No heat on top zone - purging air is only a temporary solution

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Old 11-06-12, 08:55 AM
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No heat on top zone - purging air is only a temporary solution

Hi guys,

I don't know much about boilers and terminology, so I will do my best to describe the situation, but please forgive me if I screw something up.

I have a hot water baseboard heating system, with 3 zones (basement, 1st floor, 2nd floor). Last winter-spring, we noticed that the heat was very noisy on the top floor - like loud glugging/gurgling that would wake us up in the middle of the night, and then one day the heat stopped working on the 2nd floor.

Searching on the web indicated that the problem could be air trapped in the pipes, taking into account the noises we heard and the fact that only the top zone wasn't working. So I purged the system - and the heat went back to normal for about a week, but then the same issue would occur, the 2nd floor would not get heat. After a few weeks of doing this, it got warm again, and obviously it became less of an issue...

Now it's getting cold again and purging the system appears to last only 1 or 2 days. Whenever the top floor does not get heat, I go downstairs, do a quick purge of the top zone, and the heat works for about a day and then I'm back to the same situation. When the heat does not work, the zone valve makes a humming sound and listening up close, it sounds like it's trying to push the water up but it can't. Pressure looks good. When I do the purge, I do hear *some* air come out of the hose but not that much.

Does it seem like I'm doing the purging wrong? I've tried basically all logical combination of valves open/closed and each results in a temporary fix. Why would it work for just a day or so? I'm at work right now but I can provide pictures at the end of the day if requested. Any ideas or suggestions would be appreciated. Thanks so much!

Will
 
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Old 11-06-12, 09:05 AM
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I'll start by saying I'm no boiler expert either so take this as face value, hopefully someone more knowledgeable can jump in and correct me if I'm off.

Air is of course lighter than water so it will rise to the highest point in the system or at least in that zone. Purging it downstairs probably won't yeild a whole lot of results. I'd suspect you'd probably want to purge that air off from the baseboard heaters upstairs, each should have a bleed screw on it.

Ultimately though the question would be "why is there air in the system". If it's purging properly and it keeps happening then air is getting into the system from somewhere, I'd start looking for leaks and get those fixed and ensure all the bleed screws are properly tightened.
 
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Old 11-06-12, 11:49 AM
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Please post a dozen or so wide-angle photos of your boiler - from various directions. Make them in focus, preferably not with a cell phone.
 
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Old 11-06-12, 12:08 PM
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Going over your post, I'm under the understanding that you "purge" your system, it works for a bit, something changes, and then you need to purge again...?

Right after you purge and it's working, what pressure reading is your boiler gauge showing?
When it stops working, what pressure is your boiler showing?

I'm thinking you might have a leak (air or water) somewhere on your second floor zone.
What type of rads do you have (cast iron or fin baseboard)?
Are there bleed screws on your rads or anywhere along the zone loop?

Any of them look like this monster or similar (probably would be a lot cleaner. Has a bicycle valve on the top)?
Name:  French River-20120922-00905.jpg
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Old 11-06-12, 02:11 PM
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Deja vue. It was a similar problem that brought me to this forum many years ago. A member was having almost exactly the same problem after adding on to his house and extending the heating system. The problem was one of an improper placement of the expansion tank in regard to the circulating pump.

I agree with gilmorrie, we need to see several pictures of your system and how it is piped before offering advice. Northern Mike's questions are also valid.

Please make sure the pictures are well lit and in focus. Posting pictures directly to the forum doesn't always work so I recommend uploading to a photo hosting site such as photobucket.com and posting the public URLs here.
 
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Old 11-06-12, 07:10 PM
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@Dearle Riggs: Thank you for the suggestion. I read about that possibility, and I inspected the baseboards on the top floor and none of them had an air bleeder. The system appears to bleed air from the boiler.

@gilmorrie: I've got some pictures below. I couldn't get wide angle pictures at different angles because the boiler is inside a tiny room. Let me know if you'd like a closer look at anything and I can do that.

@Northern Mike:
- Yes, your understanding is correct, I run the water through the 2nd zone for a bit, draining the water into the sink, and once I'm done, the heat on the 2nd floor works. It works for only a day or two though, and then I am back to the same problem.
- I had to purge today as the heat on the 2nd floor was not working. Prior to purging, the gauge read 12-13 psi. After purging (and the heat was working), the gauge was a *little* lower, I'd estimate 11-12 psi. But the granularity of the pressure gauge was not good.
- Based on internet pictures of cast iron/fins baseboard, I have fins. As mentioned above, I looked under the covers and no bleeders.
- Being an idiot about such things, when I read "leak" I imagine water leaking, and I have not observed any water or water stains coming out from anywhere. This is not to say that it is not the issue, just saying that there are no obvious signs of water near the baseboards or ceiling.

@Furd: This is not a new boiler so I don't think something is wrong with the installation. I think it was bought in 2005 (previous owner, not sure exact year...) and I bought the place in late 2010. Worked fine through 2010-2011 winter, worked fine through most of 2011-2012 winter, as said in OP, it started exhibiting this behavior at the end of last winter. Hopefully the pictures shed some light?

Pictures:

(As mentioned above I could only take further shots from one angle only because the boiler's in a tiny room. If anyone would like a closer look at anything, let me know, thanks.)

Front shot:
http://i1311.photobucket.com/albums/...7/SL730586.jpg

Front shot2:
http://i1311.photobucket.com/albums/...7/SL730587.jpg

Zone valves:
http://i1311.photobucket.com/albums/...7/SL730588.jpg

"Top" half:
http://i1311.photobucket.com/albums/...7/SL730589.jpg

"Bottom"half:
http://i1311.photobucket.com/albums/...7/SL730590.jpg

"Right" side:
http://i1311.photobucket.com/albums/...7/SL730594.jpg

So I had to do a purge, thought I'd show everyone what I thought was the best way to do the air purging. Maybe I'm doing something wrong...

Hook up a hose to the purge valve, close the valve from hot water tank to supply valves:
http://i1311.photobucket.com/albums/...7/SL730595.jpg

Close return valves for Basement Zone and 1st Floor zone, leaving 2nd Floor zone open:
http://i1311.photobucket.com/albums/...7/SL730596.jpg

Close cold water supply valve that directly goes to hot water tank. This prevents cold water from coming into the tank directly...I want the water to go through the 2nd floor zone:
http://i1311.photobucket.com/albums/...7/SL730597.jpg

Close supply valve for basement zone:
http://i1311.photobucket.com/albums/...7/SL730599.jpg

Close supply valve for 1st floor zone:
http://i1311.photobucket.com/albums/...7/SL730601.jpg

Leave supply valve for 2nd floor zone open:
http://i1311.photobucket.com/albums/...7/SL730602.jpg

Ok, so that's the setup, I open the purge valve and let it rip...

I did the purge and now heat is working on the 2nd floor. I anticipate that it will not work in a day or so. This is the problem.

Thank you so much for all the help! Let me know if there is anything else I can provide.

Thank you,
Will
 
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Old 11-06-12, 08:54 PM
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You need to raise the pressure in the system. Try lifting the lever on the pressure reducing valve, it is located off the side of the tee the expansion tank is hanging from, while watching the pressure gauge. Get the pressure up to at least 15 psi and then let the lever back down to the side.

When purging the system lift that lever to allow higher flow rater and not allow the pressure to drop too much.

Your pumps and expansion tank are plumbed correctly, not problem there.
 
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Old 11-07-12, 08:56 PM
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Well, after a day of working heat on the 2nd floor, now the heat is not working.

@Furd, I lifted that lever and it doesn't appear to do anything. PSI looks like a little above 12. I read some of the boiler installation manual that came with it, the pressure is set to 12 automatically? Anyway, lifting that lever didn't change the pressure, it was very easy to lift and it didn't seem to do anything.

Any other suggestions? Thanks!
 
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Old 11-07-12, 09:10 PM
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Spoke too soon! Furd, you are the man!

I was ready to do another purge to at least get another night of heat, and I had the hose hooked up, ready to go. I started playing with that lever again, wondering why the heck it wasn't doing anything and I noticed that I could rotate the thing. It was loose! I tightened it and the lifting the lever worked! Pressure went up and I could hear the water get pushed up, and now heats working.

Thanks Furd, made my season =)

Will
 
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Old 11-09-12, 08:21 PM
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I'd like to add one thing.

NEVER TRUST A BOILER GAUGE!

Read this:

http://www.doityourself.com/forum/bo...ure-gauge.html
 
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Old 02-18-13, 06:38 AM
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I have a Takagi Tk-Jr boiler and I'm having the same issue. A few weeks ago we had a very cold spell here in MA. I have 2 zones and the upper one would stop working. it is also in a poorly insulated part of the house (can't do anything about it). purging the water to remove air didn't seem to help. I'd temporarily alleviate the problem by keeping the pressure reducing valve open. or shutting off the yellow lever to stop the water flow to the lower zone. the water would flow to the upper zone and it would then warm up. this meant that the pipes weren't frozen, thankfully.

i played with the pressure lever so often that the expansion tank got full and started leaking around the sides. paid $350 to the plumber to replace the tank and the pressure reducing valve. things worked well for a few weeks, but it's been in the teens since yesterday and the heat is once again not working properly. all i have to do is to shut off the lower zone to get the upper to work again. the upper zone valve is in the manual "open" position. in spite of this, it was cold when i woke up this morning -- no water flow.

the pump seems to be working. there is no pressure gauge in my system. is it not working well enough?

any ideas, anyone?

thanks!!!!

mahesh
 
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Old 02-18-13, 07:02 AM
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Hi Mahesh,

there is no pressure gauge in my system
I don't think anyone here is a big fan of using an instant tankless water heater for space heating applications, but Takagi does condone this operation...

The installers of the system should have provided a pressure gauge external to the unit. Without a pressure gauge, how can one troubleshoot a problem such as yours? It sounds very likely that there is not enough pressure.

If they did not provide a pressure gauge, I must also question if there is anything else the 'cut corners' on in the installation...

You can fashion a pressure gauge if you are slightly handy... see the 'sticky' thread at the top of the forum list entitled "How to verify a pressure gauge" for information about this.
 
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