Purging Air from Multi Zone System - Navien 240

[Pippen S.]

Hi All - Bone-Headedly I introduced quite a bit of air to my system.

I theoretically thought I knew what to do, but am having all sorts of trouble in practice. this system is a few years old and i usually do have my local guys service who are great, but i wanted to get in there and clean some of the filters, become more familiar, and work on the system a bit.

Its a Navien 240 tankless with 6 zones. 5 of the zones are to areas of the house (2 top, 2 bottom, 1 converted garage, 1 to an indirect hot water heater). they pumps are automatic variable speed tacos. I guess my thinking now is to isolate each zone individually at the pump valves, and let water out on the outlet on the return (red sillcock?) to the right of the Navien. is that correct? Any guidance would be helpful as I'll be working on getting it up and running tonight so the family isn't huddling for warmth later tonight.

 

[Breplum]

 

[Sponsor]

 

[Pippen S.]

Update!

Going through each zone and shutting isolating them one by one, turning the pump on and also running the "purge air SH" from the settings in the Navien seems to have done the trick. At least at this point I am now up and running.

I had an error message after the 2nd to last zone purge, "Error 351-00" Abnormal Fill Valve, Check Valve and supply water. I cycled the power and the boiler fired right up and went got up to operating temp at 180 degrees. I did notice that my pressure is now at ~ 29 psi, close to the max of 30 psi, and I think higher than it was when operating prior to the issue, so released some pressure and back to 12 psi now. Monitoring it and I plan on calling my plumber out for a consult tomorrow to at least help me understand what I can do better in the future.

I'll follow up post on a full list of my mistakes for everyone to enjoy.

 

[Fitter30]

Above the ex tank is a red valve handle. That brass valve is the air removal device ( micro bubbler) which is the best kind of air removal. Brand and model? Is there a cap that can be unscrewed on the top loosen it. Your way over pressure. One or two story house? Take two steps back take another pic.

 

[Fitter30]

Above the ex tank is a red valve handle. That brass valve is the air removal device ( micro bubbler) which is the best kind of air removal. Brand and model? Is there a cap that can be unscrewed on the top loosen it. Your way over pressure. One or two story house? Take two steps back take another pic. Want to see top of boiler bottom of piping.

 

[Pippen S.]

Thanks for the response. I felt like I had done something with the ex tank to overpressurize the system. it's sitting at 20 psi now.

It's a webstone but i can't tell the model. Apologies on not enough photos last night i was having trouble compressing them to fit into the attachments. As i was running the "remove air" 15 min cycle on the Navien last night I did hear and see air coming out of of the air removal device for one of the zones.

It is a 2-story house. I'll edit this to post to add a few more photos in a couple minutes.

 

[John Gayewski]

Yeah you have it right. Isolate reach zone and bleed then let the system run the "purge air" mode for a while.

When you're doing this next time check the expansion tank. It's the most likey thing to break on these systems.

 

[Fitter30]

Thanks for the response. I felt like I had done something with the ex tank to overpressurize the system. it's sitting at 20 psi now.

It's a webstone but i can't tell the model. Apologies on not enough photos last night i was having trouble compressing them to fit into the attachments. As i was running the "remove air" 15 min cycle on the Navien last night I did hear and see air coming out of of the air removal device for one of the zones.

It is a 2-story house. I'll edit this to post to add a few more photos in a

Don't see a water regulator on the fill line just a backflow device. 15 lbs is more than enough pressure. Setup -Water temp under 100° pumps and boiler off adjust water regulator to 15 lbs adjust air pressure in ex tank to 15 lbs. Scharder valve opposite piping end under plastic cap. Water blows out of it it would need to be replaced. Need a 0-50 lb tire gauge and a hand tire pump or air compressor ( be very careful short bursts and check it after each one).These directions use the same parts as yours.

https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Webstone-H-74003-V-Install-Instructions.pdf

 

[Pippen S.]

ok yeah it looks like there's no water regulator on my system. you say to adjust the water regulator to 15 lbs and ex tank to 15 lbs so i'm just a little confused on that process: I was planning on shutting off the boiler until boiler temp is under 100 deg, then using my bike pump instead of compressor to carefully add air pressure to 15 lbs. if water blows out of the Webstone air removal device then the ex tank will need to be replaced?

Thanks for finding that install instructions for the Webstone.

Also the part that i'm concerned about doing correctly is the best method to draw down to 0 pressure - should I cut off the inlet water and drain until the boiler shows 0 psi?

 

[Fitter30]

ok yeah it looks like there's no water regulator on my system. you say to adjust the water regulator to 15 lbs and ex tank to 15 lbs so i'm just a little confused on that process: I was planning on shutting off the boiler until boiler temp is under 100 deg, then using my bike pump instead of compressor to carefully add air pressure to 15 lbs. if water blows out of the Webstone air removal device then the ex tank will need to be replaced?

Thanks for finding that install instructions for the Webstone.

Also the part that i'm concerned about doing correctly is the best method to draw down to 0 pressure - should I cut off the inlet water and drain until the boiler

What pressure are u at 100°? What model of Navian?

 

[Pippen S.]

I'm monitoring the temp now, letting the system cool. it's been at 21 psi when not under load and 29+ when under load, reaching 30.5+ psi when 4+ zones are calling for heat, so i definitely want to depressurize it asap.

it's a Navien 240/130H

side question:
also curious (to me) is that the cold inlet is going into the Auto-Feeder, "H" in the manual. is this because the boiler is being used as an indirect heater for the hot water tank instead of a directly heating the water that goes to the tap?

 

[Fitter30]

Pages 49 and 53 for boiler water pressure. 4 lbs below set point it fills system back to set point. Look at 53 first. Second from the bottom, 49 get u to log in.
www.manualslib.com/manual/1059790/Navien-Ncb-150e.html?page=2

 

[Pippen S.]

oh cool this is solid, i'll try logging in and changing the boiler water pressure to 15.