We have a four story plus cellar 1840's 2 family house with a hydronic
heating system with large radiators that was probably installed in the
1920's. The gas boiler is about 20 years old. The system has both a
conventional expansion tank (that has not been emptied in years) and a
Filltrol diaphragm expansion tank in series.

Every place I looked on the web (including the Filltrol site) says that the
system pressure should be set at 12 psi when cold and should be 20 psi when
hot and circulating. That is exactly where it is, but the radiators on the
4th floor seem to have some air left in them. When bled, water does not
come out of the valve and the top of the radiators are not very hot (the
bottom halves are).

Should the pressure be higher in a 4 story house that in a shorter one? And
if so what should it be? And how do I adjust it? The Filltrol manual does
not give instructions other than to say that it is adjusted via the intake
air valve and should be adjusted when the tank is empty.

So (if I really do need to increase the pressure) do I add air (and how
much) or remove air from the Filltrol expansion tank. And do I have to
completely drain the system to do it? Or just let out a few gallons of
water? Or not concern myself with letting any water out.

A link to a good website will suffice. As I said, my Google search was
unproductive.
--
Peace,
BobJ

"Marilyn & Bob" wrote in message
news:dkdyh.3252$yH3.575@trndny07...
We have a four story plus cellar 1840's 2 family house with a hydronic
heating system with large radiators that was probably installed in the
1920's. The gas boiler is about 20 years old. The system has both a
conventional expansion tank (that has not been emptied in years) and a
Filltrol diaphragm expansion tank in series.

Every place I looked on the web (including the Filltrol site) says that
the system pressure should be set at 12 psi when cold and should be 20 psi
when hot and circulating. That is exactly where it is, but the radiators
on the 4th floor seem to have some air left in them. When bled, water
does not come out of the valve and the top of the radiators are not very
hot (the bottom halves are).

Should the pressure be higher in a 4 story house that in a shorter one?
And if so what should it be? And how do I adjust it? The Filltrol manual
does not give instructions other than to say that it is adjusted via the
intake air valve and should be adjusted when the tank is empty.

So (if I really do need to increase the pressure) do I add air (and how
much) or remove air from the Filltrol expansion tank. And do I have to
completely drain the system to do it? Or just let out a few gallons of
water? Or not concern myself with letting any water out.

A link to a good website will suffice. As I said, my Google search was
unproductive.
--
Peace,
BobJ

http://heatinghelp.com/ Tons of info there if you can not find what you need
on the site they have a forum where you can post questions. My feeling is 20
psi should get to the fourth floor. 1 psi will roughly lift water 2.31' so
20 psi should get you 46.2 feet-- there are other varibles that may come
into play too that may shorten that estimate. If you search google using
combos of verticle lift, psi, water, head-- you will find some more of what
you are looking for.

Steve

You dont even know if your gauge is accurate, Add water to a COLD boiler
of 70f while bleeding air out of the top floor while boiler is running
till water comes out the radiator. Your issue is not enough Altitude or
Pressure. Dont mess with anything else. Then see how it works and
monitor pressure cold and hot, it may only take a Lb or 2 of water to
get heat to the top. After a few hours bleed radiators again. It may
take a few tries over a few days.

"m Ransley" wrote in message
...
You dont even know if your gauge is accurate, Add water to a COLD boiler
of 70f while bleeding air out of the top floor while boiler is running
till water comes out the radiator. Your issue is not enough Altitude or
Pressure. Dont mess with anything else. Then see how it works and
monitor pressure cold and hot, it may only take a Lb or 2 of water to
get heat to the top. After a few hours bleed radiators again. It may
take a few tries over a few days.


Thanks, I'll try that.
--
Peace,
BobJ

"SuperPoo" wrote in message
news:Oleyh.1955$Yl3.1182@trndny09...

"Marilyn & Bob" wrote in message
news:dkdyh.3252$yH3.575@trndny07...
We have a four story plus cellar 1840's 2 family house with a hydronic
heating system with large radiators that was probably installed in the
1920's. The gas boiler is about 20 years old. The system has both a
conventional expansion tank (that has not been emptied in years) and a
Filltrol diaphragm expansion tank in series.

Every place I looked on the web (including the Filltrol site) says that
the system pressure should be set at 12 psi when cold and should be 20
psi when hot and circulating. That is exactly where it is, but the
radiators on the 4th floor seem to have some air left in them. When
bled, water does not come out of the valve and the top of the radiators
are not very hot (the bottom halves are).

Should the pressure be higher in a 4 story house that in a shorter one?
And if so what should it be? And how do I adjust it? The Filltrol
manual does not give instructions other than to say that it is adjusted
via the intake air valve and should be adjusted when the tank is empty.

So (if I really do need to increase the pressure) do I add air (and how
much) or remove air from the Filltrol expansion tank. And do I have to
completely drain the system to do it? Or just let out a few gallons of
water? Or not concern myself with letting any water out.

A link to a good website will suffice. As I said, my Google search was
unproductive.
--
Peace,
BobJ

http://heatinghelp.com/ Tons of info there if you can not find what you
need on the site they have a forum where you can post questions. My
feeling is 20 psi should get to the fourth floor. 1 psi will roughly lift
water 2.31' so 20 psi should get you 46.2 feet-- there are other varibles
that may come into play too that may shorten that estimate. If you search
google using combos of verticle lift, psi, water, head-- you will find
some more of what you are looking for.

Steve


Thank you for the info. I did not see your response before I responded to a
later post reasking the question that you already answered. Since the water
only has to rise about 35 above the circulator pump outlet, I should be
fine.
--
Peace,
BobJ

In article %VIyh.2734$da1.685@trndny03, "Marilyn & Bob" wrote:

Thank you for the info. I did not see your response before I responded to a
later post reasking the question that you already answered. Since the water
only has to rise about 35 above the circulator pump outlet, I should be
fine.

Not correct, on two counts.

First, the water needs to rise 35' (if indeed that's correct -- see my other
post in this thread) above the inlet where [pressurized] replenishment water
enters. The position of the circulator is irrelevant.

Second, you need enough pressure at that point to lift the water to the
highest radiator when the system is *cold*. The dynamic pressure (when the
system is operating) is immaterial. You must have enough *static* pressure to
get the water all the way up to the top, and 12 psi is not enough to lift
water 35 feet, let alone the 38 to 40 that I suspect is really the case.

Measure the height carefully. Don't forget to include the depth of the floor
joists: you have four sets of floor joists between the basement and the rads
on the top floor. That's at least 2 1/2 feet, and maybe as much as four.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

On Feb 6, 11:20 pm, "Marilyn & Bob" wrote:
We have a four story plus cellar 1840's 2 family house with a hydronic
heating system with large radiators that was probably installed in the
1920's. The gas boiler is about 20 years old. The system has both a
conventional expansion tank (that has not been emptied in years) and a
Filltrol diaphragm expansion tank in series.

Every place I looked on the web (including the Filltrol site) says that the
system pressure should be set at 12 psi when cold and should be 20 psi when
hot and circulating. That is exactly where it is, but the radiators on the
4th floor seem to have some air left in them. When bled, water does not
come out of the valve and the top of the radiators are not very hot (the
bottom halves are).

Should the pressure be higher in a 4 story house that in a shorter one? And
if so what should it be? And how do I adjust it? The Filltrol manual does
not give instructions other than to say that it is adjusted via the intake
air valve and should be adjusted when the tank is empty.

So (if I really do need to increase the pressure) do I add air (and how
much) or remove air from the Filltrol expansion tank. And do I have to
completely drain the system to do it? Or just let out a few gallons of
water? Or not concern myself with letting any water out.

A link to a good website will suffice. As I said, my Google search was
unproductive.
--
Peace,
BobJ

You do not say whether you are getting enough heat in the top floor.
If the rooms up there are comfortable, then there is nothing wrong
with having the radiators half full, and if I were you I would not
touch it. If you need more heat up there then first try bleeding air
from the radiators. The system should have an inlet valve that adds
water automatically when the pressure drops below 12 psi. -- H

"Heathcliff" wrote in message
oups.com...
On Feb 6, 11:20 pm, "Marilyn & Bob" wrote:
We have a four story plus cellar 1840's 2 family house with a hydronic
heating system with large radiators that was probably installed in the
1920's. The gas boiler is about 20 years old. The system has both a
conventional expansion tank (that has not been emptied in years) and a
Filltrol diaphragm expansion tank in series.

Every place I looked on the web (including the Filltrol site) says that
the
system pressure should be set at 12 psi when cold and should be 20 psi
when
hot and circulating. That is exactly where it is, but the radiators on
the
4th floor seem to have some air left in them. When bled, water does not
come out of the valve and the top of the radiators are not very hot (the
bottom halves are).

Should the pressure be higher in a 4 story house that in a shorter one?
And
if so what should it be? And how do I adjust it? The Filltrol manual
does
not give instructions other than to say that it is adjusted via the
intake
air valve and should be adjusted when the tank is empty.

So (if I really do need to increase the pressure) do I add air (and how
much) or remove air from the Filltrol expansion tank. And do I have to
completely drain the system to do it? Or just let out a few gallons of
water? Or not concern myself with letting any water out.

A link to a good website will suffice. As I said, my Google search was
unproductive.
--
Peace,
BobJ



You do not say whether you are getting enough heat in the top floor.

The 4th floor is occupied by our tenants. They tend not to complain, but
did alert us to the radiator problem at the beginning of the winter when it
was not cold. I did note an electric space heater in a room when I last bled
their radiators. In any case, I would want it to work right.

If the rooms up there are comfortable, then there is nothing wrong
with having the radiators half full, and if I were you I would not
touch it. If you need more heat up there then first try bleeding air
from the radiators.

I have bled the radiators twice this winter. In both cases only air came
out few a few seconds. Water never came out of these radiators no matter
how long the valve was left open.

The system should have an inlet valve that adds
water automatically when the pressure drops below 12 psi. -- H

Yes, I understand this. My question is whether 12 psi cold pressure (20 psi
hot with circulator pump on) is enough for a system with large radiators
that are about 35 feet above the level of the boiler.
--
Peace,
BobJ

Marilyn & Bob wrote:
"Heathcliff" wrote in message
oups.com...

On Feb 6, 11:20 pm, "Marilyn & Bob" wrote:

We have a four story plus cellar 1840's 2 family house with a hydronic
heating system with large radiators that was probably installed in the
1920's. The gas boiler is about 20 years old. The system has both a
conventional expansion tank (that has not been emptied in years) and a
Filltrol diaphragm expansion tank in series.

Every place I looked on the web (including the Filltrol site) says that
the
system pressure should be set at 12 psi when cold and should be 20 psi
when
hot and circulating. That is exactly where it is, but the radiators on
the
4th floor seem to have some air left in them. When bled, water does not
come out of the valve and the top of the radiators are not very hot (the
bottom halves are).

Should the pressure be higher in a 4 story house that in a shorter one?
And
if so what should it be? And how do I adjust it? The Filltrol manual
does
not give instructions other than to say that it is adjusted via the
intake
air valve and should be adjusted when the tank is empty.

So (if I really do need to increase the pressure) do I add air (and how
much) or remove air from the Filltrol expansion tank. And do I have to
completely drain the system to do it? Or just let out a few gallons of
water? Or not concern myself with letting any water out.

A link to a good website will suffice. As I said, my Google search was
unproductive.
--
Peace,
BobJ



You do not say whether you are getting enough heat in the top floor.


The 4th floor is occupied by our tenants. They tend not to complain, but
did alert us to the radiator problem at the beginning of the winter when it
was not cold. I did note an electric space heater in a room when I last bled
their radiators. In any case, I would want it to work right.


If the rooms up there are comfortable, then there is nothing wrong
with having the radiators half full, and if I were you I would not
touch it. If you need more heat up there then first try bleeding air
from the radiators.


I have bled the radiators twice this winter. In both cases only air came
out few a few seconds. Water never came out of these radiators no matter
how long the valve was left open.


The system should have an inlet valve that adds
water automatically when the pressure drops below 12 psi. -- H


Yes, I understand this. My question is whether 12 psi cold pressure (20 psi
hot with circulator pump on) is enough for a system with large radiators
that are about 35 feet above the level of the boiler.


Short answer: NO! Cold pressure must be enough to maintain
the head at 35 Feet. Anytime the pressure drops (cold or hot)
below that required at the highest elevation, air *will* be sucked
into the system. On the next startup, that air will block flow
to the highest rads, even if pressure rises.

You may need more expansion tank capacity to reduce the swing
between cold and hot pressure.

In any case, you need higher system pressure.

Jim

In article , Speedy Jim wrote:
Marilyn & Bob wrote:
"Heathcliff" wrote in message
oups.com...

Yes, I understand this. My question is whether 12 psi cold pressure (20 psi
hot with circulator pump on) is enough for a system with large radiators
that are about 35 feet above the level of the boiler.

If you haven't actually measured, I think you should. This sounds a bit low to
me, for rads on the top floor of an older 4-story building.

You need to measure from the bottom of the boiler to the top of the rad.

Consider also that older buildings frequently have 9- or even 10-foot
ceilings, and floor joists were often 2x10 true (instead of 2x10 nominal = 1.5
x 9.25 true).

The 12 psi recommendation is based on having the boiler in the basement of a
*two* story building, where the head probably won't exceed 20 feet. I wouldn't
be at all surprised if the head in your building is closer to 40 feet than it
is to 35.

Short answer: NO! Cold pressure must be enough to maintain
the head at 35 Feet.

Entirely correct (as is what follows) -- but incomplete.

The missing part is that 1 foot of head = 0.4335 psi. Thus 35 feet of head is
a bit over 15 psi, and 40 feet of head is 17.3 psi.

Anytime the pressure drops (cold or hot)
below that required at the highest elevation, air *will* be sucked
into the system. On the next startup, that air will block flow
to the highest rads, even if pressure rises.

You may need more expansion tank capacity to reduce the swing
between cold and hot pressure.

In any case, you need higher system pressure.

Exactly.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

"Doug Miller" wrote in message
. net...
In article , Speedy Jim
wrote:
Marilyn & Bob wrote:
"Heathcliff" wrote in message
oups.com...

Yes, I understand this. My question is whether 12 psi cold pressure (20
psi
hot with circulator pump on) is enough for a system with large radiators
that are about 35 feet above the level of the boiler.

If you haven't actually measured, I think you should. This sounds a bit
low to
me, for rads on the top floor of an older 4-story building.

You need to measure from the bottom of the boiler to the top of the rad.

Consider also that older buildings frequently have 9- or even 10-foot
ceilings, and floor joists were often 2x10 true (instead of 2x10 nominal =
1.5
x 9.25 true).

The 12 psi recommendation is based on having the boiler in the basement of
a
*two* story building, where the head probably won't exceed 20 feet. I
wouldn't
be at all surprised if the head in your building is closer to 40 feet than
it
is to 35.

Short answer: NO! Cold pressure must be enough to maintain
the head at 35 Feet.

Entirely correct (as is what follows) -- but incomplete.

The missing part is that 1 foot of head = 0.4335 psi. Thus 35 feet of head
is
a bit over 15 psi, and 40 feet of head is 17.3 psi.

Anytime the pressure drops (cold or hot)
below that required at the highest elevation, air *will* be sucked
into the system. On the next startup, that air will block flow
to the highest rads, even if pressure rises.

You may need more expansion tank capacity to reduce the swing
between cold and hot pressure.

In any case, you need higher system pressure.

Exactly.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

OK. It's about 36' to the bottom of the top radiator about 39' to the top
where the bleeder valve is. So about 17 psi. Now the question is how do I
get to that? We have a Filltrol diaphragm expansion tank and standard
expansion tank. I have not drained that standard tank in many years. m
Ransley suggested bleeding the radiator with the water cold (but the
circulator pump on), is that a place to start? I've always bled it with the
system on full blast.


--
Peace,
BobJ