Draft Test Port Install in Stove Pipe...

I have wanted to post this for some time and a forum member PM'd me asking about this so I figure since I now took the time to take the pictures I would go ahead and post it up for all to check out...

Over time now viewing many peoples draft tubing installs on this forum I have seen the good, the bad, and the ugly!!! I want to share with all of you here what I find to be the absolute cleanest and neatest install of tubing into a stove pipe for the purpose of measuring draft whether on a permanently installed basis or for just occasional testing/monitoring without leaving a nasty hole in your pipe or other...

For purpose of example I will use the setup on my Mag Stoker... This setup is a permanent type setup that is hard piped to a pair of Magnehelic gauges mounted next to/behind the stove, I prefer the ability to monitor draft at a glance at any given time due to the marginal chimney that it is vented into... So Here are some pics of it as some of you here have seen before: So I use these pics as an example of what one can expect from a "looks" standpoint if you use the parts I will list below... No high temp RTV sealant, no wondering how to secure the fitting in the pipe, just a system that works great and looks the part...

So, maybe you have no need or no interest in bending tubing or putting together some type of permanent tubing install and just want to be able to easily attach your manometer or draft gauge of sorts with a piece of vacuum hose or other for just a quick check of the draft but don't want to leave behind an unsightly hole in your stove pipe and don't want to worry about a fitting that leaks or if it's going to fall out of the pipe etc after you're finished...

Here are some pictures of the parts needed to put together a setup that lets you easily attach/check draft when you want to and a clean, finished look when you're not... Parts list:

1) 1/4" Tube Compression X 1/8" male NPT brass adapter fitting
2) 1/4" Brass Compression Cap
3) Length of 1/4" Steel Tubing (as long as you want it to be) I cut them at to 4" length
4) 1/8" NPSL Stainless Steel Locknut
5) 2 Stainless Steel Flat Washers 3/8"

Most all of these items can be had at any descent hardware store, however the NPSL locknut is in most cases not going to be found there, but can be had at a plumbing supply house or industrial supplier such as McMaster Carr etc...

Real simple, drill either a 11/32" or drill letter "R" hole in your stove pipe, tap the hole using an 1/8" taper pipe thread tap, put one of the two washers on the male NPT end of the adapter fitting, thread it into the hole you just tapped and snug it up (on real thin wall 24-26 gauge stove pipe don't crank it down too hard or you'll tear the threads out of it), then reach into the pipe and slip the remaining washer over the fitting and install the NPSL locknut and tighten it down... Now take your cut to length piece of 1/4" tubing (deburr both ends inside), slip the tubing nut and ferrule onto one end and insert it into the compression end of the fitting and tighten it up to set the ferrule, now you're all set to attach your manometer or gauge... When your done measuring draft just loosen the tubing nut and remove the "test tube" and install the compression cap on the adapter and just snug it up... So there you have it!!!

Looks awesome, thanks for the tip

Eric

Very nice job. Good photos and parts list too.

I use brake line for my connection at the stove pipe and find it gets restricted by fly ash. Not completely, but enough to lower the Magnehelic gauge reading. Perhaps its because my AHS boiler has a combustion blower. A simple blast of compressed air to the tubing cleans it. Perhaps an improvement to your setup would be a valve at the gauge isolating it and allowing a blast of air to clean the tubing run to the stovepipe.

Thanks Eric, no sweat!!!

Yanche, great idea there!!! I do have rubber flex hose between the hard piping that is mounted to the stove and the Magnehelic hard piping for that reason along with vibration isolation... I remove the rubber flex from the Magnehic side of things and give it a blast every now and again then just slip it back onto the tubing... And yes my fellow Mag Stoker operators, that is an extra electrical outlet added to the feed gear motor shaft removable access panel, I wanted one close by for my ash vac!!! If you want to add an outlet to your Mag just be cautious, there is no room for bolts/nuts behind that access panel, the cam arm and pusher fork are right there smacked up close to the backside of it... You will need to drill and tap holes in the panel to mount your box and cut off any excess bolt length that protrudes on the backside of the panel!!!

Very nice setup!! Neat job also!! Why the two draft meter's? One for pipe and one for the stove?

very good looking setup.
im having a hard time thinking you can tap a stove pipe, did I read it right?? your putting a nut on the back side (inside) of the pipe also??im guessing the special nut is one with a hole in it? sorry for all the questions but I think I want to add a perm gauge to my new setup.

theo wrote:Very nice setup!! Neat job also!! Why the two draft meter's? One for pipe and one for the stove?

Theo, the purpose of the dual gauge setup is to monitor the differential between the firebox and the stove pipe, ideally I want both gauges to have the same reading at all times, such as .04 firebox and .04 vent pipe... Lets say that daytime outside temp is mild and on the humid side I may find that now my readings are getting very low, like .02-.01, almost no draft, very close to becoming a positive pressure situation, instead of shutting down I can first try reducing combustion air by closing the restrictor plate some and perhaps my readings will come up to a level I'm more comfortable with, maybe .03, I'm cool with that...

BeerMonley wrote:very good looking setup.
im having a hard time thinking you can tap a stove pipe, did I read it right?? your putting a nut on the back side (inside) of the pipe also??im guessing the special nut is one with a hole in it? sorry for all the questions but I think I want to add a perm gauge to my new setup.

Beer, YES, you can tap stove pipe, LOL!!! At least 22gauge pipe you can... It is not all together necessary to tap the hole, but you would be surprised how much you can snug up the fitting in the tapped hole before it rips out your fresh threads!!! The "special nut" is exactly that, its special in that it is not a commonly found item on most peoples shelves, but outside of that it is just a nut like any other nut, only it will thread properly onto taper pipe thread... I have all the pieces listed in my original post, I buy them in bulk and keep them on hand, let me know if you wish to purchase them...

Same setup, I used a compression fitting and small piece of copper tubing, about 1-2' long. then to the rubber piece to the manometer. A piece of brake line with fitting works slick too, just cut on fitting off and hook your tubing to it.

If you look thru the Manometer Install Thread, there are a lot of good pics of many different ways to do it.

That sure is neat & purty! But ...........

Bad + ugly = CHEAP, QUICK, & EASY.

MURDOC1,

Great post! While waiting for my LL110K boiler to come in I thru this together some brass tubing I had laying around. I sleeved down a length of ¼” tubing to fit snugly over some medium size silicone fuel line tubing from the hobby shop. The manometer (2) I got from discount shop selling them shipped them with oil but no tubing.

Your right about finding the 1/8” NPSL locking nut. I went with the plain vanilla NPT nut.

Perfect draft setting with the computer fans running

Thanks for the post!

Dick

dh1200s wrote:MURDOC1,

Great post! While waiting for my LL110K boiler to come in I thru this together some brass tubing I had laying around. I sleeved down a length of ¼” tubing to fit snugly over some medium size silicone fuel line tubing from the hobby shop. The manometer (2) I got from discount shop selling them shipped them with oil but no tubing.

Your right about finding the 1/8” NPSL locking nut. I went with the plain vanilla NPT nut.

Perfect draft setting with the computer fans running

Thanks for the post!

Dick

Dick, looks great!!! That's the way to be my friend!!!

BeerMonley said ““your putting a nut on the back side (inside) of the pipe also??im guessing the special nut is one with a hole in it?””

Yep Murdoc1 setup/process is great! See pic of stove pipe I added to my TLC 2K today.

Wife said you’re going to hang that thermometer thingy on my wall

See second pic I’ll be using the compression cap after draft measurement. I’ll get her to maybe add a women’s touch to dress up the manometer wall mount down the road…………..Dick

thanks for this posting...didn`t go overboard....kinda just looked at it as a gadget....but it`s done and reading right...mounted it on my hopper with stainless machine screws with nylon washers and small rubber dampners in between hopper and gauge..complete set up with gauge and everything else was 45 bucks