Rising sight glass and banging is back and I don’t know why - need a steam detective!

bipbap

So after solid advice I got here when my water feeder was on the fritz, I had my steam guy put in a VXT. He left the old one connected as you can see in photo, maybe as a backup? I’m not sure.

For the first time in a long time, things seemed as good as the system ever was. Not much banging. Sight glass 1/2-2/3 full. I could track water use now and while it was still more than ideal, there were no obvious leaks and otherwise things were running ok.

Now just a couple weeks ago, things changed. The sight glass regularly shows filled just 1/2” from top, the banging is insane on the basement main, like I see dust blasting off it and the whole pipe shakes every time it bangs when the system fires up.

I don’t know what changed.
One odd thing is the VXT hasn’t recorded any added water for a month when before it was recording a couple of gallons a week which I know isn’t good but it was at least consistent.

My steam guy wants to replace the LWCO as a fix but he’s not sure that’s the issue. He’s playing educated trial and error which is an expensive game after dropping so much money on other boiler repairs this season.

Any suggestions given these clues?

Fyi, this is a gas fired single pipe steam system 350k btu for a 4-family building.

My goal is to get rid of the basement main banging- the banging had been totally gone from Feb until now so I don’t think the pipe is not pitched properly- and also to keep the water level at the correct spot in the sight glass.

 I just don’t know what would’ve changed suddenly to throw things off when it had been working relatively good since the VXT was installed.

  All ideas appreciated! 

mattmia2

Is there another valve further up out of frame of your pictures for the water feeder? If so turn it off and drain the boiler to the water level mark and see what happens.

Is there a tankless coil or indirect water heater or hot water loop that is isolated with a heat exchanger?

bipbap

I did try turning the water off, drained it down to the proper level, but it rose back up higher than it should once I put the water back on.
Nothing else connected to this setup- there are water heaters down there, but they are totally separate.

mattmia2

Wait, you kept the water shut off, right?

bipbap

Once I drained it down, I turned the water back on hoping that it would stay at the correct level but it did not.

Are you suggesting I drain it down to the proper level and just leave all water supply turned off?

mattmia2

Yes. One of those valves is probably leaking, either the automatic valve or the bypass valve (or the old water feeder if it is still connected).

Check the level at first frequently then every couple days or weekly if it seems to be staying stable or only going down a little. If it stops filling you know one of those valves is bad.

bipbap

Ok but isn’t it odd that it fills it high but it doesn’t flood it- it stops about 1/2” from top of sight glass?
if it was the valve wouldn’t it just keep filling and flood it?

mattmia2

Is it running out of a vent somewhere in some dark corner of the basement?

The Steam Whisperer

That electronic LWCO is installed completely wrong. Should be on 1 inch pipe with a special fitting ( made by Hydrolevel) and with a blow down valve. This is a safety issue as the control could read that the boiler is full of water, when it is empty.

bipbap

I really don’t think so, Ive checked 

mattmia2

The Steam Whisperer said:

That electronic LWCO is installed completely wrong. Should be on 1 inch pipe with a special fitting ( made by Hydrolevel) and with a blow down valve. This is a safety issue as the control could read that the boiler is full of water, when it is empty.

Oh, so it is filling some extraneous piece of pipe to some level, not seeing the level in the boiler so that is why it is repeatably wrong.

bipbap

Ok I’ll ask him about that .
But why would it have worked fine for a while, kept the water at proper level, and then suddenly have issues again?

JUGHNE

I wonder if the pipe going into the boiler is partially plugged.
It could then give a low water indication on the probe.

Your set up actually places the probe a distance from the actually boiler water level

Your install manual may point out a good port for the LWCO probe...going directly into the boiler.

Jamie Hall

I think your man may be on the right track -- the low water cutoff may be hanging up once in a while. They do...

pedmec

are you treating your boiler water with any chemical? you say you the vtx hasn't added to the system in a month but the water line is really clean, as if its been treated. also with the high water it doesnt have to feed as its above the normal water line anyway.

you might have to check the water quality for tds. this will effect your water line in the boiler during a run cycle and might have caused the Lwco to think it was low during a run cycle and now you have a new water level.

you can check this by completely draining the boiler of the existing water. then refill and see what happens. if it is tds you will have a normal water line for a while but evetually it will start to get erratic and and cause the lwco to initiate a fill. it will settle at a high water line again. you also should see an erratic water line in the boiler sight glass.

mattmia2

You could turn the power off to the boiler and keep the valve on and see if it fills. if it does it is a valve that isn't holding. if it doesn't then it is feeding.

EBEBRATT-Ed

@bipbap

The low water cutoff is installed all wrong. It looks to me like both connections could be in the steam space at the same tome.


no good

KC_Jones

The Steam Whisperer said:

That electronic LWCO is installed completely wrong. Should be on 1 inch pipe with a special fitting ( made by Hydrolevel) and with a blow down valve. This is a safety issue as the control could read that the boiler is full of water, when it is empty.

I’ll go one further, that looks like a Weil Mclain EG series.  That tapping in the boiler is designed to have time probe installed directly into it.  I can’t imagine why he added all that instead of a direct install.

And funny thing, those look like new fittings.

Is there something I’m missing?

bipbap

Yes all that piping by the lwco was redone quite recently, I think when he installed the vxt in February, though the lwco is not new.
I don’t know why it was done this way.
Is there any logical explanation?

The Steam Whisperer

Probably because if it was installed in the probe location, it would not have worked properly with the other control that was installed on the gage glass tappings. EG boilers require a water column be installed when installing primary and secondary low water cut offs. One would be on the water column the other probably the secondary probe in the boiler. The overfilling issue could just be contaminated water. A complete draining an refilling a couple times will tell you if that is the case.

That electronic control is still not installed properly and is a safety issue as it can easily get a false positive reading of water on the probe when junk collects inside the fittings it is installed in. Also the bottom piping connection can clog easily, holding water against the probe when there is no water in the boiler.

reggi

bipbap said:

Yes all that piping by the lwco was redone quite recently, I think when he installed the vxt in February, though the lwco is not new.
I don’t know why it was done this way.
Is there any logical explanation?

Here's a photo from a earlier post this year of your pipes prior to the vxt

( I tried aligning the perspective so any angles may appear skewed )

And there have been quite a few threads about this system and issue with water level and options and choices since January... Ultimately someone had to decide and agree on the setup you have now... You have the responsibility of 4 families and safety and operation isn't a luxury.. it's required by law..
My .02

bipbap

Yes I hear you.
I am not working with a random plumber. This guy is one of the steam pros/specialists in my area and I really do think he knows his stuff and I don’t think he would do anything unsafe or unethical. He’s been fair and upfront in all the time I’ve known him and he has a good reputation among neighbors and others.

I’m only here to get second opinions since with this recent issue it seemed like we were in trial and error territory.  I really value all of your thoughts and opinions on this and all my other recent issues.