Fixing old system: Where to put expansion + air separator?

lukenurn

Hi all,
I’ve had major air issues with Hot water baseboard heating In my home- painfully noisy at night. Everything I read says my piping is dated and inefficient. Currently, path goes...

supply: cold water inlet, T to old compression steel expansion tank one way and boiler cold inlet the other way, hot water exits boiler to 1 circulator pump, splits into 2 zones

Return: both zone return pipes have their own circulator pulling from their zones and pumping into boiler

hot water leaves boiler pulled through the one circulator pump to go to zones again. 3 pumps total: two pushing into boiler from each zone, one pulling out for both zones.  No air vents or separators. Located in basement of ranch home, so usually have pressure around 12psi, no more than 15. 

I’m thinking I want to get rid of the old compression style tank mounted in the ceiling and replace with bladder, and add air separator with vent.  Considering water temp, pressure, etc, where are most ideal places to do this?

Any ideas (besides repiping everything)? please share a few options in order of most ideal as not all locations are able to be modified due to pipe length/location. Hoping this setup will get me by some more years until this old munchkin kicks the bucket. Thanks!

luke

mattmia2

the tank and micro bubble air separator should be between the boiler and the primary pump if the primary pump is pumping away from the boiler and it is a primary-secondary setup which it sounds like it is.

There should be a device on your current system that collects the air and sends it back to the tank. if the boiler was replaced, perhaps someone removed that device.

STEVEusaPA

If you want it trouble free, air free, and noise free, you're going to have to repipe, using the pump away method.
I picture of what you have now, back far enough to see all the near boiler piping and the room it's in would help.

lukenurn

Thanks all for comments so far. 

See photo. Cold return (2 pumps jade / red color) in blue. That is a black iron gas line by my blue arrow FYI

Hot supply (1 primary red pump) in red. 

Current expansion tank location in yellow. 

Excuse all the junk. Remodeling

Ironman

The place where the expansion tank connects to the system piping is known as the Point Of No Pressure Change. The pumps should always be arranged so that they "pump away" from the PONPC. That means that they should be moved to the supply line immediately after the air separator which you're gonna install. The new expansion tank should be connected to the bottom of the air separator (MBR). Each pump or loop should have a flow check (internally or externally).

STEVEusaPA

You have plenty of room. Why is the valve to the expansion tank closed?

lukenurn

STEVEusaPA said:

You have plenty of room. Why is the valve to the expansion tank closed?

I have been relocating some piping throughout the basement for the remodel, so I have water source valve and expansion tank valve shut. 

lukenurn

mattmia2 said:

the tank and micro bubble air separator should be between the boiler and the primary pump if the primary pump is pumping away from the boiler and it is a primary-secondary setup which it sounds like it is. There should be a device on your current system that collects the air and sends it back to the tank. if the boiler was replaced, perhaps someone removed that device.

Could I put a vertical spirovent jr between the primary and boiler (lower left pink circle) and replace compression tank with bladder expansion tank in current location? (Right pink circle). 

Again, trying to move as little as possible before winter, which is just around the corner in Wisconsin. 

Hopefully whatever I do will get me by at least a few years until I’m ready to replace entire system. 

Thanks all

Ironman

Don't do anything to the boiler loop. Everything needs to be done in the house loop.

The air separator needs to be in the house supply line and the circs placed after it. The expansion tank MUST connect to the supply BEFORE (upstream) the circulators. The way it is now is what's causing your air problems.

Ironman

Like like this:

The fill connection can remain where it is.

lukenurn

Ironman said:

Like like this:
(Image)

The fill connection can remain where it is.

Awesome art!  That makes sense. Thanks for drawing. 

lukenurn

Where would I put valves to shut off each zone? 

JUGHNE

You can download the piping diagram for the Munchen boiler.
The very first ones showed only one pump.....do not look at that.
You want the ones that show primary/secondary piping.

The boiler pump (lower one) should be pumping directly into the boiler. This could be cause of water hammer noise you might hear. The boiler needs good constant flow into it to avoid making steam. That pump is usually larger than the other two pumps.

hot_rod

How old is that boiler?  Has it been serviced regularly? Asking for a friend.

It is best to pump into that type of small coil boiler.  That added delta p from the circulator pumping in helps keep them from having flow and banging issues, often.
The air purger is best at the hottest point in the system, right at the boiler. Up in them house loop would work also.
The tank does not need to be at the air separator location, it needs to be upstream of the circulator, however.
A few options.

Ironman

lukenurn said:

Where would I put valves to shut off each zone? 

Use iso flanges on the pumps and put a ball valve in each return above the boiler.

lukenurn

hot_rod said:

How old is that boiler?  Has it been serviced regularly? Asking for a friend.

Around 15 years old. Bought the home 2 years ago and it had been serviced 3 years prior.

i did major service on it last year. (Clean chamber, flush condensate, new pump, new gaskets sensors, chamber door and other parts). 

hot_rod

If you pump them properly, keep the burner dialed in and clean out the hx by removing the burner it could be a 20 year or more boiler.

lukenurn

hot_rod said:

If you pump them properly, keep the burner dialed in and clean out the hx by removing the burner it could be a 20 year or more boiler.

That’s my hope!  Based on what everyone has said,
does this setup from munchkin look good?  I would flip the primary from pulling out to pumping in, then move the two zone pumps on the returns to each zone hot supply with air separator and ex tank just before split to zone pumps. 

hot_rod

How deep do you want to get into a repipe?
A hydraulic separator cleans up the piping and provides 4 critical functions in one device.
High efficiency air, dirt, magnetic separation. In addition to hydraulic separation (primary secondary)
Time to move beyond basic primary secondary piping

mattmia2

Note that your main problem is that you don't really have any specific place that air that finds it way out of the tank will collect and the way it is connected doesn't really encourage it to move to the tank even if it finds its way to the area of that tee to the tank.

lukenurn

hot_rod said:

How deep do you want to get into a repipe? A hydraulic separator cleans up the piping and provides 4 critical functions in one device. High efficiency air, dirt, magnetic separation. In addition to hydraulic separation (primary secondary) Time to move beyond basic primary secondary piping

What about Caleffi 5461 where I was planning to put air separator?  Not sure where ex tank would go though... 

mattmia2

that isn't a bad idea but not really necessary for a copper baseboard system. you would have to tee the tank off separately. apollo makes some combination valves that combine the valves to service the tank in to one valve.

lukenurn

mattmia2 said:

that isn't a bad idea but not really necessary for a copper baseboard system. you would have to tee the tank off separately. apollo makes some combination valves that combine the valves to service the tank in to one valve.

Combo of copper, a little brass, and whatever the taco pumps are made of- assuming those are iron?

hot_rod

lukenurn said:

hot_rod said:

How deep do you want to get into a repipe?
A hydraulic separator cleans up the piping and provides 4 critical functions in one device.
High efficiency air, dirt, magnetic separation. In addition to hydraulic separation (primary secondary)
Time to move beyond basic primary secondary piping

What about Caleffi 5461 where I was planning to put air separator?  Not sure where ex tank would go though... 

Yes a 5461 is air, dirt and magnetic function, good to have a magnetic function for the day an ECM circulator gets installed.

The hydro Sep 4 give you the hydraulic separation between that high pressure drop boiler and the distribution, the 4th function.