Red led on low water shut off blinking intermittently

helpineed

I think that I may have started celebrating my success prematurely.
Last night 2 of my radiators which previously worked refused to heat up. I had not made any changes/adjustments since getting all radiators to work.
Tonight I put on the heat and while staring at the boiler ( perhaps waiting for it to tell me what's wrong) I noticed that the red led on the low water cutoff was blinking occasionally.
The water level was about 1inch above the low level.
The auto feeder came on and filled it to about 1 inch from the max water mark.

1. Can this have been what prevented the radiators from heating up?

2. What could have caused the water loss? My thoughts on this is that more steam was used to fill the now fully functioning system, more steam more water used?

What are your thoughts and advice

Jamie Hall

Cheer up -- you are by no means the first one to stare at a boiler, hoping for illumination!

Three things. First, when the boiler has shut off for a while and is vaguely cool, what is the water level? What you are looking for is the possibility of a slow return.

Second, it is quite possible that the low boiler water level shut the boiler off before it had a chance to heat those last radiators. There may be a time delay in there, as well.

Third, it's a bit of a nuisance, but did you, when you were doing the other work, clean that probe? Long shot, and if the boiler gauge was showing low, chances are the probe is fine, but it doesn't hurt to mention it.

Fred

When is the last time the Low water Cut-off probe was taken out and cleaned or replaced? When the boiler is idle for a while, is the water higher than it should be? If it's higher, then the probe is suspect, if the water level in the boiler is at or below the normal water line, look for a leak somewhere, either in the boiler or on a wet return. If not there, look for vents that aren't closing, radiator valves that need repacking.
As for the radiators that didn't heat last night, how far down the main are those run-outs? Sometimes a heat cycle is so short that all radiators may not get hot before the thermostat is satisfied. Fine tuning the radiator vents will help that but again if the heating cycle is very short, it may not. Set the thermostat up 2 to four degrees and see if they get hot. Also, if the boiler is over-filled, there may not be enough room to make enough steam to fill the entire system.

acwagner

Was the water level 1 inch above the LWCO probe location or a marking near the site glass that said something like "minimum water level"? You can see where the probe goes into the boiler by looking between the LWCO box and the boiler jacket. The probe is usually placed above the minimum water level for the boiler. It might be working properly.

acwagner

I realize now that you were not asking about the LWCO but the water loss and the radiators not heating up.

I found some types of radiator vents are prone to becoming "waterlogged" and stay shut preventing the radiator from heating up. Try pulling those vents, going to the sink and shake
the water/debris out of them. If the radiators heat back up after putting the vents back on, that might explain one of your problems.

helpineed

acwagner said:

I realize now that you were not asking about the LWCO but the water loss and the radiators not heating up.

I found some types of radiator vents are prone to becoming "waterlogged" and stay shut preventing the radiator from heating up. Try pulling those vents, going to the sink and shake
the water/debris out of them. If the radiators heat back up after putting the vents back on, that might explain one of your problems.

I removed the vents on the 2 radiators and just as you thought, they were "waterlogged", in fact the very second I removed the vent I felt the radiators heating up.
I shook out the water but i replaced the vents with some that i had been exchanging while working the kinks out. I left them to "dry out" on top the radiators.
That hopefully solves one problem. On to the other now.

helpineed

acwagner said:

Was the water level 1 inch above the LWCO probe location or a marking near the site glass that said something like "minimum water level"? You can see where the probe goes into the boiler by looking between the LWCO box and the boiler jacket. The probe is usually placed above the minimum water level for the boiler. It might be working properly.

The water level was 1 inch above the marking on the boiler that says "minimum water level" The probe is just above the minimum marking.

helpineed

Fred said:

When is the last time the Low water Cut-off probe was taken out and cleaned or replaced? When the boiler is idle for a while, is the water higher than it should be? If it's higher, then the probe is suspect, if the water level in the boiler is at or below the normal water line, look for a leak somewhere, either in the boiler or on a wet return. If not there, look for vents that aren't closing, radiator valves that need repacking.
As for the radiators that didn't heat last night, how far down the main are those run-outs? Sometimes a heat cycle is so short that all radiators may not get hot before the thermostat is satisfied. Fine tuning the radiator vents will help that but again if the heating cycle is very short, it may not. Set the thermostat up 2 to four degrees and see if they get hot. Also, if the boiler is over-filled, there may not be enough room to make enough steam to fill the entire system.

I don't know when last the LWCO probe was taken out or cleaned. I paid no attention to that "Black Box" when I dealt with the Pigtail.
There's no "normal water level" marking only minimum and maximum markings.
I've not had any visible leaks of water or steam, all piping is 99% visible.
The radiators which did not heat up last night are on the 3rd floor. (I just got them to heat up, acwagner recomended that I check for "waterlogged" vents which was indeed the case)
I'm hoping to get to the bottom of the "disappearing water" case now

acwagner

Look in the manual for the boiler on what the "normal" waterline is. Use a marker to mark it on the site glass and fill the boiler to it. You'll have to run it some and observes what's happening to the water level after the boiler finishes. Does the waterline recover really quickly? Does it never recover? Does it come back to a position slightly lower? Let us know, that will help understand what's going on.

Also, what kind of radiator vents to you have? I don't know why, but on my system Hoffman 1A vents are prone to becoming waterlogged. Gortons work fine. I never figured out why.

Also, I wouldn't recommend taking the radiator vents off while the system is on. Do it when it's off so you don't risk getting burned by the steam.

nicholas bonham-carter

I had a disappearing waterline with a new boiler. While firing, the waterline dropped, and when off the water reappeared. There was a large horizontal dry return a few inches above the boiler waterline. The pressuretrol was faulty, and allowed the pressure to go up to 3 psi! This caused the water in the wet returns to rise up to the horizontal return, and try to fill it. This “hid” the water from the boiler, and triggered the LWCO.
Repiping the wet returns solved that, along with a vaporstat.
Always check for any horizontal which may be capable of getting filled.—NBC

helpineed

Found the culprit! there's a leak on one on of the mains

Fred

Good that you found it! Did is rust through? If so, look at that main as see if there is a sag in that area or it is pitched incorrectly. Mains rarely rust through unless there is water sitting in it. Did you have any banging/hammer in that area? Pooled water will condense steam and will prevent it from properly moving through the main to the radiators.

helpineed

@Fred there is a good pitch on that main. It however looks to have been replaced sometime ago, the pipe looks different
Surprisingly enough this was the main who's radiators worked perfectly from the beginning.
No hammering at all.
Do you think that the leak caused condensation to occur, affecting the first radiator on the other main. This is the one that only worked when I did the increase in vents.

Fred

No, I don't think that leak (I'm assuming it is relatively small) is causing your problem on the other main. Do we know what the SQ. Ft. of steam is on that boiler? Should be on the boiler plate. Have you calculated the total connected radiation on the system? Have you ever had the gas company out to check the gas pressure? It may be that the gas pressure is low and the boiler isn't firing at the rated output and only feeding the radiators that have the least resistance. Changing vents will increase/decrease resistance. Are the vents water logged again?

acwagner

I agree with @Fred phase II of this is to see if your boiler is appropriately sized for your system and is firing correctly. It's possible it is undersized or not fired right. Post some pictures of your radiators and we can come up with what the system demand is. I think you posted a photo of the boiler plate on one of your posts.

Fred

@helpineed , I just happened to think about one more thing. If you have a Programmable thermostat, make sure it is set to "1" cycle per hour. They come from the factory with a default of "5" cycles per hour for forced air. The number of cycles setting makes a huge difference.

helpineed

pictures of some of the radiators

helpineed

Information on boiler

helpineed

In the pictures above, the black radiator is the trouble maker, this one as well as the picture to the right side of it are both on the first floor. The next two pictures show the radiators for the second floor. The remaining 5 radiators in the house are exactly the same as the picture with the radiator that has vents on top of it.

helpineed

my thermostat is a regular honeywell CT87K Round Mechanical Thermostat Heat Only. I also made sure the switches are set up for steam

acwagner

@helpineed OK, here's the next step. Measure the height of your radiators from the floor to the top in inches. They look like they are all the same height.

You can use this guide to calculate how much EDR all your radiators need. It looks like you have the tube type radiators.

http://www.columbiaheatingsupply.com/page_images/Sizing Cast Iron Radiator Heating Capacity Guide.pdf

Add up all the radiators EDR. Then, compare that total number to the IBR steam rating on your boiler (281 SF is what is shown in your photo). It should be reasonably close.

My guess is your boiler is too small for all your radiators...looks like by half, but it's hard to tell what the height of your radiators is.

Fred

Yes, I think we may find out that boiler is too small for the connected radiation. Do the calculation and let's see.