Welcome! Here are some tips for using this forum.
gas lines to boiler and other appliances
I am a homeowner that has several questions regarding natural gas piping in general and a few specific. First of all we have CSST piping. It would appear that we have 1/2 inch coming up through the wall to the main shut off for the gas. We have an outside regulator. After the shut off there are fittings and a black iron elbow that is fairly large with fittings that goes directly into a 5 PSI regulator -- then almost immediately another black iron elbow -- off of that there is a 3/4 inch CSST pipe that goes directly into the boiler . There is also a T off of that black iron fitting that goes directly into a manifold. Off the manifold are 1/2 inch CSST supplies to a Fireplace probably 30 feet away 35,000 BTU, gas cooktop (which I abandoned) and a 40 gallon hot water heater which has been replaced by a Rinnai tankless which is 180,000 BTUs -- they did not change out the CSST pipling -- still 1/2 inch. In the Rinnai book it says it should be 3/4 inch but they are saying that 1/2 is okay.
Originally I had a 3 psi regulator and found out after they installed the tankless system it was undersized. They came back and put in a 5 psi regulator The regulator is big enough I think on the outlet side for all the attached appliances at full load. I am just concerned now about the pipe sizing that was used by both the builder and the installer of the tankless system.
I do not really understand any of this but I was told that
1. You cannot go from a 1/2 inch line o a 3/4 inch line -- is that true? The 3/4 inch CSST pipe feeds an 80,000 BTU boiler which is about 10 feet away from the PSI regulator.
2 The book for the tankless heater says a 3/4 line is needed -- can it run on 1/2 line. It seems to be working (producing hot water) but I am not sure if it will start to malfunction . It is also about 10 feet away from the PSI regulator. The top capacity is 180,000 BTUs
3. Also I was told that at least 10 inches of straight pipe needs to be on either side of the psi regulator before the elbow. Every single picture of the installation of a regulator I saw on the internet did have straight pipe. I am being told by the builder that it is not true or necessary.
From the outside regulator to where all this stuff sits (up on the second floor) is a fairly long way up. I have no idea how much CSST there is or how it run because it is behind walls. I would think that as a rough estimate maybe it is 60 feet away from the outside service.
There are absolutely NO inspections by the utility company, by the county or any other agency. If the plumber does not do the proper job you have no way of knowing except by researching and hopefully nice people in the know respond.
I am very concerned that this was not done correctly. I just need some idea of what the implications might be.
The boiler -- a high efficiency boiler called a Munchkin is what we have. Again 80,000 BTUs
All seems to be working but I am concered that there could be potential problems.
Any help would be so very very much appreciated. Just remember to not use super technical terms as I would not understand it. I am still trying to understand the difference between Water Column and PSI!
Thanks again -- I have attached a picture of the lines. Hope this helps. On the right is the line with the shut off. The line all the way to the left is the line that goes to the boiler. The three down the middle -- one goes to the fireplace. One was actually disconnected (it is still shown connected in this picture) and the 3rd one goes to the Rinnai. Again those 2 are 1/2 inch CSST and the line coming up is 1/2 inch.