Mikepier wrote:
A few weeks ago I posted a problem with too much negative air pressure
in my house caused by my attic fan. The motor I have on the fan is
similiar to this.

http://www.amazon.com/gp/product/B00...TM0Q87VFEGEJM8

I wanted to get somekind of speed controller to slow down the speed of
the fan. I've seen them on Broan's website, and they are rated for 6
amps.
Any issues if I put the motor on a rheostat? Are these motors designed
to work on low voltage?

I already told about my green plug, slows fan down 10-30% depending on
motor and load.

Grab the old incense stick and check all wall outlets, switches, pot
lights, etc. With Ac off also check all air vents. Most tend to have leaks
to the attic when mounted in walls.


While your at it, you can do a check of leaks in windows, doors, etc.

I use my fans to do an energy audit.



Greg

"Mikepier" wrote in message
...
This is a roof mouted fan, not a whole -house fan.

I don't have issues with my furnace since in the cold weather, the
attic fan is off anyway. Its my water heater I have issues with.

I have a pull-down attic stairs in the second floor hallway. I know
it's not 100% sealed, but for the most part its pretty tight.

I hadn't read about your match test, b/4 I posted about the flue size. I
would suggest as I seen someone else suggest, open a window or two when
your attic fan is on. Then, do the match test at the flue hood of WH. If it
doesn't go out, you know you have a deficiency in your thermal envelope.

I would also do a match test with the attic fan running, away from the
exhaust hood, with windows closed. Think close to the wall where a _chase_
for the chimney would be.

Depending on the test with a window open, I would start thinking leakage
around light fixtures, electrical going into attic through top plates, the
pull down staircase for starters.

Does your water heater have a standing pilot, or electronic pilot?

Standing pilot

Did you do this match test when the main burners on the water heater
were on, or off?

Both, and both times the flame was blown out with the attic fan on

What is the condition of your home's windows and doors?

Fairly new

Do you think you have an ultra-sealed house? *A house that's so air
tight that the only place that negative pressure can be relieved is
through your water heater flue stack?

I honestly don't think my house is air-tite, but obviously the attic
fan is pulling the air somehow.

Is your furnace near your water heater? *Does it have open or closed
combustion venting (ie - is it high efficiency?).

I don't believe it's high efficiency. It's a Trane XR80, the exhaust
goes out on its own 6" duct, which by the way when I do a flame test
on the furnace duct without the water heater or furnace running, the
flame gets blown out also.

What happens when you have the attic fan turned on, and you open a
window (a high window - second floor if you have one - you haven't said
if this is a single story or 2 story home). *What happens with this
match test if the attic fan is on and you have a window open?

If I open a window or door, the backdraft problem goes away. Once I
close the door or window, it takes a couple of minutes for the
backdraft problem to appear again.
This is in a 2 story split house.


But I still wouldn't expect an attic (roof) fan to significantly
depressurize an entire house, unless you have the following MAJOR
problems:

1) you have insufficient passive soffit or gable venting (you haven't
said if you have soffits or a roof overhang)

I have vented soffits, but I mentioned I also have 2 roof vents and a
gable vent.

2) you have gaps in the ceiling that connects your household airspace
with the attic airspace (perhaps where interior walls meet the attic, in
closets, etc). *Generally hard to see areas.

I can't really see anything unusual.

3) Where are interior fans (kitchen, bathroom) vented? *Into the attic,
or through the attic directly to the outside?

Through the attic to the outside , and they are sealed rigid duct.

You need to tell us more about 1, 2 and 3. *If you're too disinterested,
motivated or lazy to come up with an answer to those questions, then you
are not really serious about fixing your home and making it right, and
all of our efforts here are wasted on you.

You've obviously misjudged me for someone else.

On Tue, 23 Aug 2011 15:45:36 +0000 (UTC), gregz
wrote:

Mikepier wrote:
A few weeks ago I posted a problem with too much negative air pressure
in my house caused by my attic fan. The motor I have on the fan is
similiar to this.

http://www.amazon.com/gp/product/B00...TM0Q87VFEGEJM8

I wanted to get somekind of speed controller to slow down the speed of
the fan. I've seen them on Broan's website, and they are rated for 6
amps.
Any issues if I put the motor on a rheostat? Are these motors designed
to work on low voltage?

I already told about my green plug, slows fan down 10-30% depending on
motor and load.

Grab the old incense stick and check all wall outlets, switches, pot
lights, etc. With Ac off also check all air vents. Most tend to have leaks
to the attic when mounted in walls.


While your at it, you can do a check of leaks in windows, doors, etc.

I use my fans to do an energy audit.


Probably getting around the basement sill plates, HVAC ducting and
piping, then up through the walls and into the attic.
In my house, circa 1959, none of that is sealed.
Haven't looked at the attic sills, but I'm sure they're not sealed
either.
I don't think they sell green plugs any more.
You have the right idea, but he should go after the basement overhead
first if wants to solve the attic fan induced downdraft in the water
heater vent.
Somebody wrote about a thermal switch between HW and attic fan and
that's a good solution too.
Personally, if the draft didn't take long to be established with the
attic fan running, I'd put the horizontal diverter back in.
This is what they look like, and Mike had one on his old heater.
http://www.standexadp.com/specs.php?spec=28
That would prevent pilot blow-out and overheating the top of the tank.
I never had a pilot blow out with these but have with the hood style
diverter.
I'm not sure about spillage, but just guess it would be less.
You also need a CO detector nearby to play it safe.
This isn't a new draft problem, just a new water heater and venting.

--Vic

On Aug 23, 12:26*pm, Vic Smith
wrote:
On Tue, 23 Aug 2011 15:45:36 +0000 (UTC), gregz
wrote:





Mikepier wrote:
A few weeks ago I posted a problem with too much negative air pressure
in my house caused by my attic fan. The motor I have on the fan is
similiar to this.

http://www.amazon.com/gp/product/B00...k2_dp_sr_1?pf_....

I wanted to get somekind of speed controller to slow down the speed of
the fan. I've seen them on Broan's website, and they are rated for 6
amps.
Any issues if I put the motor on a rheostat? Are these motors designed
to work on low voltage?

I already told about my green plug, slows fan down 10-30% depending on
motor and load.

Grab the old incense stick and check all wall outlets, switches, pot
lights, etc. With Ac off also check all air vents. Most tend to have leaks
to the attic when mounted in walls.

While your at it, you can do a check of leaks in windows, doors, etc.

I use my fans to do an energy audit.

Probably getting around the basement sill plates, HVAC ducting and
piping, then up through the walls and into the attic.
In my house, circa 1959, none of that is sealed.
Haven't looked at the attic sills, but I'm sure they're not sealed
either.
I don't think they sell green plugs any more.
You have the right idea, but he should go after the basement overhead
first if wants to solve the attic fan induced downdraft in the water
heater vent.
Somebody wrote about a thermal switch between HW and attic fan and
that's a good solution too.
Personally, if the draft didn't take long to be established with the
attic fan running, I'd put the horizontal diverter back in.
This is what they look like, and Mike had one on his old heater.http://www.standexadp.com/specs.php?spec=28
That would prevent pilot blow-out and overheating the top of the tank.
I never had a pilot blow out with these but have with the hood style
diverter.
I'm not sure about spillage, but just guess it would be less.
You also need a CO detector nearby to play it safe.
This isn't a new draft problem, just a new water heater and venting.

--Vic- Hide quoted text -

- Show quoted text -

What exactly does that diverter do? It is open on the bottom, right?
Thats what I had on my old water heater. Plus whoever installed the
previous water heater eliminated the draft hood for some reason, and
just put the 3" duct directly on top of the exhaust outlet. Now I'm
wondering if they did this because of the backdraft problem.

On Aug 23, 10:50*am, Home Guy wrote:
" wrote:
If he really does have a reverse airflow through his flue caused
by his roof fan, then a chimney liner is going to do ****-all to
help that situation.

Excuse me, ignoramus, but first, *if you look at that in context,
which you did not, the problem I was specifically referring
to the chimney liner solving is the case where the chimney
is too large for the water heater.

You can't say that his chimney is too large unless you know if he lives
in a northern climate and if he has a high-efficiency furnace.

That is why I never said that his chimney is too large.
I only stated that the chimney needs to be correctly
sized to the appliance, in this case a water heater.




In a northern climate, you can have condensation inside the chimney if
there is not enough total combustion flow (furnace + water heater).
Normally for a regular furnace, it's putting out enough exhaust to keep
a good convective heat flow going and "help" the water heater flue stack
flow.

In the summer, there really isin't a problem with needed help from the
furnace (which you won't get anyways because the furnace doesn't run in
the summer). *The water heater exhaust flow should have no problem
getting up and out the chimney in the summer. *Now if you have a reverse
air-flow in the chimney, then nothing you can do to the chimney
(including using a liner) is going to help with that.

Answer me this. Have you ever lit a fire in a fireplace?
Does the fireplace draw air the same when you light
the first piece of paper as it does when the fire is hot?
Do you think this principle is unique to a fireplace?
Or will a water heater on a correctly sized chimney have
a better draft because the hot air stays hot, fills the whole
chimney and rises, pulling more combustion products
behind it?



So unless you know what type of furnace he has, and just how cold it
gets where he lives, then you can't say that he *needs* a liner for his
water heater exhaust. *

Again, you must have a reading comprehension problem.
I never said he needs a chimney liner. I only said that
if the chimney is too large for what's connected to it,
then he needs a chimney liner.



And like I said before, even in cold climates it's standard to have a
non-lined chimney and have furnace and water-heater exhaust run
passively up and out the chimney.

Uh huh.

*It's only when you have a
high-efficiency furnace do you start to look at using a draft motor or a
liner to help the water-heater exhaust.

Don't know what you're talking about here. I've never
heard of anyone looking at using a "draft motor" to
help the water heater exhaust. I've
heard of people buying high efficiency furnaces or
water heaters that have them.



And second, having the flue correctly sized to the appliance
helps create the correct draft.

**** the draft, and the sizing. *This isn't rocket science. *

So says you, the ignoramus. The NFPA and local codes
say that while it isn't rocket science, it is science and
there are standards for chimney sizing related to what
it's connected to for safety and proper operation. A
chimney needs to be in a certain size range. Too big
or too small, neither is good.




When you've got something creating a negative pressure in the house,
causing reverse air-flow through the water heater flue, then you put
down your books and graphs and tables and you fix the reverse air
problem.

If the flue is sized correctly the hot gas stays hot and rises.

Again, you're completely disregarding the whole point that started this
thread.

Not disregarding anything here.



This boob thinks that he's getting a breeze flowing into his water
heater exhast flue and blowing out a match that he holds against the
draft intake vent (presumably the gap between the water heater and the
flue intake above it).

None of your correctly-sized **** is going to make that breeze go away.

I'll leave it for others to decide who the real boob is here.

On Aug 23, 12:14*pm, Mikepier wrote:
Does your water heater have a standing pilot, or electronic pilot?

Standing pilot

Did you do this match test when the main burners on the water heater
were on, or off?

Both, and both times the flame was blown out with the attic fan on

What is the condition of your home's windows and doors?

Fairly new

Do you think you have an ultra-sealed house? *A house that's so air
tight that the only place that negative pressure can be relieved is
through your water heater flue stack?

I honestly don't think my house is air-tite, but obviously the attic
fan is pulling the air somehow.

Is your furnace near your water heater? *Does it have open or closed
combustion venting (ie - is it high efficiency?).

I don't believe it's high efficiency. It's a Trane XR80, the exhaust
goes out on its own 6" duct, which by the way when I do a flame test
on the furnace duct without the water heater or furnace running, the
flame gets blown out also.

What happens when you have the attic fan turned on, and you open a
window (a high window - second floor if you have one - you haven't said
if this is a single story or 2 story home). *What happens with this
match test if the attic fan is on and you have a window open?

If I open a window or door, the backdraft problem goes away. Once I
close the door or window, it takes a couple of minutes for the
backdraft problem to appear again.
This is in a 2 story split house.

But I still wouldn't expect an attic (roof) fan to significantly
depressurize an entire house, unless you have the following MAJOR
problems:

1) you have insufficient passive soffit or gable venting (you haven't
said if you have soffits or a roof overhang)

I have vented soffits, but I mentioned I also have 2 roof vents and a
gable vent.

2) you have gaps in the ceiling that connects your household airspace
with the attic airspace (perhaps where interior walls meet the attic, in
closets, etc). *Generally hard to see areas.

I can't really see anything unusual.

3) Where are interior fans (kitchen, bathroom) vented? *Into the attic,
or through the attic directly to the outside?

Through the attic to the outside , and they are sealed rigid duct.

You need to tell us more about 1, 2 and 3. *If you're too disinterested,
motivated or lazy to come up with an answer to those questions, then you
are not really serious about fixing your home and making it right, and
all of our efforts here are wasted on you.

You've obviously misjudged me for someone else.

Is there any path direct from the basement to the attic?
A chimney chase? Other chase? Unconnected extra
HVAC duct?

It would seem more likely that would be needed to
draw significant air from the basement to the attic than for it
to happen by going through the living space.

On Tue, 23 Aug 2011 10:44:32 -0700 (PDT), Mikepier
wrote:

On Aug 23, 12:26Â*pm, Vic Smith


Probably getting around the basement sill plates, HVAC ducting and
piping, then up through the walls and into the attic.
In my house, circa 1959, none of that is sealed.
Haven't looked at the attic sills, but I'm sure they're not sealed
either.
I don't think they sell green plugs any more.
You have the right idea, but he should go after the basement overhead
first if wants to solve the attic fan induced downdraft in the water
heater vent.
Somebody wrote about a thermal switch between HW and attic fan and
that's a good solution too.
Personally, if the draft didn't take long to be established with the
attic fan running, I'd put the horizontal diverter back in.
This is what they look like, and Mike had one on his old heater.http://www.standexadp.com/specs.php?spec=28
That would prevent pilot blow-out and overheating the top of the tank.
I never had a pilot blow out with these but have with the hood style
diverter.
I'm not sure about spillage, but just guess it would be less.
You also need a CO detector nearby to play it safe.
This isn't a new draft problem, just a new water heater and venting.

--Vic- Hide quoted text -

- Show quoted text -

What exactly does that diverter do? It is open on the bottom, right?

Diverts the backdraft, same thing the vertical hood diverter is
supposed to do.
But it works better.
There's a flat baffle plate that runs half way down the box,
interrupting the air/gas flow.
A backdraft hits that plate and dumps out the bottom of the box.
Never hits the top of the heater flue, where it can blow out the
pilot.
Hot gasses from the heater also hit the baffle, and drop down.
But those hot gases rise back up at the bottom of the baffle, and
continue up the vent..
Elegantly simple.

Thats what I had on my old water heater. Plus whoever installed the
previous water heater eliminated the draft hood for some reason, and
just put the 3" duct directly on top of the exhaust outlet. Now I'm
wondering if they did this because of the backdraft problem.

I saw somewhere that the hood type diverters came into play in 1992.
Your old heater was probably just an original installation.
Unless you know the heater was put in after that time.
I noticed the one in the pic showing your old installation, and
remembered examining and moving mine while doing some chimney sealing
in my old house. I figured out its purpose out of curiousity.
I also think I left it on when I put in a new heater with a dome vent.
But it is really amazing how you can find absolutely no information on
horizontal diverters on the net.
Everything I said is from memory, not the net.
All the so-called experts in the HVAC forums never mention it when
answering questions about how to stop downdraft from blowing out
pilots or melting plastic on the top of tanks.
Now me and the other folks in this group who happened to read this are
the only ones who know about horizontal diverters.

--Vic

Vic Smith wrote:

Now me and the other folks in this group who happened to read this
are the only ones who know about horizontal diverters.

This guy doesn't need a horizontal diverter.

His pilot isin't being blown out.

If you've got a constant down-draft in the chimney caused by negative
air pressure inside the house, your horizontal divertor will do squat at
helping exhaust from the water heater to make it up and out the chimney.

So are you going to keep telling him he needs a horizontal divertor?

On Tue, 23 Aug 2011 22:58:31 -0400, Home Guy wrote:

Vic Smith wrote:

Now me and the other folks in this group who happened to read this
are the only ones who know about horizontal diverters.

This guy doesn't need a horizontal diverter.

His pilot isin't being blown out.


I must have confused that with the match blowing out during his
testing, and all the crap I've read on the net.

If you've got a constant down-draft in the chimney caused by negative
air pressure inside the house, your horizontal divertor will do squat at
helping exhaust from the water heater to make it up and out the chimney.


Maybe, maybe not. It for sure would dump the heat elsewhere instead
of melting the plastic atop his heater.
And he never said how long it took the draft to get established when
the heater went on with the attic fan running.
My reading indicates spillage is pretty standard for up to a minute.

So are you going to keep telling him he needs a horizontal divertor?

Only if it's acceptable to him, and it works for him.
Since his pilot isn't blowing out it would just move spillage away
from the heater top. Burnt plastic atop the heater appears to be a
fairly common occurrence.
Here's my order of preference, "by the book."
1. Crack open a basement window during attic fan season.
Easy, and he said that works.
2. Thermal switch between heater and attic fan. Moderate job.
3. Seal the basement so attic fan has no effect. Big job.
4. Modify chimney for better draft - if possible. Big job.


Throwing out most of the book, here's what I'd do.
1. Crack open a window if it doesn't affect anything else.
2. If the cracked open window wasn't acceptable, I'd measure how long
it took a draft to establish with attic fan running.
If less than a minute I'd forget about it except to make sure I had a
working CO detector near the heater.
If the heat melting the plastic bothered me, I'd add a horizontal
diverter. Then I'd check spillage again.
That would the interesting part.
Anything I did that wouldn't keep spillage under a minute would get me
back to the "by the book" list.

--Vic

Vic Smith wrote:

This guy doesn't need a horizontal diverter.

His pilot isin't being blown out.

I must have confused that with the match blowing out during his
testing, and all the crap I've read on the net.

What the hell is wrong with you people?

He holds a match near the gap where his draft hood meets the water
heater, and the match goes out.

He says his pilot (way down at the bottom of the heater) does not get
blown out.

Why he even thought he should even check to see if he's getting a breeze
blowing out of the draft hood - I don't know.

If you've got a constant down-draft in the chimney caused by
negative air pressure inside the house, your horizontal divertor
will do squat at helping exhaust from the water heater to make
it up and out the chimney.

Maybe, maybe not.

I see that basic physics is beyond your grasp.

It for sure would dump the heat elsewhere

He doesn't have a problem with "dumping heat".

And by the way, if a divertor is dumping heat to some other place
besides the flue, what does that tell you about where you're dumping the
combustion exhaust gases?

And he never said how long it took the draft to get established
when the heater went on with the attic fan running.

I don't think he even said it ever gets established with the roof fan
running.

So are you going to keep telling him he needs a horizontal divertor?

Only if it's acceptable to him, and it works for him.

He's a boob because he doesn't want to climb a ladder or pick up a saw
and cut some more holes in his soffit.

I wonder if he really knows how much of his soffet venting is actually
clear vs obstructed?

Does he have insulation jammed into the corners of the roof line,
obstructing his soffits?

He obviously must have a direct path in his house from attic to basement
that he doesn't know about.

Since his pilot isn't blowing out it would just move spillage away
from the heater top.

What spillage?

WTF are you talking about?

Burnt plastic atop the heater appears to be a fairly common
occurrence.

The OP (Mikepier) has NOT SAID (at least not in this thread) anything
about burnt or melted plastic on his water heater.

Here's my order of preference, "by the book."
1. Crack open a basement window during attic fan season.

Bull****.

If you don't have enough ventilation in the attic (soffits, gable ends)
then why bother running the roof fan in the first place?

2. Thermal switch between heater and attic fan. Moderate job.

More bull****.

3. Seal the basement so attic fan has no effect. Big job.

He should find out why there is such an easy path between his attic
space and the rest of the house / basement, and close that path.

4. Modify chimney for better draft - if possible. Big job.

That won't help if there's still a negative pressure inside the house or
basement caused by the roof fan. Why is that concept so hard for you to
understand?

The **ONLY** way you can have proper drafting for the furnace and water
heater in his case if he allows his house to achieve a negative pressure
is to seal the room or the area where his furnace and water heater is,
and give them a new combustion air intake from the outside.

Or he can turn his furnace and water heater into a closed system by
bringing sealed ductwork directly to the combustion air intake vents or
the cabinets and running that ductwork to a dedicated outside air
intake, and then use lots of aluminized tape to seal up his furnace and
water heater so there is a completely closed path from from the outside
air intake to the furnace / WH to the exaust flue to the chimney.

On Aug 24, 12:43*am, Home Guy wrote:
Vic Smith wrote:
This guy doesn't need a horizontal diverter.

His pilot isin't being blown out.

I must have confused that with the match blowing out during his
testing, and all the crap I've read on the net.

What the hell is wrong with you people?

He holds a match near the gap where his draft hood meets the water
heater, and the match goes out. *

He says his pilot (way down at the bottom of the heater) does not get
blown out.

Why he even thought he should even check to see if he's getting a breeze
blowing out of the draft hood - I don't know.

What the hell is wrong with you people? He told us he
started checking because he noticed the plastic
on the pipes at the top of the water heater were melted.




If you've got a constant down-draft in the chimney caused by
negative air pressure inside the house, your horizontal divertor
will do squat at helping exhaust from the water heater to make
it up and out the chimney.

Maybe, maybe not.

I see that basic physics is beyond your grasp.

It for sure would dump the heat elsewhere

He doesn't have a problem with "dumping heat". *

And by the way, if a divertor is dumping heat to some other place
besides the flue, what does that tell you about where you're dumping the
combustion exhaust gases?

And he never said how long it took the draft to get established
when the heater went on with the attic fan running.

I don't think he even said it ever gets established with the roof fan
running.

So are you going to keep telling him he needs a horizontal divertor?

Only if it's acceptable to him, and it works for him.

He's a boob because he doesn't want to climb a ladder or pick up a saw
and cut some more holes in his soffit.

I wonder if he really knows how much of his soffet venting is actually
clear vs obstructed?

Does he have insulation jammed into the corners of the roof line,
obstructing his soffits?

He obviously must have a direct path in his house from attic to basement
that he doesn't know about.

Since his pilot isn't blowing out it would just move spillage away
from the heater top.

What spillage?

WTF are you talking about?

Burnt plastic atop the heater appears to be a fairly common
occurrence.

The OP (Mikepier) has NOT SAID (at least not in this thread) anything
about burnt or melted plastic on his water heater.


He sure did in the other thread he referred to when he made
the first post in this thread. I even gave you a link to it
yesterday. I would think a guy who's so interested in this
and spends half his time cursing and calling other people
lazy boobs would have read it by now. But obviously that is
expecting too much





Here's my order of preference, "by the book."
1. Crack open a basement window during attic fan season.

Bull****. *

If you don't have enough ventilation in the attic (soffits, gable ends)
then why bother running the roof fan in the first place?

2. Thermal switch between heater and attic fan. *Moderate job.

More bull****.

3. Seal the basement so attic fan has no effect. *Big job.

He should find out why there is such an easy path between his attic
space and the rest of the house / basement, and close that path.

4. Modify chimney for better draft - if possible. *Big job.

That won't help if there's still a negative pressure inside the house or
basement caused by the roof fan. *Why is that concept so hard for you to
understand?

The **ONLY** way you can have proper drafting for the furnace and water
heater in his case if he allows his house to achieve a negative pressure
is to seal the room or the area where his furnace and water heater is,
and give them a new combustion air intake from the outside.

Nonsense. You can get proper drafting by providing a fixed
ventilation
opening to outside for the basement in the area of the water heater
and furnace.




Or he can turn his furnace and water heater into a closed system by
bringing sealed ductwork directly to the combustion air intake vents or
the cabinets and running that ductwork to a dedicated outside air
intake, and then use lots of aluminized tape to seal up his furnace and
water heater so there is a completely closed path from from the outside
air intake to the furnace / WH to the exaust flue to the chimney.

I'm sure that hack job with tape will impress the code inspector
or the home inspector if he sells the place.
But what should we expect from the guy who claims that proper
chimney sizing for appliances doesn't matter.

" wrote:

What the hell is wrong with you people? He told us he
started checking because he noticed the plastic
on the pipes at the top of the water heater were melted.

I don't know what you're talking about.

The ONLY posts that I see Mikepier posting in is this thread, with the
subject "Putting speed control on attic fan". If he started an older
thread about melted plastic on water heaters, then I didn't read it at
the time, or he didn't post it to this newsgroup.

He hasn't said anything about melted plastic in this thread.

The OP (Mikepier) has NOT SAID (at least not in this thread)
anything about burnt or melted plastic on his water heater.

He sure did in the other thread he referred to when he made
the first post in this thread.

Read my statement more carefully. I said "at least not in this thread".

My 4-year-old water heater also has melted disks of read and blue
plastic surrounding the two water pipes (hot and cold) at the top of the
tank. I don't have a negative air-pressure situation in the house. The
melted plastic doesn't bother me.

The **ONLY** way you can have proper drafting for the furnace and
water heater in his case if he allows his house to achieve a negative
pressure is to seal the room or the area where his furnace and water
heater is, and give them a new combustion air intake from the outside.

Nonsense. You can get proper drafting by providing a fixed
ventilation opening to outside for the basement in the area of
the water heater and furnace.

Why can't you read properly?

Look what I said:

"and give them a new combustion air intake from the outside"

Look what you just wrote:

"by providing a fixed ventilation opening to outside for the basement"

You look like a fool when you disagree with me, and then go on to give
the same answer using different wording.

Or he can turn his furnace and water heater into a closed system by
bringing sealed ductwork directly to the combustion air intake
vents or the cabinets and running that ductwork to a dedicated
outside air intake, and then use lots of aluminized tape to seal up
his furnace and water heater so there is a completely closed path
from from the outside air intake to the furnace / WH to the exaust
flue to the chimney.

I'm sure that hack job with tape will impress the code inspector
or the home inspector if he sells the place.

If he doesn't want to actually fix his home's internal air circulation
and attic venting problem, then he doesn't have many other alternatives
to deal with a negative air pressure. I'm not saying that pulling a
rube-goldberg ductwork job on his water heater and furnace is the first
thing he should do - I'm saying it's the last thing he should do.

But what should we expect from the guy who claims that proper
chimney sizing for appliances doesn't matter.

It doesn't matter when you've got a negative air-pressure situation in
the house that you need to deal with first.

On Aug 24, 9:32*am, Home Guy wrote:
" wrote:
What the hell is wrong with you people? * He told us he
started checking because he noticed the plastic
on the pipes at the top of the water heater were melted.

I don't know what you're talking about.

The ONLY posts that I see Mikepier posting in is this thread, with the
subject "Putting speed control on attic fan". *If he started an older
thread about melted plastic on water heaters, then I didn't read it at
the time, or he didn't post it to this newsgroup.

He hasn't said anything about melted plastic in this thread.

His first words in this thread we

"A few weeks ago I posted a problem with too much negative air
pressure
in my house caused by my attic fan."

I even provided youi with a direct link to that post yesterday.
Seems for someone so interested you would take a look.



The OP (Mikepier) has NOT SAID (at least not in this thread)
anything about burnt or melted plastic on his water heater.

He sure did in the other thread he referred to when he made
the first post in this thread.

Read my statement more carefully. *I said "at least not in this thread"..

Still to lazy to read the other thread?



My 4-year-old water heater also has melted disks of read and blue
plastic surrounding the two water pipes (hot and cold) at the top of the
tank. *I don't have a negative air-pressure situation in the house. *The
melted plastic doesn't bother me.

The **ONLY** way you can have proper drafting for the furnace and
water heater in his case if he allows his house to achieve a negative
pressure is to seal the room or the area where his furnace and water
heater is, and give them a new combustion air intake from the outside..

Nonsense. * You can get proper drafting by providing a fixed
ventilation opening to outside for the basement in the area of
the water heater and furnace.

Why can't you read properly?

Look what I said:

"and give them a new combustion air intake from the outside"

Look what you just wrote:

"by providing a fixed ventilation opening to outside for the basement"

You look like a fool when you disagree with me, and then go on to give
the same answer using different wording.

Not the same answer at all, you claimed he had to seal
the area around the water heater or the room. He's already
proven that just opening a basement window fixes it.




Or he can turn his furnace and water heater into a closed system by
bringing sealed ductwork directly to the combustion air intake
vents or the cabinets and running that ductwork to a dedicated
outside air intake, and then use lots of aluminized tape to seal up
his furnace and water heater so there is a completely closed path
from from the outside air intake to the furnace / WH to the exaust
flue to the chimney.

I'm sure that hack job with tape will impress the code inspector
or the home inspector if he sells the place.

If he doesn't want to actually fix his home's internal air circulation
and attic venting problem, then he doesn't have many other alternatives
to deal with a negative air pressure. *I'm not saying that pulling a
rube-goldberg ductwork job on his water heater and furnace is the first
thing he should do - I'm saying it's the last thing he should do.

You didn't specify first or last, you just said he should do
it. Whether it's first or last, I think everyone else here
would agree that it's wrong to be using tape to fashion
some kind of hack job connection from the water heater
and furnace to outside air. You think that will pass
inspection?





*But what should we expect from the guy who claims that proper
*chimney sizing for appliances doesn't matter.

It doesn't matter when you've got a negative air-pressure situation in
the house that you need to deal with first.

Again, there was no qualification in your blanket statement saying
that correct chimney sizing does not matter. Correct chimney
sizing does matter, as you've apparently now learned, so you're
trying to now get around it with a qualification.
That's like saying it doesn't matter
if you use a ground conductor to carry current because someone
is having a problem with a switch. Code is code and it always
applies.

On Wed, 24 Aug 2011 00:43:43 -0400, Home Guy wrote:

Vic Smith wrote:


If you've got a constant down-draft in the chimney caused by
negative air pressure inside the house, your horizontal divertor
will do squat at helping exhaust from the water heater to make
it up and out the chimney.

Maybe, maybe not.

I see that basic physics is beyond your grasp.


You've probably never seen a horizontal diverter.
I can make a good case why they're better than a dome for establishing
draft, but won't
And why do you think a downdraft that blows out a match can't be
overcome with heat to establish an updraft?
Lots of houses have negative pressure.
Depends how bad it is.

It for sure would dump the heat elsewhere

He doesn't have a problem with "dumping heat".


That's what melted the plastic on top of his heater.
He seems to think that's a problem.
I wouldn't like it if it happened to mine.

And by the way, if a divertor is dumping heat to some other place
besides the flue, what does that tell you about where you're dumping the
combustion exhaust gases?


I don't want to confuse you here, and since I don't have all the info
from Mike I could be wrong.
This assumes he had the same attic fan running before with the old
heater and hasn't tightened up the house.
The downdraft existed before and nobody was poisoned by CO.
He only noticed it now because with the horizontal diverter gone
the dome diverter on the new tank spilled enough heat before it
established a draft to eventually melt the plastic.
If he has a working CO alarm and there was no draft established
it would have went off.
Mine went off when a squirrel got in the vent.
Mike can say if my assumptions are wrong.

And he never said how long it took the draft to get established
when the heater went on with the attic fan running.

I don't think he even said it ever gets established with the roof fan
running.


I don't think he tried. He's not too talkative.
But if he has a CO alarm and no draft with a firing heater it would go
off. And he'd most likely smell it and feel the heat if he was
nearby.

snip soffit vent stuff.

Since his pilot isn't blowing out it would just move spillage away
from the heater top.

What spillage?

WTF are you talking about?


That's what HVAC guys call gases escaping diverters until draft is
established.
They also test with negative pressure in the appliance room.
http://virginiahomeperformance.com/y....185172811.pdf
You can get an idea of how many houses are under negative pressure
here. Pretty good study they did when homes were near an airport were
soundproofed.
http://www.state.mn.us/mn/externalDo...tionReport.pdf

Burnt plastic atop the heater appears to be a fairly common
occurrence.

The OP (Mikepier) has NOT SAID (at least not in this thread) anything
about burnt or melted plastic on his water heater.


He mentioned it in a prior thread.

Here's my order of preference, "by the book."
1. Crack open a basement window during attic fan season.

Bull****.


Got no idea why you say that. It already worked for him.


If you don't have enough ventilation in the attic (soffits, gable ends)
then why bother running the roof fan in the first place?


So you think that because an attic fan causes some negative pressure
in the basement it's not cooling the attic? Nonsense.

2. Thermal switch between heater and attic fan. Moderate job.

More bull****.


Somebody else did it to solve the problem.

3. Seal the basement so attic fan has no effect. Big job.

He should find out why there is such an easy path between his attic
space and the rest of the house / basement, and close that path.


Already been covered, And it doesn't have to be an "easy" path.
Older houses have hundreds of paths where air can migrate.

4. Modify chimney for better draft - if possible. Big job.

That won't help if there's still a negative pressure inside the house or
basement caused by the roof fan. Why is that concept so hard for you to
understand?


You still don't understand a negative draft can be reversed by heat.

--Vic

On Wed, 24 Aug 2011 09:32:11 -0400, Home Guy wrote:

My 4-year-old water heater also has melted disks of read and blue
plastic surrounding the two water pipes (hot and cold) at the top of the
tank. I don't have a negative air-pressure situation in the house. The
melted plastic doesn't bother me.


Sound like you have bad draft. Shouldn't be that much spillage.
Probably won't matter though.
Do you have a CO alarm? That's a good safety measure.

--Vic

Mikepier wrote:
A few weeks ago I posted a problem with too much negative air pressure
in my house caused by my attic fan. The motor I have on the fan is
similiar to this.

http://www.amazon.com/gp/product/B00...TM0Q87VFEGEJM8

I wanted to get somekind of speed controller to slow down the speed of
the fan. I've seen them on Broan's website, and they are rated for 6
amps.
Any issues if I put the motor on a rheostat? Are these motors designed
to work on low voltage?

No. The frequency of the mains controls the speed.
The voltage has minor influence, and low voltage can damage the motor
by overheating it.

Mikepier wrote:
If the attic fan is being used as a whole house fan, you need to
open more windows when you run it. If you are using air conditioning
at the same time as the attic fan, the leakage into the attic is
just throwing cooling money away through it.

In my situation however, I think the attic fan helps with the A/C on.
My house was originally installed with force hot air heat, with the
supply ducts low to the ground. Like many other people in my
neighborhood, I added on Central A/C using the existing ductwork.
Because the return vent is low on the floor along with the supply
vents, I think the attic fan "draws" that air upwards, making it feel
cooler. I could be wrong though.

It may make it feel cooler, but it most likely makes the A/C run a lot more.

gregz wrote:
I always call my whole house fan, an attic fan, because that's what
it is, in the attic.


Which may totally mislead people you are trying to communicate with.

There is a difference.

Why doesn't sombody answer the original question. Can you put a speed control on a roof fan

On Mon, 1 Aug 2016 08:56:50 -0700 (PDT), wrote:

Why doesn't sombody answer the original question. Can you put a speed control on a roof fan

Short answer, probably not. They are generally synchronous motors that
determine speed based on the windings in the motor and the frequency
of the line voltage. You could do some adjustment with a VFD but at a
certain point the motor will not be going fast enough to limit
current.
It would be cheaper to buy a 4 speed blower motor and use a rotary
switch.

writes:
Why doesn't sombody answer the original question. Can you put a speed control on a roof fan

Perhaps you can include enough information for someone
to make a workable recommendation.

For example, one needs to know exactly what _kind_ of motor (e.g. universal
or induction) is being used. The brand and model of the fan would also
be useful.

On Monday, August 1, 2016 at 12:21:17 PM UTC-4, wrote:
On Mon, 1 Aug 2016 08:56:50 -0700 (PDT), wrote:

Why doesn't sombody answer the original question. Can you put a speed control on a roof fan

Short answer, probably not. They are generally synchronous motors that
determine speed based on the windings in the motor and the frequency
of the line voltage. You could do some adjustment with a VFD but at a
certain point the motor will not be going fast enough to limit
current.
It would be cheaper to buy a 4 speed blower motor and use a rotary
switch.

+1 assuming it's a typical attic fan for a house. And IDK if you can
find a replacement multi-speed motor that fits. Easier solution is
probably to get a fan with less CFM or even better, increase the available
air inlets. If it's a reasonable size fan to begin with, what's the
point to slowing it down? It's going to move less air and not do what
it's supposed to do.

Yes you can put variable speed control on any motor that is design for that.
Motors which use start capacitor or internal switch no you can not, but you
can
get taped motor and use of switch from one tap to other, or you can use
same motor
hooked up to highest speed and use Variable speed control on it with (Triac)
out put
Variable Light dimmer that have Triac output will also work on Shaded pole
Motor


wrote in message
...

Why doesn't sombody answer the original question. Can you put a speed
control on a roof fan

On Mon, 1 Aug 2016 08:56:50 -0700 (PDT), wrote:

Why doesn't sombody answer the original question. Can you put a speed control on a roof fan
Sure you can - if you have the right roof fan.

More info required.

My father had this same problem! When attic fan was turned on, the pilot light on HWH would get sucked out! Also sucking carbon monoxide back down the HWH exhaust. So I asked him if this was always an issue, and he said no. I knew he had the attic fan motor changed when I was living there. So I asked him if he had the booklet for the original roof fan and he did! After matching specs from the old motor to the one that was in there now I found that the new motors RMPS were much faster. So I replaced the motor with one of equal specs to the original motor! Problem solved. The house has plenty of venting in the attic. The motor that replaced the original was just way too powerful! Also the attic entrance is in his bedroom closet accessed through a 3 foot by 3 foot opening. Just thought I would share. Good luck

You have solved partially problem you will still get from time to time
sucked carbon monoxide in
because you are making up air through the exhaust of HWH. Suggestion get
some one who knows
how Ventilation works. It is better to pay then being dead.

wrote in message
...

My father had this same problem! When attic fan was turned on, the pilot
light on HWH would get sucked out! Also sucking carbon monoxide back down
the HWH exhaust. So I asked him if this was always an issue, and he said
no. I knew he had the attic fan motor changed when I was living there. So I
asked him if he had the booklet for the original roof fan and he did! After
matching specs from the old motor to the one that was in there now I found
that the new motors RMPS were much faster. So I replaced the motor with one
of equal specs to the original motor! Problem solved. The house has plenty
of venting in the attic. The motor that replaced the original was just way
too powerful! Also the attic entrance is in his bedroom closet accessed
through a 3 foot by 3 foot opening. Just thought I would share. Good luck