# Rannai tankless



## Bill (Jun 17, 2008)

Installed few. Never had to work on one yet. Got a call, water getting cold at showers. Checked all the sinks, endless hot water. Turn on hot water at shower, 1 minute, cold water. Found out shower heads were clogged. Changed them out, worked fine. Just thought I would share this in case someone else runs into it.


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## The Dane (Feb 19, 2015)

Bill said:


> Installed few. Never had to work on one yet. Got a call, water getting cold at showers. Checked all the sinks, endless hot water. Turn on hot water at shower, 1 minute, cold water. Found out shower heads were clogged. Changed them out, worked fine. Just thought I would share this in case someone else runs into it.


So you got called for it taking a long time for hot water to get to the shower? Not for bad water pressure at the shower? I would think a clogged showerhead would get you a call for no pressure.

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## Bill (Jun 17, 2008)

The shower was getting hot for about a minute, then the unit would shut down causing water st showers only to get cold.


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## Bill (Jun 17, 2008)

Shower seemed ok. But the heads were clogged just enough to shut the heater off. Changed the heads, works fine.


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## Debo22 (Feb 15, 2015)

Usually a summer time call. Tankless water heaters turn on with a designed gpm flow rate, higher inlet cold water temperature means less hot water mixed in at shower valve. Coupled with clogged low flow shower head the tankless won't fire. Clean the shower head like you did, if trouble persists lower the output temp on the heater.


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## Tommy plumber (Feb 19, 2010)

So if the flow rate is too low, then the tankless shuts off....Hmmmmmm.....another reason to recommend a tank-type W/H. 

I really don't like tankless. Maybe because I haven't done many.


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## OpenSights (Mar 23, 2015)

I honestly don't know anything about tankless, installed one and repaired one.

I once had a customer who had one, this was 7-9 years ago, asked him how he liked it. His one and only complaint was he couldn't trickle hot water into his glass at the kitchen sink....:blink: Told me they only heat with so much flow.

Thinking about it, that's not a bad idea. How many faucets do you see dripping or running from the hot side.

Sometimes you can learn something from a HO.


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## sparky (Jan 8, 2014)

Tommy plumber said:


> So if the flow rate is too low, then the tankless shuts off....Hmmmmmm.....another reason to recommend a tank-type W/H.
> 
> I really don't like tankless. Maybe because I haven't done many.


I messed with ya tommy,don't care for tankless at all,now if they could come up with a way for no maintence I would like them more


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## OpenSights (Mar 23, 2015)

sparky said:


> I messed with ya tommy,don't care for tankless at all,now if they could come up with a way for no maintence I would like them more


We un-sell them for for this reason alone. Every heater needs to be flushed, but adding chemicals to the flush twice a year minimum generally turns people off.


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## dhal22 (Jul 30, 2010)

We install 20 or so a year. Every single customer loves them. I was a big Eternal fan partially due to stainless heat exchanger requiring FAR less maintenance than copper heat exchangers. We now install Navien heaters, also stainless heat exchangers. 

I make more money installing tankless than tank so don't get the dislike for them.

Most of my long time customers now have tankless so they better perform.


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## Tommy plumber (Feb 19, 2010)

dhal22 said:


> We install 20 or so a year. Every single customer loves them. I was a big Eternal fan partially due to stainless heat exchanger requiring FAR less maintenance than copper heat exchangers. We now install Navien heaters, also stainless heat exchangers.
> 
> I make more money installing tankless than tank so don't get the dislike for them.
> 
> Most of my long time customers now have tankless so they better perform.


 










What part of the country do you live in? How cold is the incoming cold water in your locale? 

Where the incoming cold water is not that cold year round, like south Florida and Hawaii, they work great due to the low temperature rise needed. But up north where the incoming cold is really cold, say 40 F, that tankless has a bit more work to do. With only one shower going, that might not be a problem, but with multiple showers going on a cold winter day with incoming cold barely above freezing, there might be a shortage of hot water. I don't know, I haven't studied them in detail.

For the longest time the minimum pipe size {for gas tankless water heaters} was 3/4". Then tankless mfgs. came up with the sales pitch that their gas tankless units will work on a 1/2" line. But many a plumber will tell you that on a 1/2" line, when the gas tankless kicks on, it sucks gas down to the point where it will starve other appliances. 


Also, when taking a tankless class, they point out that, on that 1/2" line the tankless heater should be close to the meter; in other words it should be the first appliance branching off the gas trunk line.

Then with the elec. tankless models, there is a beefy upgrade of the electic, not to mention the cost of the tankless being equal to or greater than a tank W/H.


I'm glad you like them and your customers are eating them up. But I have heard too many negative things about them.

A quick story about an elec. tankless; I recently took one out for a man. It fried and melted his CPVC water piping attached to it. So he ordered a new one and had it there for me to install. Brand new out of the box. It was from a company in Miami, FL. I don't remember. Titan maybe? I don't recall. Anyway, I get the new one installed and the current hooked up and it didn't work! He was pee owed. He thanked me and paid me telling me that he would send the replacement unit back for a new one.

Call me old-fashioned, but I am not a fan of tankless water heaters.


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## dhal22 (Jul 30, 2010)

I live in Atlanta Ga. Fairly mild water, both temp and hardness. I run 3/4" full bore to a tankless, even the gas valve and even 1/2 connection units. It gets a lot colder in Tulsa where several members of my family all have tankless heaters (Eternal, Rennai, Navien and Noritz) and they all love them. My parents and 1 brother have Rennai's so they get descaled every year or 2.


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## The Dane (Feb 19, 2015)

Not me but our shop, has installed a couple of them. Haven't heard of any problems with them and we don't do any maintenance on them as far as I know. My parents in Denmark has had one for probably 10 years now with no problems.

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## sparky (Jan 8, 2014)

sparky said:


> I messed with ya tommy,don't care for tankless at all,now if they could come up with a way for no maintence I would like them more


That should have been I'm with ya and not messed lolol


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## sparky (Jan 8, 2014)

OpenSights said:


> We un-sell them for for this reason alone. Every heater needs to be flushed, but adding chemicals to the flush twice a year minimum generally turns people off.


Yes people just will not do the maintence on them as required,heck I wouldn't want to do it in my own house lololololo,there was one heater I installed that required monthly maintence or warranty was void


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## 5onthefloor (Sep 13, 2017)

When I pull the cover off a tankless unit I let the homeowner take a look at the innards. I tell em it looks like it belongs on a space station. I have replaced PC boards, fan motors, transformers, heat exchangers, gas valves. They are not fun to work on but since most companies shy away from them I've been thinking when I go on my own I wanna become a tankless expert. Entire subdivisions here are being outfitted with one to two units per house. 

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## 5onthefloor (Sep 13, 2017)

Bill said:


> Installed few. Never had to work on one yet. Got a call, water getting cold at showers. Checked all the sinks, endless hot water. Turn on hot water at shower, 1 minute, cold water. Found out shower heads were clogged. Changed them out, worked fine. Just thought I would share this in case someone else runs into it.


Working on ems a PITA. I don't have monster paws for hands but even I had trouble on this one I worked on a couple days ago. Bad flow sensor servo. Plus the unit was outdoor in a garden. My luck is I'm always a few feet away from the shade. Got it done though...

















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## Tommy plumber (Feb 19, 2010)

5onthefloor said:


> Working on ems a PITA. I don't have monster paws for hands but even I had trouble on this one I worked on a couple days ago. Bad flow sensor servo. Plus the unit was outdoor in a garden. My luck is I'm always a few feet away from the shade. Got it done though...
> 
> 
> 
> ...


















What was the original call, no hot water? Or something else? Good quality pictures by the way. I like the up close as well as the long distance shots.


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## Eddy k (Jan 30, 2015)

I have only installed 3 navian' this one is 3 years old. Domestic + Radiant, I did go back and change out copper condensate to pvc. Regular flushing no problems so far.


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## breplum (Mar 21, 2009)

Chiming in along with dhal22's post. We only install Navien, my choice. 
Having been trained to do factory tear-downs from Takagi and Noritz, and having liked Eternal for a few years, the Navien NPE 96% efficient condensing water heaters are supremely well designed and constructed...and really easy to service.
The box is larger than the low efficiency models, so everything is readily accessed and simple c-clip parts access.
Only done a few Combi units, and not much hydronic experience, so no comment about them.


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## 5onthefloor (Sep 13, 2017)

Tommy plumber said:


> What was the original call, no hot water? Or something else? Good quality pictures by the way. I like the up close as well as the long distance shots.


Yah no hot water was original call. That's one of the things I don't like about the company I work for. I was not the original tech that diagnosed issue and I had never been to this house before. Pick up my work orders for the day and this one says, install part for Rinnai. Don't mind the challenge but I'd feel dumb if I replace the part and issue is misdiagnosed or other issues are found. Fortunately that was all that was needed. Thx about the pix. Long shot was to show how had it been closer to that corner I woulda been in the shade. Also that small bush or palm or whatever it is was really pokey and I did not like that. 

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## 5onthefloor (Sep 13, 2017)

breplum said:


> Chiming in along with dhal22's post. We only install Navien, my choice.
> Having been trained to do factory tear-downs from Takagi and Noritz, and having liked Eternal for a few years, the Navien NPE 96% efficient condensing water heaters are supremely well designed and constructed...and really easy to service.
> The box is larger than the low efficiency models, so everything is readily accessed and simple c-clip parts access.
> Only done a few Combi units, and not much hydronic experience, so no comment about them.


Man I way prefer the Naviens. Swapped out a heat exchanger about a month ago (we suspect water quality issues as they're on a well). It took two of us but that's because they installed the unit in the attic. Living in TX we don't see any hydronic heating so that makes things pretty simple. 

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## breplum (Mar 21, 2009)

This is at a school where we replaced a 1,200 lb commercial 120 gallon water heater. There is a giant 80', 1-1/2" recirculation loop.
It serves about 45 sinks in all the classrooms and a few bathrooms but the chance of simultaneous draw is so low, we have received no complaints.
I piped for a future additional unit, just in case.

It took longer to remove that heavy, cumbersome heater (no forklift) than it did to replumb the Navien.


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## OpenSights (Mar 23, 2015)

5onthefloor said:


> Yah no hot water was original call. That's one of the things I don't like about the company I work for. I was not the original tech that diagnosed issue and I had never been to this house before. Pick up my work orders for the day and this one says, install part for Rinnai. Don't mind the challenge but I'd feel dumb if I replace the part and issue is misdiagnosed or other issues are found. Fortunately that was all that was needed. Thx about the pix. Long shot was to show how had it been closer to that corner I woulda been in the shade. Also that small bush or palm or whatever it is was really pokey and I did not like that.
> 
> Sent from my SM-G930V using Tapatalk


Why aren't you working for yourself? You're a master, you sound like you know your ****.... It is more stressful, but worth it IMHO.


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## 5onthefloor (Sep 13, 2017)

OpenSights said:


> Why aren't you working for yourself? You're a master, you sound like you know your ****.... It is more stressful, but worth it IMHO.


Working on it brother...

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## OpenSights (Mar 23, 2015)

Good.


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