Need/want to replace hot water heater with tankless

[slash007]

I currently have a large water heater at one wash that I am absolutely sick of. For the six years that I have owned it, I have spent countless hours every year trying to get it to work. I usually replace both thermocouples and that does the trick for a few months, but the last couple of years that hasn't worked. I usually replace both then have to tinker with every wire until it decides to work. Currently I have it working but only for maybe a day or two before the pilot goes off. Or the pilot will stay on an it just won't fire. Either way, I am sick of it and want to replace with a tankless or two. I see a lot of threads on using tankless for the floor heat, but didn't find much on just for hot water. Honestly, I am not even sure how much I need it. Currently my hot water is used for my soap, wax, pre-soak and foam brush. I have been keeping it off in the summer once it quits working then fixing it in time for the winter which is where I am at now. My main reasons for having it are because I use it thaw out the lines when they freeze and also to weep hot when it gets super cold. I know a lot of people are against weeping hot, but when it gets under 10-15 degrees and I am weeping cold, I get a lot of freezing. Weeping hot, I have survived down to 0 and below, so for me it makes a difference. This is based on a lot of trial an error. I was thinking that If I replaced the water tanks with tankless, I would only let the hot water run to my soap and to the weep system when needed. I feel like the soap does a better job hot, but I'm not really sure. I could also just have it there for my personal use to thaw out pipes and for weeping hot. Any thoughts on what I should run hot water to, and also what a good tankless would be for my situation? Here is a pic of my current headache. Thanks. View attachment 535

 

[Eric H]

Let's start with what are your production needs: how many ss bays and what tip are you running on the guns? is there an automatic?
Check these out: http://www.htproducts.com/direct-fired-water-heating.html
I probably would have used on of these units if they had been out when i did my conversion a few years ago. I have not looked at the production rates on the above units. The chart is in the link.
At my wash I used 2 Navien tankless units which gives me more than enough GPM. The reason I used 2 units instead of one unit and a tank was because the tank and pump to get to my needed production was more money than the second tankless unit.

 

[2Biz]

Check these out: http://www.htproducts.com/direct-fired-water-heating.html
I probably would have used on of these units if they had been out when i did my conversion a few years ago. I have not looked at the production rates on the above units.

I just had one of these delivered yesterday. Its the best unit I could find online. SS Tank, 199K BTU Modulating-condensing...The one I purchased was the PH199-55. It's a 55 gallon tank style and has a 300GPH heating capacity at 80° temp rise (130° set temp). The capacity increases by about 100 gallons if you temper the water back to 100-110° which I plan on doing. More than enough for my 4 bay, but hopefully its the last time I'll ever have to do this...

http://bostonheatingsupply.com/phoenixph199-55.aspx

This is the best place I found to purchase. It came packaged very good on a pallet. Shrink wrapped. Not a scratch. $200 to ship.

I evaluated going tankless since My Takagi is doing SO good at handling the floor heat. But I would have needed 2 tankless units wired/plumbed together to handle max load and it made much more sense to go the Phoenix route. Plus it has 2 extra 1" ports for space-heating or for what ever you want to use them for. I'm going to use the extra ports to put a heat exchanger in the hot water float tank to keep it hot during off peak hours....

You might want to consider this route for many reasons...Its the best I could come up with!

 

[slash007]

Of course I forgot the important facts I have a six bay and am currently using 3206 nozzles. I think the biggest thing is for me to decide what functions to heat to determine how much hot water I need. If I only heat the soap or no functions, then one tankless should be fine, correct? 2biz, what do you heat in your 4 bay? Whenever my water heater is working, the gas bill seems pretty high, so my theory was that I would save with tankless, especially during the winter when there isn't much use a lot of days.

 

[2Biz]

2biz, what do you heat in your 4 bay? Whenever my water heater is working, the gas bill seems pretty high, so my theory was that I would save with tankless, especially during the winter when there isn't much use a lot of days.

Nothing at the moment!

I'm replacing the old boiler that hasn't worked in years...I'll be heating Soap and wax with cold water rinse. Its possible I could have all 4 bays using heated water at a given time so I need to supply a minimum of 12 gpm. There is no demand heater I know of that can keep up with that flow. You'd need a boiler with no restrictions and size the BTU accordingly. A demand will only give you as much water it can supply based on temp rise. It will not allow flow through at a lower temp if the demand is more than the heater can produce. This could cause a problem if your not careful. That's why you'd need two demands to get the capacity needed or use a storage tank. Then you'd be looking at more $$$ than just buying the HTP like Eric said... Plus if you have 6 bays, even 2 demands can be marginal. You have the potential for 18 gpm if all bays are using hot water at the same time. Something to consider.

Some of the reasons I settled on the HTP...I'll never have to worry about starving a pump. Clogged screen or any issues you might have with a demand style heater. The demand heater has a very fine mesh inlet screen the diameter of a dime that the water has to pass thru. If this clogs for any reason, it will cause problems. There are other restrictors inside the demand heater you'll have to keep an eye on. Since most self serves are unattended, I don't think I'd go this route. But that's just me. I've researched this for many weeks and the HTP seems to be the best fit.

Although the demand has been perfect for my floor heat. If something happens with it, it shouldn't cause a customer any problems. When its running I check the status screen to check temp and flow rates every time I'm at the wash. I can tell if the screen is starting to get obstructed by checking the GPM output. So far its never deviated from 6.6-7.0 gpm...That's at a 30-35° temp rise.

There is a lot to consider. Just be careful you size the system correctly if you intend on going tankless.

BTW...The tank has 2" Styrofoam insulation...I think it only looses something like .05° per hour. Its something ridiculously low. I didn't even consider this when making my decision...Plus you have to remember this WH modulates. If it needed to bring the temp back to set point after setting idle, it would do so at about 40K btu, not the full 199k btu.

 

[slash007]

I never figured in the flow restriction, I thought it would just pass through colder water. I guest that was just ignorance on my part. Thanks for the heads up. You say that you would heat the soap and wax. Any particular reason? Do they work better heated? My unit is so old, that keeping the same style and updating it I'm sure the new unit would be way more efficient.

 

[2Biz]

Most of your heat goes up the flue along with heat from your Er...Your getting double whammied! The Mod/Cons flue temps are lower than 140°. Actually you can touch the exhaust PVC pipe, and its only warm to the touch. You capture just about every BTU out of the gas.

The reason I'm heating wax and soap is because it will be a simpler install. I am replumbing my stand at the same time I install the heater and I'm using Erie 3 way's much like my stand is already plumbed. And here I've always said I was getting away from them! BUT I am replumbing in a way that will make the whole Pump Stand easier to work on. Anyway, Hot water will be on the N.O. side of the Erie. So when soap and wax are called for, there is no input to the valve, so hot water will flow to the bay. When rinse is called for (Rinse is wired to valve) the valve switches and sends cold water to he bay. No more than wax is used, I'm hoping the heated water will entice the customer to use wax more often...Plus there is no lag time on the valve when Hot water is already on the N.O. side of the valve. There IS about a 10 second lag going from hot to cold. Only 2 seconds from cold to hot. Its just how the Erie's work.

If I were to ever want to go to cold water wax, I'd have to put in a relay so Rinse and wax can share the same position on the valve. Not a biggy...I just want to do it this way to start and have the ability to change it later if needed.

 

[Randy]

Years ago I had a friend whose 80 gallon 199, 000 BTU water die, burner assembly went bad. The tank was still good so he plumbed in on demand water heater with a circulator pump to circulate the water, he used a thermostat to start and stop the pump. I think it’s still being used today, must be 15 years old. I don’t think you’ll get enough flow from your weep system to kick on the on demand water heater.

 

[2Biz]

Good advice Randy. If my burner Assembly ever takes a dump, then I'll have a good SS tank to do exactly what you suggested. I don't know if I'd risk it with a glass lined steel tank that is old to start with. You might go to all the trouble only to have the tank get a hole in it! That would be my luck!

 

[slash007]

Years ago I had a friend whose 80 gallon 199, 000 BTU water die, burner assembly went bad. The tank was still good so he plumbed in on demand water heater with a circulator pump to circulate the water, he used a thermostat to start and stop the pump. I think it’s still being used today, must be 15 years old. I don’t think you’ll get enough flow from your weep system to kick on the on demand water heater.

My current tank is pretty old and rusty, I have been waiting for it to spring a leak but so far it has held up. I wouldn't risk converting it in it's current shape, though that is a great idea if it was newer. I hadn't thought about the weep not being enough to trigger the tankless either, so that's another con. I'm just going to put up with this heater for a little then just change it to another water tank, probably the same one as 2biz.

 

[robert roman]

“I have spent countless hours……trying to get it to work. I usually replace both thermocouples and that does the trick for a few months……I usually replace both then have to tinker with every wire until it decides to work. ….maybe a day or two before the pilot goes off. Or the pilot will stay on and it just won't fire.”

Many things can affect thermocouple. For example if misaligned, carbon can build up on the sleeve causing a hot spot that will create a pinhole and bi-metal strip inside will be ruined.

There is a reason why many operators do not use hot water weep. It’s called the Mpemba effect; hot water freezes faster than cold does.

Put two glasses of water in “freezer” compartment of a refrigerator; one hot, one cold. The glass of hot water will freeze before the cold one.

One explanation is warm water evaporates rapidly and since this is a process in which one substance is changed into other accompanied by the absorption of heat it cools the water making it freeze more quickly.

A friend and I recently compared math for tank-less hot water. My use is low volume, his is high volume. His payback is 8 years. I’m 62 and may nearly be dead by payback.

However, we both needed to save space and he needed endless supply of hot water. So, if you need endless supply of hot water and need to save space, tank-less is hard to beat.

However, tank-less is more complicated meaning more expensive than tank heater.

 

[2Biz]

Currently my hot water is used for my soap, wax, pre-soak and foam brush. I have been keeping it off in the summer once it quits working then fixing it in time for the winter which is where I am at now. My main reasons for having it are because I use it thaw out the lines when they freeze and also to weep hot when it gets super cold. I know a lot of people are against weeping hot, but when it gets under 10-15 degrees and I am weeping cold, I get a lot of freezing.

Slash, to add to what Robert said....We are close enough geographically that we have about the same weather patterns. I only weep cold un-softened water and have only froze a bay because of a plugged weep gun or when I had problems with an old Dema Weep solenoid. I switched the solenoid out with a 1/2" Asco N.O. solenoid and haven't froze since. Maybe something to consider. I can't see any reason to weep hot water....Maybe you're having problems somewhere else....

 

[I.B. Washincars]

Put two glasses of water in “freezer” compartment of a refrigerator; one hot, one cold. The glass of hot water will freeze before the cold one.

Seriously? You have obviously never tried this. Been there, done it. The cold water froze and the hot was just as liquid as it was when I put it the freezer.

 

[Earl Weiss]

“

There is a reason why many operators do not use hot water weep. It’s called the Mpemba effect; hot water freezes faster than cold does.

Put two glasses of water in “freezer” compartment of a refrigerator; one hot, one cold. The glass of hot water will freeze before the cold one.

One explanation is warm water evaporates rapidly and since this is a process in which one substance is changed into other accompanied by the absorption of heat it cools the water making it freeze more quickly.

.

Mpemba was an idiot. The problem with the freezer experiment is typicaly a small layer of frost is on the floor of the freezer. This insulats the containers from direct contact with the cold. The cold water container does not melt this frost insulation like the hot does. Once the hot / warm melts it the more direct contact freezes it faster.

Often Hot water pipes freeze before cold because the water is used less so the more stagnant water freezes faster.
Hang a couple of water containers from a string outside when it's 10 degree and see what happens, I've won several bets from Mpemba beleivers this way.

Hot weep keeps lines open better than cold. Also helps keep trough warm and less ice buildup on floor grate where floor heat does not reach.

 

[Earl Weiss]

See link below - Skip to page 7

http://arxiv.org/ftp/arxiv/papers/1003/1003.3185.pdf

Mpemba did his expoeriment in a refrigerator freezer in Tanzania.

The average temperature year round in Tanzania is over 80 degrees Farenheit.
I think Mpemba went on to be a wildlife professor.

A couple of red flags about what this guy knew about freezing conditions.

He observed Hot water freezing before cold which can happen but,
it was like observing the world is flat.

 

[slash007]

At my newer wash I don't have any hot water and survived last year all the way down to 5 degrees just weeping cold, so I know that you can weep cold and be fine. Problem is, at my older wash if I don't weep hot and it gets that cold then I freeze up. Not sure of the science behind it, but that is how it has been the past 6 years. Maybe it's because all of my lines are just housed in a steel beam right on top of the boom and covered by a piece of wood as opposed to being in a nice trough in an attic like the other wash? Not sure, but it is definitely more prone to freezing. 2biz, how many ounce per minute do you weep at your wash? I am up to 16-18 ozs. on my bays at the older wash except for one bay that doesn't go past 14 no matter what I do. I plan on messing with it today as there has to be something limiting the output on that bay in regards to weep. So far it is the only bay that froze up this year.

 

[mjwalsh]

I've won several bets from Mpemba beleivers this way.

Hot weep keeps lines open better than cold. Also helps keep trough warm and less ice buildup on floor grate where floor heat does not reach.

This could be relevant to the warm water weep portion of the discussion ... based on 100s of times of blowing our all our lines in below freezing weather ... there is no question that it is better to warm up the lines first with warm water.

2Biz,

The below link is a worthwhile discussion on the CLA forum on the heating hot water subject. I wonder if you now have something similar to the HTC 199K BTU Phoenix modulating hot water heater from HTC as Larry Adamski? Larry has had some updates on his experience after a year or more of use & so far ... it has been very positive for him.

http://www.planetlaundry.com/forum/showthread.php?t=7230&highlight=phoenix+water&page=8

mike walsh king koin north dakota USA

 

[2Biz]

Mike,

Mine is the PH199-55..Thanks for the link. It gave me the "warm fuzzy feeling"....It was a lot for me to spend, but I compared the Phoenix to an AoSmith condensing glass lined heater and the AoSmith cost more. So getting one that modulates as well as SS tank was a huge plus. I could have bought a std 70% efficient heater for about $2g and not had the capacity or efficiency. Plus I have space constraints. So stepping up to the Phoenix was a no brainer.

I read the whole thread and he never said what model he bought other than it was the 119 gallon 199K btu model. The only difference is mine has a 55 gallon tank. I'm still collecting all my install parts, so will keep you updated along the way.

Slash,

I've checked my Weep flow and it compares to others...But I will check it tonight and let you know.

I have to admit, my trough is a bit different than yours. Maybe your trough and steel I-Beam is giving you the issues. My trough consists of a 5-6" PVC tube that lays on the rafters in the attic. It extends up and out of the building to supply High and Low pressure to my semi/Truck bay. Its 15' tall. Anyway I have Raychem heat tape and also a zone from my floor heat that is in this trough. BTW..I cut a 2" wide strip in the pipe after the first time I had to pull a HP hose thru it. I couldn't believe it was set up like this. I seal the trough with a tube of insulation wrapped in plastic. There is no air space in the tube. When it gets below 20°, the floor heat loop plus the Raychem Heat Tape is on. The trough is a toasty 90°. SO MAYBE! The water is heated by the time it gets to the bay! I hate freeze-ups...The heat tape uses a mere 450w and the floor heat is running by then, so this is as good as I could get it.

I have about 10-12 feet of exposed PVC housing the lines to my truck bay. I've only froze once and it was the weep gun. The PVC pipe is strapped to an 8" I-Beam....Something for you to consider....

 

[2Biz]

Slash...

I checked all 4 of my bays this evening and they weep an average of 16-18 oz's per minute.

 

[GoBuckeyes]

We weep 11-12 oz per minute of 110F hot water using the Weepmiser's default settings and are good down to zero. We do this for HP and FB. Only time we have a freeze up is if something has gone wrong like a clogged strainer, plugged tip or kinked FB hose. We're actually more likely to freeze a bay at 30F than when less than 15 F . Sometimes if a far run is on the lighter side, say 10 oz/min, if conditions are just right it might freeze. I think its because at 28 or 29 the weepmiser is only on for about 10 seconds and then off for 50 sec so its just not quite enough to overcome the length. Once the temperature drops more and the flow is more consistent, its pretty bullet proof.