Tankless Option for Hot Water

[Bubbles Galore]

I have been reviewing the old threads and forum posts relating to this and have gleaned a lot of great information so far. I installed this heater for my presoak passes in the automatic and it has worked really well so far. To keep things consistent, I was considering using this same style for my hot water. I use my hot water for my 6 self serve bays (Soap, Rinse, Wax), my LP mixing tanks and for making spot free water. Very rarely do I have more than 2 or 3 bays running HP features all at once. Would you think that this would be a reasonable solution for replacing my hot water production boiler?

Questions and feedback are welcome.

Thanks!

John

 

[MikeV]

John, I took my boiler out years ago and replaced it with 2 of the tankless heaters you reference. I use hot water for all the HP functions in 5 s.s. bays and the presoak for the auto. Best thing I ever did and it saves me a binch on the gas bill.Neverrun out of hot water, even on the busiest of days. Hope this helps.

 

[Bubbles Galore]

Any issues with low fire levels with the low flow water demand or anything like that? Did you have to do anything special?

 

[MikeV]

John, no...no issues with low demand, as the demand for water passes thru the tankless, it fires up immediately and makes hot water. Didn't have to do anything special, had a large enough gas supply, just plumed from the old boiler to the new heaters and haven't had to do anything else. Freed up a lot of extra room when I removed the old boiler. Mounted the new heaters on the wall, out of the way and that was it. My advice...go for it and don't look back.

 

[JMMUSTANG]

Mike how hot can you get the water?
If I have the temp. set at 140 vs. 110 does it take any longer to heat up or is it instant?

 

[MikeV]

Regardless of the temp you set your heater at, it is instantly hot to that temp. I set mine at about 100, so as not to let anyone get burned or scalded. Customers are happy with the hot water.

 

[Bubbles Galore]

John, I took my boiler out years ago and replaced it with 2 of the tankless heaters you reference. I use hot water for all the HP functions in 5 s.s. bays and the presoak for the auto. Best thing I ever did and it saves me a binch on the gas bill.Neverrun out of hot water, even on the busiest of days. Hope this helps.

In your opinion, since I already have the heater for the pre-soak, would one heater be sufficient or would I need both?

 

[MikeV]

You can probably get by with one.

 

[2Biz]

Does anybody know the difference between the residential and commercial models of the TAKAGI boilers besides the BTU rating. I'm wondering if the coils are more heavy-duty in the commercial?

Also since these are condensing uinits, are the coils stainless steel or aluminum? I read where they have to be to hold up to the acidic properties of the condensation that forms on the coils because of lower operating temps. Hence the higher efficiencies. Has anybody ever used one of these as a floor heat boiler? I'm afraid my 25 year old Jarco doesn't have much life left and am exploring options..

 

[Bubbles Galore]

Does anybody know the difference between the residential and commercial models of the TAKAGI boilers besides the BTU rating. I'm wondering if the coils are more heavy-duty in the commercial?

Short answer is yes, they are more robust in the commercial models.

Also since these are condensing uinits, are the coils stainless steel or aluminum?

My documentation stated that they were stainless

I read where they have to be to hold up to the acidic properties of the condensation that forms on the coils because of lower operating temps. Hence the higher efficiencies. Has anybody ever used one of these as a floor heat boiler? I'm afraid my 25 year old Jarco doesn't have much life left and am exploring options..

I'm going to use it as my floor heat boiler if I can get things situated quickly enough before winter sets in...

 

[2Biz]

A little off topic again, have you settled on a pump for your floor heat boiler? I have a 4 bay with one bay being an outside truck bay. No protection. I'm struggleing with coming up with the right GPM flow or should I size based on flow rate of the boiler. I'm thinking about going with the Takagi TM32, 240,000 btu @ 9 gpm.

My current boiler and pump are a 350,000 btu Jarco and a 9 amp 220v pool like pump. Super outdated and cost a fortune to operate. The Taco pumps run on 110v and considering the Taco 008 only runs on .79 amps and has a 0-14 gpm flow rate, just changing to a pump like this would be a huge savings.

 

[pitzerwm]

I'd think that measuring the return line temp, would tell you if it will work, I'm not sure what the return water min. needs to be but above freezing for sure. I used 70F, but I would imagine 50F would also work.

 

[2Biz]

Yea, I guess thats the objective...Just don't like spending lots of $$$ on trial and error...Its expensive enough to do it right the first time.

I found this link in an old thread: http://www.pexuniverse.com/content/how-size-circulator-pump


But I need to go back to school to figure it out!

 

[2Biz]

2Biz: Also since these are condensing uinits, are the coils stainless steel or aluminum?

Bubbles Galore:
My documentation stated that they were stainless

I copied this information from a Takagi T-M32 ASME Document I found online...Looks like the coils are copper. The burner is S.S. After reading the manual for the T-M32, the condensation is controlled by a "Vertical Condensation Drain" installed just above the unit in the flue pipe. http://www.kleen-ritecorp.com/p-21258-4-universal-condensate-drain.aspx


Mobius water heater(s) shall be Model T-M32 ASME as manufactured by Takagi Industrial Company, Inc. The Mobius water heater(s) shall be a copper coil integral fin and tube construction with quick release brass or bronze waterways. Heater(s) will be factory assembled and tested.
The heater shall be vented with 4” Stainless steel Category III vent pipe a distance not to exceed 50’ (equivalent) feet terminating vertically or horizontially as prescribed. Intake air with optional direct vent kit may be of such material as PVC not to exceed a total of 50’ (equivalent).
The heater(s) shall be controlled by onboard solid state printed circuit board monitoring incoming and outgoing temperatures with factory installed thermistors, sensing and controlling flow rate to set point temperature with control both air and gas mixture inputs to maintain thermal combustion efficiency. Unit also consists of ground fault interrupter, inline fusing, spark ignition and sensor system, aluminized stainless steel burners, air-fuel ration rod, Hi limit switch, modulating and proportional gas valves, freeze protection sensor and heating block and overhead cut-off fuses.
The water heater(s) shall be CSA listed, exceeds the energy efficiency requirements of ASHRAE 90. 1b-1992.

 

[Bubbles Galore]

A little off topic again, have you settled on a pump for your floor heat boiler? I have a 4 bay with one bay being an outside truck bay. No protection. I'm struggleing with coming up with the right GPM flow or should I size based on flow rate of the boiler. I'm thinking about going with the Takagi TM32, 240,000 btu @ 9 gpm.

I have not determined the proper pump, but I will be going with one of the more efficient Taco models than my current pump. I haven't gotten to that point yet, but if you come up with something, let me know!

 

[2Biz]

Sure will. This seems to be the hardest part in putting the system together and coming up with the calculation "Determining Head Loss or Pressure Drop" for pump sizing . I have (4) zones/bays not counting the zone in the overhead trough. (I'm heating it now with the Raychem Heat Tape. It works very well @ 450w for 75ft...)

I have my eye on this one: http://www.pexsupply.com/Taco-0011-F4-0011-Cast-Iron-Circulator-1-8-HP-1987000-p

It has 0-31 GPM Flow rate and 0-31 Head Range and runs on 1.76amps. But I want to make sure my calculations are right before going with this one. I might try to call Taco and see if I can get some technical help once I know/estimate how many feet of tubing I have in each zone.

 

[pitzerwm]

In my system they used a multi stage pump, I don't know why but it worked very well.