resealing analyzer probe holes in vent

Apr

hi all, regarding boilers and furnaces, what is the best way to seal ( and have future access to ) 5/16 analyzer probes holes in sheetmetal and plastic vent pipes. Thanks.

Brad White

I have seen

Over-sized stainless steel pan-head sheet metal screws in galvanized and for larger holes, those chrome snap-in caps with tabs. There must be a name for them! The kind electricians sometimes use to plug knock-outs.



For PVC? No idea.



Too often I see aluminum tape but have my doubts long-term. But it seems to stand up but am not suggesting it.

Tim McElwain

For any of the metals

a sheet metal screw preferably stainless steel with some high temp RTV sealant (600 degrees)



On PVC/CPVC if acceptable to your local AHJ (authority having jurisdiction) a stainless steel bolt I am not sure of the size I have all that at my training center. Pre-tap a coupling or an elbow and screw the bolt into the elbow to make a thread. Then glue all you pipe together, carefully drill a hole just slightly smaller than the bolt and use the bolt to tap through the existing thread on your elbow. Then pull it out and put some RTV sealant 400 degrees or less and you are done.



Make one up and show it to the AHJ and see what they say.



Many of your direct vent concentric now come with pre-fab test points from the manufacturer.



When I get down to the center I will get you the part numbers on the bolt. 

Jean-David Beyer

Aluminum tape.

"Too often I see aluminum tape but have my doubts long-term. But it seems to stand up but am not suggesting it."



I am not qualified to recommend or dis-recommend anything. But if one gets one's furnace or boiler serviced every year, why should "long-term" even enter the picture?

Brad White

Defined

I do not consider aluminum tape to be temporary, yet I see it apparently holding up and replaced after each servicing. The temperature specs just do not hold up to the service, not by a long-shot, so I cannot recommend it.



I like Tim's high temperature silicone tip, with the screw. Metal, not paper with some unknown adhesive

Ron Jr._3

I use a drill bit

that is perfectly sized for a hot water coil bolt ( got tons of them ) . It's so close you can actually screw the bolt in for a tight fit . But if it's natural draft I wouldn't worry too much about sealing too tight around such a small hole .

clammy

Same as ron jr

I do the same thing for oil stuff as ron and for mod cons i use nylon 3/8 bolts for the plastics vent systems . i like using the nylon instead of a steel 3/8 bolt on plastic vent systems .I also have used stainless steell bolts on oil flues but i usually don't have them sitting on the truck most of the time.Either way i am not a big fan of the aliumiun tape over the hole looks kinda haky.Peace and good luck clammy

Big Ed_4

Recommend

On a natural draft hide the hole in the back of the smoke pipe ... Saves you on a concern phone call ...

Paul Fredricks_3

.

I agree. Remember (and I tell customers this too) that the test hole is much smaller than the 6" hole that the draft regulator makes in the pipe. If that doesn't have to be sealed, neither does the test hole.



Positive pressure, direct vent, is another issue. I like the plastic screw idea for PVC, and I have used the large sheetmetal type screw on metal pipe.

Jr_12

PVC

For PVC I use 5/16" PVC hex bolts. Got them from Mcmaster-Carr.

hot_rod

A stainless steel hose clamp

will cover a hole up to about 1/2" in diameter. You can join multiple clamps to build a large diameter one, if you do not have a large size.



Or the band from a Mission cast iron no-hub coupling for larger holes, use the smooth bands not the ribbed ones.



hr

Glenn Harrison_2

Plugs available from McMaster

www.mcmaster.com



for 5/16" hole, nickel plated steel snap in hole plug- part number 9563K83



for PVC, drill 5/16"hole, and tap with 1/8" pipe tap, then use part number 48335K151



Both are easily reusable over and over again.

MikeyB

Plugs

Glen, do you have another part # for the PVC plugs, that number is too long, thanks

Glenn Harrison_2

Number worked for me

That number worked for me.



However, here is a direct link:



http://www.mcmaster.com/#48335k151/=bcznl3

MikeyB

Plugs

Got it, thanks Glenn, I love that site, buy from them all the time