I can tell you that you could fry the circuit board if you try to run less than needed gas on a Navian TWH.
Professional Tankless installation
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Jeff Handy
Pro Handyman, NOT A Pro Plumber
The project you are planning is nothing like just changing your car tires.
I feel sorry for your neighbors if your house explodes or burns, taking their houses with it.
Do you know if you even have enough gas pressure coming from the meter?
I feel sorry for your neighbors if your house explodes or burns, taking their houses with it.
Do you know if you even have enough gas pressure coming from the meter?
Why should we continue to try and offer advice when you do not listen and refuse to heed warnings. You are in over your head and obviously cannot figure it out yourself. A dangerous combination when a mistake could have devastating consequences. Have fun “changing your tires”, but get your advice elsewhere im done trying to help.
You will not get any viable advise for gas on this forum. Some things need to be left to professionals. Would you ask your doctor advise on performing your own open heart surgery?
ok thanks I will make sure I have enough gas supply first
I will not start anything until everything is clear to me. Trying to get it safety done.
My gas meter says 5 psi. 1in pipe
I am only going to run furnace ( 40,000 BTU) and New tankless (199,000 BTU) , so that high pressure and pipe size. I assume it will be enough gas supply ?
I came here to look for help. I did listen and trying to learn from you nice guys here.
The venting part I already took the advice and will use PVC. now looking for a way to seal the existing vent with my 2 or 3 " pvc pipes , after that venting part should be good
Still not sure about the gas.
you win, if you compare this to a heart surgery
not sure what we can say or can not say here. again my questions are all just common sense. no one should take any responsibilities except myself.
Will a 12in run 1/2in pipe have too sufficient pressure drop and affect tankless system to have problem?
Jeff Handy
Pro Handyman, NOT A Pro Plumber
Having 5 psi doesn't say anything. You need a manometer test to verify sufficient volume for the TWH.
the meter says 250 CFH, I assume 250k BTU? should barely make it with furnace ( 40,000 BTU) and New tankless (199,000 BTU) when running all full capacity ?
CFH is cubic feet per hour MAXIMUM. Whether you have the maximum coming from your lines can only be measured by using a Manometer. BTU is British Thermal Units, which is a measurement of applied heat. Similar to candlepower given off on a lightbulb. Apples and oranges.
ok, I should have said BTUH (btu per hour). now cfh should be more inline with btuh. From my understanding, the regulator(meter) can supply maximum of 250 CFH (approx 250k btuh). btuh - btu's lost in one hour.
can we find out by calculation or expenience instead of using Manometer? I don't want to touch the gas line (using Manometer) Yet as everyone here seems recommended.
can we find out by calculation or expenience instead of using Manometer? I don't want to touch the gas line (using Manometer) Yet as everyone here seems recommended.
Trying to simplify what is going on, my Cadillac has a speedo that goes to 160 mph. Will it hit 160 mph? Hell no. Your meter says it's capable of pushing 250CFM's. Will it? One 90• elbow will reduce it drastically. One 1/2" pipe will also reduce your flow drastically.
A manometer you can consider as similar as putting your car on a dyno. It will confirm whether you have the power necessary to drive 160 mph. Does this make sense to you?
A manometer you can consider as similar as putting your car on a dyno. It will confirm whether you have the power necessary to drive 160 mph. Does this make sense to you?
Jeff Handy
Pro Handyman, NOT A Pro Plumber
This poster is either a troll just pulling our legs, or someone dead set on blowing up their house by not hiring a pro as they should.
IMHO.
IMHO.
again, I am not doing anything yet until I am completely sure its safe
I don't believe you need an engineer degree to install a simply use tankless heater. It just I am not as handy as you guys but still want some help
Jeff Handy
Pro Handyman, NOT A Pro Plumber
The project you are proposing is complex, and not really safe for an amateur, that is my point.
so I was checking the current old water tank says
Gas pressure - Manifold 4.0 w.c.
Inlet supply - Max 14.0 w.c.
Min 5.0 w.c.
And the new Tankless requirement is
Manifold - 3.9 w.c.
Inlet Gas Pressure Max - 10.5 w.c.
Inlet Gas Pressure Min - 4.0 w.c.
sounds like the current set up can already supply enough pressure as old water tank has higher demand of gas pressure. Correct ?
Would another option be installing a pressure garage after the valve to check and even monitor incoming pressure to the tankless?
Gas pressure - Manifold 4.0 w.c.
Inlet supply - Max 14.0 w.c.
Min 5.0 w.c.
And the new Tankless requirement is
Manifold - 3.9 w.c.
Inlet Gas Pressure Max - 10.5 w.c.
Inlet Gas Pressure Min - 4.0 w.c.
sounds like the current set up can already supply enough pressure as old water tank has higher demand of gas pressure. Correct ?
Would another option be installing a pressure garage after the valve to check and even monitor incoming pressure to the tankless?
Mitchell-DIY-Guy
Well-Known Member
Those are not the requirements, those are the maximums. Big difference.
Your tankless in question burns at a rate of 199,000 BTU/Hr. BTW, that is as large as a tankless gets; anything larger than that is called a boiler.
Your existing water heater in all likelihood burns at a rate of 40,000 BTU/Hr.
So, do the math: the new tankless at full burn (which you MUST plan for) burns FIVE TIMES as much gas as your older tank style water heater.
This you must plan for; not only for the specific tankless in question, but also to ensure you don't shortchange the other gas appliances in your home.
The only way to do this is to have a gas specialist with the proper tools take the measurements. This is what everyone has been telling you here.
In my old neighborhood (homes built 1992), when a few people switched from identically-specified units such as you are proposing, not only did the gas company have to change the line from the street to the home, but they had to change the meter, and the size of the gas line going into the home. I didn't go into these homes but assumed there was some other piping work (all in black iron) inside the home to make these accommodations. It wasn't cheap, wasn't easy, and was costly.
Now, here in NC, a new home (built 2019), we have a hybrid gas system with a higher PSI coming into the home. We have a manifold that has a 2 PSI side and a 1 PSI side, and most of the gas lines are ½" soft copper. The higher capacity appliances are fed off the 2 PSI side, while the smaller appliances are fed off the 1 PSI side. This hybrid system is relatively new and like it or not (I do not, but that's just me) allows for caddywampus gas lines running at wackadoodle angles all over the place, but being able to feed large capacity appliances with a ½" or similar copper line and NO JOINTS. Yes, we have a straight run of continuous pipe from the manifold in the crawl space up around floor joists to a wall, up two floors to the attic, and finally to the furnace in the attic. (Don't even get me started on this southern tradition of furnaces and water heaters in attics...)
It is possible that this higher pressure may be available to you and you could get by with smaller piping. But you can't do this; a licensed gas fitter must work with the gas company on this, and it needs to be permitted work. No sane gas fitter would risk his hard-earned license by doing unpermitted work...
Your tankless in question burns at a rate of 199,000 BTU/Hr. BTW, that is as large as a tankless gets; anything larger than that is called a boiler.
Your existing water heater in all likelihood burns at a rate of 40,000 BTU/Hr.
So, do the math: the new tankless at full burn (which you MUST plan for) burns FIVE TIMES as much gas as your older tank style water heater.
This you must plan for; not only for the specific tankless in question, but also to ensure you don't shortchange the other gas appliances in your home.
The only way to do this is to have a gas specialist with the proper tools take the measurements. This is what everyone has been telling you here.
In my old neighborhood (homes built 1992), when a few people switched from identically-specified units such as you are proposing, not only did the gas company have to change the line from the street to the home, but they had to change the meter, and the size of the gas line going into the home. I didn't go into these homes but assumed there was some other piping work (all in black iron) inside the home to make these accommodations. It wasn't cheap, wasn't easy, and was costly.
Now, here in NC, a new home (built 2019), we have a hybrid gas system with a higher PSI coming into the home. We have a manifold that has a 2 PSI side and a 1 PSI side, and most of the gas lines are ½" soft copper. The higher capacity appliances are fed off the 2 PSI side, while the smaller appliances are fed off the 1 PSI side. This hybrid system is relatively new and like it or not (I do not, but that's just me) allows for caddywampus gas lines running at wackadoodle angles all over the place, but being able to feed large capacity appliances with a ½" or similar copper line and NO JOINTS. Yes, we have a straight run of continuous pipe from the manifold in the crawl space up around floor joists to a wall, up two floors to the attic, and finally to the furnace in the attic. (Don't even get me started on this southern tradition of furnaces and water heaters in attics...)
It is possible that this higher pressure may be available to you and you could get by with smaller piping. But you can't do this; a licensed gas fitter must work with the gas company on this, and it needs to be permitted work. No sane gas fitter would risk his hard-earned license by doing unpermitted work...
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