Plumbing Forum - Professional & DIY Plumbing Forum > General Plumbing Discussion > Water Heaters and Softeners > Determining if current gas line is sufficient to run Tankless Water Heater



Reply
 
Thread Tools Display Modes
Old 04-04-2014, 03:58 PM   #1
clarehills
Junior Member
 
Join Date: Jul 2013
Posts: 6
Liked 1 Times on 1 Posts

Default Determining if current gas line is sufficient to run Tankless Water Heater

Hi, I intend to install a Rennai Tankless Water Heater on the outside of my house. There is an existing gas outlet at the location that was probably put there to run a barbecue. It is a 3/4 inch line. How do I determine if the outlet has sufficient flow to run the water heater? Is there test/device I can use?
The heater requires 199,000 BTU
Thanks,
Clarehills



__________________
clarehills is offline  
 
Reply With Quote Quick reply to this message
Old 04-04-2014, 10:16 PM   #2
Caduceus
Senior Member
 
Caduceus's Avatar
 
Join Date: Apr 2011
Location: Pittsburgh, PA
Posts: 970
Liked 227 Times on 159 Posts
Likes Given: 123

Default

There's more to it than just using a device. First question is if it's natural gas or propane? You would need to know the total gas use of all gas appliances in your home (BTUs). You would then need to know the total length of all piping from the meter to the furthest appliance.
Then a manometer or gauge needs to be safely connected to test the pressure, measured in water column.
A pipe sizing chart is then used to determine what sizes the piping needs to be throughout the system.
Adding a 199,000 BTU appliance to an undersized piping arrangement could starve the tankless unit or another appliance of the needed gas to operate normally.
Natural gas is a safe energy source when installed and tested by a trained professional, but I'm reluctant to give any more advice than I have due to the risk of a little mistake or oversight turning into a dangerous situation.

__________________
Caduceus is offline  
 
Reply With Quote Quick reply to this message
Old 04-05-2014, 06:30 PM   #3
clarehills
Junior Member
 
Join Date: Jul 2013
Posts: 6
Liked 1 Times on 1 Posts

Default

Caduceus!
Thanks very much for the reply! That is very helpful.
It is natural gas.
I can gather the pipe dimensions, lengths and junctions and the BTU needs of the other appliances.
It seems the best thing to do after that is hire a plumber to bring the manometer and make a recommendation on how to proceed.
This is a medium term (and part of a much bigger) project so I will post back as soon as the project moves along with an update
Thanks again,,
Clarehills

__________________
clarehills is offline  
 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Under Counter Tankless DV Water Heater savvydog Water Heaters and Softeners 3 01-21-2014 06:50 PM
determining the cause of hot water issue evolve General Plumbing Help 5 01-03-2014 11:08 PM
Bad tankless water heater pianofritz Water Heaters and Softeners 2 09-02-2013 01:47 PM
Tankless Water heater rgf Water Heaters and Softeners 19 08-11-2012 05:52 PM

Newest Threads

LATEST SPONSOR DEALS