Boiler Exorcism

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Old 05-18-19, 11:25 AM
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Boiler Exorcism

Hey all, new to the forum here - looking for some ideas on this boiler exorcism project (sure feels that way)..

Here's the run down. Up here in Alaska, home owner for 6 years, seriously ready for a warm shower. 3 level house, 3 zones, oil burner with a blower in the garage on the lowest zone line.

EK System 2000, 1986. Professionally serviced (although 2 years on general clean out and oil filter, etc), system makes heat like a champ. Started getting banging in the pipes about a year ago, air would fill in slowly. When it got loud enough, called my guy and he helped purge the system (3 times). Lasted for less than a week, air would get back in, repeat a few times. Last trip over to bleed we decided to replace all of the old leaky hose bibs as bleeding was a pain, he was here sweating copper for about 12 hours. Figured that could be the source of air, as there are no leaks we can find anywhere in the house otherwise.

Also replaced boiler expansion chamber, currently at 12 psi. Replaced the T&P relief on top of the boiler, added a Supervent to auto purge air just north of the pump. Replaced the backflow preventer, cleaned the Taco auto-fill. Replaced the 2 small Taco air collectors (one on boiler, one on the garage blower). Replaced the pressure gauge. New circ pump (later). Yadda yadda, 5,000 in labor and parts, still no hot shower for the wife.

About the only thing we haven't replaced are the 2 aquastats and the heat exchanger to the 40 gal hot water tank next to her.

Thought we were good to go initially. Filled the system (~15 psi), fired her up, got to temp, massive banging and blowing the 30 psi relief. Shut it down, bleed/re-fire (bunch of times), same thing. My guy calls his guy, suggests we look at the pump. Pull the pump, all of the fins are melted. Entire new pump unit (Taco), same thing, melted fins 15 minutes after. Assumed this new one was also bad.. Replaced the cartridge, she started flowing like a champ. All looked good for about 6 hours, lots of cycling. Finally got a shower and the wife calls me out, massive banging downstairs. Pressure gauge pegged/stuck on max psi (temp gauge not crazy if i recall), T&P had been pouring out steam (garage windows all fogged). Pulled the pump, it had collected about 6 loose fins from the system in the impeller and assume it jammed and stopped flowing - but it had not melted this time. Drained, cleaned, refilled, new pump cartridge anyway, ran great for a 4 days, then the massive steam and banging ensued (caught it quicker this time). Found one more fin in the pump. Cleaned/refilled, and now I have a repeatable situation..

I start the system and have to shut her off when we get to about 180 degrees, first cycle. System runs with flowing hot water (confirmed with super hot return lines and enough water for a hot shower with 1 run up to 180 degrees F). As soon as she gets to 180, I get rattling in the expansion chamber and leaking from the hot water tank T&P relief valve (not the boiler T&P, yet). I shut her down manually pop the T&P on top of the boiler, mostly steam, with some water. I drain, pull the circ pump (to check for fins), haven't found any more. Did this twice, then replaced the pump cartridge again with a brand new unit for good measure. Pulled the relief valve off, cleaned, reinstalled, filled system and the same issue occurs. After the system is cooled a bit and the pressure brought to 0, I can hear faint gurgling in the boiler as it cools, for a good few minutes.

It appears this unit is making steam while correctly pumping water, and temp/pressure all look to be within spec.

I'm wondering if maybe the aquastats are bad, since it's about the only thing we haven't changed out yet.. Otherwise might try to force purge the boiler lines with a garden hose in the relief inlet today, but judging by return lines, water is flowing well.

I'm not getting kettling, just starts as clanks and rattles in the expansion chamber area and would move up into the zones if I let her run.

Note with the water tank relief leak, we did just install a new Grundfos SCALA2 booster for the house and removed a well-x-troll pressure tank, so the 40 gal hot water tank has nowhere to expand to currently. I pop the T&P when she starts leaking and get a little blast of water and it settles. Oh, that T&P relief has been replaced 3 times now as well, for good measure.

 
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Old 05-18-19, 06:25 PM
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Is it possible to post pics of your system. It would be helpful to see what you have. Have you verified your temp gauge is correct before you go changing any more controls. At about 12psi it takes about 242 deg. to make steam. Is your t&p valve going off on temp or pressure.

Your t&p valve is protection for your domestic hot water and has nothing to so with your boiler situation or shouldn't anyway.
 
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Old 05-20-19, 10:31 AM
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Hey spott, sure thing, pics below.

The system appears to be blowing the T&P due to pressure. The gauge is brand new as well, we replaced after the last gauge stuck on max after one of the episodes. I re-bled the system and topped up to ~13 psi, it ran smooth to around 180-185 and then started the pinging in the expansion chamber again and I could see the pressure gauge dancing around 15-18 psi as if air pockets are being created and moving around - then i shut it down, manually relieving steam/air from the T&P before it reaches 30 lbs. No banging in the pipes at any time during this procedure, and the zones are flowing/returning full hot.

Totally understand with the domestic hot water tank, just noting that as well since it is repeatable as that T&P starts leaking just as the pinging begins in the boiler expansion chamber around 180 degrees F.









The pressure gauge pic above was taken when cooling just before 6 old circ pump fins were found when removing the pump and assuming blocked flow, pipes in the house started banging like nuts. Now, similar issues but no more blockages found (and new pump).
 
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Old 05-20-19, 10:48 AM
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I'm not sure if the members can see these pictures as photobucket no longer offers third party linking. I can see them as I run a special program to see all attachments. You can post them directly to the board or if that doesn't work.... let me know and I'll tell you where to email them to and I'll post them.
How-to-insert-pictures.

145 degrees and way over 100psi. Doesn't seem like the gauge is working correctly.
That gauge in your pictures looks to be installed in a pipe at the bottom of the boiler.
Isn't there a gauge directly in the boiler itself ?
 
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Old 05-20-19, 11:46 AM
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Thanks Pete, I'll re-post them here via the forum method.

At the time of the gauge picture, the system had been cooling down for a little bit - I did not get the temp when it was hot and blowing steam. With the fins stuck in the pump, the T&P had been releasing major blasts of steam and upstairs pipes banging hard enough to shake the floor - enough hot air was released via T&P to divot the Styrofoam block under the water tank (system had just been bled/refilled as well).. Basement was half full of steam, all of the windows fogged, gauge psi pegged. My best DIY-guy guess was that air pockets forced a spike to max the gauge..

That gauge has since been replaced (can see the new one in pic 2), and as far as anyone can tell that is the only gauge on the unit (welcome to Alaska systems). Now, similar symptoms, I don't let it get to the point above, but with no blockage in the pump and return lines hot it still seems to be creating air, since when I pop the T&P at 180 manually it's mostly steam..

Not knowing how the internals operate on this boiler, is it at all possible that there could be a partial plug internally, causing some of the issues but still allowing enough water to circulate for hot lines?

I thought about hooking the garden hose to the top T&P location and flushing the boiler, but haven't went that route yet.. Giving a call to a boiler guy here today, but the wife isn't super thrilled to be out $5,000 already with no heat. At least each time I start the system and run it to 180 once, it makes enough hot water for a few showers and some dishes..

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Last edited by PJmax; 05-20-19 at 03:40 PM. Reason: resized pictures
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Old 05-20-19, 11:52 AM
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C,
It looks like you have a heat plate installed for your domestic hot water with a yellow handle Ball Valve closed. Any special reason why that is closed. Open that valve and see if it relieves the pressure in the tank. A little hard to follow lines. Does that needle go back or is it pinned.
 
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Old 05-20-19, 11:59 AM
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Hey spott, in the pic the unit is off, the yellow handle ball valve for supply to the water tank has been open during all situations listed above - T&P leaks with it in the open position.

When we removed the gauge, some tapping on it brought it back to 0 from being pegged, but we did not reinstall (new gauge for good measure), so it was not stuck completely.
 
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Old 05-20-19, 12:26 PM
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@ spott..... can you see the pictures in the first post ?
 
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Old 05-20-19, 12:49 PM
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Wanted to add this as well, from the situation where the pressure gauge maxed - check out the bluing on the Supervent..

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Last edited by PJmax; 05-20-19 at 03:42 PM. Reason: resized picture
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Old 05-20-19, 01:16 PM
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The bluing is from the soldering install process.
 
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Old 05-20-19, 01:20 PM
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Thanks - was hoping so but hadn't noticed it prior..
 
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Old 05-20-19, 01:48 PM
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Yes Pete. They posted on mine.
 
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Old 05-20-19, 01:54 PM
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CW,
Has this always done this or is it a recent development and when did it start and what made you notice it. Is that tank supplying your hot water and what is your house pressure. Might sound foolish but are your pumps going in the right direction.

That bluing is pipe dope and is common. Sorry, missed Pete's answer.
 

Last edited by spott; 05-20-19 at 04:38 PM.
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Old 05-21-19, 08:40 AM
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Spott, seems like this entire issue started slowly with air getting into the system about a year ago - noticed banging in the pipes which grew slowly louder over a few months. We bled the system, all good then but same thing came back a few weeks later, repeat 3 times, time frame getting shorter each time. Last round the banging was very aggressive after a 4-5 days, house was almost groaning with the banging (sounded like a foot of snow shedding from the roof), tons of air but still heat and hot water.. We went to bleed again but decided to replace the leaky hose bibs, T&P's, zone valves, backflow, autofill, etc and add a Supervent to try and alleviate via auto-purging. Had a hard time getting her back running without air, found the melted pump fins. New pump, melted fins again, second new pump, flowed like a champ for a short time until the incident with the maxed gauge where we found the loose fins jammed in the pump (current fins not melted). New pump cartridge, flowed for a few days until the same thing and one more fin was found (but not melted). Now, same thing happens immediately as she gets to temp the first time but no blockage in the pump (and no melting) and still getting heat and hot water during the run up to 190.

Pump is installed in the correct (up) direction, further verified with a zone open and the supply line heating before the return line. I do not have a pressure gauge on the domestic water, but the Grundfos SCALA2 has been turned down to the #2 (of 5 being highest) setting. Pressure at the tap and shower seems reasonable.

I gave this one more attempt yesterday and collected some videos to assist with the diagnosis (and the wife wanted a round of hot water, which it made just fine).

2 pics below are of the system refilled cold (14 psi) and of the temp where noises begin and I shut her off, 190 degrees F and ~20 psi. She does dance a tiny bit when moving up from 15 to 20. I also confirmed prior to filling the boiler that the (new) expansion chamber is at 12 psi empty, and once I fill to 14 psi, the expansion chamber also reads 14 psi.

So, I fire her up and she seems to run great, no noise, heat in the lines for whichever zone is open as well as to the hot water tank. The last round I did this with the garage zone open, yesterday I left all zones closed and hot water was the only call.

Note you may need Google Chrome for the videos.

She runs to about 180, then water leaks from the hot water tank relief: https://youtu.be/ja3Kssah-9I

At 190 I get pinging/banging in the expansion chamber (and maybe in the boiler? tough to tell): https://youtu.be/BFv-O6cUr8s

I shut her down, and this is what I get from the T&P (lots of air, with a little water): https://youtu.be/n815W-UH0ak

After relieving some pressure, I get this gurgling/boiling sound from the expansion and boiler until below maybe 120 F or so: https://youtu.be/6GvfS3ai3EQ

The gurgling is also noticeable from the relief tube, this is with the T&P in the closed/standard position: https://youtu.be/po_IrEYqcpE

Hope the videos help explain it a bit, and really appreciate any assistance here!
 
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Old 05-21-19, 03:28 PM
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CW,
It sounds like you are making steam which means the water is not circulating. First off where is that Grundfos pump you mention. I only see 2 Taco's.

Does that vent on top of the boiler ever release any air. It doesn't look it would where it's located and with the pinging in the expansion tank it sounds like air is trapped right there and not letting hot water into the tank when it expands causing increased pressure.

When your boiler is cool tap that expansion tank with a screwdriver. The top should sound solid and the bottom half hollow or tinny. Then run your boiler up to temp and tap again. If your whole tank sounds solid it's bad. Either the air is out of the bladder or it burst.

I may be out in left field but that section of piping coming from behind the aquastat to the pipe coming off the top of the boiler where the relief valve is should be done differently so the air can be released from that vent. Do you have the installation manual.

That boiler only has 2.5 gals. of water in it so the circulator must run when the burner comes on and recirculate either through the boiler or the zones or else you may get steam which I think is happening to you. Air stops the water from circulating.

Why I'm concerned about the tank is because you mentioned the pressure in the tank increases with the boiler pressure and it shouldn't. Once that tank is pressurized and installed that is the only place in the system that the pressure remains the same. If it's fluctuating then you may have bladder issues. That pinging is telling me you are getting flashes of steam and it should only be water so you may have an air pocket in that piping area plus the fact that you are getting steam out of the relief valve.

When the boiler is cold do you get water out of the relief valve. Just curious.

Just a thought.
 
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Old 05-22-19, 07:40 AM
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Hey spott, the Grundfos pump for domestic water is located in the other room, comes in through the darker line next to the hot water tank. For the last run I did, I shut off the valve behind the auto-fill to be sure no water was added erroneously during the test via autofill.

The silver Taco vent on the boiler does release air after the system starts banging around - same with the Supervent, once I manually open them. Prior to starting the test I can confirm when the Taco was open that water was coming out that vent, to verify the system was full to that point. Also with the system full/cold, I cracked the T&P and did get water. I slightly opened both to confirm she was full to the top.

For the expansion chamber which is installed horizontal, with the system cool if I tap the side on the intake I get solid, if I tap the other side closest to the air nipple I get hollow/tinny. With the system cooled and pressure reduced it has returned from 14 psi to 12.

For the piping, the system has been running this way since 1995 - we haven't changed the layout except for adding the Supervent in line, otherwise only replaced parts where they sit. I don't have a local copy of the install manual, but the newer EK1/2 manual is available from Energy Kinetics here: https://energykinetics.com/wp-conten...k1-ek2-gas.pdf

When the unit kicks on I can feel the circ pump vibrating, boiler fires up shortly after. At 180 the pipe to the water tank is scalding hot and we have enough hot water for 2 showers and dishes at least. Also in the prior test with the garage zone open, both supply and return were hot. But I'm with you it seems like no flow = steam, but I have been assuming the zone return and hot water tank heating were indicating the flow... ahhh

I don't know if a partial blockage is a potential, say one of the loose fins jammed somewhere, reducing flow enough to create the steam but allowing the circ pump to heat the zones, etc. Ugh. With the zone open the other day, the return heated as quick as I would expect under normal circumstances..
 
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Old 05-22-19, 11:29 AM
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CW,
The cap on that silver air vent and the Supervent should be left loose for automatic venting under normal operation. They will not vent with the cap tightened.

I'm guessing that Grundfos is actually a recirc pump to get hot water delivery to your faucets faster. You most likely have a good size home with long domestic water line runs.

If you are getting water out of that silver vent it either has debris in the float or is defective. Those vents can also fail by sucking air in when the pump comes on. That vent should be installed above the boiler line in the pipe coming off the boiler where the expansion tank is to bleed properly so when the boiler is filled it forces the air out of the top.

That relief valve on the boiler is pressure only and not a t&p valve. It releases on 30psi and temp does not effect it. A t&p valve is for hot water tanks only.
 
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Old 05-22-19, 11:38 AM
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As an update, I sent this issue off to EK technical support as well - received an email from an EK employee and got a call from our state EK dealer (+1 EK customer service) within 24 hours. Both opinions matched that the high limit aquastat is bad, replace that as well as the heat exchanger, test the return temp sensor on the manager and also to test the lower/return aquastat. Going to get with the local shop to bring some parts out and give her a good ol' fashion tune up at the same time, and see how that goes.

They made the point that with the temp gauge showing 190 F on the return line, the supply is most likely running 210+ F and not shutting down, putting the system into something they called "a type of thermo nuclear meltdown" per say.. They've seen the circ fin melting scenario related to this and often they flow into the heat exchanger as well, blocking flow there, so we'll freshen that up. More to come..
 
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Old 05-24-19, 10:50 AM
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I am sorry if I did not see this question asked, but could the coil in the hot water tank be leaking? It would not explain the air in the boiler.
Sid
 
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Old 05-31-19, 12:55 PM
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Hey sidny, not sure about that but the hot water tank was just installed in December 2018.

As an update to the thread, we appear to be back online at this time. The hot water tank does still leak from the T&P on occasion, but after a round of professional maintenance the issues appear to be resolved! (been running for about a week)

Along with the standard filter/nozzle/tune-up, the tech installed a new heat exchanger and tested the aquastats. Apparently, the aquastats were set to about the max, so he adjusted after confirming they did work when turned down, and we did not replace either. Not sure why, since they have never been adjusted that I know of, but maybe they were running at the edge for some time. System starts right up, shuts off at about 170 now, full heat and no banging in the pipes. Crazy!
 
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