my boiler is boiling water!

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Old 03-02-13, 06:57 AM
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my boiler is boiling water!

ok, it's not as dramatic as subject might imply, but I still think it's true - I have overheated areas in the heat exchanger where water goes over the boiling point. I hear a sharp relatively quiet sounds when I'm next to the boiler and I can see a pressure needle jump down (bubble burst?). when particular zone is on I could hear it louder on the floor where that zone is on, but it's more muffled sound. it's more like someone taps on the pipe with a hand.

The boiler is 32 yo in a 32 yo house. it's my 3rd heating season and I don't know the history prior before we moved in. It was doing the same thing last year but not to the same extend. the reason I think it might be more pronounced now is because I'm running 8-10 psi system pressure due to the broken PRV.

When I replace the PRV at the end of the heating system I will try to flush sediment out as much as I can and I will bring the pressure back to 12 or maybe 15 psi. That should help with the boiling to some extend. Is there anything else I could do? I've read that some people use diluted acid in attempt to dissolve the sediment but I don't want to do that.

I understand localized overheating is putting extra wear on the boiler, but how critical is it? Can it be an indication of anything more serious or is it more of annoyance and it could still work ok for a while? 32 yo is old for a boiler, but I've heard them to go much longer.

the boiler is gas fired, 100kbtu input atmospheric.
 
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Old 03-02-13, 07:14 AM
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There was a recent thread ... forget what it was called... where at least one member used a Rhomar chemical to solve his problem of 'kettling'. Try a search of the forum with the word RHOMAR and see what comes up.

Basically, you pump this stuff in and run it for a few months... not sure if I read that Rhomar says you don't even have to flush and refill afterward? Not sure about that and I would probably F & R afterward in any case.
 
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Old 03-02-13, 07:26 AM
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I would imagine you would need to flush afterwards, otherwise you're running an acidic media thru your system.
 
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Old 03-02-13, 07:32 AM
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I would imagine that too... but perhaps as it dissolves the 'lime' it will neutralize the acid?
 
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Old 03-02-13, 07:41 AM
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By the way, Rhomar claims that the 9100 treatment contains NO ACIDS

Residential Hydronic Radiant | Rhomar Water Management, Inc.
 
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Old 03-02-13, 08:09 AM
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You can get a 'kit' with both the 9100 cleaner, the 922 inhibitor and some test strips here:

Rhomar Boiler Chemical Treatment 83287. Aluminum Boiler Treatment. Hydronic Boiler Treatment

I might even do this my own self!
 
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Old 03-02-13, 08:38 AM
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quick question after reading their pdf - can one run recirculator without boiler running? i understand it's a simple 24VDC pump, but how one overrides the rest of the boiler function to only run the circulation?
 
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Old 03-02-13, 09:03 AM
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can one run recirculator without boiler running? i understand it's a simple 24VDC pump, but how one overrides the rest of the boiler function to only run the circulation?
Your pump is most definitely 120VAC powered.

According to directions, the stuff will work best if the system is hot, so you would probably just want to push the thermostat up and burn some fuel, at least for a part of the time it's in the system anyway.

Since it's a 120VAC pump, one could temporarily wire the pump with a plug and cord and simply plug it in to a wall outlet.

OR, you could disconnect one of the power wires to the gas valve... yeah, that would be easier! Run it hot for an hour or two, shut it down, disconnect a burner wire, power it back up and just run the pump without the fire.

If you have zone valves, lock them manually open.

What make/model your boiler again?
 
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Old 03-02-13, 10:06 AM
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Repco LA100c circa 1982. i don't know why i thought it was 24VDC. i could wire it fro 120VAC as you suggested since it would me more straight forward or maybe think about the gas valve disconnect.

i'm not sure i'll go for chemical flush yet. i might just water flush it when i replace PRV and see if it makes it better. the boiler is old and i'm somewhat torn regarding it.

on one hand i want to milk it as far as i can, on other hand my work on tightening the house in the last 2 years resulted in marginal chimney draft and i still have things to tighten up. i want to go closed combustion, but the old boiler is still chugging along, so i don't want to get rid of the working system. i could do an elephant trunk into the part of the boiler basement, but that's half measure. so as i said i'm somewhat torn.

chemical flush will tax the system, regardless of what manufacturer says. whatever dissolves calcium chloride will have corrosive characteristics towards cast iron and mine is old and rusty. so i want to be as non invasive as possible. if 'kettling' doesn't have a huge adversive affect on the system, i might try the simple F&R and leave it along.

we'll see, i haven't decided it yet

NJ Trooper, thanks for you contribution to this forum, i feel like you're always there waiting for all our silly questions
 
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Old 03-02-13, 11:18 AM
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OR, you could disconnect one of the power wires to the gas valve... yeah, that would be easier! Run it hot for an hour or two, shut it down, disconnect a burner wire, power it back up and just run the pump without the fire.
Just turn the gas valve off or put it on pilot... No need removing wire... Turn both T stats all the way up. Circ will run but boiler will not fire.

Just go the big orange and get this stuff.... Follow the instructions. You want the boiler to heat with this stuff. I have had good results with it. Even treated my 40+ yr old boiler with it.


Hercules 1 qt. Boiler and Heating System Cleaner 35206 at The Home Depot

Boiler And Heating System Cleaner | Heating Chemicals & Anti-Freeze | Hercules

 
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Old 03-02-13, 11:35 AM
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lawrosa, good idea on a gas valve being on pilot or off.

the cleaner that you referenced seems to be for flux and not for calcium sediment. would it work for both?
 
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Old 03-02-13, 11:40 AM
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i'm somewhat confused on how to add any of the cleaners to the system. is there some kind of a common contraption that i could install in the system that would allow me to anything?
 
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Old 03-02-13, 12:16 PM
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I took my relief valve off and lowered the water level. Then just poured it in. Refilled and ran the system. Its been in there two years now. I did not remove it per instructions. There is a different procedure for really dirty systems.....
 
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Old 03-02-13, 12:24 PM
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Just turn the gas valve off or put it on pilot... No need removing wire...
Duhhhhh... uh, yeah, what he said!
 
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Old 03-02-13, 03:52 PM
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lawrosa,


when you refill the system do you keep draining with intake valve open until the water coming out doesn't have much air? or do you keep the drain open until water start coming out, close it and then circulate it until air eliminator lets all the air out?

the reason i'm asking is that i planned on keeping one of the drain valves on each zone open (one at the time) until the water is clear of air, clear all zones first and then close the system. if i use this approach, i would drain all the cleaner.

if i use the other approach i believe i would end up with too much air in the system to begin with and it would be possible to get air locked or simply it would be a lot for air eliminator to get rid of.

am i overthinking it?
 
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Old 03-02-13, 05:12 PM
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That was me that did the Rhomar treatment, search for my thread.
It worked excellent, I've got absolutely no kettling at all anymore and I think the heat output of the system also improved. The quart package isn't enough to clean a system. Buy it in the gallon size.
After I finished the flush, I also used their corrosion protection.

P.S. you can leave the 9100 cleaner in the system for quite a while.
 
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Old 03-02-13, 06:01 PM
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lawrosa,

i looked at msds of the cleaner from HD you recommended and it looks like it's water + defoamer + TSP (de-greaser), so it shouldn't have much effect on mineral sediment.

tomf63,

i only found a single post of your on the Rhomar - http://www.doityourself.com/forum/bo...ml#post2061647, is there a separate thread?
 
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Old 03-03-13, 05:37 AM
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Diver, yes read that whole thread. Wasn't started by me but does outline the process.
 
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Old 03-03-13, 06:01 AM
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will do, Tom. thanks. i'll come back if i have some questions.
 
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Old 03-03-13, 11:11 PM
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Flashback...

When I bought my old house it had a Repco oil fired with tankless coil. When the engineer inspected the house he said mine had a new chamber installed at some point. He also commented that the company as known for "builders specials" and tehy actually went out of business from so many burn throughs of the chambers. He likened mine which was in "good condition" to a well running Yugo. I hope the best for you for continued good luck using it.

After wasting much oil, many breakdowns and constant hot water issues I replaced it with a Weil Mclain and indirect water heater.

Thanks for the info on the Rhomar anyway. I'll need to look at that as I get ready for springtime boiler work.
 
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