PUMP FOR BLEEDING MY BOILER

Rongold

Hi all,

I recently flushed out 15 year old anti freeze from my boiler. I also replaced the immersion well, as it had started leaking, and also replaced the 2 air vents and a stuck pressure relief valve. My house is a split level--It's considered a 1 1/2 story. The bedroom level is about 12-14 feet above the basement level. The boiler is in the basement. I filled the boiler itself with Cryotek 100--I managed to get 15 gallons into the boiler. Before I filled the boiler, I installed the new immersion well, air vents and PR valve. I filled all 3 zones with water using the feeder valve and bleeding air through the hose bibs that you normally would bleed the system through. I closed all 3 zone valves and also closed the valves under each hose bib trapping the water in the 3 zones--or so I thought. I fired up the boiler, and the playroom zone heats up well, the kitchen zone also heats up well, but the highest zone, the bedroom zone, does not get hot---only luke warm after the circulator has been running for about 10 minutes---it's airbound. The circulator evidently cannot push the air through that zone. Being that I have anti freeze in the system, I cannot bleed that zone the normal way without losing all my anti freeze. I am going to use the submersible pump & bucket method, and keep recirculating until there are no bubbles visible.

How strong a pump do I need to push the air out of that zone ??? I can get this style pump with a 1/4 HP, or a 1/3 HP rating at a decent price. Both of them will lift at least 21 feet according to the manufacturer. How strong a pump do you guys use ??? What do I need to push that air through ??? If the circulator (Taco 007) is only 1/25HP, shouldn't the 1/4 HP submersible pump be enough ???

RON

JUGHNE

What pressure does the boiler sit at?

Rongold

At 140 degrees, it's about 12 PSI--A little less if I shut it down and let it cool off.

JUGHNE

The pressure in the system is what raises the water up there.
IMO, you need at least 12 PSI when cold, maybe 15.

Then you could bleed air carefully from top radiation.

Do you have to have antifreeze in the system?

mattmia2

I don't think he has a bleeder of any sort in the high part of that loop judging from his other posts..

EBEBRATT-Ed

Typically the anti freeze is put in at a 30% mix. Hopefully its not straight anti freeze

Rongold

JUGHNE said:

The pressure in the system is what raises the water up there.
IMO, you need at least 12 PSI when cold, maybe 15.

Then you could bleed air carefully from top radiation.

Do you have to have antifreeze in the system?

It's hot water baseboard---There are NO bleeders other than at the boiler.

Yes there is anti freeze in the system---Between 30-40 percent if my calculations are correct.

If there were no anti freeze, I would just isolate that zone and open the hose bib at that zone's return and let the feeder valve pressure push the air out.

hot_rod

1/2 hp transfer pumps do a good job, plenty of gpm and psi for residential systems, Keep an eye on pressure so you don’t pop the relief when power purging. May put a 5 gallon bucket under the relief valve 

Rongold

Rongold said:

JUGHNE said:

Do you have to have antifreeze in the system?

Yes---There is 1 zone that has the baseboard pipe come up out of the slab past the sheetrock and past the insulation---Builder screw up.

BDR529

That pump is fine.
fill and purge with water. Pump AF in bottom of boiler, pull water out the purge valve as it is replaced with AF.

Rongold

BDR529 said:

That pump is fine.

Which one---The 1/4 HP or the 1/3 HP ???