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Old 08-24-2010, 07:32 AM   #16
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tankless water heaters


BTW...... Regarding the previous pics of the tankless units installed...

Good job guys/gals. I like how all piping and lines are installed in a proper and neat manner....... makes for a much cleaner / nicer look.


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Old 08-24-2010, 08:40 AM   #17
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Originally Posted by 57_Hemi View Post
I'm looking into a Rheem tankless that Home Depot sells..........reviews seem to be pretty decent.

If I do go ahead with the purchase I will be installing it myself. The only issue I am concerned with is the cold climate up here in Toronto Canada during the winter months. I have been told by a few people I know in the area that have them say they've had nothing but problems b/c of extreme cold air backdraft entering the intake / exhaust piping. When a cold gust of air enters the piping it creates alot of condensation problems which over a period of a few short months collects in the tankless unit and eventually corrodes the heat exchanger. I know they sell condensation collecting pipes but apparentley those dont work as well as the manufacturers claim they do. It is nothing but a nipple (outlet) tapped into the intake pipe (leading up just before the elbow used to exit the exterior wall)with a clear (or rigid) pvc line directed to a nearby floor drain. This is supposed to divert all condensation towards the floor drain and eliminate it from collecting in the unit itself.

I know of one person in the area that has had this installed (by a licensed pro) but is already on thier 3rd heat exchanger within 1 year. Bosch (the manufacturer) refuses to replace anymore for them b/c they say its installer error. I donno if this is just a problem with the Bosch tanks but its something I will have to look into before I decide to go ahead with the purchase and install of mine.

Anyone hear anything regarding this issue???

There is a guy on youtube who had the same problem (with a Bosch) but Im not sure where exactly he's from or if his unit was installed correctly.

what to do....
what to do....

You're a lot farther north than I am but Rinnai if you direct vent you do not use this set up. The drain is only used if the vent is greater than a certain length. Not sure if this is "universal?" I also have the hydronic coil and the unit is providing heat so it's pretty much always running. Not sure if that prevents condensation as the unit never really fully "cools down."
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Old 08-24-2010, 03:59 PM   #18
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Originally Posted by dawktah View Post
You're a lot farther north than I am but Rinnai if you direct vent you do not use this set up. The drain is only used if the vent is greater than a certain length. Not sure if this is "universal?"
I see, well in my case the vent would be about 2 ft total length and thats including the elbow. i would be mounting it directly where my existing exhaust pipe exits the wall.

Quote:
Originally Posted by dawktah View Post
I also have the hydronic coil and the unit is providing heat so it's pretty much always running. Not sure if that prevents condensation as the unit never really fully "cools down."
Well if thats the case than I guess the hydronic coil would play a part in aiding the prevention of condensation.

Are you satisfied with your new tankless system?
Would you say there is a worth while difference in money saved on natural gas ?

Like i mentioned earlier, this is something i would like to have but have not done the complete research on it yet.

Thanks and LMK
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Old 08-24-2010, 07:48 PM   #19
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Quote:
Originally Posted by 57_Hemi View Post
I see, well in my case the vent would be about 2 ft total length and thats including the elbow. i would be mounting it directly where my existing exhaust pipe exits the wall.



Well if thats the case than I guess the hydronic coil would play a part in aiding the prevention of condensation.

Are you satisfied with your new tankless system?
Would you say there is a worth while difference in money saved on natural gas ?

Like i mentioned earlier, this is something i would like to have but have not done the complete research on it yet.

Thanks and LMK
Savings I don't have anything to compare to as I did this install right after buying the house. The home was 100% electric when we got it. Not sure how electric water heaters fend under use, recovery time has go to be annoying.

Only thing not to like about tankless is the same thing that is well known about all of them, cold water sandwich. We have learned how to keep it from being an issue.

We are now running hybrid heat. hydronic coil serves as emergency heat and also based on differential I set in software for thermostats kicks in when temps get low and heat pump starts losing its efficiency. Will post in my project showcase about how that is working out and what final set points I'll use mid winter
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Old 08-24-2010, 07:59 PM   #20
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tankless water heaters


Quote:
Originally Posted by 57_Hemi View Post
Im looking into a Rheem tankless that Home Depot sells..........reviews seem to be pretty decent.

If I do go ahead with the purchase I will be installing it myself. The only issue I am concerned with is the cold climate up here in Toronto Canada during the winter months. I have been told by a few people I know in the area that have them say they've had nothing but problems b/c of extreme cold air backdraft entering the intake / exhaust piping. When a cold gust of air enters the piping it creates alot of condensation problems which over a period of a few short months collects in the tankless unit and eventually corrodes the heat exchanger. I know they sell condensation collecting pipes but apparentley those dont work as well as the manufacturers claim they do. It is nothing but a nipple (outlet) tapped into the intake pipe (leading up just before the elbow used to exit the exterior wall)with a clear (or rigid) pvc line directed to a nearby floor drain. This is supposed to divert all condensation towards the floor drain and eliminate it from collecting in the unit itself.

I know of one person in the area that has had this installed (by a licensed pro) but is already on thier 3rd heat exchanger within 1 year. Bosch (the manufacturer) refuses to replace anymore for them b/c they say its installer error. I donno if this is just a problem with the Bosch tanks but its something I will have to look into before I decide to go ahead with the purchase and install of mine.

Anyone hear anything regarding this issue???

There is a guy on youtube who had the same problem (with a Bosch) but Im not sure where exactly he's from or if his unit was installed correctly.

what to do....
what to do....

Of the tankless water heaters, Bosch has by far the worst reputation. I think they went through a few years with a bad design and lots of failures. I'm not sure if they have addressed the problems as they were not on my list of ones to research.

I have a similar install with about 2' of vent to the outside. I just made sure that the vent had a downward slope as per the instructions so the condensation would flow out. That should take care of the problem.

Heaters are rated to how many degrees they raise the water temp so if your water supply is very cold you may have some issues if you need LOTS of hot water at one time and have a very cold water supply. My Rinnai allows me to go about the stock 120˚ if I want with an external controller. That said, my water from the meter is very warm here in SC. I was able to shower pretty comfortably with NO water heater while I installed my new one. YMMV.
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Old 08-24-2010, 08:07 PM   #21
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Another thing I'll add about eliminating the cold water sandwich (Cue Homer: mmmmmmm). I bought the small 4 gallon Bosch point of use tank water heater to put in my kitchen under the sink but haven't installed it yet. It gets great reviews.

These are very efficient, use a small about of electricity and will give instant hot water where they're installed. This can bridge the gap for the delay of hot water from the tankless.

http://www.amazon.com/Bosch-GL4-4-Ga...2698137&sr=1-4
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Old 08-24-2010, 08:18 PM   #22
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Quote:
Originally Posted by dawktah View Post
Only thing not to like about tankless is the same thing that is well known about all of them, cold water sandwich. We have learned how to keep it from being an issue.
Im sorry but you lost me....lol
What exactly is meant by the term "cold water sandwich" ?


Quote:
Originally Posted by dawktah View Post
We are now running hybrid heat. hydronic coil serves as emergency heat and also based on differential I set in software for thermostats kicks in when temps get low and heat pump starts losing its efficiency. Will post in my project showcase about how that is working out and what final set points I'll use mid winter
Oh I see, so the hydronic coil is used to assist when the heat pump starts losing efficiency........interesting.

Forgive me here..... Im still fairly "green" when it comes to the newer systems of heating (air / water) in homes these days. Im more familiar with your basic forced air (furnace), electric baseboards and gas/electric hot water tanks so I hope you dont mind my questions.

Look forward to seeing your project showcase in the future and how you have eveything is setup.

Thanks
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Old 08-24-2010, 08:50 PM   #23
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Quote:
Originally Posted by Hack View Post
I have a similar install with about 2' of vent to the outside. I just made sure that the vent had a downward slope as per the instructions so the condensation would flow out. That should take care of the problem.
Ya know, now that you mention it a downward slope outward on the vent should surely cure the condensation issue for such a small pipe run (2ft or so)..... Thanks

Who knows, maybe the people complaining they had condensation issues with thier tankless systems never had them installed correctly in the first place.........everyone is quick to complain when something goes wrong.....lol

Its like something my father once told me .....

"Ahhh these people of today, they're so quick to complain. If someone has 5 good days in a row they might mention it once, but if someone has 5 bad days in a row you can bet they'll mention it 4 or 5 times" ..........lol

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Old 08-25-2010, 06:07 PM   #24
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tankless water heaters


Quote:
Originally Posted by 57_Hemi View Post
Im sorry but you lost me....lol
What exactly is meant by the term "cold water sandwich" ?

Look forward to seeing your project showcase in the future and how you have eveything is setup.

Thanks
My understanding of "cold water sandwich" is that all tankless heaters by heating water on demand have to get the exchanger up to a certain temp to continuously heat the water. I'd guess they vary on how long of a delay that is. So when you switch off all demand for hot water and wait longer than the recovery period(?) then turn on a faucet again you get a brief period when water that hasn't been heated hot enough passes through the unit while its getting back up to speed.

This is a searchable term and can get better explanations with photos.

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Old 08-25-2010, 08:17 PM   #25
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Quote:
Originally Posted by dawktah View Post
My understanding of "cold water sandwich" is that all tankless heaters by heating water on demand have to get the exchanger up to a certain temp to continuously heat the water. I'd guess they vary on how long of a delay that is. So when you switch off all demand for hot water and wait longer than the recovery period(?) then turn on a faucet again you get a brief period when water that hasn't been heated hot enough passes through the unit while its getting back up to speed.
Wow ! I totally understand... I was just thrown off by the word "sandwich" in the term.........lol

thanks

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