Ditching the boiler for a tankless water heater(s)! Input...

[Officer]

Evening fellow operators. I own a wash (3 SS and 1 IBA Touchless). Love being an operator, by the way! I'm looking to ditch our boiler and hot water tank for two tankless hot water heaters. I'm looking at some of the Bosch ones on Kleen-Rite and Paloma from another vendor.

For those of you that have done so already, did you see savings? If so, how much?

Do I really need two tankless heaters for my wash?

How much did the plumber charge you to remove your old boiler and holding tank and install the new one(s)? I know this variable will vary.

I'm using hot water for my presoaks (and maybe triple foam - not sure at the moment, new Razor!) for my IBA. Also, using hot water for all my mixing tanks that feed my SS bays. That is, hot water rinse, and hot water used to mix presoak, HP soap, polish/wax and foam brush soap. Before you insist that hot water is not needed in some of these mixtures, just know I bought the wash with the SS set up this way.

Looking at the Paloma 199k BTU and Bosch 199k BTU.

Thank you in advance!!!
-Brandon

 

[Jeff_L]

That’s a lot of hot water. Not sure if two will give you the volume you need. Might want to add up worst case scenario for demand, then check max output of each tankless heater. 3 SS and 1 IBA plus all the other items you mentioned, makes me think two would be too little.

 

[2Biz]

For those of you that have done so already, did you see savings? If so, how much?

I installed a 199K Takagi in place of a 350K BTU Jarco Webn floor heat boiler. The savings was huge and it worked great!! The savings was big enough, that I just turn it on in the winter and let it come on at 32° without micro managing. So yea, any time you can go from a low efficient boiler to a HE design, there will be savings.

As for how many demand heaters you need for your wash, like Jeff_L mentioned, you need to figure out usage at worse case scenario and see how much hot water the heaters will produce at the temperature you want. Then go from there. Keep in mind, most demands are not flow through like a normal Hot Water Heater. They restrict flow to get what temperature output you have them set at. The higher the Delta Rise you want, the more they restrict flow. So you have to study the flow graph in the manual to make sure it will meet your needs at the temperature you want. For me, using a demand heater to supply heated water to my pumps is too risky.

It sure would be nice if a few on here that have done this would come back and give feed-back as to how well it worked...Good or Bad....

 

[chaz]

Yeah...that’s a lot of hot water...I’d consider dropping that on S/S rinse...my opinion?

Also...my IBA (markvii) has on board water heater and doesn’t draw from my main tank....so that would not be part of the equation.

 

[OurTown]

We went down that road recently and started a thread on it. I should update it too. The only tankless water heater that I found to not restrict water flow was Navian and you had to get the remote controller to run them in the unrestricted mode. If you add up all your flow rates you will probably find that it is unrealistic to go tankless with your hot water demand. The other issue is that they also drop the pressure so hooking them to a series of hydrominders might end up not letting them draw the proper amount of chemical. I think that what 2biz has is a good idea but those are about $5K. Another way is to have a tank/pump/tankless water heater. It is basically what you have but replacing the boiler with a more efficient tankless unit. You could start off with one unit and add another later if needed. That is the direction we are heading in.

 

[JGinther]

Why ditch the boiler? The reason should dictate some of the answer. Space? Efficiency? Environmental concerns? Change in equipment setup? Each has a different answer...

 

[2Biz]

We went down that road recently and started a thread on it. I should update it too. The only tankless water heater that I found to not restrict water flow was Navian and you had to get the remote controller to run them in the unrestricted mode. If you add up all your flow rates you will probably find that it is unrealistic to go tankless with your hot water demand. The other issue is that they also drop the pressure so hooking them to a series of hydrominders might end up not letting them draw the proper amount of chemical. I think that what 2biz has is a good idea but those are about $5K. Another way is to have a tank/pump/tankless water heater. It is basically what you have but replacing the boiler with a more efficient tankless unit. You could start off with one unit and add another later if needed. That is the direction we are heading in.

So you did your homework! I would have to agree that a separate tank/circulator/demand heater might be a better option, price wise compared to what I purchased...At least you'd have full flow through if you ran out of hot water...In another thread you mentioned you got another SS storage tank. Do you mind telling us what the price was? You can get a 199K Takagi like mine for about a grand now. The only problem I see with a circulator is you'd need (2) Taco 0013's to make enough pressure (40psi) to give you enough capacity through a restrictive heater like mine. @ 40psi, I get 6.7 gpm at 105° setpoint. Delta rise is about 35-45°....So the cost goes up...The Taco 0013 are $325 each....In my floor heat system, I have (2) 0013 Taco's supplying pressure to the heater. Both in series only yield 40psi...The concept is very similar to what you'd need for a storage tank.Real world advice...

 

[2Biz]

To avoid confusion with the last post. Here is the HTP heater I purchased instead of going the Demand route for the bays.

 

[OurTown]

Do you mind telling us what the price was?

$2,080 plus tax for a Lochinvar SJS060.

 

[2Biz]

By the time you add it all up including t-stats to turn on the circulators, you're not far from the cost of an HTP. Although, a little over 4 years ago I got the HTP shipped for $3800! They've gone up a lot in such a short period of time.

Something I've wondered if going the demand heater/holding tank/circulator route, where would you put the T-stat that would fire the circulators? Would the plumbing have to be some sort of Primary-Secondary system like I have set up for floor heat with a small circulator running 24-7?

Still thinking Demand heaters aren't the way to go unless it is full flow through. I still would like for operators who have tried it to come back on here and give us some Feedback.

 

[PaulLovesJamie]

I installed a Takagi tankless with a circulator and an HTP storage tank. T-stat is in the tank.
In addition to the full flow reason for using a tank, 2 additional reasons I had for doing it this way:
a) I like redundancy - if my floor heat takagi acts up, I have a second takagi right next to it that I can swap over to the floor heat.
b) modularity. I like to replace/upgrade components, not full systems.

I dont recall exact prices I paid, but iirc it was only slightly higher, not significant to me at the time. Also I think my setup may be slightly less efficient that the dedicated unit 2biz has, but maybe not? Not sure about that. 2biz' dedicated heater is a little simpler though, less thought required.

 

[JGinther]

I think the reason for the decision is the determining factor. I have needed the equipment room space to add an automatic. In that case, I didn't have room for a pressure tank, so wall space was the best option. I did the 2 tankless heaters design, where one was pressure fed and supplied pressurized hot water to the whole facility including the automatic supply tank and the self serve hot water gravity tank. I installed a lower 2nd float in the tank to fill with cold water when tank ran lower which prevents running out of water, but allows the water to cool. Then installed a second water heater hooked to the holding tank with a recirculator pump. A remote bulb aquastat is mounted in the holding tank... Probably should be a thermoconductive well, but I opted for holding the bulb submerged 2/3 of the way to the bottom using bare copper wire to hold it in place (fast and easy). The setting on the tstat is 5 degrees less than the feed water (120 feed water, 115 turn on recirculator.). No problems with the set up and only used about 5 foot of wall space for 800k btu.

But I like the simplicity and reliability of good quality boilers. I been using tankless heaters for 20 years now.. different types for different applications. I have had to replace 5 or 6 water heaters, but never a maintained boiler. You can barely carry a heat exchanger from a boiler, but grandma could throw a tankless heat exchanger if you dared her to. They aren't designed for constant duty of car wash applications. That's why the small print of the warranty drops from 7 or 10 years for domestic water (commercial or residential) to pretty much none for industrial uses. If thermal efficiency is the purpose, you have to add back in much faster real life depreciation in my opinion.

 

[mjwalsh]

2Biz, JGinther, & others,

It is great to read a bit of pro & con actual experience ... since there can be a bit of a frenzy when it comes to pretending that the wall mounts are a best fit panacea for everyone. Hopefully, others will share their real life experiences. These hi performance stainless steel heat exchangers in conjunction with closed loop boiler water strategically placed have been life savers for us since about 1990. https://www.spirec.com/

The challenge was to get the optimal pressure & volume from single pumps. Hopefully, there will be more pumps besides just the on the expensive side Webtrols that meet the gpm-pressure requirements. Similar to what 2Biz had to deal with ... needing two ... in series pumps???

There definitely are still unmet needs out there in the manufacturing world IMHO! Merry Christmas everyone!

 

[2Biz]

Good Point MJ...There were other pumps available that would deliver the correct pressure when I put in the floor heat. But after doing all the math and research, I decided on (2) 0013 Taco's in series to give me the 40 psi needed. With the main circulator being a 0013 Taco too, I would only need to stock (1) cartridge (Motor) for repair parts if ever needed. The pump motors are rebuildable with only having to put in a new cartridge at less than half price of a new pump. Plus this particular pump only runs on 2 amps....Another part of the calculation and decision. You've gotta love new technology. My original floor heat used a 220v 12amp pump to circulate the glycol....I went from that to 120v @ 2amps to do the same thing or maybe even better! And quiet! You can't even hear them run! I remember the sound was deafening with the 220v pump.

 

[MEP001]

Something I've wondered if going the demand heater/holding tank/circulator route, where would you put the T-stat that would fire the circulators?

In the tank's thermostat well. Just turn on the pumps with the thermostat and the on-demand heater(s) will sense the flow and start heating. As long as the pump can handle the pressure while the heater comes up to temp, you wouldn't even need to modify anything in the heater.

 

[OurTown]

In the tank's thermostat well. Just turn on the pumps with the thermostat and the on-demand heater(s) will sense the flow and start heating. As long as the pump can handle the pressure while the heater comes up to temp, you wouldn't even need to modify anything in the heater.

That is how we were thinking of setting it up.

 

[JGinther]

My answer was to 2biz question. I understood it that he was referring to an open air gravity tank installation (same tank the pumps pull from), not to a pressure storage tank installation. Maybe I misunderstood.

 

[mjwalsh]

Good Point MJ...There were other pumps available that would deliver the correct pressure when I put in the floor heat. But after doing all the math and research, I decided on (2) 0013 Taco's in series to give me the 40 psi needed. With the main circulator being a 0013 Taco too, I would only need to stock (1) cartridge (Motor) for repair parts if ever needed. The pump motors are rebuildable with only having to put in a new cartridge at less than half price of a new pump. Plus this particular pump only runs on 2 amps....Another part of the calculation and decision. You've gotta love new technology. My original floor heat used a 220v 12amp pump to circulate the glycol....I went from that to 120v @ 2amps to do the same thing or maybe even better! And quiet! You can't even hear them run! I remember the sound was deafening with the 220v pump.

2Biz,

Back in 1990, when a mechanical engineer took a desperate me under his wing ... he never let on how to arrive at final pressure & volume from 2 pumps in series??? Maybe it was something he personally just never did before. All I know is that the below super expensive Webtrol clumsy mounting pump was the only one he could find that would have the specific needed lift & flow!!!???

I am wondering what "other brand" specific pumps installed in series would accomplish & possibly then some ... as the following Webtrol PC33R-LM pump ... that the certified mechanical engineer specified way back in 1990. This documentation shows the PC33R=LM performance curves: http://webtrol.com/assets/pc-series-centrifugal-pumps.pdf

 

[2Biz]

Something to store under your belt....2 pumps in parallel output double the volume and pressure is the same as using one pump. 2 pumps in series output the same volume as one pump but output is double the psi....Something I learned from the hours and hours of research I did when learning all about floor heat!


To answer your question about the pump you linked to. The 1hp pump PC100R is a 1hp pump that puts out 10 gpm at about 44 psi....I don't know what the cost of the pump is, but the (2) Taco 0013's have similar performance on 1/3 total HP and only 4 amps....I would assume that 1hp pump would use more current than the 2 taco's...

Something else to consider. If the city pressure in the storage tank is 40psi, then the inlet AND outlet to the demand would be equalized at 40 psi at Idle....The circulator wouldn't even see this as an issue. The Taco is rated for 125 psi. So good to go in this application. If you used 0013's, you'd need (2) in series to get the right output pressure to the demand.

 

[Officer]

So we bought the tankless heaters. What should I expect to pay - or what did you pay - to have them installed?