instantious water heater

JackFre

Go to www.foreverhotwater.com and you can find a trained installer in your area...for the Rinnai product that is!

steve_125

instantious water heater

i am a homeowner and am switching from electric to gas to heat and hot water. i am considering instantious water heater but have yet talked to a plumber that thinks it's a good idea. is there anyone out there that installs, services, or recomends them. i like the idea of only heating the water as you use it , but am concerned about getting the unit serviced if something goes wrong. is there any other downsides that i should consider? I am looking at the paloma 7.4 model at home depot. it is supposed to suply two showers simultaniously ? any thoughts or coments would be appriciated.

Ed_26

instant h2o htr

Pay serious attention to gpm & temp rise - this is the most important, next to efficiency & maintainence issues, if you are to supply your family with hot water. Your supplier/installer will deal with the above issues & warrantee, so choose carefully.

hvac-tech

long pay back

In the C.R. Mag. of 2/05 or 3/05. Pay back is 25 years.
For going to a tankles water heater.
The life of the tankles is 20 years & needs cleaning of
pipeing in unit.
Most tank gas heaters will only run to maintain tank temp. about 10 mins. in 24hrs. that is only 0.6944%

Go with a 50gal. heater with a mixing valve.

Unknown

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jp_2

I agree,

lots of hype out there. does it really make sense to fire up a 100,000 btu burner just to wash your hands?

JackFre

Personally, my gas bills

upon installing my Rinnai water heater dropped from 36-44 therms per month to 10-14 therms per month. IF...you have hard water, you MAY have to clean the coils but if you have a good plumber who follows the installations instructions the unit will be piped to accomodate this. Personally, in six years I have not done it once and have suffered no reduction in hot water capacity. Yes I can run two 2.5gpm shower heads all day long. Do you have hard water?

To the question, does it make sense firing a 100kbtu burner to wash your hands. The answer is definitely, yes! My water heater will fire from 15kbtu UP TO 180kbtu. It looks at the incoming water temp and the vol, to a tenth of a gal and fires only the amount of gas necessary to heat that specific volume of water to the precise temperature. Just great technology!

Ed is correct. On demand water heaters are all about flow and temperature rise. I will, if given the chance, take a bucket and clock the actual flow rate.

Your current water heater may be far from the primay points of hot water use. DO NOT install your new on demand unit there. Move it closer to the primary hot water uses. I made the mistake of putting mine down by the boiler/indirect as that "is where it goes". I now get up in the morning turn on the shower, brush my teeth and then after a minute get hot water. The wait is annoying and wastes energy. I am in the process of re-doing my upstairs bathrooms (she said she has waited long enough...she is correct, but that is another story). I am going to take my very quiet, compact Rinnai and put it between the two bathrooms. By doing so I will get the best performance and economy out of my system. As well, I will reduce the amount of hot water piping in the house by about 75% as I will only need to make about a 15' drop of 1/2" pipe to pick up the downstairs lavie and kitchen/dw

In many localities there are rebates available from the utility. There is a $300 federal tax credit for '06. I wouldn't put it past the gov't to issue a tax credit on something that took 25-30 yrs to pay back, but this...they got right. You will see a dramatic reduction in energy consumption. One possible caviate there. Once people find that they can run the shower all day, they tend to take longer showers. Hot water is a comfort issue, so enjoy it.

Don't buy the damned thing from HD. If you want a 2X10 or a bag of concrete mix, then fine, but this is a sophisticated gas appliance and you want to deal with contractors who have enough experience to properly support you, themselves and the manufacturer.

Plumdog_2

are there any shortcomings you can think of?

what is the Cold Water Sandwich? Will it be easy to pipe in a re-circ line for those far away faucets?

Unknown

If your tank would be installed in unconditioned space, I might consider a tankless.

Otherwise, I would definitely stick with a tank.

Steverino

indirect

Rinnai's website has 2 different configurations for circ loops. It also addresses the issue of the "cold water sandwich" (basically installing a small electric water heater).

jp_2

short cycling

I'd call hand washing short cycling, and I think 95% of people here consider short cycling inefficient.

I admit there are Ok units out there, but the efficiency ain't there for short cycling.

as far as your decrease in gas bills, that kind of depends on the condition of your old water heater. anything old and in crappy condition is not a proper comparsion to a new unit.

JackFre

Cold water sandwich

Is a primary characteristic of ALL on demand units. Every time the water flow stops, the burner does too. As a result, when the water flow is re-started you will get a few seconds of water flow thru the unit before it can go thru its proper sequence (recognition of flow, inducer prepurge, release spark, release gas, prove flame current and produce desired temp) and deliver the set-point temp. Rinnai's used to take about 4-5 seconds on start-up. They have reduced the time to ignition to about 2 seconds. Personally, I don't have a problem with the CW sandwich but it drives some folks nuts. If I am in the shower and I see it I simply step to the side and within a couple seconds I have hot water. It should always be explained to the customer. Good **** chewin' prevention.

Recircs are okay when properly done. A few things first though. I represent Rinnai so I know it best so I'll use their performance as the reference. The min firing rate is 15kbtu. with a recirc the unit cannot fire unless the water flowing thru it can absorb the 15k. If you have a 1 gpm flow rate that means unit cannot fire unless the temp drop 30F. So if you have a set point of 120 your return water will be 90F. No good, eh? With a 2gpm flow the drop is 16F. Still not great. At 3gpm the drop is 6f. Now we are talkin' but try to put 3gpm thru a 1/2" line. You will in most cases, from units I have seen, peak at about 2.3 gpm, and that is not with a 006.

the other re-circ issue is the control of the circ. I think that all strap-on aquastats whould be gathered up into one place and melted down and made into something useful. We had one unit come back to the factory which had a very poor control package (strap-on)and the Rinnai fired 88,000 times in 6 months. Now, yes, that is extreme, but it did happen. They can pull that kind of info off the board. I much prefer a 24 time clock and operate the recirc as little as possible. BTW, I got a study out of Canada a couple months ago which said that a recirc line can account for 30-40% of the energy consumed. Too, in our drawings we show a small elec tank on the hot outlet and the recirc going to that tank. It is best however to eliminate the recirc all together. What I train is to bid the install in the original water heaters location (position 1)and then go for a walk with an eye to the "best" location for the operation of the unit, and therefore the best economy and consumer happiness. Bid the best location (position 2), also. Tell the customer why position 2 is really the best. You will close more work (the customer knows when you are taking care of them and you develop a better relationship) and the job will go in better. With the trends in energy costs I feel pretty strongly that we cannot keep doing what we have been doing.

I will also say that at least 90% of the calls that I get on install/operation issues are system related and not the Continuum's issue. But it is a part of the system...so we go! Can't get into it now though. Day is all ready to long!

Tim_31

Jack

You work for Rinnai? How about addressing heat exchanger failure due to condensate leaking back into the unit?

I have seen this on both the indoor unit and the outdoor unit after only 3 years.

Can you tell us how many replacement heat exchangers have been sent out by Rinnai over the past few years to replace failed ones?

Thanks.

ScottMP

Good question Tim

JAcl could you give him a responce ?

Also could you elaborate a little on the cold water sandwich thing. We have installed a number of these type of units and allways try to explain to the customers the changes that they will notice. I belive these type of domestic heaters are going to grow in installations but We as installers need to explain the difference.

"If I am in the shower and I see it I simply step to the side and within a couple seconds I have hot water."

I am a little cunfused by this statement since if you are in the shower the unit should be firing and there would be No drop in temp. What am I missing here ?

Thanks for your help.

Scott

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JackFre

I don't work directly for Rinnai

I am an independent sales rep for the New England Territory. I have represented Rinnai since '91. There is absolutely no queston that if condensation is allowed back onto the hx the unit is in trouble and so is the contractor. That shouldn't be a surprise to anyone in the business, as it would apply to any other piece of non-condensing equipment in the same sitaution. It is one of the key points of discussion in the training which Rinnai requires prior to the installation of the units. The installation manual is clear in requiring the condensate tee when you go vertical, or cannot grade the horiz vent section to the outside. When anyone asks me when they need it I say, "protect the equipment". If you aren't sure, put it on! As to the outside unit having any issues, as I live in New England, I do not sell a lot of the outside units except for seasonal use, but am totally unaware of any issue with them. I will inquire! Net/net here, if you are having such issues you need to contact your local rep, your regional service mgr or tech service (800 621-9419), or all three, to discuss the particular issues you are referring to. Do you have condensate tees on the units you are referring to?

JackFre

My poor composition...

What I meant Steve, was that if someone took a shower, turned off the water & got out, I got in and started up the flow again, I would get the hot which was in the pipe all ready, I would then get the colder water which went thru the unit on start-up for a short time and I would then get hot continuously. That is why they call it the cold water "sandwich". Does that make sense?

Also, in reading over my post on hx replacement I realized I didn't exactly answer the question. I do not know how many hx have been replaced. I do know that failures have been caused by improper venting (condensate) and/or hard water. Rinnai's installation manual is very clear on water quality issues. If you are unsure, regardless of who's unit you are using, save yourself some heat burn and test the water.

As well, Rinnai has some excellent tech info available at www.rinnaisolutions.com and on the heating products www.ductlessheating.com. On the heaters...I've been selling them since 1991 and they are absolutely outstanding. They represent an excellent "solution " product for you. Quick/easy install, 84% net to the space, cool to the touch. They are an excellent profit center for any heating contractor. But, we hall have to get out the door this am so...off to work!

Plumdog_2

Btu loss for indirect heater

I clocked the temperature loss out of a 40 gal Superstore the other day. Came out to about .57 deg/hour. I'm no math expert, but I believe that works out to 184btu/hr. Thats about the rate of a pilot burner, I believe.

Tim_31

Condensate issues

One of the Rinnai's I am talking about is an "outdoor" unit. There is no way to put a condensate tee on that model. the other exchanger that failed was vented directly out the side wall...no cond. tee is recommended by Rinnai in that set up.

On the cold sandwich issue, I have seen considerable temp fluctuations with standard Moentrol press. bal. shower valves well after the unit has been firing continuously. Talked to Rinnai....no solution from them. Therefore I do not, in good conscience, suggest Rinnai's for any shower applications.

Don't get me wrong. I would like to like these water heaters. But I think we are going to see many many failures and lots of heat exchanger changeouts.

Tim_31

Rinnai

Perhaps someone that works directly with Rinnai could honestly answer the question about the number of exchangers they have replaced since they began selling them in the U.S.

Thanks