Move pump or expansion tank, rusted flange

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Old 03-06-20, 05:04 PM
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Move pump or expansion tank, rusted flange

So I'm going to move my pump to pump away from the expansion tank rather than towards. There's no way I'm going to un-thread the flange, that baby is rusted. I'm assuming cold chisel and angle grinder are my best tools.

Right now the expansion tank is connected to the pressure relief valve pipe. Would it make more sense to move the expansion to the return side rather then move the pump to the supply side. Orientation of the expansion tank doesn't matter, right. I can mount the tank vertically, upside down, or horizontally
 
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03-10-20, 06:59 PM
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Any air that gets into the bladder tank on the system side of the bladder does not stay there if there is a decent air separator. When water cools it absorbs the air and aids in removing from the upside down tank.I short any air in the tank on the system side of the bladder will always move out and may return depending on quality of air separator and amount of make-up water.
Pumping away from the expansion tank will always add pressure to the system thus making any air bubbles smaller. Adding pressure to moving air bubble will break up the bubbles trying to drive the air back into solution.
The smaller the bubbles the easier to move air down a vertical pipe to the boiler to get heated up and removed by air separation
I can recall so many jobs where moving the circulator to the supply side after the expansion tank taping has resolved so many problems. There were times we just moved one circulator on a problematic circuit just to eliminate that particular problem when the owner would not pay to move all circulators.
Manufacturers know their products best and even though liability is always an issue as it should be even with contractors they still enjoy problem free longevity. No manufacturers want to have their products as the problematic part of the system.
 
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Old 03-07-20, 08:07 AM
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As a practical matter it does not make much difference whether pump is on inlet or outlet side of boiler.

Theoretically there is a difference. Long ago I removed old ceiling expansion tank. Replaced it with diaphragm type and shut off valve on floor behind boiler. There has been no issues

What m3ath3ad might consider is using mating flanges to install isolation valves so pump can be removed without draining system. On a cold winter day will be quicker and easier to depressurized system and service pump.

Rusted flange can be still be used with full sized gasket (not square O ring) and gasket sealer.
 

Last edited by doughess; 03-07-20 at 09:55 AM.
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Old 03-07-20, 11:33 AM
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Bladder type tanks are supposed to be mounted with the nipple up.
https://www.amtrol.com/wp-content/up...nSight-Cap.pdf

I would clean that flange well using a wire brush & install new full sized gaskets. You can use sealer if you want to but I've never found the need.
 
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Old 03-07-20, 07:44 PM
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I mount diaphragm type tanks nipple down to keep debris out of them. When tanks are at basement level that can reduce issues. Whatever floats your boat.
 
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Old 03-07-20, 09:14 PM
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Can you install expansion tank upside down?
if you install it upside down, then air goes up into the tank, and cann't get out -reducing the functionality of the tank. vertical, opening up is best.Feb 18, 2008.

This was from an article on Amtrol tank installations and the best place to install them. Enough said on that subject from me.
 
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Old 03-08-20, 04:24 AM
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Looking at the picture of the pipe and flange, that may be teflon tape that was used as the thread sealer. If it is teflon tape the flange should be easy to remove.
 
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Old 03-09-20, 09:42 PM
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Any air in expansion tank installed with nipple on bottom may provide additional compressible air space to system. That does not reduce functionality of tank and may increase it. And, with air fitting on top it is easier to check pressure when tank is located on floor behind boiler.
 
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Old 03-10-20, 09:32 AM
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Do what you want. Forget about manufacture's intructions. They are only suggestons, kind of like stop signs. NOT
 
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Old 03-10-20, 05:43 PM
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Tank manufacturers sell hydronic components not systems. Their top priority is to avoid liability so limit instructions to minimum.

Companies making door locks are not much help on many security system issues.
 

Last edited by doughess; 03-10-20 at 07:42 PM.
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Old 03-10-20, 06:59 PM
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Any air that gets into the bladder tank on the system side of the bladder does not stay there if there is a decent air separator. When water cools it absorbs the air and aids in removing from the upside down tank.I short any air in the tank on the system side of the bladder will always move out and may return depending on quality of air separator and amount of make-up water.
Pumping away from the expansion tank will always add pressure to the system thus making any air bubbles smaller. Adding pressure to moving air bubble will break up the bubbles trying to drive the air back into solution.
The smaller the bubbles the easier to move air down a vertical pipe to the boiler to get heated up and removed by air separation
I can recall so many jobs where moving the circulator to the supply side after the expansion tank taping has resolved so many problems. There were times we just moved one circulator on a problematic circuit just to eliminate that particular problem when the owner would not pay to move all circulators.
Manufacturers know their products best and even though liability is always an issue as it should be even with contractors they still enjoy problem free longevity. No manufacturers want to have their products as the problematic part of the system.
 
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Old 03-11-20, 01:30 PM
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Smile

Homes have commodes because things happen. Hydronic systems often have unwanted air.

Regardless of where that air comes from it can be automatically vented with auto vent valves at highest point of zones. I focus on venting that air, not how it developed.

For $8.99 per zone can forget about venting and deal with other issues in my life. Ignorance can be bliss.

https://www.supplyhouse.com/Watts-05...Vent-3679000-p
 
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Old 03-11-20, 03:04 PM
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doughness,
This post started about expansion. You have now taken this conversation from expansion tanks to door locks to security systems and to commodes and finally while sitting on that commode where excess air comes from.

You are nothing if not entertaining. You have made my day. I hope your commode gives you as good service as you auto vents with your air problems.

My best to your family. lol
 
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Old 03-11-20, 03:32 PM
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The point I was making was that air is a common, on going problem in hydronic systems ...so focus on finding a way to deal with it. Vendor's information is not always reliable or applicable.


I was trying to help DIYers by suggesting an easy way to to vent the air.

If Spott has a way to find source of air in systems to end problem he should share it. Instead of helping DIYers, he criticizes another's post. His posts define him. Readers can judge for themselves.
 

Last edited by doughess; 03-11-20 at 04:51 PM.
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Old 03-11-20, 03:50 PM
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doughness,
Since you asked I will share this much with you. As you know I'm sure, air is introduced into a closed loop system in only a couple of ways.

The first of course is by introducing fresh water into the system which brings air that must be bled to get proper circulation of water. The next is if you have a leak somewhere which allows water to escape that eventually must be replaced and the 3rd and the one that people don't think much about unless you are in the trade and actually work in the field is when AUTO VENTS fail and air gets sucked into the system when the pump comes on. Auto vents fail in 2 ways, by leaking and by allowing air to pulled in by the circulator.

Doughness, you have to lighten up a little. The world will still be spinning tomorrow.
 
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Old 03-11-20, 06:48 PM
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Old type auto vents in sealed can types like JACOBUS-MAID-O-MIST had high failure rates. On DIY.com see many pictures of them that leaked then cap shut off. I have one in my scrap box. Maybe those are what Spott was referring to:

https://www.supplyhouse.com/Jacobus-...xoCg-8QAvD_BwE

New technology vents with two part bronze housings can be opened for servicing are very reliable. I have 13 of them on my home system. None leaked. One stopped venting and swapped in new $8.99 spare:

https://www.supplyhouse.com/Watts-05...Vent-3679000-p

Over 50 years have gone from manual vents on each enclosed element to auto-vents. In old age appreciate the modern Watts vent.

I am offering solutions that worked well for me to other DIYers. That is what this site is about .. helping others.
 

Last edited by doughess; 03-11-20 at 08:05 PM.
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Old 03-13-20, 05:31 PM
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Mis-placed air vents in the heating system like at the high points can also suck air into the system. The lowest pressure point in the system is the hihest point where the pipe turns and heads back into the basement. When the circulator is on the return side the pressure at thet point is the lowest. You should always have a minimum of 4 psi at thet point. When pumping away from the expansion tank the pump will add pressure to the system and keep the pressure above 4 psi, Thus, no need for the auto air vents up in the system.
 
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Old 03-14-20, 08:54 AM
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Auto vents work regardless of how air gets into system. If air comes in due to system water pressure variation or some other source, vent will purge it. Focusing on source of air is little benefit when venting is easily accomplished with auto vents.

https://www.supplyhouse.com/Watts-05...Vent-3679000-p


This is not leaking boat hull or roof where first concern is to stop leak. If the air comes from Tooth Fairy farts auto vents will get rid of it. Today we have more important issues to deal with.
 
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Old 03-14-20, 12:30 PM
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doughness,
You do inspire me with your thinking process.

It's true if the weather happens to be 50 or 60 we tend to be a little more tolerant and concentrate on other issues but if you are in Michagan and the weather is 10 below and your in the house with 3 little kids with no heat because the TOOTHFAIRY had a bad night I think I would wonder exactly how the air got into the system repair the cause.

Eliminate the cause and there is no need for the remedy.
 
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Old 03-14-20, 03:25 PM
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I think this topic has been well covered. It looks like plenty of info for the OP.
If there is a need to carry this further.... PM me.
 
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