Sizing NG Usage For Tankless WH - Plumbing - DIY Home Improvement | DIYChatroom
Advertisement


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Plumbing

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread
Display Modes
Old 12-28-2015, 09:46 PM   #1
Member
 
Join Date: Feb 2014
Posts: 168
Rewards Points: 145
Default

Sizing NG Usage for Tankless WH


I was looking in to tankless hot water heaters and my current NG supply lines. I have a 250 CFH regulator with 1.5" pipe feeding a 196K BTU steam boiler and a 3/4" line going to my existing hot water heater and Pro range.

Do I need to size my NG supply for everything running at once? I would need:

196k Boiler
199k Tankless WH
100k Range (4x 18k burners, 25k oven)

That's almost 500k BTU or 488 CPH. Are people really getting the gas company to come out and install new regulators? Seems like a lot of $$ when I could just swap out the hot water heater for $500.

Thanks.
kjmass1 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 12-29-2015, 08:17 AM   #2
Member
 
Join Date: Sep 2012
Posts: 416
Rewards Points: 767
Default


Back in 08 when i went back to the field for a year people were paying 700 for the gas upgrade. then add the cost of the tankless install and they were over 2 grand. The tankless was all the craze back then and people were getting rebates on there bills by switching to the tankless. I hate the things and would never install one unless i had a big jacuzzi tub or just didn't have the space for the power vent.
ct18 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 12-29-2015, 09:40 AM   #3
Member
 
Join Date: Feb 2014
Posts: 168
Rewards Points: 145
Default


Quote:
Originally Posted by ct18 View Post
Back in 08 when i went back to the field for a year people were paying 700 for the gas upgrade. then add the cost of the tankless install and they were over 2 grand. The tankless was all the craze back then and people were getting rebates on there bills by switching to the tankless. I hate the things and would never install one unless i had a big jacuzzi tub or just didn't have the space for the power vent.
Thanks, that's good to know. Seems like the breakeven point is pretty high.

My gas bill is $30/mo in the non-heating months. It's going to take a while to recoup $$ no matter how efficient it is.
kjmass1 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 12-29-2015, 11:29 AM   #4
Master General ReEngineer
 
Bondo's Avatar
 
Join Date: Dec 2007
Location: Greenfield Maine
Posts: 9,473
Rewards Points: 1,056
Default


Ayuh,.... What are the odds of the boiler runnin', 'n the tankless heater runnin', 'n havin' every single burner, 'n oven in yer range runnin',....
ALL at the same time,.....

If ya wanta go tankless, just hook it up at the line ya got now for the water heater,....

It might make more sense to run a branch circuit off yer existin' boiler to a DHW exchanger,....
Bondo is offline   Reply With Quote
Old 12-29-2015, 05:45 PM   #5
Member
 
Join Date: Dec 2015
Posts: 99
Rewards Points: 114
Default


Quote:
Originally Posted by kjmass1 View Post

Do I need to size my NG supply for everything running at once?
Yes. The meter and supply lines must be sized for everything running at one time. You may not get proper combustion if your appliances are being starved of fuel.

Another option is to go with a combi condensing boiler. Getting 85-95% efficient heat will save you a lot more money then 85-95% efficient hot water and loosing the minor standby loss on the tank. That of course would entail ditching your steam system.
2x_Tom is offline   Reply With Quote
Old 12-29-2015, 07:03 PM   #6
Member
 
Join Date: Feb 2014
Posts: 168
Rewards Points: 145
Default


Yeah I don't think I want to lose my one pipe steam system.

Ever heard of a Phoenix hot water heater? It's like 97% efficient tank HWH but expensive- about $2k plus install.

From researching a bit more I have some hesitation going to tankless. Cost, yearly warranty maintenance and long ROI are concerns. Thanks for the input.
kjmass1 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Painting over wallpaper sizing MsKitty32 Interior Decorating 3 07-14-2015 11:17 AM
Clarification on cam-lock usage for private residential applications spowell71 Electrical 3 01-29-2013 01:35 AM
Sizing a dual shut off valve for a water line to fridge ericman Plumbing 10 08-19-2011 09:47 PM
help for gas usage Amy28 HVAC 1 04-27-2011 04:39 AM




Top of Page | View New Posts