Takagi jr, hot out ok, but 8' pex=cold

[fybar]

Hi all, we just hooked up a propane Takagi Jr in a mother in law cabin.
The hot out is plumbed to a sink and a shower.

A Delta universal mixing valve in the shower is rough plumbed in, and the hot and cold lines to the bathroom sink are in the wall but not hooked up to the sink yet. Braided lines with shut offs for the sink hooked up to PEX.

All the lines are PEX and Sharkbite tees.

When the water valve on the braided hot line to the sink is turned on, the heater turns on and says the water out is 122°F, but 8 feet away it comes out cool. The PEX just below the valve out of the heater gets hot, but even 4 feet away feels cool.

We are getting 1.1 gpm from the braided line which looks like about 3/8" at the end, so well above what the WH needs to stay on, and it does stay on.

We hooked up a 50 foot garden hose to the Libra Supply hot side isolation valve and ran it out the door. Turned on the heater and got nice hot water at the end, at a flow rate of 2.6 gpm it I remember right.

So, no hot water after 8' of PEX, plenty of hot water after 50 feet of 5/8" hose.

Can anybody guess what's wrong?

Thanks!

 

[Plumber69]

Put the cartridge in the delta rough. Turn it to off position. Or if you have shut offs on the rough in turn one off. Where do I send the bill?

 

[Sponsor]

 

[fybar]

Oh, how funny! I had actually speculated that maybe the water was mixing in the shower valve, and had my husband hold the pex lines in the shower to see if there was a temp change. Couldn't detect any, but we were running the water from the hot side of the sink line into a 5 gallon bucket for testing, so couldn't keep the water on for long.

Thanks so much, we'll put in the *test plug* for the mixing valve tomorrow and try again!
I actually had to look at the mixing valve directions just now to find out what that part was. I thought it was something that would be installed when ready to put the Delta Trinsic control handle on.

THANK YOU SO MUCH!

 

[Plumber69]

Oh, how funny! I had actually speculated that maybe the water was mixing in the shower valve, and had my husband hold the pex lines in the shower to see if there was a temp change. Couldn't detect any, but we were running the water from the hot side of the sink line into a 5 gallon bucket for testing, so couldn't keep the water on for long.

Thanks so much, we'll put in the *test plug* for the mixing valve tomorrow and try again!
I actually had to look at the mixing valve directions just now to find out what that part was. I thought it was something that would be installed when ready to put the Delta Trinsic control handle on.

THANK YOU SO MUCH!

I don't know anything about a test plug. You may have to use the actually cartridge

 

[fybar]

Yes, it turns out there was a test plug, but I suspect there were two, one for each port, but stuff has been unpacked and not always kept together so only one.

We tested again this am with my husband sticking his finger in the cold port,( test plug in hot side) and sure enough we got plentiful hot water from the sink line.

Again, thanks so much for solving the mystery!

 

[Plumber69]

Where do I send the bill?

 

[Jadnashua]

Delta seems to waffle between including the test plug and making it optional, but without it and just the test cap installed, the hot/cold just flow through, giving most things lukewarm water. The water will take the path of least resistance...the fully open shower valve rough-in will have less resistance than the flow restricted kitchen faucet, so that's why.