How do you add a recirculating pump to a basic Rinnai V751 tankless water heater with no pump or return pipes?

At about the 20-min mark you diagrammed something similar to what I have, 40ft of 3/4" from meter to water heater with a furnace in between. I think my meter is only 250K, not enough for the bigger tankless unless I don't use my furnace in winter.

The Navien condensate drain already has a tiny relief vent hole built in above the threaded discharge and CPVC is not a manufacturer requirement in fact it’s just PVC. Adding a T and an additional 1/2” vent is good practice but not necessary because condensate just drips out and a gusher. I run all 3/4” PVC for the condensate drain into a dirt patch and have never had a problem. CPVC is not a requirement or necessary for condensate discharge. Copper or CPVC must be used for the PRV line. I use a commercial grade CPVC (grey color) pipe.

How do I buy the filter removal tool?

do you think the filters needed? I have a 199k propane unit I’m using for radiant floor heat. It’s a sealed close loop setup and on my setup I do have a larger filter screen before water gets to the unit. I’m using a 50/50 radiant coolant and distilled water mix and several times a year that little screen gets plugged with green slime. Super easy to just shake it off the screen but when clogged the system doesn’t work. Not sure what the harm would be to remove that screen and let the unit burn that slime up or not let it collect at all! The larger screen doesn’t collect the slime. Not sure what micro ports or channels are inside the unit where that green slime could accumulate and that’s a place I can’t get to for cleaning if it happens. But I think the unit will run better with more free flowing fluid vs a very tiny choke point that gets worse by the day.

Speaking of protecting the unit but kind of an off topic question, do you think the micro filter on the cold side before water enters the unit, that filters needed? I have a 199k propane unit I’m using for radiant floor heat. It’s a sealed close loop setup and on my setup I do have a larger filter screen before water gets to the unit. I’m using a 50/50 radiant coolant and distilled water mix and several times a year that little screen gets plugged with green slime. Super easy to just shake it off the screen but when clogged the system doesn’t work. Not sure what the harm would be to remove that screen and let the unit burn that slime up or not let it collect at all! The larger screen doesn’t collect the slime. Not sure what micro ports or channels are inside the unit where that green slime could accumulate and that’s a place I can’t get to for cleaning if it happens. But I think the unit will run better with more free flowing fluid vs a very tiny choke point that gets worse by the day.

Thank you so very much 😊

Great job thanks Sir.

This is a late comment. I hope you see it. And I hope all is going well with you. thank you so much for sharing your expertise with us! Regarding the unplugging of the water heater., Could you just not turn the breaker off to that water heater and then after the generator is flowing, providing electricity. Turn the breaker back on? I have a Renai tankless water heater in my basement that plugs into an outlet.

Thank you , very thorough and helpful video. My install is in Baja California

Thanks for making this video. I opted for the NPE-240A2 to replace my very early 240A. I have three girls in the house, and more often than not have two showers and a load of laundry going at the same time.

Well done sir ! Thanks .

does the master or primary have to be cold first in or last in, or hot first out or last out?

Thanks for the great videos!

My NaviCirc valve squeaks any time the circ pump shuts off. Any solutions for that noise?

Shouldn't you drain the water out of the unit instead of diluting the concentration of your vinegar (or whatever you are using)?

Brainless guy 😂

Thanks! Great video. Is it normal that there is moisture around the rod and mounting bracket.

I ordered 2 new filters from amazon and they came with an aluminum piece that had a cut out that went around the "tabs"! Perfect!! I had broke part of tab off trying the needle nose pliers and this solved the problem.

Great video. Which spring loaded check valve did you use?

Mike you are the best! I’m a DIYer and have looked at many a video on how to. Your explanation and steps were spot on in getting my unit back up and running. Thank you for sharing your knowledge! Again excellent video!

Nice presentation Mike, really enjoyed it !

Hey mike tool bag ok 😮

Have you done a video on gas utilization to heat water with a tankless vs heating with a regular nat gas water heater ? I’m a plumber in Massachusetts, Iv always said YES, tankless is great for endless hot water BUT ,the down side is if your constantly on and off with the water these units fire off with full btu which yes modulates down once satisfied but how does that compare to a regular tank type

You are the best teacher out there. Thankyou so much for your help

The Rinnai RXP199i appears to have a tiny built in vent into the condensate nipple. Do you still recommend the U vent on this system?

Great job you explained it very good. Thank you.

It appears my recirculation line has been routed to be used to heat my forced air hydro furnace. I'm figuring i need to descale both systems but there is no way to flush the furnace side of the system that i can figure out. I have a shutoff valve above a faucet on the recirc port below the water heater and a shutoff valve before it connects back to the hot water line for the house. Then the usual hot and cold water service ports with an expansion tank before the cold water port. I have a Navien 240A. Any advice?

Hi Mike, I took all the steps in your tutorials when having a code 12 on the water heater. I cleaned the ignitors, replaced the regulator, got a larger gas intake hose. flushed the tank and I still get a code 12. Bluestar propane will not service the tank because it is not fixed on a permanent structure. No other place will service it. Can I ship the Rinnai V53DeP Tankless Hot Water Heater to you for repair? I dont know what else to do and hate to spend the money on another tank since this one is only a few years old. Please help, thank you. PS, When I turn on the water just a trickle the burner stays on. If I turn the water just a little more up the burner shuts off.

Thank you Sir, this was just the video I needed! I now have a happy family..

At about 13 min, you stated that the NPE is not field convertible. . I just installed one in my house and came with the LP kit needed to field convert.

Thanks for sharing, very informative.

Does anyone know where to find a video about the i120 water pressure sensor? I see it's a common problem but haven't been able to find any videos on it.

Excellent video! Thanks for all the details!

Thanks for great video Mike! This is a horrible design from Rinnai. I just finished this burner replacement. The actual work was not that bad. You could probably get it done in 3 hours as a novice.

Hi There, Where is the bottom end connects to?

Thank you 😊

Can I use the old Mc-91-1US-S controller with my new RE180i unit or do I have to buy a new controller if I want one?

Cool!!! Its just like a furnace, then. Ive done maintenance on a furnace before so ill know exactly what to do with the help from this video. Many thanks!

What if I’m using a Navi-circ thermal bypass at the furthest fixture. Two cascaded npe 240 a2s

Great video! Thank you for making this. I am currently having issues with my Navion Comby boiler. My front display will not turn on at all. I’m pretty sure it is my control board however, if I have a short circuit or my flame rod went out would that kill power to my control board?

Great video. I have replaced multiple parts on my NPE 240A...Flow sensor and PCB. After I changed those parts , we started getting cold water on the hot. So I think it is the check valve The unit is about 2 years old.

I have a Rinnai tankless boiler i150SN for baseboard heating (not a Combi boiler just baseboard heating) so my question is do I need to have plumber install service valves on a tankless boiler and descale once a year? Or because it’s a closed loop circulating the same water I should leave it alone? Any input would be greatly appreciated. Thanks in advance

This is killer info Mike.. Thankyou

Hi Mike! Thanks for your helpful videos. I know you have said multiple times about when using PVC for direct vent that it needs to be for pressure (not foam core), but I haven't ever heard anything about the fittings. Most fittings that you can find are for DWV with a max pressure of 5 psi. Is it more of a need for solid core than for pressure? Also, are the more commonly found PVC fittings (elbows and such) fine even though they aren't rated for pressure?

Mike, I sent email to your AOL account and tried on Facebook. If you can find a minute please look for an email about a screw in a rinnai heat exchanger.

Mike, love your videos, these heaters aren't used much in the UK but I have one and thinking of another just for a shower - would you have any reccomendations for showers?

Desperately looking for a PCB replacement #U245-1200-G-HX02. Rinnai discontinued in 12/23. Any ideas?

How does the freeze kit drain the pressure relief and condensate?

Thank you. Your videos are so helpful. I live 100 miles from any major city with big box stores etc, so learning this for myself and knowledge thank you.