Weil-McLein CGM Series 8 HEADACHES

Manor24

My old reliable Weil-McLain has been anything but this season.

We had heavy banging noises in the walls and so we called a local plumber to service the system. He installed new valves, expansion tanks (2), pressure relief valve and automatic vents, and purged the system. He told us it was a top-of-the-line system in great working order.

Everything seemed to be working great for a couple weeks and we started hearing noises again, sounded more like "kettling", opposed to banging. Called the plumber, he insisted there was air in the lines so he came to bleed them AGAIN... and AGAIN.

The noise never stopped so I asked my friend an "HVAC Specialist" to look at the boiler. For some reason he decided to close the automatic air vents. This is when the trouble kicked into high gear.

Later that night I heard what I sounded like a hurricane gushing through the walls. I went downstairs to check on the boiler and noticed the pressure oscillating like crazy. Thinking it okay because my buddy must've known what he was doing, I went back upstairs. A few hours later I heard the noise again and went to check the basement. This time I found a flooded boiler room filled with steam. I immediately turned the boiler off at the emergency switch.

Time to call the plumber again! This time since it was an emergency the owner of the company was dispatched. After looking at the boiler for a few minutes, he determined that it was not in the best condition and should be replaced, a far cry from what we were told just a few weeks earlier from his subordinate. When called out on this, he backpedaled and said he could replace the High Limit Control (Aquastat), but only if he could locate the part.

The next day he came by with a Honeywell Aquastat that he attempted to retrofit into the system because he said the system wasn't turning off at 180ºF as it was set to. (I have since found out after reading the owner's manual that the system is supposed to run at 210-240ºF. Some insight here would be appreciated.)

After all that, the pressure relief valve is still shooting out water and the system is tripping off. Every day I come home to a new puddle of water and have to reset the boiler via the Aquastat. Is there any hope for this thing or should I cut my losses and buy a new system?

Gordy

Your system is NOT suppose to run at 210-240 degrees. Water boils at 212 degrees, and this is not a steam system. If it is there's the problem. I can't believe that none of them didn't stay to make sure the boiler was shutting down on the high limit setting.

lchmb

I'm surprised they couldnt locate the high limit controller (or something closer than what they did).. It is the small box top left in the boiler. the one with the wires cut off... It is an older boiler but should be repairable. I would also look at the circulator to make sure it's moving water...

Ironman

You need to get a REAL hydronic pro out there immediately. Someone has disconnected the high limit safety and tried to replace it with a strap on aquastat above the boiler. I could understand that as a bandaid for a night time emergency, but it should have been immediately repaired correctly the next day.

As Gordy pointed out: that's a hot water boiler, not steam. It should not be run above 190*. 180* is the normal high limit setting.

The boiler is old, but probably repairable. Better pics from farther back of the boiler and near piping might help us see something else.

Jamie Hall

The boiler probably survived the abuse. It's a good boiler, and Weil-McLains are tough. But the control system is a catastrophe, and the fact that the pressure is bounding around indicates that whoever is servicing it ... can't do it properly.

Manor24

Took matters into our own hands and decided to go through the checklist in the owner’s manual... I think we found the problem...

You guys were right about the plumber being clueless - turns out he left the manual feed valve OPEN.

So we bled the system and closed the valve after fill, and (fingers crossed) we are good to go!

Gordy

What is the system psi? Check when system is ambient temp., not while boiler, and radiation are hot.

Manor24

System PSI is 24 (higher when hot). House is three stories and boiler is in the basement.

Ironman

Should be 18 psi cold.

Jamie Hall

PSI is a little high still, but not bad -- and if you're hot, you're hot. Sometimes we are our own best technicians, eh?

Gordy

The expansion tank(s) come factory filled to 12 psi. They must be adjusted to the system pressure while not connected to the system.

I'm assuming you have diaphragm tanks from your initial post.

JUGHNE

It sounds like you just had 2 new expansion tanks installed.
They should be pressurized to 18 PSI, cold, with no water pressure applied or removed from the system to check.
It would be good if the were charged the same amount before install. (did he leave the old ones there....could be spares for the future....put air in them and if they hold for a couple days they would be good).

Manor24

I'll take care of the expansion tanks tomorrow. Do you think these Maid-o-Mist #67 are adequate air vents?

misterikks

Maid of mist are unlikely to last long but the air separator is piped too close to elbow . A common problem. So even a high quality valve wood have trouble.a spirovent would do wonders for air noises but then you get into repipe issues.

Tim McElwain

For your information the control system for that boiler is a obsolete White Rodgers system and is no longer available. It is a mercury pilot system, the pilot uses spark ignition from the white box shown in the picture. It is a 5059 control and is not made anymore.

Not that this has anything to do with your present problem but certainly for planning purposes. If it goes it will require an entire control system replacement including the gas valve. Weil McLain was offering a Hot Surface Ignition kit replacement. I will try to find the numbers for the kit replacement and post here.

EBEBRATT-Ed

What cracks me up is the owner of the plumbing business want's to replace the boiler. Why? He won't be able to work on the new one any better than the old one that he didn't have a clue about.

The sad thing is (3) technicians looked at the job and didn't do crap. That's what scares me. Unqualified.

And worse than that, there simple problems that you don't need to be a genius to fix

Manor24

Swapped out the Maid-o-Mist #67 for Taco #400 and pressurized the expansion tanks to 18-19PSI. So far the system is running much better. Will post any updates later if there are (or hopefully are not) any problems.

Steamhead

Tim McElwain said:

the white box shown in the picture. It is a 5059 control and is not made anymore.

Sure about that, Tim? R.E. Michel still shows the 5059-23 and -134 still available...................

Tim McElwain

Steamhead that may be the case or even E-Bay but here locally we can't get replacements at any of the supply houses.

Manor24

Came home and found the boiler off again with no apparent symptoms. Could be too much pressure?

As requested, here are more pictures of the system with specs on the components...

neilc

OP
you're having to reset the strap on manual reset high limit, strapped to the pipe above the boiler, cause the operating limit / temperature control, the one with the 2 clipped wires under the cover, isn't doing its job. This control needs to be wired back in and work.
You have nothing there monitoring pressure, or to stop or disable the boiler by pressure. The boiler pressure is controlled by the fill valve and the expansion tank(s), and then in worst case scenario, by the pressure safety relief valve.
Has that been discharging?
You should put your zipcode into the Find a Contractor at the top of the page.

Manor24

Yes, the relief valve has been triggering at 30PSI. The pressure builds so quickly once it reaches 20PSI. Cold it's running around 10 now...

Gordy

Did you check the expansion tanks pressure isolated from system? It was brought up to do, and you said you were going to do it.

neilc

you need that operating limit !
with the manual set to 240 you're making steam, and there's your pressure.
Understand, that red button is the dooms day safety.
it should be set lower, like 200, once you get the operating limit repaired.
Right now your banging off at 240 and that's too high.
you need that operating limit !

neilc

You're probably tripping on high temp when only one or 2 zones call, and the boiler can't shed the heat it's making.
I would lock all those zone valves open and maximize flow right now until you get the operating control dealt with.
dial that high limit down to 210 and see if it will hold there with everything open

Manor24

Gordy said:

Did you check the expansion tanks pressure isolated from system? It was brought up to do, and you said you were going to do it.

Hi Gordy, I pressurized the tanks to 18PSI like you had suggested.

neilc, The Aquastat is actually set to 130º, which corresponds to 180º (measured offset of 50ºF).

Gordy

so of system is set to 18, and X tanks are filled properly that only leaves a run away boiler if you are still popping the relief valve. Is relief valve new?

You need to get this fixed asap! The aquastat.

neilc

yeah, sorry , I was concentrating on the high limit reset tab,
isn't that dialed over to 240?
It is that red button your resetting, right?
your hitting the manual reset high limit, (?)

Gordy

It's set at 130.

neilc

i see the pointer tab at 130.
what's the metal tab at 12:01 oclock ?
I see that at 250

neilc

I'll admit I missed the 130 operating,
I was keyed in on the manual reset, and it's temp,
Was that tripped?

then I also have to ask,
what's the differential set to?
and isn't 130 too low a cut out?
(i still think we're making steam at 250)

Manor24

Are we sure this isn't a steam boiler?

Gordy

I hope not with an air removal device, and a circulator. A lot of boilers are rated for steam, or hot water.

Question for the OP what is the differential dial on the back of the aquastat set at?

Manor24

I don't think my Aquastat has a differential; if it does, I haven't been able to find it. It doesn't look like the OEM has one either? https://www.supplyhouse.com/Weil-McLain-510-312-250-Operating-Temperature-Control-All-Sizes?gclid=EAIaIQobChMIu87Y9cXW2AIVk0wNCh2JhgMnEAQYASABEgKDaPD_BwE

JUGHNE

Did you unscrew the tanks from the system, then check for the 18 PSI for the air bladder?

Gordy

That link is not the one in the picture. The one in the last set of pictures is a strap on aquastat.

Manor24

The differential is 50 degrees based on activity...

The link was is the OEM High Limit Control (not operational)

Gordy

Sooooo,the strap on is the controlling device?

Manor24

Gordy said:

Sooooo,the strap on is the controlling device?

Yup, probably going to need to swap that out. I know we can't discuss specifics, but if I told you what he charged me for that disaster you'd fall out of your chair

Manor24

JUGHNE said:

Did you unscrew the tanks from the system, then check for the 18 PSI for the air bladder?

Yes, but should they still be at 18 when my system now is running at 10-12?

Gordy

Just so you understand the job of the aquastat is to turn the burner off at its set high limit usually 190, or lower depending. Then relight the burner at low limit, or set differential usually 30-50degrees usually no lower than 140 so flue gas does not condense. It is also a saftey feature to prevent the boiler from over heating the system water past the boiling point.

My stance on this is you need to get someone to fix this ASAP, and not the person who has been working on it.