Sizing gas piping for a Rinnai tankless heater

[@jlkearl]

Mike, thanks for taking a phone call and providing further insight into better understanding the sizing of my gas line. I'm no pro but I like to do my due diligence and gain as much knowledge as I can before I have the professionals stop by to do their thing. Greatly appreciated!

[@abhinavgaur13]

Mike advised me a third time over phone when I had a question regarding gas pipe sizing for my Rinnai .. It was very detailed and informative. Thanks Mike.. You are among the few popular youtubers who walk the talk of helping out their subscribers.. Much appreciated !! :)

[@djryan8944]

Mike advised me over the phone too and fixed my issue. He could charge for his solid expertise.

[@PaulCTownsend]

Well said and great info thank you. We installed a 4 cylinder 1300cc generator that adds another hiccup in this deal. We had to step up to the commercial meter with a 1-in pipe to run that generator.

[@MrTictawk]

Great video, thank you for sharing your expertise. Much appreciated!!!

[@thenexthobby]

At about the 20-min mark you diagrammed something similar to what I have, 40ft of 3/4" from meter to water heater with a furnace in between. I think my meter is only 250K, not enough for the bigger tankless unless I don't use my furnace in winter.

[@TruthThatSetsFreeMinistries]

WOW!!! I just got off the phone speaking to Mike who SOLVED my tankless v75in water heater problem! It was a unique situation; my furnace and current water heater are intertwined and go/vent out through the same hole in the roof. I found out (confirmed my thinking) that I couldn't use the existing water heater area due to living in a 2 floor townhouse (Mike was sure to ask that - how many stories) and both units are located in a mudroom on first floor. This would require a new hole and capping off the furnace. The Lord had already suggested(gave me) to have the tankless installed in the upstairs laundry room. But after talking to Mike (I never told him what the Lord showed me) - he suggested the better place to install a tankless in a situation like this (2 floors, cant vent out the sides because houses are attached, furnace and water heater intertwined) is to install it in the 2nd floor laundry where less vent piping through the attic to the roofing is better! While creating a new hole is an expense, its a relief to know I won't be taken advantage of by now knowing the least expensive way of doing it before talking to a person doing the work. I thank the Lord for some people who can give advice without showing favoritism and partiality which is sin, but will just tell the truth - getting nothing in return for telling truth of what it is! Amen...

[@bkoz319]

oh lord.

[@sdgardner1954]

Mike I am looking at replacing my 40k BTU storage gas water heater with a Rinnai 199,000 BTU heater. My piping is 1" from the meter all the way to the water heater 66' from the meter. There is a 80,000 BTU Forced air furnace at the 52' mark of the line from the meter. Adding 8, 90 degree L's adds another 21' of loss. NFPA 54 answered my question, per the 3.0 in WC chart I can support a little more than 544K BTU/Hr. I only need about 280K BTU/Hr. so my existing pipe should be fine. Thanks for explaining where to find the chart.

[@markkinney1310]

The Uniform Plumbing Code and the International Residential Code do not prohibit the use of galvanized pipe for gas. But some local regulations make it illegal to use galvanized pipe. Due to such prohibitions, many homeowners and professional opt to use black iron pipe in natural gas installations.

[@plips71755]

Thanks for the information, just found you so haven’t had a chance to look at all the videos yet. Also thinking of building a new house and looking at tankless. It will need to be electric or propane as we have limited natural gas. Maybe you have addressed this, if so, just let me know where - but can you talk about electric tankless. Also what about putting in a my current small house where all the plumbing backs up to the same short wall - kitchen and the one bathroom. Hot water tank under the kitchen counter - was a short 50 but now due to insulation changes, is only a 30 gal when it was replaced which they failed to tell me - long story won’t bore with details. So I thought about a electric or if I have to a propane tankless. I have a 100 gal (??) or maybe it’s 100 lbs - not sure right now but it’s an upright tank about 5’ tall piped to my vented gas fireplace heater (opposite direction from the plumbing). Can I put the tankless in the attic (very limited space as it’s a little 5/12 or 6/12 roof). Or is a outside unit better. They are telling me they are going to have to tear up so much inside and it won’t fit they say under the counter which backs up to an outside wall to a deck and I don’t understand why? They are saying I have to give up a whole closet. It seems it would fit under the counter and vent to the outside with the gas line run over to it. I wish you were nearer to Virginia. I don’t know if you really know what you are talking about but you got me convinced that’s for sure. Some of these young guys coming out don’t give me much confidence. Besides the fireplace 32,000 btus I think- I don’t currently have any thing else on gas. Might put a grill at some point but I doubt it as I like hardwood charcoal. So the issue was to solve my running out of hot water - with the 30 gal tank - and I’m getting about a 5-6 minute shower and for us girls that’s just not enough time. I can’t get my long hair washed twice and conditioned in that time, much less legs and getting rid of the dry skin soaks and scrubs. Using a hose off the shower head as it is. I do have an old shower head been in 20 years but friends that have put these really efficient shower heads in, the wives hate them and they end up cleaning and putting the old one back in (if they kept them) so they have enough pressure and water to rinse their hair. I believe in energy conservation and don’t want or need 1/2 hour to hour long showers but I do want to be able to get good and wet to rinse well and to take the occasional nice hot 15 minute shower to ease my almost 70 year old bones. I had no issues prior to the tank change and it seemed to recover better too than the current one. Currently I’m running the water pretty hot (140) so I just add in a little cold - more at the beginning and less and less at the end to try and keep some warm going. In place of a propane Rinnai tankless which is $4,000 plus they say, they are offering to do a $800-900job to install a mixing valve, and replace current elements with 2 long heating elements. Now they didn’t look at the tank except to peek at it as they would have to slide the washing machine out - but maybe it’s already got long heater elements in, didn’t check to see what wattage it is either. Maybe they just know from the size. It was put in by a plumbing company - I think the guy has retired. But I don’t understand how this solution is going to give me more volume of water and over a longer period of time. I thought the mixer valves were to keep people from getting scalded and from what I have read it seems the elements no matter whether long or short are the same surface area. The short ones are bigger diameter and the long ones are narrower diameter so it equals out. Do you understand this or is this just going to be a waste of $800. I had asked about something called a booster tank but said that won’t work and no room to put it. You know people just don’t have the money to put these expensive options in and I’m on fixed income getting ready to do major heart surgery ... and I’m not a let’s finance or let’s just charge it person, not at my age. Need to come up with a working option that I can afford BUT that works. They can’t seem to give me a figure by how much this less expensive option will add in terms of water time I will gain. If it’s only 5 minutes maybe 10, it’s not worth almost a $1000. But they can’t tell me at all - “just depends”. They say they won’t be pulling the old tank out to do the above but won’t be able to replace the anode units - I have moderately hard+ water - leaves spots on everything, the tank has been in since 2013 - seems like it would need the anodes replaced. Especially since when I came back to this home (was gone before and after the tank was installed taking care of a relative 4-5 years and didn’t realize the volume issue but did notice an awful smell when trying to use the hot water. Would forget I had turned the electric off to the tank, the cold water was coming in but wasn’t hot of course and just sitting most of the time. After I returned, even after emptying the tank several times it still smelled but they turned the water to 140 and with time it got better. Won’t do that again without draining the tank. It was going to cost a fortune to pull the tank, take the top off and shock it etc.l drain it - they said it wasn’t dangerous, just smelled, some kind of bacteria. But it’s been fine for several years now with fresh municipal water coming in and being emptied and filled often as used. Wouldn’t you think a tank this age should be ready for the anodes to be replaced with the hard water. Another question, what makes a hot water tank sound like tinkling glass when it starts up to heat the tank - never noticed on my old tanks. I know these are non tankless questions but are important questions I’m sure for a lot of people now stuck with these new water heater tanks and of course they (companies) are telling us the tankless will solve all our problems. But I have seen they have cons too and more maintenance and concerns being gas. I have been told the electric ones are just not worth two cents.. I mean I want to save money on electricity but mostly want lots of hot water without being wasteful. But I don’t want to spend more money each year on maintenance and running costs for something that already costs at least 4x the price to install. Thanks bunches for possibly covering some of these in your videos.

[@marvinholmes7925]

Love watching your videos, they are very imformative. Im in the Central Florida area and am currently studying for my license any tips on the best course to take?

[@ThatTanklessGuy]

I run a training class at my studio its either a one- or two-day class given on the weekends. It covers all you would need to know about installing a tankless heater. I cover Navien and Rinnai. e-mail me at [e-mail] for details

[@johnThornton-t9b]

What kind of paint are you talking..like spray?? And what just the threads. Hammock never heard of that. Wouldn't the paint scrape off while threading on? Or ..Wouldn't the pipe dope work as a barrier for rust? Thanks Mike

[@jimnancymoore1347]

When you measure the length of the gas line do you include the length of the drops?

[@johnThornton-t9b]

Hi Mike quick question: do you need a separate regulator to the tankless? If i have a propane tank regulating a stove Im using 3/4 pipe now for the stove.

[@jasonpatterson947]

Anyone what to speak about sizing on the negative pressure gas valves (Navien) ?

[@3rdBNDeltaCo]

I have a question that that does not stand from this video however, I don’t know how to message you any other way. When using a tankless water heater system do you recommend using a expansion tank on the cold water supply line?

[@vnsclaice5200]

If I have a 1 inch line in to the house, that has a T down to a half inch can I just add a 3/4 inch line back to the 1/2 inch line that has 8 feet horizontal then 8 feet vertical down to the old water heater? Can I add a Half inch back up to a 3/4 inch without it break code

[@njzc6077]

Hey, Mike, Learned a lot from your videos, thanks! I have a Takagi T-H3-OS-N (199k BTU, max10 GPM) be installed, I like to add a recirculate water pump. I have two questions would like to get your advice; 1. Can I use a Rinnai GTK15 Grundfos Pump on my Takagi? 2. Which pump do you recommend？there is no recirculating pipe line in my house. I really appreciate your help.

[@jsp0785]

can you use CSST? or only black iron?

[@vnsclaice5200]

If I have a 3/4 inch gas line coming in and a T down sizing the gas line down to a 1/2 inch line can I add a T back up to a 3/4 inch line so I don’t have to replace the 1/2 line that went to the old water heater? It travels 8 feet horizontal then eight feet vertical down to the old water heater.

[@ThatTanklessGuy]

Yes you can just try to get as much 3/4” as you can

[@spintail86]

@ThatTanklessGuy i have a similar question anyway i can contact you to clarify my question?

[@joekrach1655]

What if you only have a gas furnace do still a regulator

[@vickyr8360]

I have a situation, my new firepit requires 240k and it is 60’ away from meter. The current pipe line is as follows-from gas meter 1” pipe size for 50’ distance and then branch out for 1/2” size for next 10’ distance to fire pit.Does this current pipe system would be good enough for 240k btu firepit?

[@deweyjones2284]

The line has a tee and a 90°. Do you account for these into the calculation for footage?

[@GUNNERBASS]

This is crazy helpful thank you! I’m working with a sub-par contractor and double checking his proposal for gas line sizing right now. Question for you: When it comes to meter sizing, is it possible to have one meter supply two homes? The current meter I have is an AC-250 5PSI meter. I’m adding approx 300,000BTU’s to the existing setup that already supplies my home. So between the two like 400,000 to 500,000 btu’s. The pressure seems like it would work, but I’m going to need a bigger meter correct?

[@ThatTanklessGuy]

Yes you will a bigger meter to supply that added BYU’s Its possibly to have one meter for two homes as long as you are going to pay for the entire gas bill.

[@GUNNERBASS]

@@ThatTanklessGuy Awesome thank you. Appreciate all your help

[@markkinney1310]

galvanized isn't allowed for natural gas. in North Carolina. maybe its black iron can't tell am I wrong.

[@glennhartman8206]

Hi Mike, We recently had a RU160P installed. Not often, but every now and then we get a code 12 and it seems like if I don't turn the water on full but let it run slowly at first, the issue does not show up. I know we need to increase our gas line size, it's currently like a 3/8th and not 3/4th (why my installer didn't change it I don't know). Anyways, is this a water issue or the gas line not being to the right size. He checked everything out after I first called him about the code 12 but of course things worked when he came. Thanks.

[@DJTJ13]

Thanks for the tips! What grey paint do you use?

[@marcoalmenares1015]

Hello sir can question can install a 94 en and not install the display with the heater still work ??

[@tawidchris]

I'm wondering if a R94LS model can be converted to LPG ??

[@ThatTanklessGuy]

it can but that’s a older model and it my be very hard to find the parts. you will also need someone a Rinnai service Tec. to do the conversion. it’s requires adjusting the gas pressure high, low on the gas valve. I hope this helped. Mike

[@OceanBlue11400]

Currently installing a V65in in my home. I’ve got low pressure gas so the gas company recommended redoing the 1/2in pipe with 3/4in all the way from the meter to the unit. Any suggestions or advice?

[@christianruvalcaba5332]

Yeah I’ve had to do that before

[@neckofthewoods24]

I’m still having trouble seeing it on paper haha. You have a email or contact?? 🙏

[@markkinney1310]

I hate codes that make no sense. its ok in some states but not in another. Why is that..