On my home forced hot water heating system, the upstairs zone will not
stop circulating heat.

I want to rule out a few factors. One of them is trying to figure out
this valve:

http://www.marcsawyer.com/pics/combovalve.jpg

I've been searching the web to simply find the name of the valve so I
can determine how that tab next to the purge functions; ie.
closed/open/partial flow...

Any takers? C'mon! it's a picture game!

Marc

Cram writes:

I've been searching the web to simply find the name of the valve so I
can determine how that tab next to the purge functions; ie.
closed/open/partial flow...

Looks like a combination ball valve and globe valve, with the ball in the
open position. Turn the ball handle across the pipe to stop the flow.

Accross the pipe; meaning perpendicular or at a 90=B0 angle?

"Cram" wrote in message
oups.com...
On my home forced hot water heating system, the upstairs zone will not
stop circulating heat.

I want to rule out a few factors. One of them is trying to figure out
this valve:

http://www.marcsawyer.com/pics/combovalve.jpg

I've been searching the web to simply find the name of the valve so I
can determine how that tab next to the purge functions; ie.
closed/open/partial flow...

Any takers? C'mon! it's a picture game!

Marc


I would guess the small valve is for controlling flow amount, The larger
valve might be for bleeding air out of the system if this valve is at a high
point of the system? If its down low it might just be to drain the system.
Could it be to isolate the pump for replacement or service ?

- If its down low it might just be to drain the system.

It's a purge valve at the bottom. I'm more interested to see which
setting on the tab or what Richard calls the ball functions to close
it.

My larger issue with this zone is that it is always on when there is
ho****er in the furnace. I first thought that it was a bad wire in the
thermostat wire running up to the room where the zone is exposed. ie.
two wires rubbing, but I tested first the ohm reading and there was no
reading which means there is no contact between the two wires going up
to the room.

I have even spliced the wire near the furnace so I could touch the two
wires and hear the pump relay click and the pump operate (just as a
thermostat would do).

So with the pump not pushing water to the zone, I am still getting hot
water forced up into the zone. I don't see how this could happen.

I am hoping to find the problem and avoid a plumber visit.

Thanks for your replies and more are encouraged...

The small valve, to the left of your photo, is likely a ball valve as
others have suggested. When the handle is parrallel to the valve body
its on, when its perpendiculat yo the valve body its closed. All 1/2
turn valves work this way. you will see them in gas applications to.
Sometimes its not a handle but just a ridge but the same holds true.

Cram writes:

So with the pump not pushing water to the zone, I am still getting hot
water forced up into the zone. I don't see how this could happen.

Gravity feed. Hot water systems were designed to run without any pump at
all, at least in the old days.

It's pretty clear to me that you have a combination ball valve (tab on left,
low profile) and a drain valve.

Neat gadget, I've never seen one in person. But it looks useful.

As photographed, the ball valve is open. Or, should be open.

--

Christopher A. Young
Do good work.
It's longer in the short run
but shorter in the long run.
..
..


"Cram" wrote in message
oups.com...
On my home forced hot water heating system, the upstairs zone will not
stop circulating heat.

I want to rule out a few factors. One of them is trying to figure out
this valve:

http://www.marcsawyer.com/pics/combovalve.jpg

I've been searching the web to simply find the name of the valve so I
can determine how that tab next to the purge functions; ie.
closed/open/partial flow...

Any takers? C'mon! it's a picture game!

Marc

Richard J Kinch wrote:

Cram writes:


So with the pump not pushing water to the zone, I am still getting hot
water forced up into the zone. I don't see how this could happen.


Gravity feed. Hot water systems were designed to run without any pump at
all, at least in the old days.

Yes, if that's it you can prevent it by installing an "anti-thermosyphon
valve" which in the olde days we called a "gravity valve". It's a
weighted check valve which remains closed and blocks the weak
thermosyphon pressure differential but gets lifted opened by the higher
pressure created by the circulating pump.

Go he

http://www.wattsreg.com/

and look at a 2000-M5 valve.

HTH,

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

On 7 Oct 2005 10:39:38 -0700, "Cram" wrote:

On my home forced hot water heating system, the upstairs zone will not
stop circulating heat.

If you have multiple circulator pumps, rather than zone valves (sounds
like you do from previous posts), there should be check valve in each
leg, otherwise hot water will circulate (in the reverse direction from
normal flow) in the off zone(s) when any other zone is running.
Sometimes the check valves are built into the circulators, but usually
they are separate. If this just started happening, you may have a
failed or stuck check valve. If it's always done this, then you need
to add the check valves. They are usually right above or below the
circulators. Get the spring loaded ball or cone type with neoprene
seats, otherwise they make all kinds of noise. Be aware that adding
the check valves will complicate purging air when filling an empty
system.

HTH,

Paul

Paul:

What precuation/procedure should be used when purging air from a
single zone heating loop that has the check valve located immediately
at the hot output of the (Peerless) boiler ?

I just went through dropping the boiler water level so that a
baseboard heater could be replaced, and I am not certain that the loop
is fully purged of air.

Thanks.


On Fri, 07 Oct 2005 23:44:16 -0400, Paul Franklin
wrote:

On 7 Oct 2005 10:39:38 -0700, "Cram" wrote:

On my home forced hot water heating system, the upstairs zone will not
stop circulating heat.

If you have multiple circulator pumps, rather than zone valves (sounds
like you do from previous posts), there should be check valve in each
leg, otherwise hot water will circulate (in the reverse direction from
normal flow) in the off zone(s) when any other zone is running.
Sometimes the check valves are built into the circulators, but usually
they are separate. If this just started happening, you may have a
failed or stuck check valve. If it's always done this, then you need
to add the check valves. They are usually right above or below the
circulators. Get the spring loaded ball or cone type with neoprene
seats, otherwise they make all kinds of noise. Be aware that adding
the check valves will complicate purging air when filling an empty
system.

HTH,

Paul

On Sat, 08 Oct 2005 10:35:40 GMT, Vince
wrote:

Paul:

What precuation/procedure should be used when purging air from a
single zone heating loop that has the check valve located immediately
at the hot output of the (Peerless) boiler ?

I just went through dropping the boiler water level so that a
baseboard heater could be replaced, and I am not certain that the loop
is fully purged of air.

Thanks.


It's hard to give specifics without knowing the detailed layout of the
piping. In general, there are two ways to purge a system, gravity and
forced-water.

Gravity purging is when you just open the feed water valve after a
shutdown, let the system fill with water as best it can, and then
purge the air using the bleed valves that should be provided at the
end of each radiator, or at least at the high point of each loop. In
theory, all the air in the system will rise to the highest point where
is removed using the bleed valves. Generally, the bleeding process
should be repeated over a few days or weeks until all the trapped air
is removed. Gravity purging usually works fine. You can run into
problems, however, if the piping design is such that there are high
spots without bleed valves or air vents. In other words, if a pipe
goes up, over, and down without there being a bleed or automatic air
vent, then an air pocket can form in the loop, and the circulator may
not be able to lift water over the loop. Usually, these kind of loops
are avoided by proper piping design. You sometimes see them when
there are floor level radiators in the basement with the boiler.

More common are air pockets caused by sloping or sagging piping, where
you can get a local high spot without a bleed. Unless severe, the air
will usally eventually be cleared from these during normal operation.

I mentioned that check valves can complicate purging because they by
limiting flow to one direction, they can create air pockets that can
not easily be eliminated. Again, very system specific.

A more positive, and faster way to purge a system is forced-water
purging. This requires a feed valve with a "fast-fill" bypass, or
another way to provide full water pressure to the feed side. (such as
a hose fitting). It also requires a drain valve at the low side of
the piping (not the boiler drain valve). Specifics are very system
dependent, but the idea is to use get full house water pressure
flowing through each loop in the system, one at a time. This is more
effective at clearing air pockets than gravity purging.

To make an already too long story short, if all you did was lower the
water level a little to work on a radiator, and you've got a well
designed system wth no severe blind high spots, then gravity purging
will probably work fine. If the zone seems to get hot quickly, and
gets hot enough, and you don't hear a lot of gurgleling noises,
chances are you are fine. Just repeat the bleeding process several
times.

You might look for a copy of "Modern Hydronic Heating" by Siegenthaler
at your local library. IIRC, he has a whole chapter on purging air
and correcting air entrapment problems.

HTH,

Paul

On 7 Oct 2005 10:39:38 -0700, "Cram" wrote:

On my home forced hot water heating system, the upstairs zone will not
stop circulating heat.

I want to rule out a few factors. One of them is trying to figure out
this valve:

http://www.marcsawyer.com/pics/combovalve.jpg

I've been searching the web to simply find the name of the valve so I
can determine how that tab next to the purge functions; ie.
closed/open/partial flow...

Any takers? C'mon! it's a picture game!

The url wouldn't fit so,,,

http://tinyurl.com/cwsmx

installation sheet: http://www.wattsreg.com/pdf/1910267.pdf

The new one must be positioned the same way regards to direction of
flow.

-zero

On Sat, 08 Oct 2005 08:13:04 -0400, Paul Franklin
wrote:

On Sat, 08 Oct 2005 10:35:40 GMT, Vince
wrote:

Paul:

What precuation/procedure should be used when purging air from a
single zone heating loop that has the check valve located immediately
at the hot output of the (Peerless) boiler ?

I just went through dropping the boiler water level so that a
baseboard heater could be replaced, and I am not certain that the loop
is fully purged of air.

Thanks.


It's hard to give specifics without knowing the detailed layout of the
piping. In general, there are two ways to purge a system, gravity and
forced-water.

Gravity purging is when you just open the feed water valve after a
shutdown, let the system fill with water as best it can, and then
purge the air using the bleed valves that should be provided at the
end of each radiator, or at least at the high point of each loop. In
theory, all the air in the system will rise to the highest point where
is removed using the bleed valves. Generally, the bleeding process
should be repeated over a few days or weeks until all the trapped air
is removed. Gravity purging usually works fine. You can run into
problems, however, if the piping design is such that there are high
spots without bleed valves or air vents. In other words, if a pipe
goes up, over, and down without there being a bleed or automatic air
vent, then an air pocket can form in the loop, and the circulator may
not be able to lift water over the loop. Usually, these kind of loops
are avoided by proper piping design. You sometimes see them when
there are floor level radiators in the basement with the boiler.

More common are air pockets caused by sloping or sagging piping, where
you can get a local high spot without a bleed. Unless severe, the air
will usally eventually be cleared from these during normal operation.

I mentioned that check valves can complicate purging because they by
limiting flow to one direction, they can create air pockets that can
not easily be eliminated. Again, very system specific.

A more positive, and faster way to purge a system is forced-water
purging. This requires a feed valve with a "fast-fill" bypass, or
another way to provide full water pressure to the feed side. (such as
a hose fitting). It also requires a drain valve at the low side of
the piping (not the boiler drain valve). Specifics are very system
dependent, but the idea is to use get full house water pressure
flowing through each loop in the system, one at a time. This is more
effective at clearing air pockets than gravity purging.

To make an already too long story short, if all you did was lower the
water level a little to work on a radiator, and you've got a well
designed system wth no severe blind high spots, then gravity purging
will probably work fine. If the zone seems to get hot quickly, and
gets hot enough, and you don't hear a lot of gurgleling noises,
chances are you are fine. Just repeat the bleeding process several
times.

You might look for a copy of "Modern Hydronic Heating" by Siegenthaler
at your local library. IIRC, he has a whole chapter on purging air
and correcting air entrapment problems.

HTH,

Paul

Paul:

Many thanks for your explanation and information. I am sure that it
has helped me. I will look for that book at the library, also.

In my case, the replacement baseboard heater is the first in the
series loop. This new unit is the only one that has bleeder valves
installed (all other heaters lack bleeder valves). And, all units are
on the same (floor) level.

The refill procedure used was to open the system supply feed valve,
close the boiler drain valve, and then open the drain valve located
above the water circulator; set the thermostat for a high room
temperature, then watch for sputterring water flow at the end of a
garden hose directed to a dry well. The supply pressure regulator has
a handle marked "FAST FILL", and that was used also operated to try to
keep the pressure level up as indicated on the boiler PSI gage.

When I felt a hot pipe at the circulator I felt that the system was
purged. However, I will repeat this process a couple more times. Now
that the new baseboard radiator includes bleeder valves, I may open
those.

Thanks again.

Jeff & Paul,

You clued me in to this part of they system - I found another valve on
the send of this zone.

www.marcsawyer.com/pics/valve1.jpg

It was not shut all the way - I could tighten it a few turns atleast.
With that I tested the system with the following:

With the pump not pushing flow (thermostat not engaged..) I Caused the
furnace to heat the water and checked for change in temp beyond that
point in the zone.

Fixed.

Exploring further around the furnace and ho****er tank, I noticed
another one of these valves that was tightened all the way. This one
was going into the hot water tank next to the furnace which is kept at
tempurature by electric.

Thanks for your input on troubleshooting this.

marc

On Sat, 08 Oct 2005 14:11:56 GMT, Vince
wrote:
snip
Paul:

Many thanks for your explanation and information. I am sure that it
has helped me. I will look for that book at the library, also.

In my case, the replacement baseboard heater is the first in the
series loop. This new unit is the only one that has bleeder valves
installed (all other heaters lack bleeder valves). And, all units are
on the same (floor) level.

The refill procedure used was to open the system supply feed valve,
close the boiler drain valve, and then open the drain valve located
above the water circulator; set the thermostat for a high room
temperature, then watch for sputterring water flow at the end of a
garden hose directed to a dry well. The supply pressure regulator has
a handle marked "FAST FILL", and that was used also operated to try to
keep the pressure level up as indicated on the boiler PSI gage.

When I felt a hot pipe at the circulator I felt that the system was
purged. However, I will repeat this process a couple more times. Now
that the new baseboard radiator includes bleeder valves, I may open
those.

Thanks again.

So you did a kind of forced water purge. Generally, I don't run the
circ or boiler while purging. The principle is the same, you want the
water to flow in the fill valve, through the loop, and out the drain.
Run it until it runs clear, doesn gurgle or sputter, etc., close the
drain, close the fill, and you're good to go.

When everythings on one level, you don't have a clear nice high spot
to bleed, so forced water is a good way to go.

Sound like you did just fine.

Paul

My heating guy sticks the drain hose in a bucket. Easier to see when the air
stops coming out.

"Paul Franklin" wrote in message
...
On Sat, 08 Oct 2005 14:11:56 GMT, Vince
wrote:
snip
Paul:

Many thanks for your explanation and information. I am sure that it
has helped me. I will look for that book at the library, also.

In my case, the replacement baseboard heater is the first in the
series loop. This new unit is the only one that has bleeder valves
installed (all other heaters lack bleeder valves). And, all units are
on the same (floor) level.

The refill procedure used was to open the system supply feed valve,
close the boiler drain valve, and then open the drain valve located
above the water circulator; set the thermostat for a high room
temperature, then watch for sputterring water flow at the end of a
garden hose directed to a dry well. The supply pressure regulator has
a handle marked "FAST FILL", and that was used also operated to try to
keep the pressure level up as indicated on the boiler PSI gage.

When I felt a hot pipe at the circulator I felt that the system was
purged. However, I will repeat this process a couple more times. Now
that the new baseboard radiator includes bleeder valves, I may open
those.

Thanks again.

So you did a kind of forced water purge. Generally, I don't run the
circ or boiler while purging. The principle is the same, you want the
water to flow in the fill valve, through the loop, and out the drain.
Run it until it runs clear, doesn gurgle or sputter, etc., close the
drain, close the fill, and you're good to go.

When everythings on one level, you don't have a clear nice high spot
to bleed, so forced water is a good way to go.

Sound like you did just fine.

Paul

Don't know if this has been mentioned earlier,
but get yourself a Spirovent. Purge the air as best
you can by the methods noted earlier, the Spirovent
will keep you trouble-free after that. (Works much
better than a simple float vent IMHO.)







On Sat, 08 Oct 2005 14:11:56 GMT, Vince
wrote:



On Sat, 08 Oct 2005 08:13:04 -0400, Paul Franklin
wrote:

On Sat, 08 Oct 2005 10:35:40 GMT, Vince
wrote:

Paul:

What precuation/procedure should be used when purging air from a
single zone heating loop that has the check valve located immediately
at the hot output of the (Peerless) boiler ?

I just went through dropping the boiler water level so that a
baseboard heater could be replaced, and I am not certain that the loop
is fully purged of air.

Thanks.


It's hard to give specifics without knowing the detailed layout of the
piping. In general, there are two ways to purge a system, gravity and
forced-water.

Gravity purging is when you just open the feed water valve after a
shutdown, let the system fill with water as best it can, and then
purge the air using the bleed valves that should be provided at the
end of each radiator, or at least at the high point of each loop. In
theory, all the air in the system will rise to the highest point where
is removed using the bleed valves. Generally, the bleeding process
should be repeated over a few days or weeks until all the trapped air
is removed. Gravity purging usually works fine. You can run into
problems, however, if the piping design is such that there are high
spots without bleed valves or air vents. In other words, if a pipe
goes up, over, and down without there being a bleed or automatic air
vent, then an air pocket can form in the loop, and the circulator may
not be able to lift water over the loop. Usually, these kind of loops
are avoided by proper piping design. You sometimes see them when
there are floor level radiators in the basement with the boiler.

More common are air pockets caused by sloping or sagging piping, where
you can get a local high spot without a bleed. Unless severe, the air
will usally eventually be cleared from these during normal operation.

I mentioned that check valves can complicate purging because they by
limiting flow to one direction, they can create air pockets that can
not easily be eliminated. Again, very system specific.

A more positive, and faster way to purge a system is forced-water
purging. This requires a feed valve with a "fast-fill" bypass, or
another way to provide full water pressure to the feed side. (such as
a hose fitting). It also requires a drain valve at the low side of
the piping (not the boiler drain valve). Specifics are very system
dependent, but the idea is to use get full house water pressure
flowing through each loop in the system, one at a time. This is more
effective at clearing air pockets than gravity purging.

To make an already too long story short, if all you did was lower the
water level a little to work on a radiator, and you've got a well
designed system wth no severe blind high spots, then gravity purging
will probably work fine. If the zone seems to get hot quickly, and
gets hot enough, and you don't hear a lot of gurgleling noises,
chances are you are fine. Just repeat the bleeding process several
times.

You might look for a copy of "Modern Hydronic Heating" by Siegenthaler
at your local library. IIRC, he has a whole chapter on purging air
and correcting air entrapment problems.

HTH,

Paul

Paul:

Many thanks for your explanation and information. I am sure that it
has helped me. I will look for that book at the library, also.

In my case, the replacement baseboard heater is the first in the
series loop. This new unit is the only one that has bleeder valves
installed (all other heaters lack bleeder valves). And, all units are
on the same (floor) level.

The refill procedure used was to open the system supply feed valve,
close the boiler drain valve, and then open the drain valve located
above the water circulator; set the thermostat for a high room
temperature, then watch for sputterring water flow at the end of a
garden hose directed to a dry well. The supply pressure regulator has
a handle marked "FAST FILL", and that was used also operated to try to
keep the pressure level up as indicated on the boiler PSI gage.

When I felt a hot pipe at the circulator I felt that the system was
purged. However, I will repeat this process a couple more times. Now
that the new baseboard radiator includes bleeder valves, I may open
those.

Thanks again.

"Jmagerl" wrote in message
...
My heating guy sticks the drain hose in a bucket. Easier to see when the
air
stops coming out.


It also gives a good visual aid to the homeowner.


"Paul Franklin" wrote in message
...
On Sat, 08 Oct 2005 14:11:56 GMT, Vince
wrote:
snip
Paul:

Many thanks for your explanation and information. I am sure that it
has helped me. I will look for that book at the library, also.

In my case, the replacement baseboard heater is the first in the
series loop. This new unit is the only one that has bleeder valves
installed (all other heaters lack bleeder valves). And, all units are
on the same (floor) level.

The refill procedure used was to open the system supply feed valve,
close the boiler drain valve, and then open the drain valve located
above the water circulator; set the thermostat for a high room
temperature, then watch for sputterring water flow at the end of a
garden hose directed to a dry well. The supply pressure regulator has
a handle marked "FAST FILL", and that was used also operated to try to
keep the pressure level up as indicated on the boiler PSI gage.

When I felt a hot pipe at the circulator I felt that the system was
purged. However, I will repeat this process a couple more times. Now
that the new baseboard radiator includes bleeder valves, I may open
those.

Thanks again.

So you did a kind of forced water purge. Generally, I don't run the
circ or boiler while purging. The principle is the same, you want the
water to flow in the fill valve, through the loop, and out the drain.
Run it until it runs clear, doesn gurgle or sputter, etc., close the
drain, close the fill, and you're good to go.

When everythings on one level, you don't have a clear nice high spot
to bleed, so forced water is a good way to go.

Sound like you did just fine.

Paul

"frank1492" wrote in message
...
Don't know if this has been mentioned earlier,
but get yourself a Spirovent. Purge the air as best
you can by the methods noted earlier, the Spirovent
will keep you trouble-free after that. (Works much
better than a simple float vent IMHO.)


Spirovents are about the best there is, but they do fail.






On Sat, 08 Oct 2005 14:11:56 GMT, Vince
wrote:



On Sat, 08 Oct 2005 08:13:04 -0400, Paul Franklin
wrote:

On Sat, 08 Oct 2005 10:35:40 GMT, Vince
wrote:

Paul:

What precuation/procedure should be used when purging air from a
single zone heating loop that has the check valve located immediately
at the hot output of the (Peerless) boiler ?

I just went through dropping the boiler water level so that a
baseboard heater could be replaced, and I am not certain that the loop
is fully purged of air.

Thanks.


It's hard to give specifics without knowing the detailed layout of the
piping. In general, there are two ways to purge a system, gravity and
forced-water.

Gravity purging is when you just open the feed water valve after a
shutdown, let the system fill with water as best it can, and then
purge the air using the bleed valves that should be provided at the
end of each radiator, or at least at the high point of each loop. In
theory, all the air in the system will rise to the highest point where
is removed using the bleed valves. Generally, the bleeding process
should be repeated over a few days or weeks until all the trapped air
is removed. Gravity purging usually works fine. You can run into
problems, however, if the piping design is such that there are high
spots without bleed valves or air vents. In other words, if a pipe
goes up, over, and down without there being a bleed or automatic air
vent, then an air pocket can form in the loop, and the circulator may
not be able to lift water over the loop. Usually, these kind of loops
are avoided by proper piping design. You sometimes see them when
there are floor level radiators in the basement with the boiler.

More common are air pockets caused by sloping or sagging piping, where
you can get a local high spot without a bleed. Unless severe, the air
will usally eventually be cleared from these during normal operation.

I mentioned that check valves can complicate purging because they by
limiting flow to one direction, they can create air pockets that can
not easily be eliminated. Again, very system specific.

A more positive, and faster way to purge a system is forced-water
purging. This requires a feed valve with a "fast-fill" bypass, or
another way to provide full water pressure to the feed side. (such as
a hose fitting). It also requires a drain valve at the low side of
the piping (not the boiler drain valve). Specifics are very system
dependent, but the idea is to use get full house water pressure
flowing through each loop in the system, one at a time. This is more
effective at clearing air pockets than gravity purging.

To make an already too long story short, if all you did was lower the
water level a little to work on a radiator, and you've got a well
designed system wth no severe blind high spots, then gravity purging
will probably work fine. If the zone seems to get hot quickly, and
gets hot enough, and you don't hear a lot of gurgleling noises,
chances are you are fine. Just repeat the bleeding process several
times.

You might look for a copy of "Modern Hydronic Heating" by Siegenthaler
at your local library. IIRC, he has a whole chapter on purging air
and correcting air entrapment problems.

HTH,

Paul

Paul:

Many thanks for your explanation and information. I am sure that it
has helped me. I will look for that book at the library, also.

In my case, the replacement baseboard heater is the first in the
series loop. This new unit is the only one that has bleeder valves
installed (all other heaters lack bleeder valves). And, all units are
on the same (floor) level.

The refill procedure used was to open the system supply feed valve,
close the boiler drain valve, and then open the drain valve located
above the water circulator; set the thermostat for a high room
temperature, then watch for sputterring water flow at the end of a
garden hose directed to a dry well. The supply pressure regulator has
a handle marked "FAST FILL", and that was used also operated to try to
keep the pressure level up as indicated on the boiler PSI gage.

When I felt a hot pipe at the circulator I felt that the system was
purged. However, I will repeat this process a couple more times. Now
that the new baseboard radiator includes bleeder valves, I may open
those.

Thanks again.

On Sat, 08 Oct 2005 08:13:04 -0400, Paul Franklin wrote:


It's hard to give specifics without knowing the detailed layout of the
piping. In general, there are two ways to purge a system, gravity and
forced-water.

Gravity purging is when you just open the feed water valve after a
shutdown, let the system fill with water as best it can, and then
purge the air using the bleed valves that should be provided at the
end of each radiator, or at least at the high point of each loop. In
theory, all the air in the system will rise to the highest point where
is removed using the bleed valves. Generally, the bleeding process
should be repeated over a few days or weeks until all the trapped air
is removed. Gravity purging usually works fine. You can run into
problems, however, if the piping design is such that there are high
spots without bleed valves or air vents. In other words, if a pipe
goes up, over, and down without there being a bleed or automatic air
vent, then an air pocket can form in the loop, and the circulator may
not be able to lift water over the loop. Usually, these kind of loops
are avoided by proper piping design. You sometimes see them when
there are floor level radiators in the basement with the boiler.

More common are air pockets caused by sloping or sagging piping, where
you can get a local high spot without a bleed. Unless severe, the air
will usally eventually be cleared from these during normal operation.

I mentioned that check valves can complicate purging because they by
limiting flow to one direction, they can create air pockets that can
not easily be eliminated. Again, very system specific.

SOunds reasonable to me. Sitting here in a cold house, I'm thinking of
starting up the furnace (well it is used for hot water too). ;-)
Question: Every fall when I first turn on the heat the system is full
of air. Where does the water go? The system is pressurized to ~14lbs, so
it can't be going back into the city supply (60ish lbs.). I dont' see any
leaks and I'd expect to see water when it's pressurized.

A more positive, and faster way to purge a system is forced-water
purging. This requires a feed valve with a "fast-fill" bypass, or
another way to provide full water pressure to the feed side. (such as a
hose fitting). It also requires a drain valve at the low side of the
piping (not the boiler drain valve). Specifics are very system
dependent, but the idea is to use get full house water pressure flowing
through each loop in the system, one at a time. This is more effective
at clearing air pockets than gravity purging.

Maybe I'll add that next time I drop the system (need to add some valves
goign to the upstairs bathroom anyway).

snip

You might look for a copy of "Modern Hydronic Heating" by Siegenthaler
at your local library. IIRC, he has a whole chapter on purging air and
correcting air entrapment problems.

Thanks!

--
Keith

snip

SOunds reasonable to me. Sitting here in a cold house, I'm thinking of
starting up the furnace (well it is used for hot water too). ;-)
Question: Every fall when I first turn on the heat the system is full
of air. Where does the water go? The system is pressurized to ~14lbs, so
it can't be going back into the city supply (60ish lbs.). I dont' see any
leaks and I'd expect to see water when it's pressurized.

No idea. It's one of the great mysteries of life, right up there with
where do all the missing socks go....

I mean, all such systems have backflow preventer, so even if the
boiler pressure were higher than the feed pressure the water could not
go out that way. And even if it did, how does air get in to take its
place? And leaks usually make themselves known, unless you've got
underground piping. There is dissolved air in the water that probably
separates out over time, but I find it hard to imagine that it is
enough to explain the quantity of air that seems to be in there each
fall.

Now if the expansion tank is the type that doesn't have a bladder
(most older ones don't), the air in there can dissolve slowly into the
water, but with no circulation going on, I don't see how it would end
up migrating elsewhere in the system.

So, I got nothin...maybe someone smarter than me knows the answer.

Paul

On Sun, 09 Oct 2005 20:06:22 -0400, Paul Franklin wrote:

snip

SOunds reasonable to me. Sitting here in a cold house, I'm thinking of
starting up the furnace (well it is used for hot water too). ;-)
Question: Every fall when I first turn on the heat the system is full
of air. Where does the water go? The system is pressurized to ~14lbs, so
it can't be going back into the city supply (60ish lbs.). I dont' see any
leaks and I'd expect to see water when it's pressurized.

No idea. It's one of the great mysteries of life, right up there with
where do all the missing socks go....

Crap! We know where they go; into the washer zone. ;-)

I mean, all such systems have backflow preventer, so even if the
boiler pressure were higher than the feed pressure the water could not
go out that way. And even if it did, how does air get in to take its
place?

.... and why does it stay there? This year I did considerable work on the
plumbing (a leak and rotted subflooring in the upstairs bathroom convinced
me to take a goo look), but amazingly the air wasn't as bad as it has been
in the past. ...search me! ;-\

And leaks usually make themselves known, unless you've got
underground piping. There is dissolved air in the water that probably
separates out over time, but I find it hard to imagine that it is
enough to explain the quantity of air that seems to be in there each
fall.

Exactly. My house usually sounds like Niagra Falls the first time I
request heat. I replaced a bleeder underneath this desk last year because
it was noisy here (and I stripped the damned thing trying to open it).
Hmm, I wonder where I put the key?

Now if the expansion tank is the type that doesn't have a bladder (most
older ones don't), the air in there can dissolve slowly into the water,
but with no circulation going on, I don't see how it would end up
migrating elsewhere in the system.

The house/furnace is ~20YO, and the expansion tank, perhaps 10 (I replaced
it since I moved here in '93).

So, I got nothin...maybe someone smarter than me knows the answer.

Yeah, I'm stumped too. ...although I did turn the heat on tonight
(it's been in the 30s-50s for several days) and it doesn't seem so bad.
I'll let it gurgle a while and then bleed the upstairs, if I can find the
silly key. ;-)

Thanks again!

--
Keith

"Paul Franklin" wrote in message
news
snip

SOunds reasonable to me. Sitting here in a cold house, I'm thinking of
starting up the furnace (well it is used for hot water too). ;-)
Question: Every fall when I first turn on the heat the system is full
of air. Where does the water go? The system is pressurized to ~14lbs,
so
it can't be going back into the city supply (60ish lbs.). I dont' see
any
leaks and I'd expect to see water when it's pressurized.

No idea. It's one of the great mysteries of life, right up there with
where do all the missing socks go....

I mean, all such systems have backflow preventer, so even if the
boiler pressure were higher than the feed pressure the water could not
go out that way.

WRONG! You should have said "All such systems should have a backflow
preventer..."

And even if it did, how does air get in to take its
place? And leaks usually make themselves known, unless you've got
underground piping. There is dissolved air in the water that probably
separates out over time, but I find it hard to imagine that it is
enough to explain the quantity of air that seems to be in there each
fall.

Now if the expansion tank is the type that doesn't have a bladder
(most older ones don't), the air in there can dissolve slowly into the
water, but with no circulation going on, I don't see how it would end
up migrating elsewhere in the system.

So, I got nothin...maybe someone smarter than me knows the answer.

Paul

Question: Every fall when I first turn on the heat the system is full
of air. Where does the water go?

It is not full of air, but it does have some air in it. There is an
expansion tank that will allow air to get into the system.


I mean, all such systems have backflow preventer, so even if the
boiler pressure were higher than the feed pressure the water could not
go out that way.

Actually, very few systems have backflow preventors. It is becoming more
popular as towns enact regulations requiring them. My house, built in 1978,
does not have one.



There is dissolved air in the water that probably
separates out over time, but I find it hard to imagine that it is
enough to explain the quantity of air that seems to be in there each
fall.

Hard to imagine, but true. One third of the formula H2O is oxygen.

On Sat, 08 Oct 2005 10:35:40 GMT, Vince
wrote:
What precuation/procedure should be used when purging air from a
single zone heating loop that has the check valve located immediately
at the hot output of the (Peerless) boiler ?

I just went through dropping the boiler water level so that a
baseboard heater could be replaced, and I am not certain that the loop
is fully purged of air.
I believe that getting all the air out requires some sort of black
magic. One good source of information is he
http://www.heatinghelp.com/
which has a forum for posting. Dan is a proponent of the "pumping
away" design, which you can probably find among the many books he has
for sale. In essence, this design says that most older systems are
installed wrong with the circ pump in the wrong place (i.e. pushing
water into the boiler, vice pulling it out). Bladder-lined tanks are
a must, and perhaps a Spirotherm vent
http://www.spirotherm.com/residential/
Got an estimate to converrt my very old, cast iron ("it will be there
when the house falls down") Brunham boiler to this design of about
$1500, including the tank, rerouting the piping and plus the
vents/pump.
My major concern is when you start wrenching on the major arteries of
a system that old that something is likely to let go in the innards.
We are going to start with the vent and the tank to see what happens.

In article , says...


Question: Every fall when I first turn on the heat the system is full
of air. Where does the water go?

It is not full of air, but it does have some air in it. There is an
expansion tank that will allow air to get into the system.

Not full of air sure, but it sounds like a waterfall and there is considerable
air in there. Why would the expansion tank allow air in? The water that's
there would have to be displaced. Where?

I mean, all such systems have backflow preventer, so even if the
boiler pressure were higher than the feed pressure the water could not
go out that way.

Actually, very few systems have backflow preventors. It is becoming more
popular as towns enact regulations requiring them. My house, built in 1978,
does not have one.


I'm not sure there is a back-flow preventer, but there is a pressure reduction
fill valve. Since the municipal pressure is above 60psi and the furnace at
14psi, I can't imagine water flowing up that "hill".

There is dissolved air in the water that probably
separates out over time, but I find it hard to imagine that it is
enough to explain the quantity of air that seems to be in there each
fall.

Hard to imagine, but true. One third of the formula H2O is oxygen.

Were is the energy coming from to separate the oxygen from the hydrogen. It
would truly be scarry if there was free hydrogen and oxygen in the furnace!
;-)

--
Keith

exactly the type of info I needed. Thanks zero.

cram