# Combi Dhw / Radiant



## Plumbworker (Oct 23, 2008)

Worked at a condo building with 50 gal high recovery combi tanks with immersion coils for infloor radiant a few days ago.. Well one of the Bradford tanks blew a coil while the heater was still under warranty in fact the warranty expired the day after the coil failure :laughing:. 

The piping arrangement was all wrong as well.. Manual fill system no autofeeder, potable expansion tank on discharge of system iron circulator, Potable water pex no air elimination device etc... The system was drawing in massive amounts of oxygen..

In san francisco california we are required to install low nox heaters.. well Bradford does not make a low nox heater with a built in coil so they sent me a Low nox high recovery with space heating taps.. I had to install a external flate plate exchanger..

So basically we did a overhaul of the system with non ferrous stainless steel circs.. water feed train with backflow , air separator , correct expansion tank with proper placement.. Did a good flush on the system added a corrosion inhibitor insulated and called it good.. system is now working nicely even though not that efficient

As for the other heaters they still have the same hacked up piping none of the residents have had their system function correctly.. So hopefully i can land the other two reworks for the building



Before 






























AFTER
New mixing valve





























Proper insulation


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## trick1 (Sep 18, 2008)

Good deal!!

Great spot to pipe in the feed water....right at the Point of No Pressure Change.

Love the expansion tank hanger

The Taco VDT circulator is great in principle, but the ones that I have in service have given me my share of grey hair when it comes to the accuracy of the programming logic.

If it's your first one, don't be surprised if you need to head back there to adjust a couple of the dip switches.

If you get jammed up PM me and I can let you know what Taco told me. I've found that the pump seems to operate a lot better in Direct Acting Mode.

I love flat plate exchangers as well...a great way to protect the tank from O2 corrosion.

Who actually installed non barrier tubing for a radiant application anyways:blink:

Great looking job!!


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## Mags (Mar 11, 2011)

Nice and clean, good job. Are those legend ball valves? My supplier just started selling them, The ones I got have no packing nut, wondering if yours are the same and if you have had any trouble with them?


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## Plumbworker (Oct 23, 2008)

Mags said:


> Nice and clean, good job. Are those legend ball valves? My supplier just started selling them, The ones I got have no packing nut, wondering if yours are the same and if you have had any trouble with them?


The ball valves with red handles are Toyo Red & White.. The flanged isolators are Taco.. I never liked the legend ball valves they remind me of mueller HD valves every one i touched always had problems seating fully..


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## Plumbdog (Jan 27, 2009)

nice work.:thumbsup: Thanks for the pics.


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## Plumbworker (Oct 23, 2008)

Guess what got called by the inspector on that rpz up high like that.. Backflow tester snitched on me  he was still able to to test the damn thing though ...needed 12" top side clearance . Well i was back relocating the device to make backflow tester and inspector happy i learned my lesson lost some minimal profit but i made it right and the owner was really cool about it :thumbsup:

im thinking about getting backflow certified

are there any guys on here that do testing and do you think the valve was to high to test?

BEFORE












After


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## trick1 (Sep 18, 2008)

The valve was a hair high to try and repair.

Actually, it might be a bit tough to get the hoses on the test cocks too.

Why did you choose a 009 for backflow prevention on the feed line. Is it under your code or was a certain listing called out (ASSE,etc..)

The new location looks good!!


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## Plumbworker (Oct 23, 2008)

the 009s are what my supplier stocks i've installed many with no problems..

I talked to the backflow tester and he said he had to put 90's on the ports to do his test


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