instant (tankless) water heaters

enough to be dangerous

I want to replace my tank type water heater with a takagi tk-jr or similar product. I currently have hot water recirc with an El Sid 10B pump (max head =3ft and max gpm=3.5).
It works fine as a recirc pump.
I asked takagi if it would be ok with their water heater and they say that for recirc to work with their heater the pump must be a 1/12HP high head model.
The implication is that there is a large drop through the instant water heater. Does anyone have any info on this? The Takagi people were completely unhelpful (they basically could only read the online spec sheet to me).

Mark_7

tankless cir.

We install Rinnai's and on single unit they want 3gpm/12feet of head, which would be a taco 006.

Jack_23

Try to...

look for a new location for the tankless unit. Your old water heater is probably venting into a chimney, if gas fired anyway. Your new unit will most likely not require a chimney. Your Rinnai tankless will last 20-25 yrs. If your hot water system requires recirc, look around the house for another more convenient location for the new WH which does not need the pump/recirc. the location change may increase the cost of the install but you will recover the cost in energy savings. Recirc are money burners

Robert O'Connor_7

Why??

If the company you want to buy this water heater from was like that now. What kind of support will be recognized when there's a problem with it?......Robert O'Connor

Larry Weingarten

a question(s)

I installed a Paloma tankless heater for friends about 23 years ago. It still works, sadly. The problem is that it (and all) tankless heaters shut off on low flow. It has become a real problem with low-flow fixtures... or maybe I just hear about the rare problem cases? Also, my experience suggests you not use tankless unless there is an odor problem or you live alone, as upfront costs and upkeep more than offset any energy savings. I question the wisdom of widespread application. Does anyone have experiences to share?

Bob_9

Tankless

I've got a Takagi TK-2-D that I installed with a Grundfos UP-15-18B5/TLC recirculation pump. It works great and the Takagi guy was fairly helpful along the way.

Jack_23

The new technology units

such as the Rinnai and takagi are a far cry from the old Paloma. Low flow limitations were the primary problems with the old units. As they could not handle low flow they also could not put a large enough burner into them to handle whole house water heating as the larger burner would further aggravate the low flow problem. The Rinnai which I know best, live with and represent is a neat piece of equipment. It will modulate from 15,000btu-180,000btu (that is modulation from 8%-100% of capacity)with flow rates from .5gpm-up to 8.5gpm (depending on temp rise). For the New England area with our cold ground water the unit will do 4.7gpm at 70f temp rise all day long...and night too, should you choose. In the south with warmer ground water the 2532 model can get to the 8gpm flow rates. With energy factors of .82 ng and .87 lp and direct vent they are competitive with anything, except the low cost, low efficiency (.60 ef), throw away tanks. Check the price of the 2520 FFU model at your wholesalers. I think you will find them very competitive with dv tanks and indirects. THESE new tankless units work and will change the way we heat our hot water. Frankly in todays investment climate it is comforting to be able to buy something for the house which delivers and will recover its cost in a short time and then last 20-25 yrs. In my 13 yrs with Rinnai I have found them to be the best most functionally reliable product I've seen in the business. When I shut down my boiler and indirect and started my Rinnai my gas consumption dropped 60+%. Paul Harvey is advertising Rinnai's now and he too reduced his energy bill by 70%. As a nation, can we afford to overlook those kind of savings? Try one, you might be surprised!

Bob Anderson_2

Tankess Water Heater and Recir

Well, tankless water heaters are great. But, with a recirc pump the problem is that twh will go off and then on and you will get a cold water plug - then hot - then cold. Also, a twh will go off and on too many times. Yes, it will work with most twh, but to get better options. Put a small tank in front of the twd and then recir through this tank. When you call for hot water - the twh will put hot water through the tank and then heat it. When the recir needs hot water - it will pull it from the tank heater. This will allow you to have hot water without cold plugs and will allow any twh to last longer. Also, if you use a timer for your recir, then this will save money because the recir will not run as long nor will the tank.

A good tank would be the Ariston 4 or 6+ (depending on your amount of pipe) and this will allow you to use any twh for a recir. Else, make sure your twh has a built-in aquastat - takagi tk2, tkd20, tk jr, Rinnai, Bosch 635 ES.

Check out this site for the all the supplies - not sure about the Rinnai. http://www.houseneeds.com

If you need anymore info - email me as I have put this into my house last year after problem with the TK2 and a recir. This fixed the problem and works great.

Bob

Nron_9

Rinnai

Ever have problems with a unit and get NO responce from the company ,in canada the rinnai runs at about 2 gal a min we have verry cold water here , 37-42 F all year round , had problems with the unit shutting down only on weekends though , ( doesent work weekends ) and got no responce from local rep of the Factory 1800 number , spoke to some service guys in califoria who said the same thing about service issuses are these rare occations just for us or are you finding the same problems

Jack_23

the factory service # is:

800 621-9419. use ext 207,501, 0r 217. Listen to the message and it will tell you, if you get voice-mail, to hit #7 and be forwarded to the cell number. I did it yesterday and I got a call back in less than 10 min. However like all factory service numbers, it ain't perfect. Canada recently had a change of reps which would explain the lack of response. If I can be of assistance (and I can on this) you can call me at 508 366-1063 (office) or 617 834-8751 (cell).

RonO

two tankless hotwater heaters one house.

I am considering replacing our 15yr old LP fired 60 gal tank water heater with two tankless LP fired hotwater heaters. The house has 4 bedrooms and 2-1/2 baths. During the week we only need hot water for myself and my wife. Currently in our the master bathroom it takes 1.5 minutes to get the water hot (over 75ft from the heater) and we have a jacuzzi that completely empties our current hot water supply. I do not want to use a circulator pump because we only use that bathroom morning and night. We often have guests, and those times we do lots of cooking, dishes and laundary. Our kitchen, guest bath and laundryroom are close enough to the existing heater which vents through a chimney (with a proper liner)but at its age, I know that I need a plan to replace it. I want to vent the first tankless water heater through that chimney and place the second tankless water heater at the opposite end of the basement which will feed only the master bathroom on the second floor. The hot water run would be about 12ft.

I don't know if I should use a power vent (we have a poured concrete foundation) or connect into a flue going up to the roof that is not yet built, but we are planning to add an LP room heating stove on the first floor just above where I am planning the second hot water heater.

I also don't know if I should:
#1. Tie the hot water lines in series.
#2. Keep them isolated.
#3. Keep them normally isolated with manual valving to tie them together during high demand times (when we might have 8-10 people).

#4. I have a 500 gallon LP tank 100ft from the house with a 1" line
leading to a 1-1/2" black iron pipe going the lenght of the basement. Will I have enough gas flow if both water heaters go on at the same time as the kitchen stove and 120,000 BTU of room heating stoves are running?

Any suggestions would be appreciated.
Ron

Kevin_in_Denver

DHW Recirc

The Taco D'mand system is by far the best solution to the problem for many reasons. (I don't sell anything) Just study how it works at: http://www.taco-hvac.com/current_category.313/prod_detail.html?Product_Group_ID=008-DM_008DMPK

Kevin_in_Denver

DHW Recirc

The Taco D'mand system is by far the best solution to the problem for many reasons. (I don't sell anything) Just study how it works at: http://www.taco-hvac.com/current_category.313/prod_detail.html?Product_Group_ID=008-DM_008DMPK

Kevin_in_Denver

Rinnai really sounds great. Would you/have you used them to heat radiant floor systems?

Jack_23

GPM X DELTA T X 500=BTU

There are a lot of them running on radiant systems but you've got to do it correctly. First, I love them as a water heater. Biggest problems there are to small a gos line and too far from the intended point of use. On radiant I like a P/S. Pump thru the Rinnai. 008 min or equiv. I've used small tanks for the primary. Immersion A stat to turn on the circ and pump your slab off the tank. BTW you will not circulate more than 5 gpm thru a Rinnai with any reasonable sized circ. I also like them for hydro air systems but make sure the flow rate on the AH is ok with Rinnai's 4-5 gpm.