Thread: Tankless water heater installation

When considering a "Direct Vent" application can the device be as simple as a constructed direction in which the exhaust will flow or is it more extensive? My question pertains to the attached photo. The specific location for the Tankless installation does have a window above the exhaust termination. In addition, (this might have been addressed already) but does the Drip leg / Sediment trap configuration change with Tankless water heaters as well (see photo)?

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I do not believe that unit is a direct vent, the unit itself is installed OUTDOORS, and using ambient air (not vented) for combustion, it is just power assisted draft venting horizontally. I question the installation unprotected from UV, weather, etc. outdoors despite location on covered porch/patio - no walls. I see no strapping. I see two insulated lines (presume cold and hot) apparently both heading out onto the balcony floor not the unit. I see what I presume are NOT full port only valves. I see apparent relief valve but where does it discharge, into gas pipe going back into wall? What's the listing information on the unit? Is it approved for outdoor installation?

Missing sediment trap on gas pipe. Appears to be a yellow coated corregated appliance connector - IIRC not rated for use outdoors. Should also be protected from damage on patio/balcony.

Receptacle cover has side hinge, and no knockout for in-use. Outdoors should be (2008) waterproof not just rain proof - covered (questionably) location or not. Likewise cord/plug set should be protected from UV, rodent chewing, birds nesting, and drip loop. As it is any wind driven rain would run along the appliance connector and drip on the receptacle.

Seems odd to have potable plumbing looped to outdoors and back indoors for anything other than a manufactured home (Mobil home). Is this dedicated for some sort of self contained, packaged, portable hot tub/hydromasage unit set on the patio/balcony? Did the Condo Association (or HOA) approve? Can the balcony/patio support the weight? Was the addition of the tankless done with permit, approval by the AHJ, AND approval by the Condo Association (mounted on wall)? I think not.

Mike,

Your best bet is to refer to the manufacturers installation instructions. They are very easy to get on-line.

As far as the sediment trap yes one is still required.

H G ,

The valves you see are for maintenance of the heat exchanger.

Its very odd to see an indoor model installed outdoors. They do make an outdoor unit that is rated for installs outside. That whole install is questionable. Even if the yellow gas line is CSST its not really rated for outdoor use, and it needs to be properly bonded. A sediment trap is required here in IL, not sure in CA, I know CA also requires a flexi gas connected on their tank heaters, unsure of the codes for tankless. Here in Illinois all water heaters are to be hard piped.

And yes the valves on the water inlet and outlet of the tankless unit is isolation valves used to service and troubleshoot the heater.

CSST is rated for outdoors and is installed that way "here" all the time. Protection may be warrant but possibly not enforceable. Many units are designed to be installed on the exterior of the home with no shelter.
Advise here is guess work and the manufactures installation Instructions is needed.

Originally Posted by Mike Schulz

CSST is rated for outdoors and is installed that way "here" all the time. Protection may be warrant but possibly not enforceable. Many units are designed to be installed on the exterior of the home with no shelter.
Advise here is guess work and the manufactures installation Instructions is needed.

Guess work? I am a licensed plumber for the last 20+ years, and I am certified installer for Takagi, Noritz and Rinnai tankless water heaters. I am also certified installer of CSST.

The unit pictured is a TK- 3 Takagi indoor unit. The proper model for an outdoor install is the TK-3-OS. Takagi does allow the use of the TK-3 outdoors if the outdoor vent cap is installed, along with the dip switches are switched for outdoor use. The vent cap is required to be used if the installer is installing the standard TK-3 unit outdoors. Lot less of a hassle if they went with a TK-3-OS

As for CSST being used outdoors it depends on the manufacture and if they had received the ANSI LC1 rating or not. If it is approved for outdoor use then the external jacketing must remain intact as much as possible Any exposed stainless must be wrapped with tape or a sleeve to prevent any threats from acids. or chloride based chemicals. Also if it is along side of a structure between the ground and the height of 6 ft., the CSST must be protected from mechanical damage inside a conduit or chase.

As for bonding it is to protect the CSST from lighting strikes which can cause pinholes in the material. All the manufactures have required bonding for some time now.

Originally Posted by Mike Schulz

CSST is rated for outdoors and is installed that way "here" all the time. Protection may be warrant but possibly not enforceable. Many units are designed to be installed on the exterior of the home with no shelter.
Advise here is guess work and the manufactures installation Instructions is needed.

One more note.
Just because things are installed "that way" by you all the time does not make it right.

I had a home inspector that thought he knew more than a plumber (me), and tag a water heater install I did for a long term customer of mine that was selling her home. He noted I did not use dielectric unions, and my T&P relief tube was not 6" off the floor. So of course my customer calls me questioning me if this guy new something I did not. I called the home inspector and asked him to meet me at the property, and I invited the cities plumbing inspector. He said someone has to pay for his time. I explained to him if he can prove to me my install was wrong in any shape or form I will pay his bill. He agreed eagerly. So once all parties was at the residence I asked him to show me in the plumbing code book where my install was wrong. He stated he did not know where in the code book that it is required to have dielectric unions and have the relief pipe 6" off the floor. So the plumbing inspector watched me as I opened the code book and showed the home inspector that the code states "Unions between copper pipe/tubing and dissimilar metals shall either be made with a brass converter fitting or be a dielectric type union. " The unions of my choice was the brass unions which met the code clearly. Then I showed him the part about the relief tube on the T&P valve which read "The discharge line shall be installed from the relief valve to within 6 inches of the floor or receptor and the end of such line shall not be threaded." My pipe was at 5" of the floor his complaint was it was to close. As you can see it says in the code within 6 inches. This is when the plumbing inspector chimed in, he asked the home inspector for his plumbing license. To which the home inspector said he is not a plumber. The plumbing inspector then told him he is not to inspect plumbing since according to the Illinois licensing law only a Licensed plumber can be a plumbing inspector. All he is allowed to do is note leaks, slow drains poor flushing water closets. Anything else must be done by a plumbing inspector.

Sorry for the length of the story up there but my point is if you are not sure if it meets the local plumbing /fuel codes call the local plumbing inspector, they will be more than happy to inspect the install of something. It is there job to ensure all the residence of that community has safe and properly installed plumbing.

Take a careful look at the third picture:



I see a (apparently six-foot) yellow-coated corregated (likely stainless steel) tubing Gas Appliance Connector. As it is still bearing its UPC paper stock/sales tag, it presumably was pre-manufactured as same prior to sale, hopefully listed to ANSI Z21.24 (which should be engraved or stamped on the collar) between the black gas pipe and the Takagi TK-3.

I see what I believe to be teflon tape at the threaded connections of the gas pipe and not pipe dope.

I do NOT believe we are seeing CSST gas line being used to connect this tankless water heater. It has been my understanding (and I am sure I will be corrected if I am in error) that "CSST", T as in tubing, does not include pre-manufactured corregated/flexible gas-appliance connectors (e.g.,a connector that runs from a gas outlet to an appliance).

Questions for Ron Hasil: Soes the TK-3 (non-OS) incorporate an anti-freeze capability, how is freeze protection applied here? IIRC it may sometimes (albeit rarely) drop to freezing temps outdoors at 246 W tujunga blvd #104 in Burbank, California. Where is that relief valve discharged in the OP's photos?

Lets look at the First and Second pictures again.

Note the bird's nesting debris on the top left of the water heater just to the left of the SS vent (next photo below - originally first OP photo).




In the next photo below (OP's second photo) note the "roof" over the installation:



I believe the prohibitions outlined in the installation instructions RH offered, for combustion clearances, ready combustion air, and against roof type coverings over the outdoor installation of the specific TK-3 unit include the propensity of fauna to NEST atop the unit when under a roof type covering or overhang.

5. When installed outdoors, the T-K3/T-K3-Pro water heater shall be wall-mounted or mounted on a stand. Locate the water heater in an open, unroofed area and maintain the following minimum clearances:

Does the OS unit have the same prohibition?

Finally, since that pipe insulation is within 12" of the tankless water heater bottom, wouldn't that likewise be a clearance violation (combustible clearance 12" at the bottom)?

Originally Posted by H.G. Watson, Sr.

Take a careful look at the third picture:



I see a (apparently six-foot) yellow-coated corregated (likely stainless steel) tubing Gas Appliance Connector. As it is still bearing its UPC paper stock/sales tag, it presumably was pre-manufactured as same prior to sale, hopefully listed to ANSI Z21.24 (which should be engraved or stamped on the collar) between the black gas pipe and the Takagi TK-3.

I see what I believe to be teflon tape at the threaded connections of the gas pipe and not pipe dope.

I do NOT believe we are seeing CSST gas line being used to connect this tankless water heater. It has been my understanding (and I am sure I will be corrected if I am in error) that "CSST", T as in tubing, does not include pre-manufactured corregated/flexible gas-appliance connectors (e.g.,a connector that runs from a gas outlet to an appliance).

Question for Ron Hasil: Soes the TK-3 (non-OS) incorporate an anti-freeze capability, how is freeze protection applied here? IIRC it may sometimes (albeit rarely) drop to freezing temps outdoors at 246 W tujunga blvd #104 in Burbank, California. Where is that relief valve discharged in the OP's photos?

You are right, that does look like the manufactured gas supply line. I do apologize, I should of looked closer at the ends.

Upon closer look at the venting which we know is not the recommended install for this tankless heater, its missing the condensation drain tee.

As long as the home has power they have a basic freeze protection, they equip it with heating blocks. It activates when the surrounding temperatures drop below 36.5ºF thats all the freeze protection that any of the Takagi Tankless units provide. They do recommend a battery backup just in case of them power outages.

Now this is where I like the Noritz brand better. Their freeze protection has the basic heating blocks, plus it will fire the heater as needed. They also have a kit we can plumb into the supply that when the power does go out, it shuts the water supply of to the heater and opens a drain valve to let the heater drain all the standing water.

Freezing can even happen on indoor models if the installer is not careful to assess the situation of the install. If there is negative pressure with in the building cold air can be drawn through the vent and cause freezing temperatures across the heat exchanger. The best solution for this scenario is to install a direct vent unit so it can get its fresh air from the outdoors. This will equalize the air pressure within the unit so cold air can not blow down into the unit.

Originally Posted by H.G. Watson, Sr.

Take a careful look at the third picture:



I see a (apparently six-foot) yellow-coated corregated (likely stainless steel) tubing Gas Appliance Connector. As it is still bearing its UPC paper stock/sales tag, it presumably was pre-manufactured as same prior to sale, hopefully listed to ANSI Z21.24 (which should be engraved or stamped on the collar) between the black gas pipe and the Takagi TK-3.

I see what I believe to be teflon tape at the threaded connections of the gas pipe and not pipe dope.

I do NOT believe we are seeing CSST gas line being used to connect this tankless water heater. It has been my understanding (and I am sure I will be corrected if I am in error) that "CSST", T as in tubing, does not include pre-manufactured corregated/flexible gas-appliance connectors (e.g.,a connector that runs from a gas outlet to an appliance).

Questions for Ron Hasil: Soes the TK-3 (non-OS) incorporate an anti-freeze capability, how is freeze protection applied here? IIRC it may sometimes (albeit rarely) drop to freezing temps outdoors at 246 W tujunga blvd #104 in Burbank, California. Where is that relief valve discharged in the OP's photos?

Lets look at the First and Second pictures again.

Note the bird's nesting debris on the top left of the water heater just to the left of the SS vent (next photo below - originally first OP photo).




In the next photo below (OP's second photo) note the "roof" over the installation:



I believe the prohibitions outlined in the installation instructions RH offered, for combustion clearances, ready combustion air, and against roof type coverings over the outdoor installation of the specific TK-3 unit include the propensity of fauna to NEST atop the unit when under a roof type covering or overhang.





Does the OS unit have the same prohibition?

Finally, since that pipe insulation is within 12" of the tankless water heater bottom, wouldn't that likewise be a clearance violation (combustible clearance 12" at the bottom)?

Good eye on catching the part about not being installed under a roof period. the TK-3-OS does have the exact same wording. As for the clearances and the pipe installation in the instruction manual they do warn you that the heater on protects the pipes and heat exchanger inside the unit from freezing that the pipes that attach to the heater must be protected by insulating them or some other means. I will be honest, I never installed a tankless unit outdoors,, so as to the requirements of not installing it under a roof and such was new to me since I never read the outdoor part of the instructions.

Here are the links to the PDF installation instructions for the tankless units.

T-K3 / T-K3 Pro http://www.takagi.com/download/product_manuals/T-K3.pdf
T-K3-OS / T-K3-SP http://www.takagi.com/download/produ...ls/T-K3-OS.pdf

I will give a lot of you home inspectors credit on this board for knowing your codes like you do, and having the will to read and learn about areas that are new to you to provide your customers with the best service you can. If any of you took offense to my post about the one inspector I dealt with, I am sorry, that was not my intent. I know when I buy home (if that ever happens) I am calling one of you guys to the do the inspection. All I know is plumbing, you fellows know a lot more to look for. Keep up the great work.

Thank you for the quick replies and links Ron Hasil.

Upon my reading of the installation instructions/manuals I'm reading that the TK-TV04 Vent Cap was to be used for outdoor installation with the T-K3/T-K3-Pro and that it (the Vent Cap) was to be installed directly on the top of the unit, INSTEAD of connecting an exhaust vent pipe. I did not know it was allowed to use a side wall or roof top terminator in free space, supported by vent pipe & offset, which is being supported by the water heater itself (not allowed according to mfg instructions) and a singular ring strap.

I honestly don't think the SS vent as pictured/supported could resist the uplift or direct winds of Santa Ana winds.

In fairness, I note upon reading the instructions, a proviso of a 3-foot clearance to roof overhang which is sealed in the US (still not met by what is photographed.

To follow-up, now that we have established it does have (during power supplied periods) freeze protection, a few more questions.

Does that look to YOU to be 3/4" supply, valve, or connector? Isn't that required at a BARE MINIMUM for a 199,000 BTU unit??

Do you see a path for the relief valve? would that valve be rated for 200,000 Btu and 150 PSI? (I see no tag either, wouldn't that be required to remain in place?)

Question to ALL:

Since all the T-K3 series tankless units CAN BE HARD WIRED, wouldn't that be MANDITORY for an OUTDOOR UNIT NOT INSTALLED in an OUTDOOR BOX, and NOT INSTALLED WITH THE OUTDOOR "Pipe" COVER?

I don't see an exception in 2005, or 2008 NEC for this non-portable applicance installed OUTDOORS (no walls) to be cord and plug connected, nor on its listing.

I believe it SHOULD be hard-wired, using appropriate Chapters 1-4 wiring methods for outdoors.

The isolation valve kits come with the pressure relief valve that is rated for the heater. It looks to me it is entering back into the building, only the OP can verify where it terminates. The rating tag should still be on the relief valve.

3/4" is the bare minimum size for gas supply on tankless water heater I would be worried if the length of the 3/4" pipe meets the requirements. With the flexi supply I would not run more than 25' of 3/4" pipe. 30' of 3/4" pipe is rated for up to 200,000 Btu's

And yes the TK-TV04 Vent Cap must be used and installed right on the heater, no vent pipe at all. They do have an allowance for an over hang which is 36" of clearance but as you pointed out the as pictured its under an enclosed roof area which does not meet the manufactures instructions.