One Zone has no heat

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Old 04-03-12, 08:57 PM
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One Zone has no heat

Hi, I'm trying to diagnose why one of my 4 zones has no heat. The circulator pump for that zone seems to be working as I can hear it. It's a Taco 007 F3 pump. I think my possibilities are:
1) air in Zone
2) bad circulator

Just for kicks, I opened the B&G Flow Control Valve for that zone and the pipes in that zone started to heat up slowly (very slowly) via gravity, I assume. Closed it back up.

I very seldom use this zone. It's a wing of the house that we close off to conserve heat. Would that make it more prone to problems?

Assuming it's air, I tried to purge that zone, but obviously i don't know how to do that because when I opened the drain valve at the circulator for that zone, only a little bit of water came out and then nothing. I must be doing something wrong. You can see in the attached picture where I connected the hose.

Any help would be greatly appreciated.


 
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Old 04-03-12, 10:01 PM
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Hi.

Turn power off of boiler and let cool to 100F

You need to open the flow control for that zone.

Then close the blue valve under that circulator

Then raise the pressure of the boiler with the fill valve to 25psi. Dont go higher then 30psi. To do that there should be a handle on the fill valve that you lift. In the down position it only maintains 12-15psi in the boiler. Higher pressure forces the water through better to push the air out.

Then bleed the line. As the pressure drops keep adding water to keep the pressure up some.

You may need to do this several times with the bucket. You should see air come out in the bucket.

Then do a reverse of everything above. make sure the pressure in the boiler is 12 psi cold before you start the boiler back up.

Note. patch that hole in the flue and make sure your CO detectors are operational. Also That air vent may not be working or there is not enough pressure in the boiler due to a faulty fill valve.

If the psi is low bumping up the psi to 12-15psi should make the water start moving. If you have to do that then that would most likely mean you may need a new fill valve.

Mike NJ
 
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Old 04-04-12, 07:30 AM
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Thanks Mike. I will follow your procedure. BTW...the psi is about 15 with a water temp of 186 right now so i suspect the fill valve is ok.

I am a little confused though and want to make sure before I start your procedure. When you say to raise the pressure with the little handle on the fill valve I think you mean the one in the following photo (the lever on top of the blue tag).



Just want to make sure :-) When I lift it, I can hear water flowing into the boiler.

But then do I put it back down after the pressure reaches 25? And if I do, will the pressure auto adjust back to 12-15 psi automatically? or will the pressure need to be adjusted back down by the bleeding process. I guess I'm a little confused about how that valve works and how to get the pressure back to where it needs to be after I finish the bleeding.

Also, that hole in the flue was put there by the serviceman that installed the boiler about 4 years ago. He said it was required for some reason (can't remember).

Thanks so much for helping.
Mike MA
 
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Old 04-04-12, 07:41 AM
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When you say to raise the pressure with the little handle on the fill valve I think you mean the one in the following photo (the lever on top of the blue tag).

Yes thats it.

just want to make sure :-) When I lift it, I can hear water flowing into the boiler.

But then do I put it back down after the pressure reaches 25?


Yes you let it back down or it will keep filling. The relief valve will trip around 30 psi if its functioning properly.

And if I do, will the pressure auto adjust back to 12-15 psi automatically?


Yes it should auto adjust. But from what you say that the boiler is at 15 psi at 186f it would seem low. Too low for the water to flow properly is a possibility if you have large zones.

So yes cooled it should adjust back to 12-15psi. If not you need a new fill valve, or you can just bump it up alittle with the handle. There is an adjuster nut but I dont recommend messing with it if you are not sure what your doing..

will the pressure need to be adjusted back down by the bleeding process.

The fill valve will raise not lower the pressure . To lower let more water out of the boiler. Below 12 psi the fill valve will try to slowly fill back up to 12psi.

Got it?

Mike NJ










 
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Old 04-04-12, 07:50 AM
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Thanks again...I think I got it now. Boiler is off and temp is coming down to 100. Will try it soon.
 
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Old 04-04-12, 08:00 AM
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One more thing......sorry.

I just noticed water dripping from this valve (I assume pressure relief valve)......wasn't doing it before.




Is this because I added some water when I tested out that lever?
 
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Old 04-04-12, 10:13 AM
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That is the air vent that automatically purges air out of the system when its running. If that is leaking water it needs to be changed.

To change you need to turn the water feed off and drain the boiler to 0psi. Unscrew and screw new one in.

While you have the boiler at 0 psi check the psi in thos two expansion tanks. There is a shrader valve like a bike tire. Those two tanks should have 12psi in them. If not add some air with a bike pump.

Also when you drain the boiler to 0 psi to service these items, you want to turn off the water feed, and shut all the valves under the circ, and any on the feed side also. This is so you dont lose water in the zones and then need to purge all the zones.

Hope this makes sense.

Mike NJ
 
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Old 04-04-12, 10:46 AM
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This is great information and it actually makes sense to me. Thanks so much for taking the time to help. I'll post results.
 
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Old 04-04-12, 10:54 AM
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pressure in both tanks is 14psi.
 
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Old 04-04-12, 11:15 AM
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I started to bleed the system. Got pressure up to about 25. A lot of air came out. Now I am getting just pure water - no air.

Now I am trying to lower the pressure before starting up. Nut the pressure stays around 20 no matter how many 5 gallon buckets I fill up and empty. Must be doing something wrong. Pressure in expansion tank is still around 14.
 
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Old 04-04-12, 11:19 AM
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Do I need to lower the pressure using the bottom spicket as opposed to the zone spicket which is still closed?
 
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Old 04-04-12, 12:20 PM
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Sorry for all the panicky posts. I think I have the boiler running again. Got the psi down by using the pressure relief valve on the boiler. What was throwing me off was my gauge didn't react right away. Went upstairs for a few minutes then came back down and the pressure was back to where it should be (around 12-14).

Everything is fired up now (the leak stopped on its own).

And there's even a bonus! The Zone that was not heating is now working great.

Thanks Mike...your advice was superb!
 
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Old 04-04-12, 12:37 PM
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pressure in both tanks is 14psi.
Did you check the pressure in the tanks when there was 0 psi on the system? If so thats fine. You should only check the pressure when no pressure on system. All other reading attempts is null.

I started to bleed the system. Got pressure up to about 25. A lot of air came out. Now I am getting just pure water - no air

That is good. That is what you want.

ow I am trying to lower the pressure before starting up. Nut the pressure stays around 20 no matter how many 5 gallon buckets I fill up and empty. Must be doing something wrong.




So you drain the system to 0 psi or so. Then stop draining water and the fill valve fills the system to 20 psi? Your not lifting the fill valve handle correct?

a) your gauge could be off. You may be able to find a replacement gauge or get a substitute to make sure its accurate.

One like this, but you want one with a lower reading like 0-50psi. Hook this to one of the purge valves and open it.



b) You may be able to adjust the fill valve down. You need to unscrew the handle. There is a rod down the center. Pull that out and don't lose it. Then loosen that nut. That will alow you to turn the shaft with a straight blade screw driver. CCW decreases pressure. CW increases I believe. You will know as you turn it.

It may take many attempts to get it right with draining some, adjusting, draing some, adjusting...etc. The fill valve fills very slowly so its easy to overshoot.

Do I need to lower the pressure using the bottom spicket as opposed to the zone spicket which is still closed?


Any hose bib will and should relieve pressure. this is as long as the valves above and below that bleeder valve are open.

I hope your getting all this. It makes sense when I am typing it, but it may not translate well. I don't know your skill set.

Mike NJ




 
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Old 04-04-12, 12:41 PM
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(the leak stopped on its own).
That air can is shot. It needs to be replace. There is no way to get the air out that is in the new make up water you added. You will have this issue again, and possible to other zones if you don't replace this.

Mike NJ
 
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Old 04-04-12, 03:14 PM
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Mike, use the 'sticky' posts up top... saves a lot of typing!

http://www.doityourself.com/forum/bo...ure-gauge.html

Would be good to read this one also even though the relief valve isn't spewing... the instructions for checking the charge in the expansion tanks are universal:

http://www.doityourself.com/forum/bo...sion-tank.html
 
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Old 04-04-12, 04:51 PM
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Sorry troop, I always forget about the sticky's. Please add anything I missed.

Mike NJ
 
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Old 04-04-12, 07:03 PM
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Just got back from a few errands and found lot's of good stuff here for me to absorb. Thanks again! You guys must really love this stuff. This was my first attempt at troubleshooting my system. I am an engineer so i can understand the stuff pretty well, but lack of experience showed it's colors for me today. It's one thing to understand the theory, but in the field, nothing helps like experience. That's where you guys were so helpful!

I checked the pressure in the expansion tanks when boiler was at 12psi, so now I know it was not a good reading.

I panicked when I could not get my pressure back down to 12-14 after the bleed. So I tried some things and hopefully didn't mess anything up too badly. I shut off the supply to the fill valve and then used the pressure relief valve on the boiler to empty it and the pressure went to 0. One thing I noticed is that my pressure gauge didn't react to what I was doing very fast. Even when I emptied the boiler using the pressure relief valve, it still read 20psi for quite a while. When I went upstairs to do something and came back, I noticed it had finally gone to 0. I like your idea about using one of those gauges on the purge valve to double check my gauge.

Once at zero, I turned the supply back on to the fill valve and once it reached 12 psi, it stopped filling the boiler as expected. So I was in good shape as far as the proper pressure. Then I just fired up the boiler and the water heated up to about 170 degrees pretty fast. The pressure rose to about 15-16 when warm and that's about where it stands now.

At this point my system is back to fully operational and all the zones worked great, including the one that I was having problems with before I bled the air out. 5 hours later, it's still running great, so I assume everything is ok now.

Now I will make a lot of notes and read the sticky's so I have a better understanding of my system.

Oh, and I'll have to replace that air vent. It's leaking on/off now with the boiler cycles. It didn't leak before this procedure so I wonder if it was always bad or something I did fried it?
 
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Old 04-04-12, 07:14 PM
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Just read the sticky on leaky air vent. I wonder if I ruined my expansion tanks when I took a reading while the system was still at 12psi?

I guess I'll have go through the process again of getting to 0psi and then take the reading. One of the instructions said to not fully empty the boiler. How do I know if I did that and what will happen if I did? Now I'm worried.
 
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Old 04-04-12, 07:25 PM
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Dont worry your doing fine. It only says to not fully empty the boiler because you only need to drain a minimal amount to achieve 0psi. And that's all you need to check the expansion tanks.

Why drain the whole system down right? It only adds more air to the system that you will need to bleed.

No you did not ruin the expansion tanks. But its a good idea to check the pressure next time you drain the boiler to 0 psi. Add air accordingly.

You will need to drain the boiler to change that air vent so that will be a good time.

And possible the gauge was sticking, and is why it did not go to 0 quick. Give it a tap next time.

Good job!!!!

Mike NJ
 
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Old 04-04-12, 07:49 PM
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Phew! I feel better now. Thanks for the vote of confidence.

The vent over the expansion tanks is still leaking pretty fast, about one drip per second. So I tightened the screw to stop the leak until i can replace the vent. I realize that now it won't be able to do it's job of letting the air out but it should only be temporary until I can replace the vent.

With this new-found knowledge, I checked the other air vent I have. The one on the supply to the boiler. You can see it on the first 2 pictures I posted. That one is very tight. I assume I should be loosening that one up as well. Or maybe someone tightened it because it was also leaking?

I wonder if these leaky vents are what caused my zone to get air-bound? Although my other zones are all ok (for now). The zone that i had to bleed was rarely used. We close that section of the house off for the winter and hardly ever heat it.
 
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