LWCO continually locks out

erussell58

Any ideas from the creative and educated steam pros here....
our secondary LWCO, 63M I continually locking out. Brand new Weil McLain 688.. switch has been replaced three times.... SMDH

Jamie Hall

Being slightly perverse, I'll reply with two questions: first, what is the water level on the sight glass when the secondary LWCO cuts out? And, perhaps much more important, why doesn't the primary LWCO stop the boiler first?

erussell58

The water level is at the normal position. My terminology, excuse my lack of thorough knowledge here, may be wrong on the word “secondary.”
the 62S LWCO is the one tripping. I’m wondering if  the two cut offs are too close together? 

ethicalpaul

Let me try. Why is either one tripping? Is the water level in fact low when they trip?

erussell58

no, the water level does not become too low. That’s what’s so unusual. 

JUGHNE

How steady is the water line?
And how clean is the water, has it been skimmed?

Could the water be surging on the right side because of the take off locations and/or lack of skimming.
It would take only one dip of the float on the right LWCO to lock out.
If the pump feeder is not keeping up, it should shut the burner off first, of course.

erussell58

The water line becomes unsteady in that it rises... about 3/4 up the sight glass. The water is very clean. I blew down the floats this am and clear water. The boiler has been skimmed numerous times since its original start up last month.

JUGHNE

Where does the feeder pump piping connect to keep the boiler full?
Is that flow throttled down from the pump?
Pictures of that part, please.

ethicalpaul

erussell58 said:

no, the water level does not become too low. That’s what’s so unusual. 

Sorry to press, but have you watched a complete heating cycle to see what it's doing?

Or do you mean that by the time you notice that the system isn't heating and is locked out, and you go down to the basement, the water level is OK at that time?

ethicalpaul

Also, let me cut to the chase and ask you if you can send some photos of the boiler and the piping near it so the photo shows from the floor to the ceiling?

I have an idea what it might show based on the welded pipes I see, and the piping there can have a dramatic effect on the water level during a firing cycle.

Is this a multi-unit residence or other large building?

Jamie Hall

Let me have another go, too. The control which is tripping and locking out is, I presume, a manual reset float type LWCO. The other LWCO -- also float type -- either is not tripping or, as it should, automatically resetting when the water level recovers.

Is that correct?

If that is correct, then my critical question remains: that automatic one should shut off the boiler before the manual reset one trips. If it does not, then there are several possibilities, none of the good.

First, the automatic reset LWCO isn't working. Float hung up, switch welded... something. It needs to be checked in any event.

Second, the two LWCOs could be set too close together in height. The automatic one should be just below the normal working level of the boiler when it is firing -- probably around a third to half way up the sight glass, but it could be higher. The manual reset LWCO should be set when the water level is about an inch above the bottom of the sight glass.

Third, the automatic LWCO may not be wired into the safety circuit properly, so even if it does trip it doesn't do anything (i there is an automatic feeder, that might still work -- it's a completely separate circuit). It's happened.

That's all I can think of at the moment...

JUGHNE

I have seen a boiler with pump feeder/LWCO unit that was manual reset (wrong install part). The LWCO switch was jumped and there was a second probe LWCO (auto reset, wrong part install) also below the first.

Is there a suspicious looking reset button on the right side LWCO? Or look inside for the 2 switch connections...one set runs the pump and another kills the burner.

erussell58

JUGHNE,...here is the boiler feed line where it connects on the equalizer line behind the boiler. It actually feeds from a condensate hold tank, 3/4” discharge from the pump to a 1-1/4” line feeding the boiler

erussell58

Ethicalpaul, I have watched a complete cycle. It has no rhyme or reason,  as it seems to me, when it locks out. It can be during the heating cycle, during boiler feed demand, etc. 

erussell58

erussell58

Jamie Hall, I’m thinking your second thought is possibly correct that the 150 S and the 63M may be too close together 

Jamie Hall

I hope that pump on the condensate tank is controlled by the boiler level, and that any makeup water goes into that tank, controlled by a float in the tank.

Otherwise -- while it may not be the cause of your present troubles, that setup may be very very problematic.

Indeed, one might ask why the condensate feed tank and pump are there at all -- it's a rare residential setup that needs them.

But back to square one: the fact of the matter appears to be that the manual low water cutoff shuts off the boiler before the automatic one has a chance to do so (and, hopefully, trigger the boiler feed pump -- see above). This is just plain wrong.

But I haven't come up with any other logical reasons other than the three I posted before...

erussell58

Jamie Hall, I’m thinking your second thought is possibly correct that the 150 S and the 63M may be too close together 

JUGHNE

How long does the feeder pump run when it comes on?
I had smaller boilers with that control/pump that put water in the
boiler too quick and rocked the water around....maybe affecting the LWCO in your case....IDK.

Can we see the feeder pump and control valves?

retiredguy

As I look at the picture you posted my first question is why is the water level so high? You may have a false water line occurring when the boiler fires. Does the water level rise when the burner first fires and does it stay high during the firing or does it level off to the normal height after the boiler has been firing for a while? When the burner shuts off does the water level fall quickly, if so does it fall from the normal water line level or from the overfill level as seen in the pictures? If the water line falls when the burner shuts off the problem is usually an overfired boiler or bad water. The water may look clear but is not correct for that boiler. If the firing rate is not above it's rating, I would have a boiler water treatment company test the water or just call a water treatment company just to be sure. When this boiler was replaced did the installing company just change like for like or did they count the radiation. My last question is does this system have zone valves installed and what is the operating steam pressure?

erussell58

JUGHNE, it usually runs for just a minute or two at most on each cycle. It’s been very frustrating. Unfortunately, the company that installed the boiler does not have a good steam tech to troubleshoot. It’s just hit and miss and replace parts... totally unacceptable in my mind, but it’s over my pay grade. Unfortunately too, we are in a remote area of Maryland and it’s very very difficult to get a good “steam guy” to come down and service, troubleshoot and some maintenance. 

ethicalpaul

Ethicalpaul, I have watched a complete cycle. It has no rhyme or reason, as it seems to me, when it locks out. It can be during the heating cycle, during boiler feed demand, etc.

This is good, but my question remains...did the water level drop while you watched it?

looking at your boiler piping, it's very very wrong and could very well be pushing gallons of boiler water up to your main. This makes your boiler water level drop dramatically. That must be fixed.

ethicalpaul

From the excellent document "the color of steam" by Peerless Boiler



I'm afraid to ask about the size of this boiler vs the radiation

Unfortunately too, we are in a remote area of Maryland and it’s very very difficult to get a good “steam guy” to come down and service, troubleshoot and some maintenance.

Pay @Steamhead and @Gordo as much as it takes to get them there. They are in Baltimore.

erussell58

Retiredguy, yes, the water level rises to what you see in the pic when the boiler fires. When the boiler shuts off, the water level usually returns a bit lower than the normal level and then calls for water, in which time the condensate pump comes on and feeds the boiler. The boiler was replaced like for like, but unfortunately I cam into the picture too late. We are grossly oversized. We’re only heating approx. 10,000 sq.ft now. We are on 5 zones running at 3.5 PSI. 

Jamie Hall

Ah. We have more in the picture here. 3.5 psi? Is 2 psi too much, unless this is some kind of commercial application. Dial it down.

Perhaps far more relevant: 5 zones? Do you have zone valves on this setup of some kind? Zone valves on low pressure steam are very problematic -- to put it charitably. Unless they are very carefully designed and piped, they can and will cause absolute havoc to water levels as they open and close. Please tell me you don't have zone valves...

I think we need a much more complete picture of what this system is and what is going on here. Or at least I do.

JUGHNE

Is this boiler in a separate building from the main house with 100' main going to the house?
Transfer pump at the house feeding water feeder pump at the boiler?

EBEBRATT-Ed

As @ethicalpaul said the header is piped wrong.

I suspect surging caused by

1. Improper piping
2. They need to boil the boiler out with TSP and skim it

Hard to tell from the pictures but the water level controls look at the right level.

Also, does the #150 operate the feed pump?

New England SteamWorks

This:

ethicalpaul said:

Pay @Steamhead and @Gordo as much as it takes to get them there. They are in Baltimore.