Switch from Air Scoop to Spirovent

salisboss

I have a hydronic heating system that uses a gas converted combi-boiler. It is not piped for pumping away (was going to do it this summer but never got around to it so its on the agenda for next summer). I currently have an air scoop with only 6 inches or so of straight pipe (rather than the normal 18) so I am in a never ending cycle of purging air then the air introduced with the city water never gets eliminated by air scoop/aav. So eventually it sounds like a river and I purge again and start over.

To remediate this until I can re-pipe for pumping away I want to replace the air scoop with a spirovent. My question is what is the best way to remove the air scoop as it is threaded in place. A picture of the setup is shown. I presume I have to remove the tank etc first but not sure.

hot_rod

Do you have a press tool?

Cut the copper tube just past them scoop. Unscres scoop screw min Discal, muse press adapter, maybe a coupling depending on length.

Could be done with sweat adapter also.

Steve Minnich

Turn off the boiler. 

Close the fill valve. 

Drain what you need to in order to isolate the scoop. That may be the entire system. I can’t tell from the photo. 

Remove the tank and it’s piping. 

Cut the vertical copper to the right of the scoop. Disassemble from there. 

Install the air sep, the new piping, and the tank. 

Refill, bleed system, recommission. 

STEVEusaPA

If you're draining and cutting, good time to get that circulator in the mix for pumping away.

salisboss

STEVEusaPA said:

If you're draining and cutting, good time to get that circulator in the mix for pumping away.

Can the zone valves stay on the return side or do they have to move also?

salisboss

Steve Minnich said:

Turn off the boiler. 

Close the fill valve. 

Drain what you need to in order to isolate the scoop. That may be the entire system. I can’t tell from the photo. 

Remove the tank and it’s piping. 

Cut the vertical copper to the right of the scoop. Disassemble from there. 

Install the air sep, the new piping, and the tank. 

Refill, bleed system, recommission. 

I would have to drain all three zones but that's fine. If the expansion tank pressure is fine now do I need to do anything special when I hook it back up?

Steve Minnich

@salisboss If the tank pressure matches the system fill pressure, you’re good. 

SuperTech

I would absolutely add in two isolation flanges and relocate the circulator too! If you have a good microbubble resorber, it's not working as well as it could be if you start pumping away. I would change it to all copper, sweat or press. A spirovent will help, pumping away from the expansion tank with a spirovent will solve all your air issues.  

Why would you want to alter the same part of the system twice? Always avoid draining the boiler repeatedly if possible. 

hvacfreak2

Man back in the day I would get smoked on here when I spoke bad about the " Air Scoop " ( or any product from them ). The air scoop is just as good just run a minimum of 30 feet straight to the inlet so I'm told.

HVACNUT

Are you sure it's a bad scoop? A frequently air bound system would point me elsewhere first. And second, and third...

Just to the left of the supply riser out of the top of the boiler is a knockout in the top of the jacket. Underneath that, someone plugged the 1/2" opening that is meant for a 1/2 x 6 nipple, a 1/2 x 1/8 bell coupling, and an air eliminator like the one on the scoop. The Weil McLain GO has an internal air scoop in the block. It'll take you an hour and a half tops. 

In a perfect world, you should be purging through the boiler. As it is, cold water feeds through the supply and purges through the return. Whatever is in the boiler is idle. 

salisboss

@HVACNUT I didn't know about the spot for the boiler vent. 

I don't think the scoop is bad per se. I think it's poorly piped and isn't operating as intended.

I wish I could purge through the boiler. I know I am leaving air.

salisboss

HVACNUT said:

Just to the left of the supply riser out of the top of the boiler is a knockout in the top of the jacket. Underneath that, someone plugged the 1/2" opening that is meant for a 1/2 x 6 nipple, a 1/2 x 1/8 bell coupling, and an air eliminator like the one on the scoop. The Weil McLain GO has an internal air scoop in the block. It'll take you an hour and a half tops. 

Will a vent on the block remove a lot of air? Would I just drain the boiler from the drain at the base then add the piping to the scoop?

Oliveone

this is on a go -5 that is over 20 years old. Not my handy work !

No air in the system

Before Jason

hot_rod

high temperature, low velocity areas are the best way to capture air. In that boiler block would be a good spot to add a quality automatic air vent. Use one with a service check or iso valve as they do need occasional cleaning or rebuild.

salisboss

hot_rod said:

high temperature, low velocity areas are the best way to capture air. In that boiler block would be a good spot to add a quality automatic air vent. Use one with a service check or iso valve as they do need occasional cleaning or rebuild.

Would I just drain all of the water out of the boiler to reduce pressure? I presume there is a plug or something blocking the end of the vent that I will tap into. Once the pressure is down I can remove that plug?

hot_rod

salisboss said:

hot_rod said:

high temperature, low velocity areas are the best way to capture air. In that boiler block would be a good spot to add a quality automatic air vent. Use one with a service check or iso valve as they do need occasional cleaning or rebuild.

Would I just drain all of the water out of the boiler to reduce pressure? I presume there is a plug or something blocking the end of the vent that I will tap into. Once the pressure is down I can remove that plug?

Cool it down reduce pressure and work fast! Have all the parts ready, pipe dope on them.
I would start with a nipple long enough to reach down to the tap with a ball valve on it. Screw that in to have a connection point and iso valve for the vent. I'd use a 1/2" not the 1/8 size.

The Caleffi 5021 is one of the most common vents worldwide. Very easy to disassemble and clean.

HVACNUT

salisboss said:

high temperature, low velocity areas are the best way to capture air. In that boiler block would be a good spot to add a quality automatic air vent. Use one with a service check or iso valve as they do need occasional cleaning or rebuild.

Would I just drain all of the water out of the boiler to reduce pressure? I presume there is a plug or something blocking the end of the vent that I will tap into. Once the pressure is down I can remove that plug?

Isolate the loops. Power off, zone valves closed. Shut the auto feed. Tighten  the cap on the air eliminator at the scoop, and any other air eliminators if any. You don't need to drain the the boiler, just drop the pressure to 0. Washer hose connected to drain valve at the bottom of the boiler into a bucket. Open drain valve. As soon as the water stops flowing, shut the valve. Prep all the new stuff so you can remove the plug and install the new piping and vent in one motion. 

salisboss

hot_rod said:

high temperature, low velocity areas are the best way to capture air. In that boiler block would be a good spot to add a quality automatic air vent. Use one with a service check or iso valve as they do need occasional cleaning or rebuild.

Would I just drain all of the water out of the boiler to reduce pressure? I presume there is a plug or something blocking the end of the vent that I will tap into. Once the pressure is down I can remove that plug?

Cool it down reduce pressure and work fast! Have all the parts ready, pipe dope on them. I would start with a nipple long enough to reach down to the tap with a ball valve on it. Screw that in to have a connection point and iso valve for the vent. I'd use a 1/2" not the 1/8 size. The Caleffi 5021 is one of the most common vents worldwide. Very easy to disassemble and clean.

What is the hookup inside the boiler jacket like? Is it a scoop with a plug that I have to remove first or is it a ball or gate valve setup that I just tap into?

hot_rod

I suppose it comes down to how much repiping you want to do
Certainly pumping away, add iso valves and a better purger would be nice
The circ is fine pumping the return into the boiler IF you move the expansion tank connection to near the inlet of the circ. Not sure which is easier for you.

salisboss

So I went to remove the plug on the boiler to add the vent and it is a square bolt head. How do I get this off?I couldn't get it to budge. There is probably a specific tool. I tried regular channel locks but it is a tight squeeze.

salisboss

Also once I couldn't get the plug out I covered the boiler back up, opened the valves and turned it back on. However even though the boiler temp is down to 109 and I am calling for heat, nothing is happening. The burner controller isn't sensing any fire and nothing is happening.

hot_rod

A little penetrating oil, and find a 12 point socket that will fit that square.

salisboss

Thanks. Had a contractor come out. A probe on the thermostat came loose by coincidence so everything is running again. He thinks that I could have bad solder joints letting air in (I don't disagree, I don't have water leaks but do have some corroded joints). I am still going to try and put the vent on the boiler 

EBEBRATT-Ed

Bad solder joints will not let air in on a house installation with minimal pressure drop in the system

Steve Minnich

Never heard that one before. That’s not it. 

Solid_Fuel_Man

Just repipe the near boiler and add the vent in the boiler block. Moving the circ, and adding an auto vent on the block will go a LONG way. 

salisboss

Solid_Fuel_Man said:

Just repipe the near boiler and add the vent in the boiler block. Moving the circ, and adding an auto vent on the block will go a LONG way. 

Ok. I am gonna do the block vent once I get penetrating fluid and a 12pt socket. I'll re-pipe in the spring. For some reason my boiler thermostat is saying low water all of a sudden. It shouldn't because the make-up water valve works fine. When I drained the boiler yesterday to originally try and do the vent, it filled back up fine as expected and the pressure is reading okay. Never seen this before but everything is working.

salisboss

Contractor came back out because the LWCO light came on. They think the probe is losing contact with the well. They recommended replacement so I ordered one to do myself. 

However literally as the guy was driving away, the high temp light on the hydrostat came on. It never does. Could it be because I jacked up the heat to test the probe with him there?