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Rinaii Tankless Water Heater - Comparisons (RU75 / RU98), & Install Questions

Rinaii Tankless Water Heater - Comparisons (RU75 / RU98), & Install Questions


  #41  
Old 09-08-14, 05:35 PM
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Yeah it's a walkout basement. Along the back totally exposed and stick built. Not fully underground.

Got it - so recirculating in tankless solves sandwich and long travel issue but at the cost of losing a lot of the efficiency of tankless.
 
  #42  
Old 09-08-14, 06:05 PM
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Got it - so recirculating in tankless solves sandwich and long travel issue but at the cost of losing a lot of the efficiency of tankless.
Sure.. Tankless with out a buffer tank and recirc line causes undesirable effects..Sandwich effect. And you actually wait longer for HW then a standard tank..

I have removed so many tankless heaters and replaced with a tank heater to original. Most were less then 5 years old..

The thing is when there is an issue and I tell them the part is $400 bucks for the failed fan assembly say, they tell me I could get a new tank heater for the same price. This is after I was there a month earlier for a failed pressure switch for say $200. And 3 months earlier for a thermistor for $200...

Guy says take it out and put a tank heater in... I say OK... I still have the unit in my shed... Its a bosch....LOL
 
  #43  
Old 09-08-14, 06:39 PM
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Got it. Tankless with sandwich effect and long wait for hot water = cheap to run but undesirable. Plus, tankless heaters are unreliable.

Given that I have the space for two tanks in the unfinished space, will talk to builder about returning Rinaiis and installing those instead.

Rinaii at least seems to have a fairly good track record but then again there's not anyone you can ask who's used one for 20 years yet either to see if they are still happy or how many times they went bad.

Sigh, I wish I'd known all that I learned from you through today two months ago before they even started talking plumbing.
 
  #44  
Old 09-08-14, 07:05 PM
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Geez... Your probably getting the standard HVAC system too,,,LOL... Now its a bit of money to upgrade but I would have suggested hydronic heat.. Baseboard or possibly radiant...

Guess you will be stuck with dry air and moldy ducts....
 
  #45  
Old 09-08-14, 07:08 PM
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So couple ideas for tomorrow if you are still around...

Can we get away with just one tank and recirculating pump maybe? Or even the one tankless and recirculation?

I guess the idea of recirculation is to eliminate sandwich and delay but doesn't help with gpm so I still need to have 2 of something...

Maybe even one tankless and one tank with recirculation. Hmmm.

Is there a way I can guesstimate the extra annual cost to have recirculation running? Put a price on no sandwich and insta-hot?
 
  #46  
Old 09-08-14, 07:33 PM
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Can we get away with just one tank and recirculating pump maybe? Or even the one tankless and recirculation?
Code dictates what a 3 and 1/2 bath home needs... Call your local authority and ask them.

IMO , no way one tankless unit... But after the inspectors leave you cant shut one tankless off as you can one of the tank heaters,,

Sure!!! , you want one HWH?

I installed these and they are great. As long as your autority approves..

This is a 50 gallon vertex. If you ever used all the 50 gallons this heater will still produce 3 gpm.. ( I have to check specs though for incoming water temps)

90% eff. Subject to rebates too.

VertexÔ„ó Power Vent 50-Gallon Gas Water Heater | A. O. Smith Water Heaters

Otherwise if authority allows a standard 75 will be good. ( Price difference though from the vertex)

ProMax® SL Power Vent Higher EF 75-Gallon Gas Water Heater | A. O. Smith Water Heaters

I guess the idea of recirculation is to eliminate sandwich and delay but doesn't help with gpm so I still need to have 2 of something...
Two tankless for GPM yes!!!... Not so with tank heaters. You will get any GPM you want with tank, but you will run out of hot water sooner or later unless the tank can keep up. Like the vertex or two 40 or 50 tanks......

Note: I installed a vertex in a home and the inspector said it was not big enough and failed me.. He did not know anything. I had to explain to him it was 90% and produced 3 gpm like a tankless... Well he passed me after I educated him...

Is there a way I can guesstimate the extra annual cost to have recirculation running? Put a price on no sandwich and insta-hot?
Standard tank heater recirc, taco 007 uses less the 25 watts when its on... ( Ill have to figure it.)

Tankless 12 gpm pump required from rianai minimum??? Who knows. I have to look that up .

Cant think now. Going to bed and had to many Pumpkin ales....LOL
 
  #47  
Old 09-08-14, 07:52 PM
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Read this again... Although the last paragraph on page 84 is bogus this link tells a true story...

http://www.chandlerdesignbuild.com/f...hbDecJan08.pdf
 
  #48  
Old 09-09-14, 10:18 AM
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Good news on going with the tanks...

Also make sure when the plumber pipes in parralell as show the tees between the units have to be dead in the middle. Hot, cold, and recirc line..

Otherwise when you use hot water you will pull from one heater over the other.
 
  #49  
Old 09-09-14, 09:23 PM
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Thanks for all the help. Work starts tomorrow on putting in the tanks. I have the space in the utility room so why not. I just never expected them to be cheaper to operate!
 
 

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