cast iron baseboard banging and breaking

bat21

hi my name is jeff and i am a plumbing and heating contractor since 1981, im having a problem on a job and would like some help solving it. the house has a 10 yr old weil mclain hot water boiler with a domestic coil and 3 zones with 3 taco 007 circs on the feeds, 2 zones are slant fin copper radiation and the main house zone is cast iron baseboard, i was called out last winter to the house when a cast iron radiator broke, the woman told me her heat stopped working during the day and when she got home she pushed the reset and the boiler fired and the radiator broke, i assumed the radiator froze and broke but didnt leak until it thawed, i capped the feed and return to the radiator and replaced the radiator the next week and have not herd from her until yesterday, she called and said another radiator was leaking so i went to look at it and it was 18 ft long and leaking in the center, not at a seam but in the center of a section from the back, i pumped boiler seal into the system and the leak stopped and told her i would return next week to replace it, she also told me her radiators make a loud bang sound when the heat goes on, it sounds like a hammer hitting the ci radiator, i looked the system over and think i know whats wrong but we will get to that later. well tonight i get a panic call that her radiator burst so i ran over and the back of the cast iron radiator blew out, now im thinking about last years break and realizing the other radiator did not freeze, houston we have a problem, ok now i have the radiator disconnected so their heat is back on, ok after questioning the homeowner here is what i know, the heat is turned down to 60 degrees when their sleeping and at 545am the heat goes to 66, then when they leave for work back down to 60 and at 330pm back up to 66, i explained to them they are burning more oil doing this and only go down 2 degrees when they go to work and bed , my theory is when the heat kicks on because the boiler maintains 160 180 its shocking the cast iron and this is the reason for her radiators banging and breaking, the boiler does not have a balancing loop (cross over from feed to return at boiler), she told me the radiators always made this noise the 17yrs she has lived there, also the heat loop is 1 inch black pipe with 1x1/2 monoflo tees to each radiator, i have asked other plumbers and heating contractors and they all say "i dont know" or "bleed the radiators" its well beyond bleeding the radiators, can someone help me out???

Ironman

How about a water-logged expansion tank and a stuck relief valve?
Or one that somebody recently posted about CI baseboard breaking like this and it turned out the HO had replaced the boiler relief valve with a hot water T&P valve that was set @ 150psi?

Thermal shock is a viable theory but I've always thought of it from the other end: cold shock. It's still hard to believe that this is the only system out there with a tankless coil and CI BBs that would have this problem. If that's the case, it should be an issue with all of them.

Getting rid of the tankless in lieu of an indirect would give a much better supply of hot water and significant fuel savings.

Paul48

Maybe expansion noise?

bat21

thanks for your replys, i thought about the indirect water heater but the boiler is still at times up to temp when the heat kicks on giving the same senerio as present, the relief is new and expansion tank is not waterlogged

Paul48

No....Pipe expansion.....Like a steam boiler with no swingjoints, splitting the sections of the boiler.

Ironman

Is there any piping that is locked down in such a manner that it will not allow for thermal expansion? The shock of that could transfer to the rads and cause what you're experiencing. It goes along the same lines as to why copper should not be use on a steam boiler's header because it won't allow the header to expand with the boiler block.

bat21

paul48 please explain? the monoflo tees have 1/2 in soft copper to radiator feed and return

bat21

finished basement with sheetrock ceiling, have no clue whats going on up there but it seems its just a simple split loop around the basement, simple basic square ranch home

Paul48

It was just a thought, that you had things expanding at different rates and causing stress.

bat21

ok wait u guys got me thinking,u think the boiler seal could have welded the relief closed???

bat21

Paul48 said:

It was just a thought, that you had things expanding at different rates and causing stress.

its definately possible

Steamhead

Check the firing rate on the burner. This will mean checking the pump pressure as well as the nozzle size. If it's too high, steam can form in the boiler and cause a sudden pressure rise.

Also check the water flow rate- if it's too high, it won't pick up enough heat in the boiler which can also cause steam to form. Yes, that sounds counterintuitive, but I've seen it happen.

What model W-M is this? What burner does it have?

icesailor

How many homes are there out there with a cast iron oil boiler, cast iron baseboards with a steel pipe main and 1/2" copper risers to the baseboards? TNTC.

The noise she's been listening to for 17 years is the sound of hot water expansion in the system when the pump comes on.

Does it come off the supply and return at the boiler 1 1/4" pipe and split to 1" mains feeding both sides of the house? Or is it all 1"? If so, that's one small Hacienda.

Where is this location?

Its my experience that some are not completely honest when re-counting stories of how things happen. You describe a house that has an addition with 2 zones of baseboard, and this older part with Cast Iron Baseboard. My scenario is this part of the house isn't used that much, especially in the winter, and they have the thermostat set at 40 degrees or as low as it will go. If that zone was operated as she claims, there is enough residual heat stored in the rooms of the zones to cover the heat being off. Or, that part of the old house has little or no wall insulation, and while the heat was off, any heat left in the rooms radiated out through the baseboards, the wall cavity, the wall, and out into space. Her futile attempt to warm the outside. Is this broken baseboard on a North or NW Wall? If so, I would consider any baseboard on these walls as having been subject to freezing and ice. Is there an enclosed crawl space under this part of the house? Are there foundation vents under the part that broke?

In my 40+ years of fixing broken/frozen pipes, pipes won't freeze and break in 8 hours in a conditioned room when the heat goes off.

As far as set back thermostats, they will freeze pipes quickly if they are buried in wall cavities, insulated or not. If the design temperature for the OAT is zero (-0), and you do a 8 degree setback, it is the same as lowering the outside OAT to -8 degrees. Its the time that the pumps are off while waiting for the temperature to drop inside that freezes up things. If the breaks are all on one section of baseboard, and it is on a North facing wall (prevailing winter winds), consider all of the baseboard as being damaged. Disconnect and cap it off.

Copper fin tube baseboard in the same house, never seems to suffer the same as cast iron baseboards. The copper stretches more than the CI. You usually see the splits on the ends, and seldom in the middle of an element. Unless for a reason. And there will be a reason. And if any cast iron has bulges on the outside or inside of a section, it froze. If it is between sections, has been painted, and the paint has separated, it froze. If it has multiple splits and leaks on one section, replace the section completely. It has been damaged. Usually, it only splits where the ice forms.

Ironman

icesailor said:

How many homes are there out there with a cast iron oil boiler, cast iron baseboards with a steel pipe main and 1/2" copper risers to the baseboards? TNTC.

The noise she's been listening to for 17 years is the sound of hot water expansion in the system when the pump comes on.

Does it come off the supply and return at the boiler 1 1/4" pipe and split to 1" mains feeding both sides of the house? Or is it all 1"? If so, that's one small Hacienda.

Where is this location?

Its my experience that some are not completely honest when re-counting stories of how things happen. You describe a house that has an addition with 2 zones of baseboard, and this older part with Cast Iron Baseboard. My scenario is this part of the house isn't used that much, especially in the winter, and they have the thermostat set at 40 degrees or as low as it will go. If that zone was operated as she claims, there is enough residual heat stored in the rooms of the zones to cover the heat being off. Or, that part of the old house has little or no wall insulation, and while the heat was off, any heat left in the rooms radiated out through the baseboards, the wall cavity, the wall, and out into space. Her futile attempt to warm the outside. Is this broken baseboard on a North or NW Wall? If so, I would consider any baseboard on these walls as having been subject to freezing and ice. Is there an enclosed crawl space under this part of the house? Are there foundation vents under the part that broke?

In my 40+ years of fixing broken/frozen pipes, pipes won't freeze and break in 8 hours in a conditioned room when the heat goes off.

As far as set back thermostats, they will freeze pipes quickly if they are buried in wall cavities, insulated or not. If the design temperature for the OAT is zero (-0), and you do a 8 degree setback, it is the same as lowering the outside OAT to -8 degrees. Its the time that the pumps are off while waiting for the temperature to drop inside that freezes up things. If the breaks are all on one section of baseboard, and it is on a North facing wall (prevailing winter winds), consider all of the baseboard as being damaged. Disconnect and cap it off.

Copper fin tube baseboard in the same house, never seems to suffer the same as cast iron baseboards. The copper stretches more than the CI. You usually see the splits on the ends, and seldom in the middle of an element. Unless for a reason. And there will be a reason. And if any cast iron has bulges on the outside or inside of a section, it froze. If it is between sections, has been painted, and the paint has separated, it froze. If it has multiple splits and leaks on one section, replace the section completely. It has been damaged. Usually, it only splits where the ice forms.

Some very good advice by the Ice man. And a very accurate observation: you should be able to tell if the breakage has been from freezing or shock.

tim smith

Is it breaking in the middle of the long run of cast rad, at a joint? Is it a crack? How are the supports under the middle of radiator. I find some times that middle bottom supports are removed and too much stress is being put on joint. Then add the thermal expansion of metal and puts to much stress at that point.

icesailor

@Ironman:

"" freezing or shock. ""

Man, if it was "shock". good thing no one was around when the shocking was going on.

That Burnham 9A baseboard is some tough stuff.

You should see and understand what ice does on a lake. Ice Pressure ridges or "reefs" and their causes are something to behold. Expanding ice will crush a ship. Heave up a road.

bat21

ok guys thanks for all the comments, great website here,sorry for delay getting back here but this snow storm and frozen pipes are keeping me busy After reading all the posts here i went back to the job and removed the extrol 30 and installed a extrol 60 and replaced the relief valve and told the customer to let know if the banging stops, she said she herd 1 bang in the morning and a few small bangs the first day, the second day she said only a few small bangs, i told small bangs are normal but the bigger bangs are not, well today she texed me and said the big bangs are back, she also told me that she leaves the t-stat at 66 and never changes it now which is what i told her to do, i called burnham tech and he had no answers for me, today i went back to lower the aquastat but when i checked the high was 170 and low 150, if i go lower she will have problems with the hot water, the guage was spot on and boiler shut off at 170 like it should, she told me she bleeds the radiators out always like her father showed her, well she is doing it properly and no air is present, the one thing i noticed is the coinvent in her bedroom is blocked by a wooden closet they made that covers the first 6 inches of the radiator, i asked how she bleeds this radiator out and she said she doesn't but the radiator is always hot, tomorrow im going to bleed out all radiators and cut hole in closet to get to coin vent, i doubt air has anything to do with this problem but im going to try anyway, any other ideas?

bat21

i forgot to mention these radiators are not freezing!!!!

Ironman

Again, have you checked to see if the piping is free to expand when heated?

icesailor

Concerning the partially covered radiator, if it is a standard stand up cast iron radiator, and the coin vent is partially covered, if the top of the radiator is hot, along with the exposed side, you don't need to vent it. Its already vented itself.

If the radiators aren't hot to the top, they don't need to be vented.

As far as the "banging", you really need to hear it personally. Describing a "Bang" is like trying to explain the color green to a blind person. What sounds like a "Bang" to her, may be a click to you. You need to make arrangements with her to leave the thermostat at 60 degrees or lower for a few hours so the system cools down. And you have an appointment to meet her there and you turn up the thermostat to 70 degrees. The noise is probably pipes rubbing on wood. It moves like an earthquake. It stores up energy and moves all at once.

bat21

ok i went there today again and blead all radiators and found 1 rad with air in it, all other radiators were perfect, no air, again i can not see the piping in the basement it is totally finished except the boiler room, the feed and return at the boiler is 11/4 and reduces to 1" at the split, as far as how loud the banging is she told me the bang was soo loud at night her dog jumped up from sleeping and ran out her room, also dont forget 2 radiators have broke and im sure they are not freezing, the castiron loop is the main part of the house and again this is cast iron baseboard BASERAY radiation not stand up radiators, again im not a noob at this i have been a plumbing and heating contractor since 1981 so as far as bleeding etc i know the routine, im just looking for help here i can not figure this out! the t-stat is set at 66 and stays there all the time now,

bat21

tim smith the radiators are not breaking at a joint its in the middle of a 2' section, also the leg was in the same location as the break, i tried to shim the rad but the leg is tight to the floor, also the radiators have a piece of quarter round trim around them so i would know by looking if the radiators are sagging, this was the first thing i looked for.

bat21

also today i had her turn the boiler off in the morning and i turned it on after i bleed the heat and it was quiet as a mouse, no bangs at all, it was off for 4 hrs, i thought for sure i was going to hear something, stayed for 11/2 hr and let it run, no banging!!! what the heck is going on here, the breaking radiators are what is driving me crazy.

bat21

icesailer i checked with my trusty iphone compass and this is not the north wall it is the east wall and im in connecticut

Paul48

Unless you can get at the piping to the radiators, you're done. It almost has to be there. Imagine the engine in your car develops a skip, and you take it to your mechanic, and you've welded the hood shut. What would he say?

icesailor

Worse, you get to the mechanic and it works fine.

As far as the noise, I've been in houses that were frozen up and broke in my presence. There is nothing quieter than a house that the boiler has gone off and the house is cold and its 20 degrees outside. Its as quiet as when someone dies in your presence, That, a BANG!!! As a pipe of radiator breaks. It gets your immediate attention. If it woke the dog up, it must be really loud.

The only thing I can add is that if CI baseboard is connected with Mono-Flows, and it is against a cold freezing uninsulated wall, because it is individually connected, if there is serious cold infiltration, it could freeze and break in a middle with the heat running in the zone. If no one was in that zone, even with the room warm, the heater could possibly freeze and break.

bat21

im going to pull the radiator off the wall next week and see whats going on here, ill keep everyone post on what i see, thanks again everyone

RobG

I'm just taking pot shots here. It's possible that the radiators were from a bad batch of castings or froze. If the banging has always been there it is probably expansitn and contraction. I would recommend a Taco I-Valve to add outdoor air reset and switch to constant circulation to keep the expansion to a minimum. Once you get the reset curved dialed in the thermostat will just be a high limit.

bat21

robg thanks for the post, why would a bad cast radiator make a bank? also the boiler has a coil so how is that going to work with constant circulation, also it seems im not the only one with this problem i have been reading through this forum , i still think its an expansion problem with the cast iron and the rapid temperature change with the hot water when the tstat calls i just need to find a solution, i have tried everything else, again these radiators are not freezing, im sure of that!

bat21

icesailor said:

@Ironman:

"" freezing or shock. ""

Man, if it was "shock". good thing no one was around when the shocking was going on.

That Burnham 9A baseboard is some tough stuff.

You should see and understand what ice does on a lake. Ice Pressure ridges or "reefs" and their causes are something to behold. Expanding ice will crush a ship. Heave up a road.

icesailor believe me i know what ice can do, again i have been in buisness over 30 yrs and have seen alot.

Paul48

Before you remove any.....Go back, and check how they are installed, compared to the manufacturers instructions.

icesailor

Better yet, if possible, post a photo of one that has broken. Where it broke in clear detail.

When they crack from ice, there's usually a "C" shaped crack in the front around a register in the sand casting mold. Its solid in the middle of a section.

Gordy

I find this interesting to have this much expansion contraction noise, and so loud. If as she says it's been doing this the 17 years she has been there.....are we looking at a fatigue break? How long prior to her has this been going on?

bat21

i dont know how long before her this has been happening. i will post a pic of break when i remove the radiator, better yet i will call her tomorrow and see if she has the 1st radiator that broke last year, i believe she saved it for the good sections,

Gordy

Get a close up best you can of the break area.

Ironman

I've seen hydraulic shock in potable water systems that ruptured water heaters, well tanks and other components because the tank was water-logged and when the pump kicked on, the weakest component broke. A pipe that is bound so that it cannot properly expand can send a massive shock wave through the system.

Like it or not, the HO is gonna have to let you open up some areas to check the piping.

Drywall repair is a lot cheaper than hydronic repair and it's gonna end up having to be done eventually anyway.