Help purging a zone on this system.

russ216

We have 3 zones, though they don’t look to be fully isolated. I see no return valves to close. There is a boiler feed valve, and 3 valves which appear to be outlets to hook the hose up to but not sure how to operate them. Boiler PSI shows about 5.

The middle zone which goes upstairs is pretty cool to the touch and the others are very hot. It wasn’t too bad andd then i tried to bleed some air out of it from upstairs yesterday and it shot some air out, 2 drops of water and then nothing. Any help is appreciated!

JohnNY

You need more pressure in the boiler via that feed valve. Post some pictures please and we'll/I'll be able to guide you through what should be a simple process.

russ216

Thank you very much for the quick response! Here are some pictures of the various valves and the system.

russ216

The boiler is from 1982 by the way. The inducer was bad and i just replaced the assembly. New exhaust too. Before the inducer was replaced one day i noticed some water dripping on the flames around where the inducer seal was. Really scared that it was the boiler but it only lasted that one day. Now im wondering if it only did it at a higher PSI. We had it checked out at our normal annual and they said all was good though days before that.

Hoping that was just some condensate as the old exhaust was very rusted. That was a month ago and everythingg was great until yesterday - though the water was much louder andd bubbly in that zone.

JohnNY

You seem to be missing some key components there. An Expansion tank, a pressure reducing valve, a backflow preventer. Where are you located that your service company hasn't added these pieces for you. They are Code-mandated everywhere I'm aware of.
Anyway, open that water feed valve until you get to about 12 PSI in the boiler, then see what happens or go bleed the radiators and try it then. Try to always maintain around 12 PSI. That's pretty standard for 2-story home.

russ216

Thanks! I do have an expansion tank - but you're right, most of those other components are missing. Anything i should do with the expansion tank? I'll upload a picture now.

Also, only add water to the boiler after it's been off for awhile I think?

I'm in the suburbs of Philadelphia, btw.

russ216

Here’s the expansion tank up top here in the rafter.

When i open the feed, the system needs to be off for quite awhile beforehand right? The circ pump goes off when the boiler is shut off too at the switch.

russ216

Also, it sounds like you’re saying i don’t need to hook up the hose to that loop?

Gordy

You must have the proper system pressure to raise the water to the highest elevation in the system. Depending on that elevation 12-15psi will do it in most 2 story homes.

To get the air out you’ll need to maintain that pressure while bleeding that zone like you were trying to do. It won’t hurt to go with a little more pressure while bleeding the zone. Just don’t go over 20-25 psi the relief valve opens at 30psi.

Also bleed the system with the circulator, and boiler off.

Zman

You have a compression tank which explains the lack of air eliminator.
Does it have a glass site on the end? Learning to manage that tank is the key to success on this one.

russ216

Thanks @Gordy ! Okay - so if i have this correct it looks like this is maybe simpler than i thought?

1. Turn off the boiler system, and circ pump
2. Wait until the water temperature is "x" lower. ?
3. Open the feed valve maybe to 15-20psi
4. Go upstairs and bleed the air.
5. Repeat until the PSI stays around 12-15 and no air is left upstairs (ie water is flowing out)

russ216

@Zman - nope, no glass sight on either end. It's been spraypainted by previous owners But it still feels and looks like both sides are totally metal.

Gordy

When your done make sure you adjust the pressure back to 12-15 psi.

When you are done start the system, and let it run for a heat cycle, or two. You should be getting heat in all the zones If you hear gurgling in the base boards then there is more air. Repeat process.

Like @zman said with the expansion tank you have it’s an air management not air removal. So there should not be any automatic air vents anywhere in the system.

Adding a Bell and Gossett airtrol tank fitting will help reduce air in the system.

Or you go modern, and install a diaphragm, or bladder type expansion tank with an air removal device.

russ216

Thanks @Gordy - how do i adjust the pressure downward if the radiator is bled and i have no PRV? It’s at about 15 or 16 now about to try turning it on. So far so good!

russ216

There’s definitely some water in the expansion tank now too. If feels warmer and heavier.

jerryb46

those three funny looking gizmo's side by side on the return are the bleeders. System looks install early 50's.Someone install hose cock caps to stop drip,those chewwed up heads are what you open a half turn to 3/4 turn with a hose attached to vent the air oh on the backside is a slotted quarter turn butterfly valve must be horizenal for bleeding and up and down for operation.

Gordy

The x tank should be about 2/3 full. This is where that airtrol fitting helps also.

Gordy

To drop pressure when done if need be. Just crack the boiler drain a little till you get to the psi, and shut it. You’ll be right there at the gauge to view the psi.

russ216

Okay i emptied the expansion tank a bit and then turned the system on. PSI went to 10 on one or both of those - imm guessing the expansion tank draining.

When i put the feed on for the boiler, should i close the expansion tank feed?

Gordy

No

russ216

okay! thanks! i’ll go another round.

Gordy

The valve between the system and expansion tank should always be open. This is how the system maintains pressure, and gets air back in the tank.

JUGHNE

Does else anyone think the white pvc fittings on the relief valve should be changed to copper?

Gordy

Yes

russ216

@Gordy @Zman @jerryb46 @JohnNY
Just an update: We have heat upstairs again! I did the same process but this time didn't drain the expansion tank at all. I believe it's about 2/3 full, and PSI is either 15 or 16. We have a 2000sqft 2 story. I would estimate the furthest point is 16 feet up, and 32 ft across. Totaling about 48 feet. I might knock it down a few, but this is performing much better than 10psi and certainly 5psi.

Two questions: I see all over the internet people saying to empty your expansion tank and fill it with air. But here you guys said leave it about 2/3 full. I suppose it depends on the water temp. Confused about where it should be. And if there's anything to look out for that would prompt me to drain it and fill it with air. It seems this caused a huge drop in PSI earlier though (from 18 to 10, even with the tank feed closed off before draining. then reopening when finished.)

Other question - those funky looking valves @jerryb46 was saying that they have the screw on the back, and the knob on the front. They do indeed - if i were to need to purge a zone in the future, does this effectively stop water from flowing into the boiler when the screw line is horizontal? Akin to the more modern approach of having the separate shut off valves under the bleeding valves?

One more question: Probably a silly one, but the big pipe coming out of the center of the boiler, is that the "output" from the boiler, and these three valves are the returns? Confused on which direction things are flowing.

Gordy

There are two types of x tanks. Compression (yours) and diaphragm, or bladder tank. The latter types use an air cushion separated by a rubber bladder to isolate the air from the water.

Yours (compression) is just a cushion of air with no barrier between it, and the water in the tank. The water in the tank gives the system it’s static pressure. The air space excepts the water expanding as the water in the system heats up.

If the tank is sized correctly then it being 2/3 full of water would set the system static pressure to 12-15 psi.

What happens is as water cools in the tank between heating cycle s it absorbs some of the air in the tank. Warm water in the system rises up through the pipe, and cold water that’s absorbed air in the tank falls into the system with in the same pipe.

This type of tank is air management as it is always taking air in the system, and putting it in the tank. It’s a continuous circle. The airtrol tank fitting is designed to help eliminate that gravity exchange, and insure the tank does not become water logged (to much water in the tank) which causes the tank to lose its volume exceptance which leads to higher system pressure until the relief valve opens.

Gordy

Supply is top of boiler, and return is the side of the boiler.

If you ever decide to upgrade the xtank to a bladder style you should move the circulator to the supply pipe, and the x tank should be plumbed to the suction side of the circulator so you are pumping away from the expansion tank, and an air removal device must be added. This will help keep the system air free.

And get rid of the pvc on the pressure relief valve. Plumb it in copper.

jerryb46

IF YOUR RELIEF VALVE IS SPITTING WATER AND PRESSURE IS AT 30PSI YOU HAVE TO DRAIN YOUR EXPANISION TANK,THE ONLY RIGHT WAY WITH THAT TANK IS TAKE A 5-6 FOOT WASHER MACHINE HOSE,CONNECT TO DRAIN COCK ON TANK,SHUT OFF VALVE COMING TO TANK FROM BOILER.WHEN YOU OPEN THE VALVE WITH THE HOSE USE A 5 GAL BUCKET,YOU MIGHT GET ONLY 1 OR 2 GALLONS,NOT YOU HAVE TO BLOW AIR INTO HOSE (YOUR MOUTH)YOU WILL HEAR A GIRGLE GET YOUR MOUTH OFF FAST,LET WATER INTO BUCKET.THIS MAY TAKE 5-6 TIMES UNTIL YOU BREAK VACUMM ,IN TANK tHAT OLD CEILING TANK WILL HOLD UP TO 15 GAL,IF FULL(WE CALLED IT WATERLOGGED)YOU WILL GET SOME NASTY WATER OUT OF TANK SO WATCH YOUR MOUTH,WHEN FINISHED AIR AND THE LAST OF THE WATER WILL SPUTTER INTO BUCKET,HOPE THIS HELPS,OH SHUT OFF DRAIN COCK FROM TANK AND OPEN VALVE COMING FROM BOILER .FEED VALVE MUST BE OPENED FOR PROPER OPERATION OF SYSTEM ,JERRY, PS. SORRY FOR BIG LETTERS,DON'T HAVE MY GLASSES

russ216

Thank you @jerryb46 ! So far so good - it's been hovering between 14-15 PSI for nearly a week now and everything seems good. Keeping an eye on things still. Thank you all very much, i'm so happy to learn more about our system and hopefully buy time to make informed decisions on upgrades rather than just have emergencies.

russ216

@Gordy @jerryb46 @JohnNY
Hey guys, a couple more questions for you. Hopefully the same post is okay.
1. The pressure has slowly gone down to 12 from 15 over the last week. I have never looked at the PSI in the 3 years living here until this year so i have no idea what to look for in the course of the year. I got a proper radiator key and made sure the one bleeder i used was tight. It was pretty solid, but i still gently nudged it tight. What are the typical causes and what should i look for?

2. Our B&G circ pump has a tiny spot of oil on the floor under it. What does this mean now, and what are the options? How do i know when it’s totally shot? How hard would it be to swap in a 007 Taco. Or a whole new 100 series pump or even just the bearing and seal assembly. There’s not much in terms of shut-off valves on my system so guessing a full swap with a Taco pump is a big job. Our HVAC guy replaced the coupling on it last season after it broke and was rattling.

Everything still works perfectly since you all helped me, i’m just monitoring everything super closely and trying to be a good boiler owner. Really hoping to avoid a replacement. I have not seen water drip in the boiler at all. And i’m guessing a heat exchanger leak would be much faster pressure drop. I mentioned in my first post that i saw some water drops before replacing the inducer assembly last month. But praying it was just condensate as the seal wasn’t very good and it only happened that one day. And has run very regularly since as it’s been in the 20’s and 30’s here.

Thanks!

Gordy

The psi variation is normal.

If everything works leave it be. The spot of oil under the pump could have been from over oiling. You may break another coupling some where down the road if the mounts were not replaced also. They wear, and cause the motor coupling assembly to not be in a straight axis with each other.

russ216

Thanks @Gordy - So the pressure was 6 cold today after not running for most of the day (it’s over 55 here)

I filled it back to 12psi tonight wth the fill valve after bleeding again upstairs (got a few spurts of air but water flowed out a second later)

Any idea what could be going on? It was still working at the lower pressure, just lots of rushing water sounds in the pipes upstairs. I’m hoping maybe it’s something with the expansion tank? I don’t see leaks anywhere.

I’m nervous the boiler itself has a slow leak. I mentioned one day i saw a drip through the burners but it was just that one day. I believe it was condensate as it was toward the front of the boiler under the inducer. And this was before i replaced the inducer assembly and that seal wasn’t great on the old one. Have not seen this happen again since. Literally one day before that our HVAC company was out to do a check up and said everything was good - just need a new inducer soon. (It was really really loud) How would i rule this out?

If the psi dropped 4-5psi over 3 weeks that seems like a smaller problem.

Gordy

You should not lose pressure like that if you are not bleeding air, or water.

russ216

If it helps at all, the expansion tank was about 2/3 full before as recommended here. And as the PSI went down, the tank emptied as well. (or filled with air).

Tonight i filled the system back to pressure and the tank is 2/3 full again.

Gordy

Water is going some where.

When you bleed air you will lose some psi. So after bleeding are you checking and topping off system psi?

russ216

Yes - it went down very slightly when bleeding, and i topped it off and then didn’t touch it for about 3 weeks.

russ216

We’ve got a quote we’re happy with to replace it, the circ and add isolation valves. Looks like an auto feed is on the quote as well.

If it’s a boiler replacement that’s fine. But i obviously want to be sure! It’s a lot of money as you know.

I’ll see if i can get the video of that dripping water up here too. Again though, have not seen it since that first day. Gonna babysit it tonight and watch again during some cycles.

Gordy

It’s possible a boiler section is leaking, and how much it leaks may vary depending on how hot, or cold the boiler is. In other words it may not leak when cold, and leak during a heating cycle, and water may flash to steam, and go up the flue never hitting the floor.

I’m not saying that’s your issue, but that’s quite a bit of pressure to lose in three weeks. If you are not finding leaks in the system which I don’t know how much of the piping is visible.

Also piping leaks look for blue/green, and white corrosive crusting. A leak can evaporate on hot piping. So it’s not all about finding a water spot.

russ216

@Gordy - unfortunately i do see that little puddle under the burners again tonight after firing it up. I have checked for this nearly every day since last month and hadn't seen it.

I think maybe why i'm seeing it tonight is the boiler has gotten a break the past couple of days with the temps being so high outside. And I've noticed the flames flicker ever so slightly the past few weeks which may be exactly what you're describing. Darn

So the boiler is from 1982, was hoping to get the 60 years out of it i hear these things are good for but perhaps not.

I imagine now it's a case where i could be filling this up every few weeks and risking the leak never getting bigger, or bursting and having no heat. Or have it replaced before going into winter.

Gordy

36 years is a pretty darn good run. Get something better sized to the load, and higher efficiency, and outdoor reset.

Make your installer do a heat load calculation, and not size to the equivalent installed radiation.

You know if you don’t do something soon, when it will most likely
blow its guts don’t you?

russ216

Definitely - @Gordy. Thank you very much for the help and advice. I'm in a good position for shopping this system now rather than being without heat and rushing it. I've got that original quote and getting some more this week.

Thanks again to all - This forum is awesome!