Removal of attic expansion tank

MIKE KURM

Sir,



Read your HeatingHelp.com. It was very informative. Now we have a particular problem and we are asking for your help.



Our heating contractor and I are puzzled. I recently asked him to remove the old expansion tank from a closet in the attic to make more usable space. He also put in a new low mass boiler and larger basement expansion tank. Finally, we also had him raise some very low hanging cast iron pipes to increase head room in the basement. He replaced the cast iron with 1” copper.



Now we are having trouble getting heat to one of two radiators in the attic, my daughter’s bedroom. He managed to get some heat by closing the valves in all the radiators in the house. We were able to get heat prior to the removal of the attic expansion tank and all of the other work done. The attic expansion take does not seem to vent openly to the roof. It appears to return downward back to the basement. In seventeen years living here we never have seen any overflow water on the outside of our home including gutters etc. I looked all around the roofline and no open overflow is visible.



Our home was home built in 1922. It originally had a coal fired boiler with a gravity piping system. Some years ago, before we moved in, the coal fired boiler was converted to oil and a pump was installed converting it to a forced circulation system.



Would the removal of an “old” attic expansion tank have something to do with the partially heating radiator?



Any heat would be appreciated.



Thanks,



MIKE KURM



Cell: 215-514-2924

Fax: 610-284-3605

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Mike T., Swampeast MO

"He replaced the cast iron with 1” copper."

Something about that statement troubles me as I believe it would profoundly affect flow in the system. If 1st, 2nd and 3rd floors all connect to this MUCH smaller pipe using their original branch sizes you're going to have a very difficult time getting flow to those on the 3rd floor as the water will shortcut through the lower/closer radiators. With gravity flow they actually had to keep heat DOWN--not UP where it went naturally.

You might want to look for restrictor plates in the 3rd and 2nd floor radiators. They are generally installed inside the valves but can possibly be in the angle unions. If you find them, remove them. SAVE them though as you may well need to add them lower if the 1st floor rads start overheating. If all are too small for the lower rads (quite possible) you can make them with thin copper/brass/stainless steel.

jackchips_2

Mike,

> "He replaced the cast iron with 1”

> copper."

>

> Something about that statement

> troubles me as I believe it would profoundly

> affect flow in the system. If 1st, 2nd and 3rd

> floors all connect to this MUCH smaller pipe

> using their original branch sizes you're going to

> have a very difficult time getting flow to those

> on the 3rd floor as the water will shortcut

> through the lower/closer radiators. With gravity

> flow they actually had to keep heat DOWN--not UP

> where it went naturally.

>

> You might want to

> look for restrictor plates in the 3rd and 2nd

> floor radiators. They are generally installed

> inside the valves but can possibly be in the

> angle unions. If you find them, remove them.

> SAVE them though as you may well need to add them

> lower if the 1st floor rads start overheating.

> If all are too small for the lower rads (quite

> possible) you can make them with thin

> copper/brass/stainless steel.

jackchips_2

Mike,

the pressure could also be low. A three story building more than likely requires more than the factory setting on the feed valve.

I would recommend checking the pressure in the system, adding if necessary and then setting the expansion tank to match.

Steamhead

Also check your runout sizes, Mike

The runouts are the pipes going from the mains to the vertical risers that feed the radiators.

Many old gravity systems had 3/4-inch, 1-inch or 1-1/4-inch runouts. If theyre this big, it explains the poor water distribution from the 1-inch mains.

The way out of this is to use smaller runouts. With forced circulation, you can use 1/2-inch runouts for radiators up to 90 square feet or so. The risers don't have to be replaced.

Note that all parts of the system must be piped the same for this to work properly. If not, the part of the system that has the smaller pipes won't get enough water.

Before doing anything, see how much radiation is on each pair of mains (flow and return). Too much radiation can cause the same problem. Get a copy of Dan's book "E.D.R." to determine radiator sizes- order it on the Books and More page of this site.

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D lux_2

how bout air

try bleading ?

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joe_17

yea i would

say air or system not balanced .Little more info would help.What type circulator is it? Whats the pressure in the system?You said 3 story house with expansion tank in basement then im guessing around a heith of what 30 feet from expansion tank to top top floor radiator? 40 feet?Is the circulator pumping away from the expansion tank or to the expansion tank where it is connected?What type expansion tank is the new one?Is it plain steel tank or is one with a bladder?Everything depends on the near boiler piping for best air removal from the system.Can you post apicture of the boiler andpiping.Have you tried bleeding the radiator that isnt heating.

Wayco Wayne

Make sure

the expansion tank is on the suction side of the circulator. Also make sure the pressure is high enough in the system. WW

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Geno_15

I agree

Check your pressure. Your system should start at 12 psi. That will give you about enough for a two story home but older houses are taller. You want to increase 1 psi for each 2.31 ft of head. Measure to the top of the radiators and add 2 ft to be safe. I think with the third floor you're going to see you need 20+- psi for a starting point. You may need to repipe the pump on the supply to "pump away" and get better flow. Remember to change the pressure in your bladder expansion tank if you're using one. The air pressure should match your running pressure. Good luck and let us know how you make out.

Eric

hopefully you have a 30 psi relief on boiler too.

kevin coppinger_4

over flow piping...

in colder climates the overflow pipe is piped to the basement and then to the sewer/building drain.I found out this fron my parents home... a 3/4" cap fixed the problem, may also explain the "pressure problem".
Why a low mass boiler in a high mass system?Better have a real good bypass set up... Can you give us a drawing of the piping? kpc