6 times per hour versus 3 times per hour


J

Jayn123

I have an 80% efficiency forced air furnace. I think it is oversized for
the temperatures I keep my townhouse at. When we had single digits in NJ it
was still cycling 6 times per hour and I don't know if it even made it to
2nd stage by running 15 minutes or longer. I changed the setting on my
Honeywell thermostat to 3 times per hour. That way, there are only 3
start-ups per hour. Even at 3 times per hour I don't even think it made it
to 2nd stage on those really cold days, except in the morning when the
thermostat setting went up by a degree.

I like 3 times per hour, because it seems to me that only 3 start-ups per
hour would be less wear and tear. Just was wondering if there is any harm
in 3 times per hour versus 6 times per hour for an 80% furnace? Would the
longer running time (mostly in stage 1) be causing more wear and tear on
the burner or heat exchanger, or not?

Thanks,

J.
 
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T

Tony Hwang

Jayn123 said:
I have an 80% efficiency forced air furnace. I think it is oversized
for the temperatures I keep my townhouse at. When we had single digits
in NJ it was still cycling 6 times per hour and I don't know if it even
made it to 2nd stage by running 15 minutes or longer. I changed the
setting on my Honeywell thermostat to 3 times per hour. That way,
there are only 3 start-ups per hour. Even at 3 times per hour I don't
even think it made it to 2nd stage on those really cold days, except in
the morning when the thermostat setting went up by a degree.

I like 3 times per hour, because it seems to me that only 3 start-ups
per hour would be less wear and tear. Just was wondering if there is
any harm in 3 times per hour versus 6 times per hour for an 80%
furnace? Would the longer running time (mostly in stage 1) be
causing more wear and tear on the burner or heat exchanger, or not?

Thanks,

J.
Hi,
You said your furnace is over sized. What is the size of furnace and
your house? I'd rather concern myself with comfort level than wear of
furnace. I didn't know 80% furnace came in multi stage model. If you
want to see if 2nd stage coming on at all, while furnace is running you
can check 2nd stage control lead marked W2.

I upgraded to 110K BTU 2 stage VS 98% furnace replacing single state 80%
eff. 120K BTU one. The old furnace used to run mostly 3 times an hour
during cold winter days. My house is 2700 Sq. St. 2 story located in
Southern Alberta. New one cycles about at same rate including 2nd state.
It gives more even temp. in the house(that's what wife noticed)

BTW, they don't sell 80% furnace any more up here. You can only install
high efficiency furnaces for new houses or replacing old furnaces.
 
J

Jayn123

The house is around 2100 square feet and the finished basement is around 800
square feet.

The furnace is 110 K BTU forced air. It uses a single stage stat, and
normally the furnace doesn't make it to the 2nd stage until after 15 minutes
of running in the 2nd stage. Everyone I talked to wanted to put in a 110K
furnace. I normally keep the thermostat only at 67 during the day, and 66
at night.

My furnace has a VS motor as well.

J.

___________________________________________________________________

"Tony Hwang" wrote in message

I have an 80% efficiency forced air furnace. I think it is oversized
for the temperatures I keep my townhouse at. When we had single digits
in NJ it was still cycling 6 times per hour and I don't know if it even
made it to 2nd stage by running 15 minutes or longer. I changed the
setting on my Honeywell thermostat to 3 times per hour. That way,
there are only 3 start-ups per hour. Even at 3 times per hour I don't
even think it made it to 2nd stage on those really cold days, except in
the morning when the thermostat setting went up by a degree.

I like 3 times per hour, because it seems to me that only 3 start-ups
per hour would be less wear and tear. Just was wondering if there is
any harm in 3 times per hour versus 6 times per hour for an 80%
furnace? Would the longer running time (mostly in stage 1) be
causing more wear and tear on the burner or heat exchanger, or not?

Thanks,

J.
Hi,
You said your furnace is over sized. What is the size of furnace and
your house? I'd rather concern myself with comfort level than wear of
furnace. I didn't know 80% furnace came in multi stage model. If you
want to see if 2nd stage coming on at all, while furnace is running you
can check 2nd stage control lead marked W2.

I upgraded to 110K BTU 2 stage VS 98% furnace replacing single state 80%
eff. 120K BTU one. The old furnace used to run mostly 3 times an hour
during cold winter days. My house is 2700 Sq. St. 2 story located in
Southern Alberta. New one cycles about at same rate including 2nd state.
It gives more even temp. in the house(that's what wife noticed)

BTW, they don't sell 80% furnace any more up here. You can only install
high efficiency furnaces for new houses or replacing old furnaces.
 
T

Tony Hwang

Jayn123 said:
The house is around 2100 square feet and the finished basement is around
800 square feet.

The furnace is 110 K BTU forced air. It uses a single stage stat, and
normally the furnace doesn't make it to the 2nd stage until after 15
minutes of running in the 2nd stage. Everyone I talked to wanted to
put in a 110K furnace. I normally keep the thermostat only at 67
during the day, and 66 at night.

My furnace has a VS motor as well.

J.
nt
Hi,
I see. I have a 1000 sq. ft. finished basement as well. Our winter is
much colder than yours. My programmed temp setting is 70/65. Our NG
price is ~3.00/GigaJoule floating rate, electric power is 8 cents/KWh
fixed for next 5 years.
 
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M

MLD

Jayn123 said:
I have an 80% efficiency forced air furnace. I think it is oversized for
the temperatures I keep my townhouse at. When we had single digits in NJ
it was still cycling 6 times per hour and I don't know if it even made it
to 2nd stage by running 15 minutes or longer. I changed the setting on
my Honeywell thermostat to 3 times per hour. That way, there are only 3
start-ups per hour. Even at 3 times per hour I don't even think it made
it to 2nd stage on those really cold days, except in the morning when the
thermostat setting went up by a degree.

I like 3 times per hour, because it seems to me that only 3 start-ups per
hour would be less wear and tear. Just was wondering if there is any
harm in 3 times per hour versus 6 times per hour for an 80% furnace?
Would the longer running time (mostly in stage 1) be causing more wear
and tear on the burner or heat exchanger, or not?

Thanks,

J.
I have a 90+% efficient (condensing) furnace and it operates in a very
similar manner. That is, the colder the day the more cycles it goes through
and many times it does not get to the 2nd stage heat and increased fan
speed. That's the way it is supposed to work--provides a more even,
consistent heat with minimum in-house temperature variation. The only
adjustment that I have control of is the time the system stays on Stage 1.
I have it set on 10 min--if the thermostat isn't satisfied after 10 min the
2nd stage gas valve kicks in and the fan ramps up to it's high speed
setting.
I don't think that you truly understand how your system is designed to
operate.
MLD
 

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