T&P Valve

Hello,

This is my first post! Exciting stuff.

I'm installing a Takagi TH-1 (LP) water heater and I had a couple questions I'm hoping someone might have insight into:

How close does the T&P valve have to be to the water heater? The reason I ask is I've read in order to connect to PEX i need a 18" flex coming out of the hot water supply. Thoughts on how I can install the T&P valve in this scenario?

Also the T&P valve per Seattle code states the T&P valve has to drain by gravity and can't be longer than 30 feet..the takagi is mounted below ground level which would put the T&P valve below ground level (i.e. can't drain by gravity outside) and no floor drain in site ...Thoughts?

Thanks everyone, this is a great site, tons of good info!

Kurt

The T&P value does not hook up in the hot or cold lines. It comes out of the water heater either from the top or side. Use 18" copper flex on both the cold and hot side too.

takagi=tankless

Thanks for the reply!

The Takagi TH1 does not have a tank so therefore there are no 'valve' attachments on top or the side

The only outlets are on the bottom of the appliance, per page 4 of the installation manual:
Hot Supply
Cold Inlet
Gas Inlet
2 drain plugs

i have 18" stainless steel flex connectors.

I guess my short question here is can I install the T&P valve so that it terminates into a drip pan below the water heater? Do seattle codes allow this?? Maybe Terry has an opinion being from Seattle area

thanks!
Kurt

I don't see much point in a drip pan if there is nowhere for it to drain to. A pump could be used for any discharge. I once had an inspector in Bellevue have me drill a small hole in the bottom of the 90 that goes up and out, so that it would drain if there was any discharge. I wouldn't recommend an install like that though. I think Seattle's plumbing inspections are done by King County, look on the permit and get the number for the inspector and give them a call, they could tell you for sure.

The tankless has overtemp protection, so I think all you are required to install is a Pressure relief, which can be at any convenient point on the cold supply line.

good stuff.

Thanks for the replies!

The Takagi does have temp protection built in, and I'm installing an expansion tank on the Main in line as i'm using this as domestic supply and radiant heat. I hope the pressure relief valve with the expansion tank is double safety/security...

The install guide for the Takagi says a Pressure relief valve must be installed per code...so I guess I'll see what happens with the inspector.

I did call the inspector yesterday got his VM, hoping he'll call back today

So the inspector said I can run a normal 150psi within 1' of the tank released straight down to the floor and then place a 125psi relief valve on the hot water line after it clears grade to drain outside by gravity.

Sounds nice huh? I guess that means no flex connector on the hot water outlet...

another question on the T&P...

Can I use a sharkbite fitting to connect the termination side of the relief valve to a run of copper pipe?