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Bleed Boiler w/ Water Supply on Return Side?

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JRizzo
JRizzo Member Posts: 6
edited April 2021 in THE MAIN WALL
Hello,

I'm trying to discover how to bleed my particular system. The guides I find online say to close of the returns to the boiler, open the drain spigot(s) on the return side, and then allow the fill valve to pressurize the system - pushing water our the return spigots until you no longer see air come out.

My issues is that my fill valve is on my return side. The order of piping goes - zone return shut offs, fill valve, main drain spigot, boiler return shut off, circulator.

The circulator then tees off into the boiler and another drain.

I will try to post better photos tonight when I get home.
https://photos.app.goo.gl/nDuFRoNPaXZYKgm5A

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  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,844
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    So it appears that you have three loops returning (and a future caped off) that all manifold into a 1-1/4 copper that enters a cast iron air scoop with vent and Filltrol expansion tank. From there it goes to a gate valve just before the circulator pump.

    From the pump, the water flows thru the boiler and heated water leaves the supply to the 3 different loops.

    In order to purge air from each loop, you can close the gate valve near the circulator inlet, then close each of the service valves. Connect a double female end hose from a house pressure spigot to the bottom boiler drain valve (below the circulator). Finally, place a garden hose on the boiler drain valve just above the closed gate valve above the circulator. Now you are ready to purge.


    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    JRizzo
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,844
    edited April 2021
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    Since you don't have a fast-fill feature on the boiler feed, you can now open the 2 valves to feed water into the boiler just below the circulator. Always monitoring the pressure on the boiler gauge to keep it below 25 PSI. Next, open one of the SERVICE valves and the boiler drain valve just above the circulator. since the gate valve is closed the temporary fill valve water pressure will need to go all the way around the open loop and force the air out under increased pressure and velocity. Once that loop is air-free, close that SERVICE valve and open the next Always monitoring the pressure. Once the second loop is air-free, then close the second SERVICE valve and open the third one.

    When the system is completely air-free, you can close one of the temporary garden hose feed valves and close the drain valve above the circulator. YOUR SYSTEM IS NOW PURGED.

    Now test each loop for proper flow by turning on the boiler and opening up the gate valve by the circulator and one of the 3 SERVICE valves. Once the boiler is up to temperature, you can open the second Service valve and make sure all return pipes get hot. Then finally you can open the third valve and make sure they get hot.

    If all three loops are air-free and heat properly, then you can disconnect the garden hoses (both purge drain and temporary fill)
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    JRizzo
  • Derheatmeister
    Derheatmeister Member Posts: 1,543
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    Heads up...Just make sure that you do not use the water from the softener as it is very bad for it.
    JRizzo
  • JRizzo
    JRizzo Member Posts: 6
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    Wow! Thanks for all this awesome information. I didn't have a chance to come back to check it over the weekend. Our washer leaked and I spent the weekend repairing our subfloor.

    I greatly appreciate the guide and the helpful tips!
  • JRizzo
    JRizzo Member Posts: 6
    edited April 2021
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    EdTheHeaterMan said:

    Since you don't have a fast-fill feature on the boiler feed, you can now open the 2 valves to feed water into the boiler just below the circulator. Always monitoring the pressure on the boiler gauge to keep it below 25 PSI. Next, open one of the SERVICE valves and the boiler drain valve just above the circulator. since the gate valve is closed the temporary fill valve water pressure will need to go all the way around the open loop and force the air out under increased pressure and velocity. Once that loop is air-free, close that SERVICE valve and open the next Always monitoring the pressure. Once the second loop is air-free, then close the second SERVICE valve and open the third one.

    When the system is completely air-free, you can close one of the temporary garden hose feed valves and close the drain valve above the circulator. YOUR SYSTEM IS NOW PURGED.

    Now test each loop for proper flow by turning on the boiler and opening up the gate valve by the circulator and one of the 3 SERVICE valves. Once the boiler is up to temperature, you can open the second Service valve and make sure all return pipes get hot. Then finally you can open the third valve and make sure they get hot.

    If all three loops are air-free and heat properly, then you can disconnect the garden hoses (both purge drain and temporary fill)

    This sounds great. I had erroneously assumed that the bottom valve under my regulator was another drain. Understanding that I can use that as a fill zone helps.

    I have a followup question. This is the exact system I have : https://www.amtrol.com/product/fill-trol-system/

    This is the auto fill valve : https://www.ecomfort.com/Amtrol-FT-109-15/p23067.html

    The automatic fill valve does have a manual valve on it (hard to see in photo). It has a label on it, but the instructions are corroded. I'm assuming it's a bypass to allow full pressure. I can't tell - but it's a moot point because I can't use this location to fill/purge since it's upstream of my drain point.

    Which leads me to my question. I don't know what PSI my well pump operates at. Is there a way to regulate that to keep it below 25PSI? Mabye just partially open that manual valve? Furthermore, once I'm done purging how will I get the PSI back down to 12? Just drain a little water?

    I realize these are probably stupid questions. Thank you for entertaining them.

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