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very first picture looks like it could have gone in a little bit further, maybe 1/4 to 1/2 inch but kind of hard to tell. my unprofessional view is operator error but again, what do i know. thanks matt for the topic. i learn something new all the time.

@ScottSecor

I remember when the 28s first came out. First one I saw was around 1975ish. Originally Smith had no torque spec for the 28s. A couple of years late we were called in to fix leaks on a 28 not our install. By this time Smith had torque specs. They had overtightened the lower push nipples and you could see cracks across the sections. I called Smith (the old foundry was only 10 miles away) and they came over and looked at it. Had me spray with penetrant. I think it was about 15 section boiler with about 5 cracked sections. We split the block in half and replaced the two that leaked. It was a PITA because it had the long tankless heater installed in the 6" rear tapping that ran the length of the boiler and we had to pull that.

The insurance company would only pay for the 2 sections that leaked so that is what we did. When the insurance inspector showed up he wanted me to retorque the entire boiler including the sections that were cracked but not leaking.

I refused and handed him the torque wrench and said "go ahead you do it".

I think we went back a year later and did some more sections. Too long ago to remember. Trying to remember the torque specs like 130 on top 30 on the other top and 50 at the bottom??

high temperature systems with PP and long horizontal run can be a problem if not supported properly.

I have seen the piping sag and leak condensate at the joints.

HTTP failed , standard PVC and CPVC isn’t the best solution, some stainless suffered gaskets or silicone adhesive failures,

Hopefully PP holds up better. It is a harsh environment for the tube and seals

Dirty or plugged HXers can run the flue temperatures up pretty hot. Hot enough to trip temperature safeties.
Mod cons in DHW mode are generally exceeding the PVC, maybe even CPVC temperature limits

Not to mention the lack of listing for flue gas conveyance on typical PVC pipe

Yet manufactures are still sending equipment out with PVC or CPVC “starter pieces” PVC fittings and rubber sewer pipe connectors😲 Some brands sent ABS start pieces, which would often get connected to PVC. Crazy!

I have been building cast iron sectional commercial boilers at least a few times a year since the 1980's. The first time I used a torque wrench on the draw bolts on Smith 28 cast iron water boiler that was going through at least two cast iron sections per season. We were hired as the "expert" trouble shooter that could determine why these sections were failing so often on a three year old boiler. I was amazed how tight the manufacture's wanted the nuts. Before this job, I realized that I was tightening the nuts to about seventy or eighty pounds (without a torque wrench). Somehow, we did not have leaks with under-torqued draw rods.

We used an old Craftsman 1/2" drive torque wrench for years when assembling cast iron boilers. Always amazed me how tight Weil McLain wanted them on 76, 78, 80, 86, 88, 92, 94 and LGB cast iron boilers. Over time, you get pretty good at guessing how tight things are by feel.

I love using torque wrenches. It is a useful tool that you can use with wet torques, dry torques, and if you dont have a specified torque, just look it up in torque tables. Out of fifteen mechanics, Im the only one with torque wrenches that frequently gets borrowed. I'm also the oldest.
One time I didnt use one on my lug nuts and I overtightened them and warped the rotors. That was expensive.

Torque is important on fiber gaskets as they have a built in "compression set" too much torque flattens the washer so it cannot accept thermal expansion/ contraction. Mixing valves are a classic fiber gasket leak potential.

Not enough torque and the gasket does not make the seal. Clean surfaces are critical!

Caleffi is changing to a Posi-stop o-ring. with this design the brass machining limits the amount of "squeeze" you put on the o-ring. The o-ring manufacturer builds the O- ring to a certain % of compression. The same concerns with an o- ring, the compression can be too great or to little.

The type of material and the durometer (hardness) are part of the seal design. Pressure, temperature, type of fluid, movement are all considered in hydronic and plumbing gasket design.

A stop or torque wrench is the only way to know you have the correct seal compression.

We have removed and replaced at least forty condensing boilers (mostly light commercial) that used PVC for venting and fresh air. All of these jobs used solid core PVC as opposed to hollow core.

On most of these jobs, the condensing boilers replaced cast iron boilers on high temperature systems. When we removed the boilers we almost always had to replace the PVC vent piping for at least the first ten feet. In many cases, we switched the venting over to Fas-N-Seal stainless or Centrotherm polypropylene vent material.

In all of these systems, I cannot remember one job that the glued joints came apart easily. As you would expect, the PVC vent piping was tan in color instead of the original bright white. As mentioned above, the heating systems with the highest average boiler water temperature had the most discolored venting. On many of these tear outs, we noticed the PVC pipe was very brittle. The fittings were also brittle, but not as much as the pipe. In the worst cases, the pipe would break if you lightly tapped it with a hammer. If you dropped a section of the pipe more than one foot off the ground it would break into pieces.

The numbers just don't work to build factories in the US. Currently the labor department estimates 400,000 unfilled factory jobs in the US. They are looking for the same people as all the trades. Looks like we may be going in the wrong direction with entry level job workers these days. Farm workers, factory workers, construction labor, hospitality and food processors are leaving by the bus loads. A shiney new factory with no workers doesn't help much.

Modern factories to be accurate, fast and competitive will be automated. 65% of those jobs will require a degree. These are not low pay entry level jobs and wages. As such the cost of the product needs to cover those wages.

With a new pickup built in Mexico costing upwards 100 grand what would a truck 100% sourced and built in America cost?

Factory jobs, just like trade jobs, and farm jobs have a stigma of low wages, long hours, dirty, possibly unsafe conditions, etc. A major PR issue like our trade. How many people do you know applying for a factory job? Money motivates American workers these days, for the most part.

Farm land and factories are still being gobbled up by foreign investor group.

Uncertainty around tariffs, their %.

Raw material, partial assemblies will still come from across the globe, as the average US built car is 45% imported components.

Not a lot of discussion on how to over-come these obstacles?

There will be a lot of lip service and promises by manufacturers to build US factories, once they run the numbers on the costs involved to build a widget, even if the tax payers cover the cost of the factory build, in the US, not enough consumers are buyers. The stall is on.

China with its 1.4 billion people, a huge, low cost labor pool, started planing in the 1970s to become the worlds tool box and manufacturing powerhouse. They started with massive infrastructure investments.

Around here we barely have enough power to keep residential AC running on a hot day. Interstate grid lock every day. What happened to the 2018 focus on infrastructure improvements?

It starts with a realistic vision, then a pathway to get there. Our leaders, whichever party, just pinball from one problem to the next on a daily basis. Flavor of the day, what makes the headlines.

It would be nice to think someone, enough of us, are working in the background to get er done??