa Fe, NM

 

[david l greenberg]

Thanks, Emery, for keeping me on my toes!

David Lee Greenberg
GMC Motorhome Registry
200 MacFarlane Drive
Delray Beach, FL 33483-6829