Quote of the Day

bigwilly104

THe first man I worked for is still a friend. I learned how to hustle working for him. I learned alot of great sheat metal skills from him. Most important I learned how a forced air system is built. However I also learned alot of bad habits from him. My point is yes what your boss said is wrong sealing unsealed duct is money out the window and poor work quality, but learn the good things he knows. I have worked for five differant shops over the years. Know I own a buisness and have guys working under me. The men who taught me all had their faults and bad habits but thats what makes a well rounded service man, installer, or owner, and I wouldnt have it any other way.

PeterGriffin

I'm a plumber apprentice, if you don't know already. I usually post up some stupid questions that I should be asking my boss... Today, you'll understand why I don't always take his word.

We got quoted $9000 for the tin work that needed to be done in the crawl space of a new building. Pretty expensive, even for Fort McMurray, considering what had to be done. The apprentice and the two helpers get the job of doing the ductwork.

As we're putting up 18x8 ducts, we're sealing our joints with tape, I've seen better ways to seal it, but it seemed to be working alright. Then my boss comes underneath as one of the helpers were taping and said,

" Oh, you don't have to be taping these up, these systems are designed to have a bit of leakage...in fact, they actually flow better when they leak..."

Am I retarded or just extremely ignorant or does that just not make any sense whatsoever???

/end rant

Rankin

Brad White

Think of ductwork

as a balloon. OK, a balloon with controlled leaks, your registers.

Maybe your leg was being pulled? I can only give the benefit of the doubt. To be clear, I am bullish on duct sealing. Having commissioned some projects and conducted duct testing and trying to recover capacity by other means, sealing ductwork has become a way of life. Our specifications call for, absent more stringent requirements, Seal Class A, Leakage Class 3 and any leakage audible or sensible to the hand must be sealed regardless.

If you can hear it or feel it, you seal it regardless of other criteria which may be met.

How on earth would more leaks which are beyond your control benefit you?

Say you have a fan system running at 600 RPM and moving 1,000 CFM but you have 10% leakage. Now for all that effort you have 900 CFM being deliverable to the rooms.

Say too that this system working at 1" static pressure, takes 0.30 brake HP or 225 Watts and is 50% efficient.

Say you have a room that requires that missing 100 CFM- you speed up the fan, right? Sure. Speed up the fan 10% to 660 RPM to recover that missing airflow and all things being equal, your horsepower goes up by the cube. That last 100 CFM will cost you another 0.10 brake HP. Now you are running at 0.40 brake HP or about 298 Watts for that last ten percent.... will your boss pay the owner's additional electric bill for the life of the system?

Don't give me the "it is all inside the building" garbage. If the air is not delivered to your bedroom or office, that warm and fuzzy feeling of "it is still inside the building somewhere" gets lost on me somehow.

I think you are doing fine, Rankin. You see things as they are, ask great questions and build really mean beer coolers too.

jim lockard

oh

An Airtight properly sized duct system is the key. Who sized the duct work your hanging ? There is alot to a properly working duct system. Good luck J.Lockard

bigwilly104

jim s_2

Huh?

That`s like saying the veins in your arms will work better if you cut yourself.

terry_5

quote this

Early on,you learn not all owners know anything &all journeymen are not trained equal!Try to find the mentor on the job who is knowledgeable and also a go getter,stay away from the drunks.

PeterGriffin

I would have to assume the boss man himself sized it. I think he used the " do you have this sized duct in stock?? No? How about this size? Ok, that'll do" method.

I honestly don't know what he used to size it, maybe it's right, I can't say yes or no myself, it's a Tempstar 100k High Efficient for about 2200sq feet of office. It's an office built out in the woods for a power line company, so it's built somewhat like a house, but instead of people sleeping in bedrooms, they'll be sleeping in nice little offices.

PeterGriffin

Thanks



Thanks for stating EXACTLY what I was thinking. I do enjoy the experience of doing things "outside" my trade, but I'd really like to see them done right.

I was going to ask him if I should solder 90% of my joints in the school project we're working on to gain a little efficiency, but I'm not usually one to push buttons.

Speaking of beer coolers, I heard a very interesting plan at the wholesaler a few weeks ago from a plumber who was going to try to route some lines from the basement to his chair in the living room for beer. Sounded like a good idea, but the two flaws would be 20+ feet of warm beer, and still having to get up to find the washroom

PeterGriffin

That's the problem...getting a good one.

When I started my job with this guy I've gone through 4 guys. I swear it's not me!! One had a bit of a booze problem, he took a few 4 day weekends, then left. The next guy was a 3rd year with good plumbing experience, he had it out with the boss, and left. We had another "journeyman" since 1984, with no tools, a drinking problem, and certainly wasn't able to read blue prints. A labourer with NO experience, and NO mechanical ability.

Now we have a 55 year old plumber's helper and a 22 year old who until I told him differently on Friday, thought Natural Gas was a liquid. When I told him it was a gas, he asked " You mean Natural Gas is an Air??" I then explained the three states of matter...


/end rant for good

now back to real heating topics, sorry.

Plumdog_2

Please don't try this at home!

Off topic; but has to do with pumps, tubing, fluid dynamics, college, and other related issues.
I heard about a guy (back in the sixties) that rinsed out his windshield washer bottle on his Corvette; filled it with Margaritas, and plumbed the plastic tubes to coil up in the glovebox; amazingly this guy is still alive.

ralphtheplumber_3

I think

I think the key here might be that this duct is getting installed in a crawlspace. It used to be common practice (around here anyway) to drill a 1/2" hole in the trunk to bleed a little air and pressurize that space. Perhaps he believes a couple cfm leaking from each joint is equivalent.

Wait 'til you meet the guy with the unfinished basement who sealed every inch of his exposed ductwork, and then chopped a grille into the plenum.

tom_49

8x18

If your installing 8 x18 duct for a 100,000 btu furnace, may I suggest that you dont seal the ducts, instead, you should take a 14" round and run it out the side of your 2200 sq ft bldg. to get rid of the 50,000 extra btus you are producing.

Tony_23

Mastic

The other day I saw a duct system that had been "sealed" with mastic by one of those weatherization agencies that get tax dollars to operate. They did every seam and joint except the one between the furnace jacket and the filter box, including the open-to-basement 6" TO

Edward A. (Ed) Carey_3

Your question

"I'm a plumber apprentice, if you don't know already. I usually post up some stupid questions"

First of all, the person who asks question is a wise person, not stupid.

You will notice that in all of the responses no one ever said that your questions were stupid.

Think about that.

And my compliments to you, in the interim.

Ed Carey

P.S. after 36 years as a professional in the HVAC field, I'm still learning too.