Commercial tankless in a home?

[4x4man514]

Hi yall. I've been lurking a while on here looks like some good info but I can't seem to find the answers I'm looking for.

Is there any reason why I couldn't install a commercial tankless in a home?

I have a new build and a Rinnai 75el (I think) propane outside tankless. this thing is pitiful . it takes 6 minutes to get warm water. and the water never gets over 90 degrees with the setting on 120. I am on a well and the water coming in is at 50 so about 40 degrees is all it will do.

I have gone overkill with all my indoor plumbing ran with 1 inch PEX. so I get that it takes longer to displace the water. the cold water in my shower flows at 10 gpm and the hot is only 5gpm so I know there there is some serious restriction in my water heater.

I was considering a Takagi TB50. its 380,000 btus, has one inch inlets, and is rated at 14.5 gpms compared to the 7.5 of what I have now. it is substantially more expensive but I cant live in my house the way it is now.

T-M50 - 380,000 BTU Propane Indoor/Outdoor Non-Condensing

The T-M32 Series, specifically designed for heavy-duty applications, is the largest Takagi tankless heater yet, and the most powerful (14.5 GPM max) in the tankless industry! The T-M50 Series is suitable for commercial applications (hotels, resturants, government, convalescent homes, etc.) that...

www.takagi.com

Is there any reason why I couldn't do this? or that it would be a bad idea?

Thanks a bunch!
Kevin

 

[Terry]

You probably need a 70 degree rise in temperature. With a 75 series, you should get 4.2 gallons a minute, enough for two showers at once.
Using 1" to supply the hot though, that would take forever to receive hot water from the tankless. Sometimes bathrooms will be plumbed using manifolds, with a 1/2" line to a shower and a bathroom sink.

 

[Sponsor]

 

[Breplum]

That commercial unit is overkill.
What you need is a recirculation pump.
I recommend Navien NPE240A2 full two line digital display, excellent recirc pump built in, adjust ability, good troubleshooting, easy to service, you can add multiple hot button for true on-demand if you like to overkill or Noritz also makes one with recirc pump built in.

 

[4x4man514]

Thanks guys.

I realize the water heater is overkill ' but my pi[pes are overkill. and redoing the pipes is a big no go' 4.2 gpm is not enough for my shower set up. that's what I have now. if I have 10 on the cold water I should have 10 on the hot water or at least closer to it.

What I'm wondering is what are the reasons I should not go with a commercial unit? Except obviously cost.

Thanks again

 

[John Gayewski]

There's no reason not to use a commercial heater if you want more gpm, but recirc feature in a Navien is pretty good.

Your shower head will only give you 2.5 gmp which adds up to about 2gpm of hot with an 80/20 mixture which is common.

Your hot doesn't need to match the cold but if you want more then go for it.

 

[4x4man514]

thanks! ill look at the navien you guys keep telling me about but im prolly going commercial.

does this heater just recirc inside the heater? it doesnt seem that would accomplish much.

 

[John Gayewski]

thanks! ill look at the navien you guys keep telling me about but im prolly going commercial.

does this heater just recirc inside the heater? it doesnt seem that would accomplish much.

The piping and water in it stays hot. There's a little baby tank in it.

You get hotter water faster if the pipes are warm.

 

[Fitter30]

Some units can be cascaded having two or more units talking with each other for increased capacity. Your doesn't have the option It might be worth a call to the company they might have a optional board to make it work. Need to talk with your gas supplier for btu capacity. Lp 91.5 k btu per gallon, size of tank and vaporization has to be considered. 10 gpm @ 80° rise = 400k btu