Hi There ... I'm going to be removing a rat's nest of gas piping left behind by previous homeowners in the crawlspace and replacing it with Pro-Flex Black CSST and I'm having a difficult time determining a trunk line calculation ( using the branch method for design ). Hoping someone here can shed some light on this.
As you can see from the attached image, my tankless rises straight out of a 3/4" meter tee ( street tee from meter ). It would be easy to simply remove all of the piping mess from under the house back to that tee, then give it a spin so that it is oriented toward the crawlspace, attach a 24" x 3/4 pipe in order to move into crawlspace ( strapped to joist here and used to bond CSST to ground system ) then transition from the 3/4" NPT to 3/4" CSST all the way to the cooktop branch CSST tee, leaving out the tee for future potential fireplace on the way ( 3/4 x 3/4 x 1/2 & capping off the 3/4 extra outlet for potential future BBQ here ), then continuing on with 1/2" CSST all the way to the dryer oxbox.
Where I run into a problem with this fairly simple approach is that according to my load of 209,000 BTUs, charts state that I am required to have a 1" trunk line until the Tankless drops out of the equation. And here is where I need clarification from an expert.
Since the tankless rises straight out of my meter, I believe the only "trunk" line is the meter side of the tee. The tankless side of the tee is then Branch 1 and only requires 3/4" .Then, with the tankless btus out of the equation the last side of the tee going into the crawlspace would also only be required to be 3/4". Would I really be required to have the meter side of the tee be 1"?
If it is required to be 1 inch, I am not sure how I would go about making that happen in regards to fittings. I've put together a drawing with my best guess of how to achieve it and it would of course make for a much bigger job as I'd have to resize things in the rise to the tankless, which is why I'd probably go ahead with the other extra tee work that is in my drawing but that I left out in the more simple version above.
Ugh ... heh ... anyway, any clarification or advice would be greatly appreciated ;-)
Okay, well, I guess I'm going to be conversing with myself here, so, I've decided to just play it safe and do the following:
1. Remove all gas piping back to the meter union ( of course being careful not to lose the important union bits ).
2. Disengage the pipe section to the tankless via the union and put aside.
3. Insert the shortest 3/4 nipple allowed into meter union and tighten ( I believe close nipples are disallowed due to inspectors not being able tell how well they are threaded ) so that I have a thread to work from.
4. Install a 3/4 x 3/4 x 1 bullhead tee oriented toward crawlspace opening.
5. Reinstall the tankless pipe section to the top of bullhead and tighten.
6. With the bullhead properly oriented insert entire pre-assembled section back in place and tighten meter and tankless unions.
7. Install a 1" x 16" nipple to the bullhead branch and strap to top of crawlspace opening.
8. Attach 1" Female CSST adapter to 1" MIP Nipple and commence CSST design in crawlspace with a clear conscience that I've got a 1" trunk line and I'm good to go on future meter switch if needed ... including having to move the meter so it isn't directly below the tankless and has its proper top clearance.
Still eager for any input should anyone have any regarding any flaws in any of these plans~
We recently removed a counter-top peninsula which had baseboard heat on the backside. I have moved the location of the baseboard to the opposite end of the kitchen, which made more sense to me anyways as it is colder on the exterior wall side. I tied back into the original location where the baseboard tied back into the main monoflow 1" pipe that feeds the entire system. I have added approximately 25-30ft of pipe with supply and return of the baseboard. I installed a baseboard elbow with vent/bleeder that I am not getting any air out of anymore, only cold water.
Any help/suggestions would be greatly appreciated.
Background:
Navien 240 combi boiler with 2 zones; main floor and basement. Taco circulator for each zone. Expansion tank with 4900 series Taco air separator.
I have kind of a strange situation and I'm hoping some of you have some ideas. I have an outdoor wood boiler which runs heated water through pex tubing in to my basement. The pex tubing runs through a 4" schedule 40 PVC conduit buried 2-3' underground. I noticed this spring that there was water in the conduit (not leaking from the pex tubing, but seeping in from the ground). I had the pipe partially replaced this summer and maddeningly enough I still have water in the conduit. I have an idea of the general vicinity where the leak likely lives as part of the pipe passes through a pretty boggy area in the yard. I have now uncovered all of the joints in the boggy area and am prepared to cut the pipe and apply a boot. However, it is not obvious to me where the bad joint is (none of them appear abnormal grossly). I've capped 1 end and mostly capped the other end and tried to pressurize the pipe with a shop vac +/- air compressor but I'm not sure that I'm getting enough pressure to actually see bubbles (I filled up the holes with water to try to see any bubbles better). At 1 point tonight I thought sure I saw bubbles near one of the joints but it was not a repeatable phenomenon. I just want to make sure I'm addressing the problem and not potentially cutting through good pipe and ignoring the actual problem in the next joint. Any ideas? I understand this is a weird setup and my explanation might be confusing - let me know what questions you have. Thanks so much for any help or ideas you have!
06-25-21, 03:27 PM
