No heat in one zone, trouble bleeding it

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Old 02-13-14, 10:33 AM
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No heat in one zone, trouble bleeding it

Hey folks. I have no heat in one zone off of my FHW boiler. After reading up on the issue, it sounded like I needed to bleed the zone to try and resolve the issue. After reading multiple forum posts and watching a few youtube videos, I tried bleeding the zone myself, but I haven't been able to fix the issue. I was hoping you all could help me out and verify I'm actually doing this right, and, if so, see if there's anything else I could try and fix the problem.

So, here's what I've done. First, I turn the heat up in the problematic zone. Then, I turn off the supply valve to the zone that is working, but leave the problematic zone open. Note, I'm talking about the valves in the back of the photo before the Taco valves.

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Next, I turn off the return valves to both zones. Attach the hose to the spigot above the return valve for the problem zone and turn it on:

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As I run the water, I'll sometimes see some bubbles and every now and then, get a good burp, particularly when I first open the spigot, but still no heat. One thing I've noticed is that after running water into the bucket for a good 30 seconds or so, the flow of water starts to slow to a drizzle, stop, start drizzling again and repeat. After doing some research, I'm wondering if that means I don't have an automatic makeup water valve. Here's a picture of what looks to be my makeup valve:

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Is there something I should do to get a steady stream of water while bleeding my zone or does it sound like I have another problem altogether?
 
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Old 02-13-14, 11:35 AM
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First, I don't think I would do this with the boiler HOT and running... I think you are best to shut the boiler OFF and allow to cool to 100F or less.

Instead of leaving the thermostat up and the system running, instead, operate the MANUAL OPEN lever on the zone valves.

You may have a 'plugged up' water makeup valve...

Did you notice before you started what the pressure and temperature gauge on the boiler was reading ? What is it reading now?

Low pressure in the boiler can also be a cause for air accumulation.

That 'lever' on the top of that valve is a 'fast fill' lever. When you have the drain open, lift that lever and water will feed at a fast rate through the zone.

I always advise that the expansion tank air charge be checked:

http://www.doityourself.com/forum/bo...sion-tank.html

and the boiler pressure gauge be verified:

http://www.doityourself.com/forum/bo...ure-gauge.html
 
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Old 02-13-14, 02:12 PM
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OK, I turned the boiler off (although I didn't give it time to cool), put the zone valve on open, lifted the fast fill lever and started bleeding the zone and got a ton of burps and bubbles as well as a steady flow of water. Before I did this, the pressure on the boiler was about 11 psi and the temperature was 170 F. After, it climbed up to about 20 psi, but temperature stayed about the same. Eventually, that pressure came back down to 11 psi. Anyway, I turned the boiler back on and turned up the heat in the problem zone and, so far, no luck. One interesting thing I've noticed is that pipes by the supply valve remain fairly cold. Even if I flip the zone valve on manually, they remain this way. My understanding of how all this works may be off, but I would think that we've proven that when the zone valve is flipped to the on position, it calls for water so it should be working properly. I've also seen that if I start calling for heat in my working zone, the pipes by that supply valve get hot relatively quickly. Have I just not given it enough time after flushing the problem zone with cold water?
 
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Old 02-13-14, 02:41 PM
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What happens if you manually open the zone that isn't heating and turn the OTHER thermostat for the OTHER zone up? Do they both heat?
 
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Old 02-13-14, 04:10 PM
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Yes, both heat up, although the working zone gets slightly hotter than the non-working one.
 
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Old 02-13-14, 04:17 PM
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Just to clarify, what I meant was do BOTH zones piping get hot and heat both zones when the one is manually opened and the other calls for heat...

Not sure if I phrased that question well.

Trying to determine if the problem is with air as you have suspected, or if the problem is with the valve.

If you manually open the valve and get heat into BOTH zones when the other thermostat calls for heat this means that the circulation is fine and not a problem with air in the zone, and that there is a problem with the valve not opening when called by the thermosatat.
 
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Old 02-13-14, 04:25 PM
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The piping closest to the supply valve gets very hot for the working zone and just slightly cooler on the non-working zone. However, I get heat in the working zone, but still not in the non-working one. By the return valve, the piping is warm for the working zone, but still fairly cool for the non-working one.
 
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Old 02-13-14, 04:32 PM
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When the working zone is NOT calling for heat and you turn up the thermostat on the NON-WORKING zone, does the boiler react to this and can you tell if the circulator pump runs, and does the boiler fire?

It does sound as if there is still a circulation problem, but would like to be absolutely certain.

PLEASE let the boiler cool off before you attempt to do any further bleeding/purging! If you do not, and feed a lot of cold water into the boiler when it is 170F you may CRACK THE BOILER! You do NOT want to do that!

I think you should try it ( the purge process ) again.

Watch the gauge when you lift that lever and try to keep the pressure up around 25 PSI while you are purging the air from the zone. You may need a HEALTHY flow of water to move a stubborn bubble. If you can put the drain hose in a bucket, you can see when the bubbles stop coming.

You need to know that your gauge is good. If the gauge is reading wrong, and you do not actually have enough pressure in the system, you will continue to have problems.
 
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Old 02-14-14, 05:04 AM
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OK, I let it cool last night and purged again. Got a lot of burps and bubbles, but after running off close to 10 gallons, they seemed to have stopped. I turned the boiler back on, but didn't turn on the heat since I was heading to bed. In the middle of the night, I kept hearing gurgling from the baseboards. This morning, I turned the heat up and still no luck. I'm guessing I just didn't bleed the zone long enough. The pressure was good at around 25 psi. I just turned the boiler back off and will try again once it cools down.
 
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Old 02-14-14, 06:15 AM
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The pressure was good at around 25 psi.
If you can believe your pressure gauge which in my experience you almost never can.
 
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Old 02-16-14, 05:36 PM
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OK, so I've tried bleeding the zone a couple more times and, each time, I was able to purge a lot of air in the first 5 gallons or so and then the bubbles stop. Unfortunately, still no heat. Even if my pressure gauge is off and I'm not blasting enough water through the zone, I'm not really sure what I can do to increase the pressure. Any other recommendations? Thanks for all the help so far!
 
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Old 02-18-14, 10:40 AM
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I tried one more time to bleed the zone. I lifted the lever on the makeup valve and watched the pressure increase to almost 30 psi and then started bleeding the zone. The pressure was never consistent, though, and dropped to close to 20 psi at times. This time, I bled close to 20 gallons of water and got a bunch of bubbles. However, still no heat and I'm still hearing gurgling noises from my baseboards. Any other ideas? I have someone coming to check everything out tomorrow, but I'd love to be able to save a few bucks and get this fixed on my own if at all possible.
 
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Old 02-18-14, 12:23 PM
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XE,
Post #3 interest me the most and the pic of the feed valve.
You said the pressure started at 11 psi & temp @ 170. After feeding pres went to 20 and the back to 11.
What made the pressure drop? 11 lbs. is too low for a maintaining pressure. Your valve is factory set @ 12 so either your gauge or the valve is off a little bit, but that aside it is still @ a low pressure. If for some reason that feed valve is constantly feeding in it's bringing air with it but that would most likely affect both zones.

As far as the boiler not changing temp. I can't tell where your feeding. It looks like @ the expansion tank on the supply line. Is that true. If so, that's why the temp doesn't change. Your feeding in the supply and drawing before the boiler. You're feeding straight through the system, bypassing the boiler.

If you unwind the top of the fastfill, loosen the nut and increase the pressure to at least 15- 18 psi.
When you bleed is the flow from the bad zone as good as the good zone. Could the valve be sticking.
Take the head off the bad zone and get a big pair of channellock pliers and see if that valve stem moves easily.

Bring up pressure again and bleed. This time when your done shut the cold water valve off and see if the boiler maintains your ending pressure. If it doesn't you have a leak somewhere.
Whenever fresh water is introduced it brings air. You have a closed system and once its bled and closed it should stay air free unless water is getting in or a auto vent is sucking air in.
 
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Old 02-18-14, 12:54 PM
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Hey Spot, thanks for the reply, let me tackles these one at a time.

You said the pressure started at 11 psi & temp @ 170. After feeding pres went to 20 and the back to 11. What made the pressure drop?
I believe I had turned the heat boiler back on and started calling for heat before the pressure dropped back down to 11 psi. Not sure if that's normal or not.

As far as the boiler not changing temp. I can't tell where your feeding. It looks like @ the expansion tank on the supply line. Is that true. If so, that's why the temp doesn't change.
Yep, it's at the expansion tank.

Bring up pressure again and bleed. This time when your done shut the cold water valve off and see if the boiler maintains your ending pressure. If it doesn't you have a leak somewhere.
OK, so turn on the cold water to bring up the pressure, bleed the zone and then turn the cold water back up, right? If the pressure doesn't drop right away, should it if I turn the boiler back on and call for heat?
 
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Old 02-18-14, 01:31 PM
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XE,
Bring the pressure up to about 28 lbs and MAINTAIN that pressure throughout the bleeding process.
Bleed the zone as you have been until you see good flow. When you're done water should be cold coming out. Not Luke Warm but cold.
Close fastfill valve and drain valve.
You should have roughly 28 lbs still in there when you're done.
Shut off cold water ball valve so no water can feed in.
Drain boiler water until you get down to 20 lbs.
Turn off t-stat on GOOD zone
Turn ON t-stat on BAD zone
Open all valves for proper operation and start boiler
If zone doesn't circulate push manual lever down on zone valve and see if that helps.

If zone valve is working properly their should be no tension on that lever. You can check that at any time and compare it to the good one later on.

The main thing is, is to keep the cold water closed to see if you maintain that 20 lbs.
The water should start to heat fairly quickly if there's no other problems.
Watch pressure to see if it goes up a lot. If expansion tank is OK pressure should be fine. Might go up a couple of pounds, that's fine.

Good Luck,
 
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Old 02-18-14, 06:18 PM
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spott,

OK, here's what I did. I turned off the boiler, let it cool to under 100 degrees (per NJTrooper's instructions). I then closed the return valve on both zones, the supply valve on the working zone and put the zone valve on the non-working zone in the open position. I then lifted the fast fill lever and let the pressure increase. It only got up to about 25 psi, so at that point, I opened the drain valve. The water was cold right away and I got a lot of burps and bubbles. Pressure started to decrease so I closed the drain valve and let it get back to 25 psi. I kept doing this until I saw no bubbles and then closed the drain valve with the pressure at 25 psi. At this point, I lowered the lever on the fast fill valve and closed the supply valve (you call it the cold water valve so I want to make sure we're talking about the same thing). I then opened the drain valve and the pressure only got down to about 22 psi while the water starter to only dribble out of it. At this point, I closed the drain valve, opened up all supply and return valves, put the zone valve for the non-working zone in the the automatic position, turned up the heat in the non-working zone while leaving it off in the working one, and turned on the boiler. It kicked on immediately and the pressure dropped back down to about 12 psi. Unfortunately, still no heat. Did I misunderstand anything?
 
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Old 02-18-14, 06:42 PM
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and the boiler pressure gauge be verified:

http://www.doityourself.com/forum/bo...ure-gauge.html
Keep doing what you're doing without verifying the pressure gauge and you'll keep doing what you're doing.
 
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Old 02-18-14, 06:44 PM
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It only got up to about 25 psi,
Are you on a private well? If so, what is the water pressure on the domestic side?
 
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Old 02-18-14, 07:39 PM
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XE,
No you didn't. You did a exactly as you were suppose to . The water never should have dribbled out at 22 lbs. and once the pump started the pressure never should have dropped.
This may sound like a stretch but could you possibly have a frozen pipe.
The water dribbling and the pressure dropping is telling me there's little to no water in that zone and yet you say it bleeds. Are you sure the water is going through the zone and not coming straight out of the drain somehow.

How does the good zone run if you shut the bad one off.

You definitely have a problem in that zone and I believe it's more than air.
If you leave your feed valve off does the pressure drop any lower than it did before.

Is there a possibility of wider angle shots of the system so I can see the supply and return lines in and out of the boiler.

This is not you, this is a problem if that helps.

Another thought.
What do you have for street pressure coming into the house. Why I ask is with that feed valve lever lifted you should have been able to feed the boiler until the relief valve let go @ 30 lbs.
THere's a reason why that stopped feeding. That's a manual override and should feed until you stop it no matter how much goes in. The relief valve should have let go.
 
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