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ok i bought a duel port manometer it has little info on how to properly use it. i noticed when i hooked it  up for checking gas valve on positive hose i got a reading of 3.2 and on negitive side i got a reading of 3.4. so whats the actual reading t or -. whats the right way for hooking up hoses to check other things like venter motors and pressure switches and hrv's its a tpi 621 please help still stuck in old school ways.

Hook up gas pressures to the positive side.  Anything that would blow out of the port, like when you open a gas valve, gas comes out,  goes to the positive side. Anything that would suck in, like on the negative or upwind side of an inducer motor would be on the negative side.  So, when you hook up the negative side to an inducer motor and get your reading, look at the pressure switch and see what the rating is that is usually stamped on it.  I did one yesterday with the pressure switch rated at .55" w.c., but the inducer motor was only pulling .22" w.c., and it was not enough to make the pressure switch.  Some pressure switchs(usually on high efficeint/direct vent) measure the pressure difference between the combustion air and the inducer motor, so you hook the negative port on the manometer to the inducer and the positive to the combustion air collecter using two tubes.  Read the diffference and compare it to the rating on the pressure switch.  On an HRV, hook your positive and negative hoses to one of the balancing collars, and then do the same on the other balancing collar.  Compare the two measurements and then adjust the dampers accordingly so that they balance out.  I usually try to make the air coming into the building about .01 or .02" w.c. more than the air exiting the building, just to lessen the chance of the building pulling negative.

You should get a few accessories from TPi for your manometer.

#A776: 2 Static tips, to measure static pressure.
#A605: 1/4" brass tee, so you can read venting systems that have a tee'd pressure switch connection.  
#A617: Extra tubing.

http://www.testproductsintl.com/

many thanks for your reply.now i'm understanding and yes i got all the accessories with the 621 need to get my combustion analyzer back its being calibrated. tssa wants us to now put a 636 tee with abushing and plug on all new furnaces so we dont drill out a hole in the venting stack. they say it might develope a hairline crack when we drill a hole every new start up has to have a combustion test done on it

Do you know if TSSA has released a Directors Order yet to enforce this?  Currently there is no code or regulation that I can find requiring this.  Only a few on demand systems require flue gas analysis to complete a startup.  I've yet to find a furnace manufacturers installation manual that requires this.

I had been drilling a hole into the exhaust vent at the furnace, and plugging it with a plug from TPI, but I would be more comfortable doing it the way you've described.

a company i sub for just got told about the tee and plug.on their tssa inspection they had the guy from tssa said we had to start putting the tees in and doing a combustion check on every new install because they are now checking everyones records for the combustion test. i was at the local whole sale shop and they just got in the tees with the plugs 15bucks each. apparently the tssa guy said its in the install books for the hot water tanks. i guess we should have read the install manual but who does when they been installing them the same way for 100yrs lol. the hot water tanks are rentals from direct energy so should they have not supplied the tees??. as guys were coming in to get hvac supplies i asked them if they knew about the tee but it seems no one knew. so are they inforcing the tee??? i'd start putting them in save the hassel later of going back are they inforcing the combustion test?// due dilligents i guess better safe then sorry.
??

oh yea one more note. the tee is 636 so gey glue the bushing is cpvc so multi purpose glue and the plug has teflon on it. i think the reason your not finding any furnace manufacture saying we have to install the tee is because they are made in the states. and in the states you can install a furnace in a tree house if you want with a garden hose for the gas line. no just kidding

^ lol good example of the states.

I havent used the tees or the plugs yet. I had been drilling holes.
Anyhow...is there a picture of a web link for these plugs and tees?

IPEX sells a testing plug and bushing kit that can be installed and used as a test port for a flue gas analyser.  You will have to install a tee in the exhaust vent to accomodate the testing plug and bushing kit.

I think all manufacturers should start incorporating this into their design.  When you install a furnace it would also be a good time to install this tee, plug and bushing.  It would make future testing much easier.

The TSSA may soon make this a mandatory requirement.

Download the IPEX Testing Plug & Bushing document - Here

Throughout the course I've heard over and over how we're not allowed to drill into the 636 in any way, and need to install this proper Tee to do combustion testing. With the company I've been working for, we've been slapping out furnaces left and right and haven't been bothered about any need to install a Tee.  Many of our installs are oil to gas conversions with new meter installs that do get need to be inspected. Is this Tee and combustion testing needed, or is it an up and coming requirement?
I have yet to work with anyone who's ever took out combustion testing equipment on anything gas. Oil yes, but never seen it on gas... During the gas course, I've heard over and over how everything is supposed to be combustion tested. Is there something I'm missing?

There is no Code or Regulation that requires mandatory flue gas analysis of natural gas appliances.  If the appliance installation manual required it, the test would have to be performed.  Also Clause 4.25.1 and Annex M require that certain natural draft boilers be tested for CO, but that's not really flue gas analysis.

The only natural gas appliance I've ever seen that required flue gas analysis before activation was a Baxi boiler.

the tees are not mandatory. but are nice if you do a combustion test. no need to go outside and stick probe in vent pipe. I did hear that one company could not use them on their carrier furnaces they caused to much turbulence.

Quote from: Admin on December 20, 2009, 01:00:05 PM

I had been drilling a hole into the exhaust vent at the furnace, and plugging it with a plug from TPI, but I would be more comfortable doing it the way you've described.

Are we allowed to drill in to ABS / PC for testing purposes anymore?  I've heard conflicting answers before and want to set the record straight.

There are no written guidelines that I'm aware of, but I did hear the TSSA does not want us to drill and plug the venting.  If you do that it's best to install a coupling and remove the drilled area.  Most furnace models now have a plug somewhere that can be removed to take a flue sample closer to the ventor motor.

Quote from: Admin on October 27, 2016, 11:20:14 AM
There are no written guidelines that I'm aware of, but I did hear the TSSA does not want us to drill and plug the venting.  If you do that it's best to install a coupling and remove the drilled area.  Most furnace models now have a plug somewhere that can be removed to take a flue sample closer to the ventor motor.

I currently try to find a spot near the vent motor or transition piece.  But some models just don't give you anything.  I would want to avoid having to pop in a coupling every time, and what about ABS,  as long as I'm not repairing the ABS I can add in a 636 PVC coupling?

As far as I know you can add 636 to an ABS termination.  Sometimes you have to cut ABS venting to change a part like a venter motor in which case you can simply use another ABS coupling to reconnect the venting.

See question 16 here,

http://www.hvactechgroup.com/files/ULCS636.pdf

You can also add a 636 fitting to an existing ABS system,

See Directors Advisory FS-101-07-R1, page 2 - Minor Venting Alterations here,

http://www.hvactechgroup.com/files/order/fs10107r1.pdf

In your case you could use a 636 or ABS coupling.

Great thanks do the info.  So there isn't any regulations against drilling in to the venting, it's just frowned upon by 4th TSSA.  What can I plug the hole with, high temp silicone? Or do I have to use a special plug ?

http://www.centurytool.net/Combustion_Enviromental_Analyzers_s/41167.htm

It's weird it doesn't seem like TPi sells these threaded plugs anymore and there may be a reason for that.

Ok thanks,  wonder why the 100 pack is more expensive than the 10 pack.