It's virtually zero. I don't have meter/guage but it will barely hold
a dime size piece of paper towel. Tonight I plan on taking of vent
blower to see if trash has fell near opening. Does it have a baffle
to seperate vent and hose fitting?
You need to determine the pressure/vacuum exactly. A gauge to do so
will cost around $100. That and the pressure/vacuum the switch is
designed to operate on and you know where the problem lies.
BTW, they rate the switches in inches wc, not what size paper towel
the tube will hold.
You can't seriously expect to come into a newsgroup of professionals
and get any sort of serious response without providing the information
needed to correctly diagnose the problem. alt.home.repair is the
proper place for group guessing.
If a tree falls in the woods and kills
a mime, does anyone care?
I may be out of my league (I'm a mechanical engineer) but it does seem
pretty cut and dry (towel reference). Furnace is about 15 years old.
1. Vent blower comes on (check) 2. creates suction to pressure
switch (no check) (Plenty of draft for burners though) 3. pressure
switch gets enough negative pressure (suction) to trip 24V switch. I
can bypass pressure switch and jump to next step to pinpoint problem
4. gas valve opens and burners ignite 5. limit switch trips when
hot enough and blower starts
Do I have it wrong???
Close. The "limit switch" your referring too is likely [or could be] the
"fan switch." The "limit switch" is to keep the furnace from overheating.
If the F.AU. is 15 years old, it is likely not a "high - low fire" unit
currently being marketed. I'd check the flu, be sure there is not an
obstruction [any obstruction would cause the draw from the inducer to
change - one of the reasons the mfg. put the little pressure switch there].
If there is not an obstruction, and the inducer is up to speed [the second
reason for the pressure switch], then it is possible the switch is bad. But
I'll bet the inducer motor isn't up to speed. They are generally a shaded
pole motor and can run "under speed" when the bearings / windings begin to
You'd be ahead to call someone who knows and is familiar with these heaters
and would be able to tell you what your problem is. I realize you are an
engineer from your posting. I don't know what type of engineering you do,
but it you are paid enough, then why monkey around. Have it fixed correctly
by the person with the right training. Unless you're broke and can't afford
a trained repair person?
"jonoh" < email@example.com> wrote in message
Thank You for your opinion and input. You are the reason I tried
this site. Thanks again.
I'll take it off and inspect for obstructions first then call for help
if that is not the problem.
Yes, you do. If you're really an engineer than you know data is
important. Having the unit run after jumping the pressure switch
tells you either the switch is bad or it's not seeing enough
pressure/vacuum. How you determine if the switch is bad is by
checking just how much pressure/vacuum the switch is exposed to. I
simply don't know any other way to tell you but you have to know what
the pressure/vacuum the switch is exposed to and what the value is
supposed to be.
BTW, the burners firing doesn't tell you the draft is adequate. The
pressure switch tells you that.
And what do you mean the limit switch trips? That shouldn't do that
under normal operation.
If a tree falls in the woods and kills
a mime, does anyone care?
Bahahahaha. Son of a bitch. I knew I should have picked up that new
"dime size paper towel" tool at the parts warehouse the other day.
Jono.....you are a flippin idiot. Gee....Id have never guessed you
were a Engineer. "Who'd a thunk". Tell me again oh bright
The flippin idiot fixed his own furnace without BUBBA's help which is
why I fixed it so quick. BUBBA will have to rip some other sucker
off. I would have thought someone named BUBBA would be a plumber,
but I guess the exam included knowledge of how a shower works.
Born and raised in Georgia (wrong again, a misdiagnosis of the problem
but try again and keep charging the homeowner for your guessing); I
don't guess I'm redneck enough though because I don't know anyone named
BUBBA. I guess the education threw you off.
That is why I disassembled it and fixed it myself. Call a repair man
is a last resort in my book, because your going to get screwed and not
get kissed. Oh, he is smart enough to fix it but it will not be a
honest amount wriiten on the bill.
A honest amount is your same hourly rate that you charge everyone and
actual part cost. Not what you "think" the home owner is dumb enough
to pay or what you need to buy that "new paper towel" tool you've heard
about. That kind of crap is what gives your profession a bad name.
And believe me when someone gets screwed by a so called Pro, the word
will get around.
Ok, so you want to be charged a flat rate??
I already do that... my prices are published in a book so all my customers
get charged the same amount for each task/repair. With flat rate, you don't
get charged for *LABOR*, and it doesn't matter how long the repair takes,
the price remains the same. FWIW, a PRO will tell you exactly how much the
repairs will be before he makes any repairs.
So tell me.... did you cal a real pro?? or just the guy with the lowest
service call price??
I'll disagree with you on this, Oscar. Most companies that charge
what the market will bear end up going belly up. Pricing first and
foremost needs to be based on the cost to provide the service, product
or whatever widget you have coupled with your desired net after tax
Now you may determine that your cost to deliver the product or service
varies depending on your client but ultimately you still need to cover
the costs and desired net after tax profit.
I agree with Scott, your theory is why more cars are being made
overseas (that and UNION labor). When the corruption goes through
all aspects of an industry then the industry is looking for trouble.
GM, Ford, Chrysler If I follow your idea, then "see_my_sig" and all
you other PROs that drive $30,000 trucks should be paying 3 times the
amount for GAS that I am paying. I have no problem paying a PRO
$100/hour (one hour minimum) and part cost along with trip cost. But
don't tell me a $45 part cost you $150. That is a pure and simple
LIE. I would not even mind paying a 40% profit margin on parts for
your trouble, but not a 333% profit.
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