LGB-8 boiler w/ new sections failed hydrostatic test at old section seals and 6" plug!

bkc

In this post I described ongoing problems with a 5 year old Weil-MClain boiler installed in a small church. I think it started leaking about 3 years ago. The leak was difficult to find given that all evidence of it went up the chimney.

Anyway Weil-MClain replaced 2 sections and seals under warranty. We had to buy additional seals for the sections that were removed to reach the inner 2 sections, plus contractor labor costs.

After the boiler was re-assembled, it apparently failed the hydrostatic test due to leaks from the section seams that had not been disassembled.

It also now leaks from the 6" plug on the left-side of the boiler. That's a plug that was installed 5 years ago and never removed.

We're now waiting on the contractor to provide an updated quote for additional labor and materials cost (more seals, more disassembly and who knows what else).

Questions:

1. Is it expected that 'old seals' would likely leak under hydrostatic pressure test because "they are old"?
2. Should we have planned to replace all the seals, even on the sections that were not being separated?
3. What would cause the 6" plug to start leaking now?
4. Would the plug have been installed by Weil-Mclain and/or provided by them?
5. How can we fix the leak from the 6" plug?
6. Contractor suggested "when the boiler is fired, it'll probably stop leaking". Is that a reasonable suggestion for plug and or old seals?

The contractor claims they could not remove the plug, even after 'heating' and 'gentle tapping'. They suggested they might have to cut and chisel the plug out. I'm concerned that could damage the cast section. If they break the section, who would normally be expected to pay to replace it (customer or contractor)?

Does anyone have suggestions on how to get the plug out?

Noting that my confidence in the contractor is not great for a number of reasons, but they're the only game in town.

Any suggestions or comments would be appreciated. Thank you.

—

'new' rust shows leak from hydrostatic test.

Shown below, sections 4 (new), 5 and 6. It sure looks to me like its been leaking between sections 5 and 6 as well, but apparently contractor did not submit that for warranty claim for some unknown reason. What do you think?

new sections 4 and 5 and old sections 5 through 8. They did loosen and re-torque the bolts on the old sections, but that didn't stop them from leaking.

Worker said "new sections are tested at the factory, so they have some surface rust".

His seal seat preparation was just a few quick strokes with steel wire brush and good to go.

Should they have used 200 grit sandpaper or something to remove ALL the rust on the seal seats or am I over thinking things?

Steamhead

It's probably best to replace all those rubber section seals.

I'd want to know why the boiler started leaking that soon. Is the system losing a lot of water?

The Steam Whisperer

I would of replaced all the seals.. they are the typical failure point for that boiler.

I'd also wonder why it started leaking. Did it start leaking at the seals? If the boiler short cycles, those seal will like fail very early.

Also, you say this is in a small church. I wonder if the boiler is greatly oversized. We have that same capacity heating in our 17,000 sq ft church in Chicago with structures built from 1892 to 1967. The sanctuary ceiling peak is about 50 feet and with no insulation. About 3/4 of that load is kept at 45 F all week and then ramped up to 69F for Sundays, so plenty of extra capacity.

bkc

Thanks everyone for your feedback. I do not know why the boiler originally started leaking.

I was told on Friday that when the boiler was installed (by the same company doing the current repairs), they would have pressure tested the boiler to 30PSI because "The original fitter is a stickler for the industry standards.".

Just noting that Weil Mclain installation instruction states 45 to 55 psig for hydrostatic testing. Who knows if they only pressurized to 30 psig 5 years ago, or if they had gone to 45 psig if leaks would have been discovered.

Can the rope seals be re-used or must they also be replaced?

Regarding oversized boiler, I calculated a conservative EDR of 481,240 btu/hour + and pipe loss factor of 1.3, giving a total load of 625,612 btu/hour.

The LGB-8 has a gross output of 724,000 btu/hour (543,000 net). I don't think its oversized. LGB-7 would be 619,000/464,000 (gross/net) respectively.

Peak water loss was 2.7 gallons per day. (System didn't have a make-up water meter until 2 years ago, 1 year after I suspect it started leaking)