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  #41   Report Post  
Old February 12th 19, 04:54 AM posted to alt.home.repair
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Default Furnace filters

On Mon, 11 Feb 2019 16:35:25 -0500, Tekkie«
wrote:

Clare Snyder posted for all of us...



On Wed, 6 Feb 2019 14:02:53 -0500, Tekkie« wrote:

Frank posted for all of us...



On 2/4/2019 7:23 PM, Ed Pawlowski wrote:
For the first time in 53 years of owning homes, my new house has a
furnace and uses filters.* It takes a 1" filter.

I see prices can vary considerably but is a MERV 8 and MERV 8 regardless
of the brand?* Should I use MERV 8 or MERV 11?* We have no pets.

I see filters with MERV 11 rating from $9.95 ($7.45ea by a dozen) to
$14.50. Any real difference if they have the same rating?

Discount filters seems cheapest.

I use air filters and had never heard the term MERV so looked up your
question:

https://airexpertsnj.com/knowledge/e...erv-11-filters

Prompted me to look at the filters I'm using and now see that they are
MERV 11. Don't know about price difference but sometimes filter may
collapse somewhat and more expensive filter might be sturdier.

I am no filter expert but IIRC if the MERV number is increased then possibly
the blower motor can overload. Research the info on your system to determine
the suitability.

Restricting airflow does NOT overload a blower motor. Restricted
filters restrict the amount of air moved REDUCING load on the blower
motor. Youknew that and forgot - right "tekkie"?


If I am wrong then teach me. I have always been willing to listen.

Plug your vacuum hose and listen to the pitch of the motor. It speeds
up. Power is consumed by moving air. Block the filter and you move
less air, therefore using less power. It's not like a positive
displacement pump like a compressoe - where you WOULD be correct.

One problem with blocked air filters and plugged vacuums (without a
bypass motor) is overheating because less air moves across the motor
to cool it. It overheats not from overloading but undercooling.

I hope that "clare"ifies things for you.

Don't take my word for it.
look at
https://www.cagi.org/news/HowInletCo...pressors. pdf
look at the intake pressure section on page 3 - just after figure 2.

  #42   Report Post  
Old February 12th 19, 03:14 PM posted to alt.home.repair
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Posts: 1,754
Default Furnace filters

Clare Snyder writes:
On Mon, 11 Feb 2019 16:35:25 -0500, Tekkie«
wrote:

Clare Snyder posted for all of us...



On Wed, 6 Feb 2019 14:02:53 -0500, Tekkie« wrote:

Frank posted for all of us...



On 2/4/2019 7:23 PM, Ed Pawlowski wrote:
For the first time in 53 years of owning homes, my new house has a
furnace and uses filters.* It takes a 1" filter.

I see prices can vary considerably but is a MERV 8 and MERV 8 regardless
of the brand?* Should I use MERV 8 or MERV 11?* We have no pets.

I see filters with MERV 11 rating from $9.95 ($7.45ea by a dozen) to
$14.50. Any real difference if they have the same rating?

Discount filters seems cheapest.

I use air filters and had never heard the term MERV so looked up your
question:

https://airexpertsnj.com/knowledge/e...erv-11-filters

Prompted me to look at the filters I'm using and now see that they are
MERV 11. Don't know about price difference but sometimes filter may
collapse somewhat and more expensive filter might be sturdier.

I am no filter expert but IIRC if the MERV number is increased then possibly
the blower motor can overload. Research the info on your system to determine
the suitability.
Restricting airflow does NOT overload a blower motor. Restricted
filters restrict the amount of air moved REDUCING load on the blower
motor. Youknew that and forgot - right "tekkie"?


If I am wrong then teach me. I have always been willing to listen.

Plug your vacuum hose and listen to the pitch of the motor. It speeds
up. Power is consumed by moving air. Block the filter and you move
less air, therefore using less power. It's not like a positive
displacement pump like a compressoe - where you WOULD be correct.

One problem with blocked air filters and plugged vacuums (without a
bypass motor) is overheating because less air moves across the motor
to cool it. It overheats not from overloading but undercooling.

I hope that "clare"ifies things for you.

Don't take my word for it.
look at
https://www.cagi.org/news/HowInletCo...pressors. pdf
look at the intake pressure section on page 3 - just after figure 2.


I thought we were discussing furnace filters. What does an
air compressor have to do with it?

The facts are that the air handler in the furnace needs to work _harder_
when the filter gets dirty. Working _harder_ requires more current.
  #43   Report Post  
Old February 12th 19, 03:37 PM posted to alt.home.repair
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First recorded activity by DIYBanter: Mar 2014
Posts: 11,403
Default Furnace filters

On Tuesday, February 12, 2019 at 9:14:49 AM UTC-5, Scott Lurndal wrote:
Clare Snyder writes:
On Mon, 11 Feb 2019 16:35:25 -0500, Tekkie®
wrote:

Clare Snyder posted for all of us...



On Wed, 6 Feb 2019 14:02:53 -0500, Tekkie® wrote:

Frank posted for all of us...



On 2/4/2019 7:23 PM, Ed Pawlowski wrote:
For the first time in 53 years of owning homes, my new house has a
furnace and uses filters.┬* It takes a 1" filter.

I see prices can vary considerably but is a MERV 8 and MERV 8 regardless
of the brand?┬* Should I use MERV 8 or MERV 11?┬* We have no pets.

I see filters with MERV 11 rating from $9.95 ($7.45ea by a dozen) to
$14.50. Any real difference if they have the same rating?

Discount filters seems cheapest.

I use air filters and had never heard the term MERV so looked up your
question:

https://airexpertsnj.com/knowledge/e...erv-11-filters

Prompted me to look at the filters I'm using and now see that they are
MERV 11. Don't know about price difference but sometimes filter may
collapse somewhat and more expensive filter might be sturdier.

I am no filter expert but IIRC if the MERV number is increased then possibly
the blower motor can overload. Research the info on your system to determine
the suitability.
Restricting airflow does NOT overload a blower motor. Restricted
filters restrict the amount of air moved REDUCING load on the blower
motor. Youknew that and forgot - right "tekkie"?

If I am wrong then teach me. I have always been willing to listen.

Plug your vacuum hose and listen to the pitch of the motor. It speeds
up. Power is consumed by moving air. Block the filter and you move
less air, therefore using less power. It's not like a positive
displacement pump like a compressoe - where you WOULD be correct.

One problem with blocked air filters and plugged vacuums (without a
bypass motor) is overheating because less air moves across the motor
to cool it. It overheats not from overloading but undercooling.

I hope that "clare"ifies things for you.

Don't take my word for it.
look at
https://www.cagi.org/news/HowInletCo...pressors. pdf
look at the intake pressure section on page 3 - just after figure 2.


I thought we were discussing furnace filters. What does an
air compressor have to do with it?

The facts are that the air handler in the furnace needs to work _harder_
when the filter gets dirty. Working _harder_ requires more current.



It would seem to me there are two competing factors. Clare says that a
fan with a dirty filter moves less air, so that means less current. That
certainly would be true, all things being equal. You raise a good point
though, that it's not necessarily just about how much air is moved, but
the force required to pull what air it's moving. If I'm lifting 30
1 lb balls a minute off the floor, it takes X power. If I'm lifting only
20 1 lb balls a minute, it takes a third less power, 0.66X. But if I'm lifting
20 1 lb balls and they are being held back now with a small spring,
representing a dirty filter, then
the power used will be more than .66X. I think in the real world, for an
ordinary blower motor, with a restricted filter it does wind up using less
power with a clogged filter. Ultimately if you clog if enough, the blower
winds up cavitating and the power drops even more. The new ECM, variable
speed blowers though, I think behave differently and may use more power
with a clogged filter.
  #44   Report Post  
Old February 12th 19, 07:23 PM posted to alt.home.repair
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First recorded activity by DIYBanter: Jul 2006
Posts: 30,225
Default Furnace filters



"trader_4" wrote in message
...
On Tuesday, February 12, 2019 at 9:14:49 AM UTC-5, Scott Lurndal wrote:
Clare Snyder writes:
On Mon, 11 Feb 2019 16:35:25 -0500, Tekkie®
wrote:

Clare Snyder posted for all of us...



On Wed, 6 Feb 2019 14:02:53 -0500, Tekkie®
wrote:

Frank posted for all of us...



On 2/4/2019 7:23 PM, Ed Pawlowski wrote:
For the first time in 53 years of owning homes, my new house has
a
furnace and uses filters. It takes a 1" filter.

I see prices can vary considerably but is a MERV 8 and MERV 8
regardless
of the brand? Should I use MERV 8 or MERV 11? We have no pets.

I see filters with MERV 11 rating from $9.95 ($7.45ea by a
dozen) to
$14.50. Any real difference if they have the same rating?

Discount filters seems cheapest.

I use air filters and had never heard the term MERV so looked up
your
question:

https://airexpertsnj.com/knowledge/e...erv-11-filters

Prompted me to look at the filters I'm using and now see that they
are
MERV 11. Don't know about price difference but sometimes filter
may
collapse somewhat and more expensive filter might be sturdier.

I am no filter expert but IIRC if the MERV number is increased then
possibly
the blower motor can overload. Research the info on your system to
determine
the suitability.
Restricting airflow does NOT overload a blower motor. Restricted
filters restrict the amount of air moved REDUCING load on the blower
motor. Youknew that and forgot - right "tekkie"?

If I am wrong then teach me. I have always been willing to listen.
Plug your vacuum hose and listen to the pitch of the motor. It speeds
up. Power is consumed by moving air. Block the filter and you move
less air, therefore using less power. It's not like a positive
displacement pump like a compressoe - where you WOULD be correct.

One problem with blocked air filters and plugged vacuums (without a
bypass motor) is overheating because less air moves across the motor
to cool it. It overheats not from overloading but undercooling.

I hope that "clare"ifies things for you.

Don't take my word for it.
look at
https://www.cagi.org/news/HowInletCo...pressors. pdf
look at the intake pressure section on page 3 - just after figure 2.


I thought we were discussing furnace filters. What does an
air compressor have to do with it?

The facts are that the air handler in the furnace needs to work _harder_
when the filter gets dirty. Working _harder_ requires more current.



It would seem to me there are two competing factors. Clare says that a
fan with a dirty filter moves less air, so that means less current. That
certainly would be true, all things being equal. You raise a good point
though, that it's not necessarily just about how much air is moved, but
the force required to pull what air it's moving. If I'm lifting 30
1 lb balls a minute off the floor, it takes X power. If I'm lifting only
20 1 lb balls a minute, it takes a third less power, 0.66X. But if I'm
lifting
20 1 lb balls and they are being held back now with a small spring,
representing a dirty filter, then the power used will be more than .66X.


I think in the real world, for an ordinary blower motor, with a restricted
filter it does wind up using less power with a clogged filter.


ThatÔÇÖs mad and trivial to prove by measuring the power the
blower is taking with a clogged filter and with the new filter.

Ultimately if you clog if enough, the blower winds
up cavitating and the power drops even more.


Blowers donÔÇÖt get that clogged.

The new ECM, variable speed blowers though, I think behave
differently and may use more power with a clogged filter.


Even madder.

  #45   Report Post  
Old February 12th 19, 08:23 PM posted to alt.home.repair
external usenet poster
 
First recorded activity by DIYBanter: Jun 2017
Posts: 1,185
Default Furnace filters

Clare Snyder posted for all of us...



On Mon, 11 Feb 2019 16:35:25 -0500, Tekkie«
wrote:

Clare Snyder posted for all of us...



On Wed, 6 Feb 2019 14:02:53 -0500, Tekkie« wrote:

Frank posted for all of us...



On 2/4/2019 7:23 PM, Ed Pawlowski wrote:
For the first time in 53 years of owning homes, my new house has a
furnace and uses filters.* It takes a 1" filter.

I see prices can vary considerably but is a MERV 8 and MERV 8 regardless
of the brand?* Should I use MERV 8 or MERV 11?* We have no pets.

I see filters with MERV 11 rating from $9.95 ($7.45ea by a dozen) to
$14.50. Any real difference if they have the same rating?

Discount filters seems cheapest.

I use air filters and had never heard the term MERV so looked up your
question:

https://airexpertsnj.com/knowledge/e...erv-11-filters

Prompted me to look at the filters I'm using and now see that they are
MERV 11. Don't know about price difference but sometimes filter may
collapse somewhat and more expensive filter might be sturdier.

I am no filter expert but IIRC if the MERV number is increased then possibly
the blower motor can overload. Research the info on your system to determine
the suitability.
Restricting airflow does NOT overload a blower motor. Restricted
filters restrict the amount of air moved REDUCING load on the blower
motor. Youknew that and forgot - right "tekkie"?


If I am wrong then teach me. I have always been willing to listen.

Plug your vacuum hose and listen to the pitch of the motor. It speeds
up. Power is consumed by moving air. Block the filter and you move
less air, therefore using less power. It's not like a positive
displacement pump like a compressoe - where you WOULD be correct.

One problem with blocked air filters and plugged vacuums (without a
bypass motor) is overheating because less air moves across the motor
to cool it. It overheats not from overloading but undercooling.

I hope that "clare"ifies things for you.

Don't take my word for it.
look at
https://www.cagi.org/news/HowInletCo...pressors. pdf
look at the intake pressure section on page 3 - just after figure 2.


Okay, I looked at HVAC TALK and they measured the amp draw which was less
with a dirty filter. They mentioned two types of motors. I stand corrected.

I was thinking? that the motor would not be running at rated cooling and
tend to overheat over time and crap out.

--
Tekkie


  #46   Report Post  
Old February 12th 19, 09:47 PM posted to alt.home.repair
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First recorded activity by DIYBanter: Nov 2017
Posts: 1,675
Default Furnace filters

On Tue, 12 Feb 2019 14:14:45 GMT, (Scott Lurndal)
wrote:

Clare Snyder writes:
On Mon, 11 Feb 2019 16:35:25 -0500, Tekkie«
wrote:

Clare Snyder posted for all of us...



On Wed, 6 Feb 2019 14:02:53 -0500, Tekkie« wrote:

Frank posted for all of us...



On 2/4/2019 7:23 PM, Ed Pawlowski wrote:
For the first time in 53 years of owning homes, my new house has a
furnace and uses filters.* It takes a 1" filter.

I see prices can vary considerably but is a MERV 8 and MERV 8 regardless
of the brand?* Should I use MERV 8 or MERV 11?* We have no pets.

I see filters with MERV 11 rating from $9.95 ($7.45ea by a dozen) to
$14.50. Any real difference if they have the same rating?

Discount filters seems cheapest.

I use air filters and had never heard the term MERV so looked up your
question:

https://airexpertsnj.com/knowledge/e...erv-11-filters

Prompted me to look at the filters I'm using and now see that they are
MERV 11. Don't know about price difference but sometimes filter may
collapse somewhat and more expensive filter might be sturdier.

I am no filter expert but IIRC if the MERV number is increased then possibly
the blower motor can overload. Research the info on your system to determine
the suitability.
Restricting airflow does NOT overload a blower motor. Restricted
filters restrict the amount of air moved REDUCING load on the blower
motor. Youknew that and forgot - right "tekkie"?

If I am wrong then teach me. I have always been willing to listen.

Plug your vacuum hose and listen to the pitch of the motor. It speeds
up. Power is consumed by moving air. Block the filter and you move
less air, therefore using less power. It's not like a positive
displacement pump like a compressoe - where you WOULD be correct.

One problem with blocked air filters and plugged vacuums (without a
bypass motor) is overheating because less air moves across the motor
to cool it. It overheats not from overloading but undercooling.

I hope that "clare"ifies things for you.

Don't take my word for it.
look at
https://www.cagi.org/news/HowInletCo...pressors. pdf
look at the intake pressure section on page 3 - just after figure 2.


I thought we were discussing furnace filters. What does an
air compressor have to do with it?

The facts are that the air handler in the furnace needs to work _harder_
when the filter gets dirty. Working _harder_ requires more current.

No - you are wrong. The squirrel cage blower of a furnace IS an "air
compressor" - and not a positive displacement one. Power consumption
is rependant and the mass of air moved, and a furnace blower draws
LESS current with a blocked filter. It draws more current per cu ft
(or lb) of air moved, but the decrease in air moved is much larger
than the "efficiency" in watts per cu ft, so the blower draws less
current.
The effect is less than in a "turbine" type blower - but it is VERY
real.


here are some actual measurements gleaned from other sources:

Dirty filters drop the amps - Less airflow equals less amperage.
Here ya go info on a squirrel cage
Low speed
filter quality amps
none n/a 7.4
panel clean 7.05
pleated clean 6.75
pleated dirty 5.4

High speed
none - n/a 13.10
panel - clean 12.92
pleat - clean 12.77
pleat - a bit dirty 12.70
pleat - dirty 12.30
pleat ~90%; blocked 12.20

Notice that on low speed with no filter the blower drew 7.4 amps, and
with a dirty pleated filter that dropped to 5.4 - a drop of 2 amps -
or 37%

On high speed the fan with no filter drew 13.1 amps and with a 90%
blocked filter that dropped to 12.2 - a drop of .9 amps - 0r about
6.9%

At high speed the percentage drop in air flow was less than at low
speed - but still significant - and more significant - the current
DROPPED in both cases with restricted filters.
  #47   Report Post  
Old February 12th 19, 09:55 PM posted to alt.home.repair
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First recorded activity by DIYBanter: Nov 2017
Posts: 1,675
Default Furnace filters

On Tue, 12 Feb 2019 14:23:06 -0500, Tekkie«
wrote:

Clare Snyder posted for all of us...



On Mon, 11 Feb 2019 16:35:25 -0500, Tekkie«
wrote:

Clare Snyder posted for all of us...



On Wed, 6 Feb 2019 14:02:53 -0500, Tekkie« wrote:

Frank posted for all of us...



On 2/4/2019 7:23 PM, Ed Pawlowski wrote:
For the first time in 53 years of owning homes, my new house has a
furnace and uses filters.* It takes a 1" filter.

I see prices can vary considerably but is a MERV 8 and MERV 8 regardless
of the brand?* Should I use MERV 8 or MERV 11?* We have no pets.

I see filters with MERV 11 rating from $9.95 ($7.45ea by a dozen) to
$14.50. Any real difference if they have the same rating?

Discount filters seems cheapest.

I use air filters and had never heard the term MERV so looked up your
question:

https://airexpertsnj.com/knowledge/e...erv-11-filters

Prompted me to look at the filters I'm using and now see that they are
MERV 11. Don't know about price difference but sometimes filter may
collapse somewhat and more expensive filter might be sturdier.

I am no filter expert but IIRC if the MERV number is increased then possibly
the blower motor can overload. Research the info on your system to determine
the suitability.
Restricting airflow does NOT overload a blower motor. Restricted
filters restrict the amount of air moved REDUCING load on the blower
motor. Youknew that and forgot - right "tekkie"?

If I am wrong then teach me. I have always been willing to listen.

Plug your vacuum hose and listen to the pitch of the motor. It speeds
up. Power is consumed by moving air. Block the filter and you move
less air, therefore using less power. It's not like a positive
displacement pump like a compressoe - where you WOULD be correct.

One problem with blocked air filters and plugged vacuums (without a
bypass motor) is overheating because less air moves across the motor
to cool it. It overheats not from overloading but undercooling.

I hope that "clare"ifies things for you.

Don't take my word for it.
look at
https://www.cagi.org/news/HowInletCo...pressors. pdf
look at the intake pressure section on page 3 - just after figure 2.


Okay, I looked at HVAC TALK and they measured the amp draw which was less
with a dirty filter. They mentioned two types of motors. I stand corrected.

I was thinking? that the motor would not be running at rated cooling and
tend to overheat over time and crap out.

That is true of cheap vacuums which are cooled by the exhaust air
going through the motor, which is why tangential bypass motors are
used in high quality vacuums. A tangential bypass motor actually cools
BETTER when the airflow is restricted,(because the cooling fan is
running faster and moving more air) while a flow through motor WILL
overheat and burn out with a blocked hose or full bag.
  #48   Report Post  
Old February 14th 19, 04:53 PM posted to alt.home.repair
external usenet poster
 
First recorded activity by DIYBanter: Jan 2016
Posts: 24
Default Furnace filters

It depends on the design of the impeller blades.
Most vacuum cleaners speed up when the airflow is blocked.
But if the blades are of a different design, it could be the
other way round.

If you are a real geek, get a couple of probe thermometers.
Stick one in the intake plenum and one in the output plenum
and even amhigh temp one in the flue.
Mark down what the normal temps are and if anything changes
you know something needs fixed. Works for AC too.
M


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