Ask Me Help Desk - Boiler bleeding

I had to take down my home heating system to repair a leak in the main line from the boiler to my baseboard heat. I shut down the furnace, drained the boiler, made the repair
Filled to boiler and tried to bleed air from the drain. It is a one zone system. I thought it was initiall working as it appeared there was a lot of air coming out of the drain however it just stopped coming out altogether (water & air) and now I have no heat. Additionally I have my hot water coming from my boiler and still get some but it runs out afetr a minute or two.

Any suggestions would be greatly appreciated.

Thanks
Jay

Is there pressure on the boiler pressure gauge? Did you remember to turn the valve back on to the pressure reducing valve ( water feeder),if so your pressure reducing valve could be plugged up with gunk. Some have a screen on the inlet that you can clean, but some of the others don't. If all your valves are on and no water is flowing, replace the pressure reducing valve.

What drain are bleeding from? Hopefully not the bottom discharge drain. Do you have a purge system or bleeders at the baseboards themselves?

Quote:

Originally Posted by cornerstonehvac

What drain are bleeding from? Hopefully not the bottom discharge drain. Do you have a purge system or bleeders at the baseboards themselves?

I did drain the boiler from the bottom most drain. What I did was shut down the incoimg water feed and drained the system from that point. When I opened the feed it did fill through with the water at which time I opened that bottom drain again to bleed out the air and did see quite a bit of spitting of the water b/4 it stopped flowing altogether

There is one "pear shaped" valave on top of the boiler - on a line however the toglle on top is frozen/rusted so I can't do anything with it.

It is a peerless boiler... guessing 30 yrs old or more.

Quote:

Originally Posted by cornerstonehvac

Is there pressure on the boiler pressure guage? Did you remember to turn the valve back on to the pressure reducing valve ( water feeder),if so your pressure reducing valve could be plugged up with gunk. Some have a screen on the inlet that you can clean, but some of the others don't. If all your valves are on and no water is flowing, replace the pressure reducing valve.

FIRST... thaNks for you help!!

What I have/had done is the following.
Shut off furnace switch to which the circulator is also connected to.
Shut down water supply.
Open bottom most spicket-drain and emptied all "hot" water out.
Made repair then...
Opened up water feed - heard it fill.
Again opened bottom most drain to purge/bleed.
Had water flow and lots af spitting air b/4 water flow completely stopped.
It is a one zone peerless boiler... guessing 30 yrs old +

First off, you cannot bleed the boiler from the bottom drain. In order to bleed the system you need to do 1 of 2 things depending on the system . I'll try to explain what to look for and how to bleed the system so bear with me. You also mentioned that there was a pear shaped valve on top, that most likely is a Hy-vent. If the hy vent is not working it should be replaced before filling the boiler. You may be able to get one at Lowe's or Home depot I'm not sure or you may have to get it at a hvac contractors shop,but I would recommend that it be replaced.
1)- On the return piping(usually the piping that the circulator is on) there may be a purge set up. It consists of a shut off valve with a drain valve above it. If your system has this, this is the way to bleed it.
Start by turning off the system. Then make sure you have approx 12-20 lbs of pressure on the boiler. Close the shut off valve and hook a hose up to the drain above the valve. Open the drain and let the water start flowing. You will get a lot of air then water then air and water, keep an eye on your pressure gauge, if the presssure falls below 10lbs kink the hose shut to allow the pressure to build back up in the system( becarefull not to go passed 30lbs. Or the relief valve will release). Let the system bleed until you are getting nothing but water. Shut the drain valve(where your hose is attached) and open up the shut off valve below it. This may need to be done a coupe of times to ensure all air is out.
2)- If you don't have a purge set up as described above then there are bleeders on one end of each of the Radiators or baseboard. You will either need a flat tip screwdriver or a bleed key and a rag and small can or cup.( bleed keys can be purchased at either Home Depot or lowes). Make sure you have at least 12 lbs of pressure on the boiler gauge then go to the baseboard/radiator closest to the boiler and open up the bleeder about1/2 a turn you will get air ,water and a mix out. Once you get nothing but water , close it down and then go to the next one and repeat. Do this until you have bled out all baseboard/radiators. Check the boiler pressure gauge occasionally to make sure there is enough pressure for bleeding. This may have to be done a few times to ensure that all air is out.

Quote:

Originally Posted by cornerstonehvac

First off, you cannot bleed the boiler from the bottom drain. In order to bleed the system you need to do 1 of 2 things depending on the system . I'll try to explain what to look for and how to bleed the system so bear with me. You also mentioned that there was a pear shaped valve on top, that most likely is a Hy-vent. If the hy vent is not working it should be replaced before filling the boiler. You may be able to get one at lowes or Home depot I'm not sure or you may have to get it at a hvac contractors shop,but I would recommend that it be replaced.
1)- On the return piping(usually the piping that the circulator is on) there may be a purge set up. It consists of a shut off valve with a drain valve above it. If your system has this, this is the way to bleed it.
Start by turning off the system. then make sure you have approx 12-20 lbs of pressure on the boiler. Close the shut off valve and hook a hose up to the drain above the valve. Open the drain and let the water start flowing. You will get alot of air then water then air and water, keep an eye on your pressure guage, if the presssure falls below 10lbs kink the hose shut to allow the pressure to build back up in the system( becarefull not to go passed 30lbs. or the relief valve will release). Let the system bleed until you are getting nothing but water. Shut the drain valve(where your hose is attached) and open up the shut off valve below it. This may need to be done a coupe of times to ensure all air is out.
2)- If you don't have a purge set up as decribed above then there are bleeders on one end of each of the Radiators or baseboard. You will either need a flat tip screwdriver or a bleed key and a rag and small can or cup.( bleed keys can be purchased at either Home Depot or lowes). Make sure you have at least 12 lbs of pressure on the boiler guage then go to the baseboard/radiator closest to the boiler and open up the bleeder about1/2 a turn you will get air ,water and a mix out. Once you get nothing but water , close it down and then go to the next one and repeat. Do this until you have bled out all baseboard/radiators. Check the boiler pressure guage occasionally to make sure there is enough pressure for bleeding. This may have to be done a few times to ensure that all air is out.

Again... thanks for your time & assistance. It is quite generous of you to assist others in need with your expertise. I am not well versed in boiler maintenance and this one has out lived its life's expentancy. I generally understand what you have expalined to me and I did not think to check the individual radiators for bleeders.