Rheem Tankless Water Heater Installation Part 5: Did I screw up my venting??

[@jeffwehrwein7606]

Thank you for the great video because I was looking at the Quick Installation guide and not the entire booklet. Just saved me a lot of trouble providing clear instruction on what I was reading since I was going to install 3” but now I can stay with 2”, thanks again!

[@westvalley411]

Great video, thumbs up. Kudos to you for working through the options; I often find errors in instruction manuals. Some product are written by ESL Chinese and they have never used the products.

[@CBVaughan27]

Very helpful info. Double-check the value of a 45. It's actually a 1'6" deduct, not a 1'.

[@CBVaughan27]

Also, you mentioned that you pitched (sloped) the pipe toward the outside. The first bullet point on page 37 of the installation manual states "It is recommended that the air intake pipe and exhaust pipe have a 1/4" per foot upward slope toward the outdoors." I like your logic, and don't understand the logic of the manual, but thought I'd point it out.

[@FixItScotty]

@@CBVaughan27 - Thanks for the clarifications. You are correct. Also, I have seen that 90+ furnaces require upward slope for venting. As a result, they occasionally have to install drainoff tees for external water intrusion. I don't fully understand the logic either. That said, my unit has been running well for several weeks. I suppose I could adjust the braces on the main run to slope upward toward my outside wall if needed.

[@snowdoggieii]

Correct! Also you want it to point up and not down because warm air rises, because you are pointing it down (for moisture) it gives it extra resistance which reduces the length again.

[@snowdoggieii]

I think there was a study where people were trapped on a burning train stuck in a tunnel that was sloped, everyone who ran up towards the exit succumbed to the fumes while everyone who ran down lived

[@FixItScotty]

@@snowdoggieii That makes perfect sense. Thanks for the explanation!

[@AnotherOCD]

I have this exact Rheem model (condensing, direct vent) and understand the length restrictions, but all the documentation I've ever seen (for any model from any manufacturer) talks about running the exhaust and the intake together - is that required? What if I want to take fresh air from the sidewall (5') and vent through the roof(15') ? Is that allowed/possible? Do they have to be equivalent lengths for some reason ?

[@westvalley411]

exactly, I will be doing the same thing soon, and even wonder if I can draw fresh air from the garage with a short duct? Isnt it almost like outside. My garage is vented with 2 square feet of chicken wire, required by code due to the gas water heater.

[@moz2186]

I believe the manual says intake and exhaust need to be near equal lengths.

[@runwayray]

Excellent explanation. Venting is very important. These systems are closed vented for a reason. Taking air from out side and venting will not effect other gas appliances like a furnace or gas dryer that usually in the same room. Some units may have a strong inducing system that can reverse the exhaust of another unit if it’s not closed and can cause a buildup of carbon monoxide. Rare, but possible, especially in small mechanical rooms.

[@carywarnottjr.8592]

thank you for your thourogh follow up. nice job man. very helpful and couragous to share!!

[@Guillotines_For_Globalists]

By the way the one mistake you did make was the backwards installation of the termination cover on the siding. But I believe you mentioned correcting that already.

[@FixItScotty]

You are correct. I link to the "User Corrections" video at the end of this video and from the playlist on my channel page.

[@elroyjelinek9308]

Thank 🙏 you. And ,.... what kind of pipe...... The name please ...

[@FixItScotty]

I am using is 2" Schedule 40 PVC solid core pipe.

[@sandywhite4024]

Great Video series! I thought I had my venting for direct vent Rheem figured out, but your video made me realize I might have an issue because I used 90 degree vent elbows (3" PVC) instead of "normal" elbows. As you may know, the Rheem manual doesn't specify the type of elbow like you did. So after watching your video, I called Rheem to confirm what you said and the support person didn't seem to know the difference between a vent elbow vs a normal elbow - she just said to use a "true" 90 degree elbow. Before I redo my vent pipes, I wanted to ask how you discovered that a "vent" elbow was not appropriate for tankless water heater vents. Thanks,

[@FixItScotty]

Sandy, thank you so much for the kind words and the great question. First off, I discussed this with Rheem support too and they may have used similar language that the "elbow" they referred to in the documentation was a "standard" or "true" elbow. Maybe a licensed plumber can give you better advice, but in my mind, a standard elbow is what is used on a drain. A vent elbow, must be only allowed for air venting. If you think about it, the water heater venting is closer to a "wet vent" which is a drain pipe that can double as a vent. As far as I know, you can't use a vent elbow on a wet vent because it is a drain line (at least on the exhaust side of the water heater). But again, I am not a licensed plumber, so that is just my opinion. The reality is, if you aren't close to the maximum distance calculation for the 3" venting, you may not have a problem with running it like you have it and see if an error code happens. But maybe consult someone who has more experience than me (or certainly the support tech you talked to). All the Best - Scott

[@sandywhite4024]

@@FixItScotty Thank you

[@zumadale]

So the quick setup guide is absolutely wrong? I set mine up with 8 foot long exhaust and 8 foot long intake...both with one wide sweep 90 angles. I'm at about 6500 feet altitude. I get code 12 about once every other week...had code 11 one time. As a test I set dip 2 ...number 2 on for extra long venting...just to see if these errors go away.

[@FixItScotty]

I wouldn't say the Quick Setup guide is completely wrong, but certainly the part where they discuss venting is very different than the manual. Error code 12 could be due to gas pressure rather than venting. Do you notice the error code when your furnace or another gas device is running? When it comes to sizing gas lines for these units, that needs to include gas meter sizing for the entire load (all gas devices in the house) and evaluating the gas line branches for pressure. As you saw, my water heater is installed as the first branch from my meter. Despite my total load being at the max for my meter, my water heater never has pressure problems due to being first in line from the meter. If, for example, it was branched after my furnace, and further away, I could have issues which may require upsizing gas lines and maybe the meter.

[@aldavison420]

Can we vent tankless PVC venting to existing tank metal venting?

[@FixItScotty]

Generally the answer is 'no'. The reason high efficiency gas furnaces or water heaters use PVC for exhaust venting is because the exhaust is not very hot, but is very acidic and wet which would cause metal venting to corrode . PVC exhaust is more like a plumbing 'wet vent' than an exhaust pipe.

[@troy2000]

The 25ft. is per pipe correct? Not combined intake and exhaust, right?

[@FixItScotty]

Correct, 25ft per side on A-1 setting.

[@waysaunut]

Very helpful, Thanks

[@FixItScotty]

You're welcome!

[@markc3659]

Any thoughts on a 22 1/2 degree pvc fittings Rheam can give no recommendation and suggested that is likely causing air flow issues on my installation which I questioned as the bend is far softer then a 45 degree pvc fitting

[@FixItScotty]

When I spoke to Rheem support about this they didn't seem to worry too much about elbows and length of pipe. They basically said to use the pipe sizing information as a guide and if it doesn't work on A-1 setting, flip it to A-2.

[@Truthfulfisherman]

I have a question. I am about to do the job of replacing to tankless in my house. I have the current vent from old water heater I know I can’t use it so I need to replace with PVC and go thru the roof up the same exit. So what the hell I do with the i take? Can I leave it inside the attic or does it have to be from outside air?

[@FixItScotty]

I have seen some attic installations where the installer just let the unit draw intake air from the attic. I've also seen attic installations where the air intake had to be plumbed to the outside. It depends on how well vented your attic is and whether you need "make-up" air in order to not create a vacuum. So if your attic is well vented, you may be able to just plumb your air intake into it. Make sure it is protected and won't pull in dust and insulation.

[@fastsvo]

Anyone know if the vent can be placed coming out the side wall which faces a front door entry? That would be about 15 feet away from the front door but the entry does have an overhang as you walk up to the front door so it’s not completely open.

[@FixItScotty]

There are rules around venting placement near windows, doors, and other utilities. I'm not sure about your situation. If you can't find answers, hire a plumbing or HVAC contractor for an hour to consult you on venting placement and arrangement. It also wouldn't hurt to have them evaluate your gas meter and line sizing while they're at it.

[@FixItScotty]

Thanks for watching! Like, Comment and make sure you SUBSCRIBE

[@thepsycomagican]

That's strange on the big box website, they claim that that 2" can run 60ft. but the manual states differently. I would need to run 3" if going by the manual. I'm curious where they are getting the 60ft of 2"

[@FixItScotty]

Watch 5:50 and on to see how you can run 60ft of 2" by flipping a dipswitch to A-2 inside the unit.

[@thepsycomagican]

@@FixItScotty ahh i see it now. Thanks for the clerification.

[@Autobot-j8k]

The maximum venting pipe is 25 ft long, do you need to change anything in A-1 dip switches?

[@FixItScotty]

A-1 is the setting from the factory. So as long as your 2" venting is under 25ft (with the reduction in elbows), you don't have to open the case and change anything.

[@dannyhernandez1381]

Is gas smell through the venting normal ?

[@FixItScotty]

To be clear, you are smelling gas outside the house at the vent cap? Because if you are smelling gas around the venting inside the house, that's a problem.

[@daveh7038]

Great info.

[@davidsson4927]

I just spent 2 hours figuring out the same venting issues. FU Rheem I am going return this and get Takagi just on principle. And I bought 2 units. Back to hd

[@omarwilliams4106]

Having error 11 issue Rheem

[@FixItScotty]

I believe error 11 is insufficient gas pressure. What kind of gas line did you run?

[@omarwilliams4106]

@@FixItScotty 3/4 piping with elbows

[@FixItScotty]

@@omarwilliams4106 Read the below document on the type of meter, length of pipe, pipe branches, and gas appliances. You may have to call a plumber to do a gas meter and line sizing evaluation. snowcrest.net/thriftysupply/pdf/RTG-Gas_Piping_Facts.pdf

[@vica153]

"The good news" is if you're reading this then you're not dead from carbon monoxide poisoning. The bad news is you need to redo your exhaust vent. Intake vent could probably be left alone. Are those DWV fittings? They look like they are. If this doesn't immediately make you think "Oh crap", then you should probably google "DWV PVC Furnace vent". That is very much not ok for exhaust venting. DWV PVC is not rated for pressure due to a lighter 'foam' or 'cellular' core. More importantly in the case of exhaust venting, the lower density material requires much less energy to increase in temperature. So DWV PVC is going to soften much quicker and likely result in deformation and leaks. Exhaust vent pipe needs to be solid core sch40 PVC.

[@FixItScotty]

"DWV" (drain waste vent) does not indicate whether it is cellular core or solid core. It is the ASTM number. This is standard ASTM D2665 solid core PVC. If you want to argue I should use ASTM D1785 for higher pressure applications, that is valid. But I have no CO levels in my basement.

[@vica153]

@@FixItScotty True, recently discovered that some DWV may be solid core. ASTM F891 would be the cellular core.

[@vica153]

@@FixItScotty Do have a scrap piece? You could look at the cross section to see if it is foam/cellular.

[@Guillotines_For_Globalists]

To hell with that quick installation guide. How could they make such a glaring incorrect statement that contrasts so significantly with the more detailed installation instructions?

[@markhoffman]

Your math is wrong. 90 is the same as two 45’s. So half of 3 is 1.5

[@FixItScotty]

It wasn't my math, I just read the instructions wrong. It does state "1 and a half" and I just read it as one.

[@wallacegrommet9343]

This whole video is nothing but hot air

[@FixItScotty]

LOL! That pretty much sums it up!