Rinnai tankless problem

[Jane In AZ]

Let's see...in my car wash that I owned for six years, I had hundreds of check valves, everything from tiny plastic ones on ¼" poly lines, to large stainless steel ones on high pressure lines (2400 psi).
My guess is you don't want any kind of spring valve in there, since they require a certain "cracking pressure" in order to open and function. In your application here, you need to be able to deal with low flow and low pressure and full flow, and a swing is the one to use. At the car wash BTW, all the checks had a relatively short life and I had a shelf full of spares, and was constantly rebuilding the high pressure ones. It was just what you did at a car wash.

That doesn't solve your issue. Try replacing with a different brand of swing. Maybe a different one will last longer. Maybe stainless steel. I cannot tell what size piping you have there, but assuming its ¾", a ¾" stainless swing check valve on Amazon is less than $15.

What the hammer solution is telling me is that the swing isn't opening until you hit it. Something's holding it up.

If this is a constantly recurring thing, I'd replace those SharkBites with unions to allow for easy replacement. There's only so many times you can open a Sharkbite before it will fail; they are not made for repeated use.

Thanks so much, Mitchell! That is extremely helpful. I will save your recommendations and show them to the plumber when our current fix-it strategy fails.

 

[Jane In AZ]

A lot of circulation pumps come with a spring check already installed.

You may not even need that stand alone check valve.

Yes, that’s true. At this time we don’t have a circulation pump. If we go that route, we’ll install one with an integral check valve. Thank you!

 

[Twowaxhack]

Why do you have a check valve ? Has anyone explained why it’s needed in your system ?

 

[breplum]

Why do you have a check valve in the system?
Just as a counterbalance to Twowax,
I have trained via factory reps for Takagi, Nortiz, Rinnai and Navien.
I prefer Navien over the rest and rarely will even bother to work on them now and ONLY install Navien.
The products are very well designed, easy to service and for plumbers at least, the tech support has been fantastic. I only recommend the NPE A series. Now version V2 is the latest.
I will say that their older units (NR) stunk for the most part.

 

[Twowaxhack]

Navien sent part after part for about two weeks then after nothing worked they disclosed that the unit had a factory defect.

Navien could’ve had me check for the factory defect the first day but chose to string everybody out and send part after part that proved good by all tests.

Pitiful tech support and I’m a professional master plumber.

I talked to 6 different tech support reps over a two week period. Make multiple service calls to replace parts that weren’t defective at their direction.

@breplum

 

[Jane In AZ]

Why do you have a check valve ? Has anyone explained why it’s needed in your system ?

Why do you have a check valve ? Has anyone explained why it’s needed in your system ?

Twowax, I am not a plumber, but was told that the check valve prevents cold water from going back into the system, or something like that.

 

[Twowaxhack]

Rinnai provides a service sheet inside the front panel of their heaters that give the ohm value each component. There’s not much need for tech support with Rinnai.

Navien to my knowledge doesn’t provide that information, you must rely on their tech support to hold your hand.

 

[Twowaxhack]

Twowax, I am not a plumber, but was told that the check valve prevents cold water from going back into the system, or something like that.

When you get your plumber out to the job I suggest questioning it’s reason for being there to begin with. It may not be needed for your system.

 

[Jane In AZ]

Why do you have a check valve in the system?
Just as a counterbalance to Twowax,
I have trained via factory reps for Takagi, Nortiz, Rinnai and Navien.
I prefer Navien over the rest and rarely will even bother to work on them now and ONLY install Navien.
The products are very well designed, easy to service and for plumbers at least, the tech support has been fantastic. I only recommend the NPE A series. Now version V2 is the latest.
I will say that their older units (NR) stunk for the most part.

Thanks for your reply. Our son, who is also in California, was told that Navien is the best. He now has a Navien along with a recirculating pump, and has lots of hot water.

 

[Jane In AZ]

Navien sent part after part for about two weeks then after nothing worked they disclosed that the unit had a factory defect.

Navien could’ve had me check for the factory defect the first day but chose to string everybody out and send part after part that proved good by all tests.

Pitiful tech support and I’m a professional master plumber.

I talked to 6 different tech support reps over a two week period. Make multiple service calls to replace parts that weren’t defective at their direction.

@breplum

Tech support from Rinnai has been good so far. I don’t think our problem is with the unit itself, but most likely the check valve. Will question the plumber about its necessity next time we see him. Thanks!

 

[Jane In AZ]

I have just emailed Rinnai and asked about the function and necessity of a check valve in our current system. They’ve been very good at responding, so we’ll see what they say. In my next life, I may have to marry a plumber.

 

[Mitchell-DIY-Guy]

Why do you have a check valve ? Has anyone explained why it’s needed in your system ?

Just for fun, you should do a Google or other search with that question and see the answers that come up. They all sound plausible until they don't. I'll save you the trouble, but some of the answers have to do with the possibility of stagnant and or contaminated water back flowing into the mains, others seem to say without a back flow, their unit turns on randomly when cold water is turned on the home and a host of other ideas. For every idea suggested there's a pro dismissing it for one reason or another. Even the dismissals need to be dismissed; one pro says you don't need back flow since "the city water meter has one built in". Sure it does...but that doesn't explain why I have to have a costly dual RPZ on my irrigation system, and have it tested yearly!

The most plausible in my opinion, is the one that was actually related to pumps, not tankless, when it said "to prevent back flow so the pump doesn't lose its priming". Now, I can get behind that one! In my former weekend home in Michigan, (well and septic), the water system (hot AND cold) in the home would "lose its prime"; meaning, the water in the homes pipes would drain, air was introduced and when you arrived on a Friday night and started to use water, every fixture would spit, burp and gurgle until you finally got all the air out of the system. Had I put in a check valve or check valves, this likely may not have happened.

As for the Rinnai vs Navien vs Noritz or whatever...some regions of the USA and within states and communities have better representation than others. Here in the Charlotte NC area, Rinnai is the one installed almost exclusively. Navien has only one rep in the area and they are not that close...so trained techs and service and parts are harder to find. If you are a plumber in this area and you install tankless, you are going to spec Rinnai.

Years ago when I needed a tankless for a closed loop driveway heat system, the ONLY manufacturer who certified their tankless for closed loop circulation systems was Takagi. So that's the one I got.

 

[Jane In AZ]

Just for fun, you should do a Google or other search with that question and see the answers that come up. They all sound plausible until they don't. I'll save you the trouble, but some of the answers have to do with the possibility of stagnant and or contaminated water back flowing into the mains, others seem to say without a back flow, their unit turns on randomly when cold water is turned on the home and a host of other ideas. For every idea suggested there's a pro dismissing it for one reason or another. Even the dismissals need to be dismissed; one pro says you don't need back flow since "the city water meter has one built in". Sure it does...but that doesn't explain why I have to have a costly dual RPZ on my irrigation system, and have it tested yearly!

The most plausible in my opinion, is the one that was actually related to pumps, not tankless, when it said "to prevent back flow so the pump doesn't lose its priming". Now, I can get behind that one! In my former weekend home in Michigan, (well and septic), the water system (hot AND cold) in the home would "lose its prime"; meaning, the water in the homes pipes would drain, air was introduced and when you arrived on a Friday night and started to use water, every fixture would spit, burp and gurgle until you finally got all the air out of the system. Had I put in a check valve or check valves, this likely may not have happened.

As for the Rinnai vs Navien vs Noritz or whatever...some regions of the USA and within states and communities have better representation than others. Here in the Charlotte NC area, Rinnai is the one installed almost exclusively. Navien has only one rep in the area and they are not that close...so trained techs and service and parts are harder to find. If you are a plumber in this area and you install tankless, you are going to spec Rinnai.

Years ago when I needed a tankless for a closed loop driveway heat system, the ONLY manufacturer who certified their tankless for closed loop circulation systems was Takagi. So that's the one I got.

Wow, Mitchell! Thanks for the discourse! I guess we have to trust the plumber who installed the unit, at least a little bit, unless we know better. I’m awaiting Rinnai’s response regarding the necessity of a check valve. All I want is consistent hot water, but a lesson in plumbing is ok too.

 

[Jane In AZ]

I did get a response from Rinnai, a little lengthy and confusing for a lay person. If anyone is interested, I can post it. If not, thanks again for all the helpful comments.

 

[TomFOhio]

In short did they say you needed it?? Maybe there is a little bit of solder in the old check valve catching the flap a little

 

[Jane In AZ]

In short did they say you needed it?? Maybe there is a little bit of solder in the old check valve catching the flap a little

T

In short did they say you needed it?? Maybe there is a little bit of solder in the old check valve catching the flap a little

They didn’t say. They just described situations in which a check valve is needed. I’m not sure if ours qualifies or not.