Torque Wrench

a 1/4" drive torque wrench and an adapter to 1/4" insert bits will do what you need for the cover on a mod con hx and is inexpensive.

torque is a proxy for the tension on the fastener and isn't the greatest proxy but is better than nothing. it is something we could discuss for hundreds of comments. on something like the cover to a mod con hx or the plate for a tankless or rods holding sections of a boiler together is it good to try to get equal clamping force all around.

the other reason torque is important is that you want the fastener to be stretched more than it will be stretched in use. If the stretch of the fastener is greater than the forces in use it stays tight, if the forces in use are more than the tightening tension, it will loosen up.

a lot of things will have a lot of variables in how they turn and making sure they are seated properly is more important than the torque

maybe that's why so many tankless coil plates leak

If you've assembled large sectional boilers, they always want the bolts & rods torqued..md

like i said, we could talk about this for 200 + comments

If it makes you feel better, no harm in owning an inexpensive torque adapter. Over tightening, by the guess method, is more of an issue with 6 mm bolts and aluminum block boiler, I would say.

I wish more tire shops would pay attention to torque specs :)

There are many doods still flaring mini line sets w-o a torque wrench. I started using one about 8 years ago, I thought it was revolutionary!

I have never seen any boiler assembly bolt or rod a mile long… You must work on some big stuff Ed. the longest push nipple assembly rod I have ever used myself was about 14" long. but I only worked on a couple of churches myself. The Catholics had the biggest churches in my area.

We had a rash of electric unit heaters burn up the terminals on the disconnects and/or contactors. I ended up getting a torque screwdriver for the replacements, no issues since then.

I wouldn't say I'm a true believer just yet, but the evidence is mounting so I use it when I can.

I had a contractor tell me one time that he tightens something down until it breaks and then give it one more turn. He was a humorous guy.

Bury the threads plus a turn for luck.

Yeah, I've followed behind him before.

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.

I've done flares both ways, with Nylog (on the sealing surface) & without, also with torque wench & without. I might've exaggerated how many times I've pushed the flare out, but for sure several times, with the torque wench. Any more I just go to 8-9 inch/lbs on the ¼".

I can imagine the lube causing some issues if it's all over the place, but a dab on the sealing surface shouldn't be an issue. I've tried those li'l blue gaskets too, the jury is still out. They do need to be torqued properly though, they will leak if not.

I got one when I started doing mini splits. The YJ digital one. I don’t like that you can easily and accidentally change the units, especially if the wrench is in a position where you can’t see the display.

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.

@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??

when I worked on aircraft and needed to use a crows foot for a flare nut, I would have to do a calculation if I used it as a extention (straight out) because I added length to the wrench but if I used the crows foot at a 90, I didnt because it didnt add length. It mattered.

True. But if the plane crashed six months later because of something totally unrelated to your work, you will still be interviewed by investigators and that is not the answer you want to give. It could cause you a suspension of license