We have a boiler/radiator system in our six-unit apartment building. We have
been flushing it -- I think it might be called "draw down" -- once a week.

But I get mixed advice on how often we should do this, and how long we
should let it flush each time.

Any guidance welcome.

"Ray" wrote in message
news:s2Eyj.403$Ie2.128@trndny09...
We have a boiler/radiator system in our six-unit apartment building. We
have been flushing it -- I think it might be called "draw down" -- once a
week.

But I get mixed advice on how often we should do this, and how long we
should let it flush each time.

Any guidance welcome.

There is only one accurate method. Get a meter that measure Total Dissolved
Solids and do a test. A meter is in the $275+ range. The one I use is
on the bottom of page 590 at www.mcmaster.com Number 1128T16

Two things you want to do. One is to flush the bottom of the boiler to
remove sediment. The second is to maintain a level of dissolved solids that
is less prone to sludging, yet is not loaded with oxygen.

When blowing down a steam boiler, the general consensus is to open the valve
three times. The first flush gets rid of what is near the valve, but if you
just let it run, much of the deposited solids just stay in place. Closing
the valve quickly stirs up some of the sludge so it can be sucked out.

Some boilers require chemical treatment to keep them in good condition. It
is not possible to give a guideline on how often as that will vary depending
on operating time, the condition of the water supply (hard, soft,, types of
minerals, etc) Tb be 100% certain, you need a boiler chemical guy that can
do the test and give you guidelines.

Thanks -- that's very helpful.

"Edwin Pawlowski" wrote in message
. net...

"Ray" wrote in message
news:s2Eyj.403$Ie2.128@trndny09...
We have a boiler/radiator system in our six-unit apartment building. We
have been flushing it -- I think it might be called "draw down" -- once a
week.

But I get mixed advice on how often we should do this, and how long we
should let it flush each time.

Any guidance welcome.

There is only one accurate method. Get a meter that measure Total
Dissolved Solids and do a test. A meter is in the $275+ range. The
one I use is on the bottom of page 590 at www.mcmaster.com Number 1128T16

Two things you want to do. One is to flush the bottom of the boiler to
remove sediment. The second is to maintain a level of dissolved solids
that is less prone to sludging, yet is not loaded with oxygen.

When blowing down a steam boiler, the general consensus is to open the
valve three times. The first flush gets rid of what is near the valve, but
if you just let it run, much of the deposited solids just stay in place.
Closing the valve quickly stirs up some of the sludge so it can be sucked
out.

Some boilers require chemical treatment to keep them in good condition.
It is not possible to give a guideline on how often as that will vary
depending on operating time, the condition of the water supply (hard,
soft,, types of minerals, etc) Tb be 100% certain, you need a boiler
chemical guy that can do the test and give you guidelines.

On Mar 2, 3:24*pm, "Ray" wrote:
We have a boiler/radiator system in our six-unit apartment building. We have
been flushing it -- I think it might be called "draw down" -- once a week.

But I get mixed advice on how often we should do this, and how long we
should let it flush each time.

Any guidance welcome.

The idea is so that you don't sludge up the system and/or stop the low
water cutout from shutting things down if water level drops.
On a boiler that size I bet you would pull about 2 gallons for a
decent blowdown.
During the heating season if it was my boiler I would look twice a
week and put an x on the calandar so it doesn't get forgotten.

Ray wrote:
We have a boiler/radiator system in our six-unit apartment building.
We have been flushing it -- I think it might be called "draw down" --
once a week.
But I get mixed advice on how often we should do this, and how long we
should let it flush each time.

Any guidance welcome.

Living the other side of The Pond and reading this site quite frequently,
I;m under the impression that central heating systems on the Left Side are
usually different to those we use.

Do you mean this sort of system powered by gas, oil or solid fuel - coal/
lumber?
http://www.gasapplianceguide.co.uk/c...ng_systems.htm

If so, then frequent bleeding could assist rusting! It would draw in fresh
oxygenated water. What is common for such a system here is to add an
inhibitor to a new system to prevent corrosion and sludge build up and then
drain every few years. We can purchase fluids here to help flush the system
for this process, then wash through with fresh water, then refill adding
inhibitor, (the cost of the process from recollection is circa $40,
excluding my time of about two to three hours).

My current system that I have had from new in a new build house has been up
for almost 25 years and I've flushed it just 3 times in that time - if my
memory serves me well! No leaks, no problems apart from assisting the
circulatory pump to wake up in The Fall some years.

On Mar 4, 5:34*pm, "Clot" wrote:
Ray wrote:
We have a boiler/radiator system in our six-unit apartment building.
We have been flushing it -- I think it might be called "draw down" --
once a week.
But I get mixed advice on how often we should do this, and how long we
should let it flush each time.

Any guidance welcome.

Living the other side of The Pond and reading this site quite frequently,
I;m under the impression that central heating systems on the Left Side are
usually different to those we use.

Do you mean this sort of system powered by gas, oil or solid fuel - coal/
lumber?http://www.gasapplianceguide.co.uk/c...ng_systems.htm

If so, then frequent bleeding could assist rusting! It would draw in fresh
oxygenated water. What is common for such a system here is to add an
inhibitor to a new system to prevent corrosion and sludge build up and then
drain every few years. We can purchase fluids here to help flush the system
for this process, then wash through with fresh water, then refill adding
inhibitor, (the cost of the process from recollection is circa $40,
excluding my time of about two to three hours).

My current system that I have had from new in a new build house has been up
for almost 25 years and I've flushed it just 3 times in that time - if my
memory serves me well! No leaks, no problems apart from assisting the
circulatory pump to wake up in The Fall some years.

I have a 60 yr old steam system, flushing it weekly meaning a few
gallons, is fine, oxygen boils out almost 100 % on the next cycle

ransley wrote:
On Mar 4, 5:34 pm, "Clot" wrote:
Ray wrote:
We have a boiler/radiator system in our six-unit apartment building.
We have been flushing it -- I think it might be called "draw down"
-- once a week.
But I get mixed advice on how often we should do this, and how long
we should let it flush each time.

Any guidance welcome.

Living the other side of The Pond and reading this site quite
frequently, I;m under the impression that central heating systems on
the Left Side are usually different to those we use.

Do you mean this sort of system powered by gas, oil or solid fuel -
coal/
lumber?http://www.gasapplianceguide.co.uk/c...ng_systems.htm

If so, then frequent bleeding could assist rusting! It would draw in
fresh oxygenated water. What is common for such a system here is to
add an inhibitor to a new system to prevent corrosion and sludge
build up and then drain every few years. We can purchase fluids here
to help flush the system for this process, then wash through with
fresh water, then refill adding inhibitor, (the cost of the process
from recollection is circa $40, excluding my time of about two to
three hours).

My current system that I have had from new in a new build house has
been up for almost 25 years and I've flushed it just 3 times in that
time - if my memory serves me well! No leaks, no problems apart from
assisting the circulatory pump to wake up in The Fall some years.

I have a 60 yr old steam system, flushing it weekly meaning a few
gallons, is fine, oxygen boils out almost 100 % on the next cycle

Ah! Difference in language across the water, I guess. Not familiar with a
steam system. does this circulate through the rads?

"Clot" wrote in message
Ah! Difference in language across the water, I guess. Not familiar with a
steam system. does this circulate through the rads?


That is the beauty of steam. Water needs a pump to push it and if you have
a large building, you need a large pump with high pressure. With steam, the
pressure of the steam will move it up and the condensate is either gravity
returned or pushed by the steam pressure. Some have a single pipe that
handles both steam and condensate.

Steam under pressure carries a lot of energy with it and it can go long
distances with minimal loss.

On Mar 2, 2:24*pm, "Ray" wrote:
We have a boiler/radiator system in our six-unit apartment building. We have
been flushing it -- I think it might be called "draw down" -- once a week.

But I get mixed advice on how often we should do this, and how long we
should let it flush each time.

Any guidance welcome.

If its a hot water, not steam system, you dont flush it or you bring
in oxygen.

Edwin Pawlowski wrote:
"Clot" wrote in message
Ah! Difference in language across the water, I guess. Not familiar
with a steam system. does this circulate through the rads?


That is the beauty of steam. Water needs a pump to push it and if
you have a large building, you need a large pump with high pressure. With
steam, the pressure of the steam will move it up and the
condensate is either gravity returned or pushed by the steam
pressure. Some have a single pipe that handles both steam and
condensate.
Steam under pressure carries a lot of energy with it and it can go
long distances with minimal loss.

Thanks for the info. Yes, I can appreciate those virtues ( and can think of
possible negatives!).