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-   -   My next project natural gas tankless hot water heater. (https://ecorenovator.org/forum/showthread.php?t=3167)

ecomodded 01-10-14 11:26 PM

I had a look at the Specifications and was pleased to see it will run on Propane 13,000btu's or natural gas 15,000btu's.
I am in the running for a tankless water heater right now, I need to do more research..
How much does this model cost ?

pinballlooking 01-11-14 04:33 PM

Quote:

Originally Posted by ecomodded (Post 34707)
I had a look at the Specifications and was pleased to see it will run on Propane 13,000btu's or natural gas 15,000btu's.
I am in the running for a tankless water heater right now, I need to do more research..
How much does this model cost ?

The Takagi has a 15 year warranty on the heat exchanger even with a circulation pump control as long as you use a aquastat and/or timer
http://www.takagi.com/download/2013-Warranty-info.pdf
You vent it with 3” PVC this is cheap. I love the Energy Factor of 0.95.

The Takagi has free isolation valve and pressure safety valve kit deal. (This saves some money)

I bought it from build.com and found a coupon code. I paid $1,096.16 shipped with isolation valve kit.
http://www.build.com/takagi-th3dv-lp...21706_u3967755
But you can buy it a lot of places.
Mark

ecomodded 01-11-14 06:32 PM

thanks for the information , it is a expensive unit although a very powerful one 15,000 Btu's should do the trick. My propane Fireplace puts out the same Btu's as your heater.
I still need to get that pressure tested before I put it into service.

!5 yrs is a good guarantee some security with a warranty that long I expect cheaper units to have a 5 yr guarantee.

regards

Mikesolar 01-12-14 07:49 PM

ECO, it is 150,000btu, not 15,000. Most tankless water heaters are a minimum of 150Mbtu. I put in Navien regularly but have put in Takagi and Rinnai (same as Bradford White).

The cold snap last week has killed more than a few tankless heaters and I have been busy putting in new ones. I will never put the venting as close to the unit as was typically done and will ALWAYS put in fresh air thermal blocking so that the cold air cannot come in unless the unit is firing. On one I am putting in tomorrow (to replace a Takagi) the venting will be 12 feet long and the unit will not be on the outside wall.

On top of this, unless they insist, I will put in a Vertex or another high efficiency tank instead of a tankless. Most people will use the tankless the same what they used to use a tank, on and off, small amounts of water and the unit needs to go through a prepurge and sense the need for flow, light up, etc, then shut down again, sometimes without getting 1L of water to the tap. It is a waste. If I can use a Vertex or Polaris, assuming the heat load is right, I can eliminate a furnace or boiler.

pinballlooking 01-12-14 09:26 PM

Yes min is 19,500 max is 199000.
I have mine mounted in my garage on the inside wall. The air intake is in my attic. That keeps the wind from coming in the intake. The exhaust is about 25’ away.

My old tankless was a little smaller but Energy Factor of 0.80 my gas bill was $12.36 - $18.44 (this was summer bills when we did not use gas heat) this is with a $7.50 meter charge included. Not bad at all I was pleased with this. This is for a family of 4.

The new tankless does not have a pilot and has Energy Factor of 0.95 but we are doing intelligent water circulation pump. I will report back in the summer what the new gas bill is.

My neighbor has a Navien npe-240a that has Buffer Tank & Recirculation Pump included. Nice unit he likes it. My other neighbor that is a plumber puts lots of these in but if you buy them on the internet they will not honor their warranty.(no deal for me)


I looked up the Vertex hot water heater it looks very sweet. Wow it is expensive. I could have easily going for this tank if the cost was similar to my tankless heater it would be a great choice.

Mikesolar 01-13-14 05:11 AM

Quote:

Originally Posted by pinballlooking (Post 34746)
Yes min is 13,000 max is 199000.
I have mine mounted in my garage on the inside wall. The air intake is in my attic. That keeps the wind from coming in the intake. The exhaust is about 25’ away.

My old tankless was a little smaller but Energy Factor of 0.80 my gas bill was $12.36 - $18.44 (this was summer bills when we did not use gas heat) this is with a $7.50 meter charge included. Not bad at all I was pleased with this. This is for a family of 4.

The new tankless does not have a pilot and has Energy Factor of 0.95 but we are doing intelligent water circulation pump. I will report back in the summer what the new gas bill is.

My neighbor has a Navien npe-240a that has Buffer Tank & Recirculation Pump included. Nice unit he likes it. My other neighbor that is a plumber puts lots of these in but if you buy them on the internet they will not honor their warranty.(no deal for me)


I looked up the Vertex hot water heater it looks very sweet. Wow it is expensive. I could have easily going for this tank if the cost was similar to my tankless heater it would be a great choice.

Maybe I misread the post. I thought he was talking about the rated input of the unit. The min of 15mbtu is correct.

The Navien I am putting in is a 180 and will be with the buffer tank (you can get it with or without). The buffer tank is supposed to eliminate the sandwiching which it does but the evidence shows that the actual efficiency of the unit goes down somewhat from the non buffer tank model but everything is a tradeoff, I guess.

I don't know of any tankless that has a pilot these days and the old Bosch one was used for off grid solar because it did not need any power to light it up. I have put them in as well in the past.

The reason I mention the Vertex is because many tankless heaters don't last 10 years and we would expect any heater to do that. Much of the time it is because the circuits are going on/off a lot more than a tank control would. It also means that there is a lot of wasted gas for those who don't change their habits to meet the heaters abilities. Time will tell.

pinballlooking 01-16-14 04:00 PM

1 Attachment(s)
Quote:

Originally Posted by Mikesolar (Post 34747)
I don't know of any tankless that has a pilot these days and the old Bosch one was used for off grid solar because it did not need any power to light it up. I have put them in as well in the past.

Yes I was replacing a Bosh AquaStar 170V.



I charged up my new boat battery connected up my real sine wave inverter 150 watt 300 watt peak. It ran the new tankless heater fine while I was running hot water.

The battery is 50 AH we would use it then turn off the inverter off until we needed hot water again. It is good to know we will have hot water if the power goes out.

http://ecorenovator.org/forum/attach...1&d=1389909852

Mikesolar 01-16-14 05:37 PM

Quote:

Originally Posted by pinballlooking (Post 34824)
Yes I was replacing a Bosh AquaStar 170V.



I charged up my new boat battery connected up my real sine wave inverter 150 watt 300 watt peak. It ran the new tankless heater fine while I was running hot water.

The battery is 50 AH we would use it then turn off the inverter off until we needed hot water again. It is good to know we will have hot water if the power goes out.

http://ecorenovator.org/forum/attach...1&d=1389909852

I would be really careful that the inverter is pure sine wave, not modified because there is a lot of electronics (furnaces with ECM motor controls, for example) that will be destroyed by modified sine wave inverters. The ice storm we just went through forced a lot of people to get cheap generators to run the furnace or boiler, just to have the electronic board blow.

pinballlooking 01-16-14 05:46 PM

Quote:

Originally Posted by Mikesolar (Post 34830)
I would be really careful that the inverter is pure sine wave, not modified because there is a lot of electronics (furnaces with ECM motor controls, for example) that will be destroyed by modified sine wave inverters. The ice storm we just went through forced a lot of people to get cheap generators to run the furnace or boiler, just to have the electronic board blow.

Thanks for jumping in and sharing some of your experience. It is nice to see someone that is in the field that does not mind sharing info.

Good point. I paid the extra for a pure sine wave inverter and it is just big enough for the heater.

I have a generator but it is not a pure sine wave inverter so this is what I will use the inverter to run the hot water tank and not the generator.

wuck 01-25-14 10:16 AM

Quote:

Originally Posted by pinballlooking (Post 34528)
I have added a small expansion tank , a check valve and a recirculation pump. I did a loop back return with Insulated pex on my hot water line.

Nice job on the install Mark, the "smart" pump control is an excellent addition.

Where does the recirc loop return to? I'm guessing it runs back into the cold feed, triggering the heater when the pump is activated? I'm also curious about the aquastat install and how it is integrated into system.

I have a recirc pump on my NG fired conventional tank controlled by a simple timer. It's about 75 feet of 3/4" copper to the guest bath at the other end of the house, the pump is really a necessity. I added a 1/2" copper return line feeding back into the tank drain, with the total loop being around 150 ft. All lines are insulated through the crawl space.

I've thought about going tankless, moving the heater into an existing outdoor closet. The new location is adjacent to the kitchen and main bath, while the guest bath pipe would be cut to 30 feet or so.

Pat


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