Thankless Water Heater

Ok I made the biggest mistake in my life - using a friend to do a permit pulled job on a property. Needless to say what a nightmare. I have remolded an entire unit down to the studs and have passed every single inspection BUT the tankless water heater. I keep getting the "inspector doesnt want to work" from the plumber with NO clear answer or plan of action. Today I finally broke down and decided to take actions into my own hands and left the inspector a message that I will be meeting with him tomorrow to see where we go from here. (I just don't know if the plumber is now lying to me - sad but true)

Here is how everything stands:
We have had two inspectors throughout this project. The first one was replaced by this new one. The first one signed off to put up the drywall etc and now the new one doesn't want to sign off final inspection stating something about not enough venting.

Now I would like to be prepared for what this inspector has to tell me tomorrow so I need to know what I should know:

I am getting the specs on the current model installed (yes it is an indoor model)
I have measured the entire apartment and have drawn a blueprint of demensions.
The tankless is located in the kitchen with a vent to the roof and a an additional vent next to it probably 5x12 (looks like an air conditioning vent) which leads to the attic
this is a small tankless for a 600sq place

I have had other buildings installed with tankless without an issue but I used a plumber who was grade A. Unfortunately he was too busy with other commitments to get this place done and I decided to go with a friend - BIG mistake.

I am extremely frustrated and I don't want to appear like an idiot and want positive feedback from the inspector so please if you guys could hit me up with what I should be ready with tomorrow I would greatly appreciated it.

I would recommend finding out the make and model of the TWH, and doing a thorough research via the Internet. Most companies have downloadable PDF files, explaining the construction requirements, up to and including the venting of the unit. Once you have the installation brochure, you will have the necessary knowledge to either agree with the inspector, or provide him with the manufacturer's instructions.

Thanks! I pulled the installation manual off the website and found the min max Btu/h the system requires.

My question now is how much space do I need for a the max number of btu/h? I have the required 5" vent going to the ceiling but apparently the inspector feels there isnt enough air venting...

is there some ratio or space vs btu/h? (is this by county in california or is a national wide acceptance?)

i really want our friendship to survive so i am trying to take this on myself

You need fresh air coming into the unit also, can't just take it from the room. Is there an intake on the unit? If not you will for sure need a fresh air inlet. Probably 4" or 5"

Thats the confusing part. According to the manual you can do two types of installation a "direct-vent" or just the exhaust vent. I guess the "direct vent" has both seperate exhaust and intake vents. if you go this route then you have to put a plate on the front of the unit (it appears those block the air intake from the front of the unit)

my plumber went with just one pipe vent to the roof which I assume is the exhaust. there is no plate cover on the front of the unit so the unit can suck air from the open space. also a vent was opened in the ceiling next to the tankless (looks like an airconditioning vent) which just allows free air from the attic.

does any of that make sense?

thanks!

Here is a picture of what I believe to be the "vents" for intake in the front...is this incorrect? why would they want to block this if you do a "direct-vent" is it because the direct vent has an air intake?

Ok I get what your saying, however it could be a code from your state that supersedes the manufacturers instructions. I know every tankless ive installed either had fresh air piped directly into the unit or the was a combustion air pot in the room. I'm betting the inspector doesn't like that there's no fresh air coming into the unit. To put things into perspective you need 10 cu ft of air for every 1000 btu/h. On tankless units that is ALOT of air usually. That tankless unit runs and you'll have a serious negative pressure in your small apartment, that tankless will suck your entire apartment into it lol. That's probably his concern

thanks! so informative i just did some rough calculations and given the room this is in it actually meets the 10 cu ft requirement. I understand some inspectors are rough and he may require a fresh air supply. I am definitely not a plumber (as evident by my descriptions) but just looking at the manual I need to add another pipe to the roof and a plate cover for the front. I mean this doesn't seem *impossibe* as my plumbers make it seem.

Thanks for all the info I didn't want to appear that I was some dim witted woman going to complain at the housing office to the inspector. Just want the truth and I want to make the inspector happy and pass.

No worries, glad I could help, however even if your room is big enough to support the combustion you still need fresh air inlet. The point being you don't want to use air in the room to complete combustion, you want it to come from outside. Maybe it doesn't apply to you in California much lol but I always think here in Alberta it's cold 7 months a year, I don't want to use this air I paid to heat as combustion air, because air will find its way in through cracks in your home but it's not what you want, like I said ideally if you bring air in from outside (fresh air inlet) the air required from combustion will draw from that pipe and not your home. If there's a will there's a way, I guarantee you one way or another it's possible to bring in a fresh air inlet. You can even use a concentric kit to avoid two penetrations through the roof. Could be an option, never used one on a roof but I don't see why you couldn't

hit the nail on the head. the last thing i want to do is make another hole in the roof. i wonder if it will be possible to just put in the air intake vent in the attic. the roof has plenty of those air round spinning things on top so there is fresh air coming in. although now to think of it i definitely do not have enough cu feet requirement if i do that.

worse comes to worse all i need is this "direct-vent conversion kit" and punch a hole in the roof...doesnt seem like its the end of the world like the plumber claims

have no idea about the concentric kit but will look that up now! thanks so much!

No worries, concentric kit is probably your best bet. Google it and you'll see what I mean. I'm sure you can get one that will work for you and avoid another hole. Don't be afraid to ask the inspector either, ask him precisely what you need to do to pass inspection and usually they have no problems informing you what needs to be done as long as your polite and courteous.

Just went to take pictures to show inspector and u won't believe this! There is a concentric vent on the unit!! Wish me luck

Ah ok that's good. Best of luck, let us know the outcome