It is not brand specific, it applies to any system with a low and high fire
gas valve.




"HeatMan" wrote in message
. ..

"CBHVAC" wrote in message
...

"HeatMan" wrote in message
.. .

"CBHVAC" wrote in message
...

"HeatMan" wrote in message
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"CBHVAC" wrote in message
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"bill" wrote in message
...
Carrier Gas furnace model 58PAV090. What is the normal heating
sequence? during the heat cycle, is it normal for the gas to
cycle
on
and off while the blower continues to run.


No.


Its like the high temp
limit switch is closing then reopening (during a cycle where the
thermostst has not been satisfied). should the gas valve cycle
or
is
this typically not normal. not enough air flow...filter, open
registers....thanks bill

No one here can tell you. Its being cause by something, and it
could
be
as
simple as a bad limit, or an improperly set gas valve.



Y'all musta found some funky gas valves lately. This is the second
thread
you've mentioned it in...



Ever seen one with the burn rate set too high?
Can cycle the unit in and out and in and out several times over the
course
of a call for heat.



Never seen that.

On the newer Yorks, Tranes, and Carriers in particular, if you set the
gas
valve too high, and dont finalize the heat rise correctly, you can
overheat
a limit, that will allow the unit to continue to run, but shuts down the
valve..since its a self resetting Kilxon, when it cools off, it resets
the
valve circuit and will fire back up.

I don't start up those brands any more, but I will remember that...

Thanks.