Rinnai E110CP explosive ignition and low heat

Mark Eatherton

Sorry for the late reply...

I am not a big fan of these devices, for heating DHW and especially not for doing space heating, hence did not follow the thread and didn't realize someone had asked a question of me...



As it pertains to DOMESTIC hot water, in MY area, the code REQUIRES that if the furthest point of use is "XX" feet away from the source, that there be a recirculation return in the system. Simply adding heat to water does not constitute pollution in my opinion.



With that said, BOTH codes currently allow the use of approved appliances as space heating and DHW heating, using the same contiguous water, which in my minds eye SHOULD be illegal. The code does not allow "water of questionable character" to be allowed in potable water (hot or cold) distribution systems. The water that sits idle in a space heating system for a very short period of time (think vacation times during the SUmmer months), can and will become water of "questionable character" in short order, and thereby constitutes a situation that SHOULD be addressed by the law.



Unfortunately (and obviously) we ( licensed plumbers and the AHJ's) do not see eye to eye on this subject. And I don't care how many pump timers/piping "flushing" configurations you incorporate into your "open" system design, bacteria WILL thrive and survive and cause an illness, some where, some day, some time. Just like DHW systems operated below 130F will and can do.



To reiterate, a conventional DHW system with a circ. return does NOT constitute a contaminated cross connection in MY opinion, but an open space heat/DHW heating system does...



To be safe, DHW tanks should be maintained at temperatures above 130 F (preferably 140 F) and mixed down ~ 120 with a code approved anti-scald mixing valve. Tankless heaters do not work well with anti-scald mixing valves based on my personal experience.



Bottom line, the local AHJ is in control, and I do not want to counter their interpretations/requirements. But I also don't like seeing people do the wrong thing in the field.



ME

Jack

MA code on "Cross Connect Recirc"

A few years ago I represented Metlund Designs in the New England an MA area. I had a conversation with Paul Kennedy, Chairman of the P&G Board in MA about getting approval on the product. He said it would not happen. I asked why and he said that "hot water exiting a tank water heater is non-potable water". Again, being slow, I did not get that so asked the question, "So I take potable cold water, feed it into a tank water heater and the water becomes non-potable exiting the water heater?" "Yes", said Paul. The break down of the anode rod and the sludge in the bottom of the water heater were to blame for this. Now, I can carry a new 40 gallon tank water heater by myself. I have seen plenty of failed tank water heaters that it took two men and a hand cart to remove, because there was so much sludge in the bottom of the tank. I understood his explanation, but pointed out that his problem wasn't the "cross connection" for recirc. but that he had a WATER HEATER PROBLEM. Given that I was the Rinnai rep at the time, I offered that the solution was to ban those pesky unhealthy tank style water heaters and have a Rinnai tankless installed in every house in MA. I was very excited at the possibilities. The conversation went downhill from there;)..., but jeez, it just made so much sense, to me at least. I never got the approval for the Metlund, which in my opinion is the best recirc system on the market.



This conversation took place 3-4 years ago, so things might have changed. MA is lucky to have Paul Kennedy in that position, imho! I miss working with the Board.

Mark Eatherton

Funny that...

So, I can see the chiefs explanation in simple terms, but does not the hot water flow through the same aerator as the cold water? Or is it also required that all faucets have to be individual, old deck mount spigot types? If no, then aren't his constituents being poisoned at the aerators?



And, I don't know WHY people do this, but it is common place for people to drink warm water. Something to do with not thermally shocking their stomachs... Do they have a health warning about consuming DHW on every faucet in MA?



Lastly, how do they address the code requirement of requiring a DHWCR if the POU is more than "XX" feet away from the source? Does MA not recognize the International Energy Conservation Code?



I too understand most reasons for the code, and as a licensed master plumber, am charged with protecting the health of my customers, but REALLY?



I am certain a conversation between the chief and the people of the wall would be an interesting one for sure...



I have more questions than answers ;-)



ME

Jack

Well, Mark

You can imagine my confusion;)

SWEI

crossing connections

Edit: I see the 'problem' they have imagined here.  It is in fact the slug of warm water that crossed to the cold side during the time the recirc pump was running.



What a stretch.  Legionella has a far better shot at infection when someone is washing their face than when they drink a glass of warm water.