Replies

1. 
   wivell | May 27, 2008 08:20pm | #1

   I have the Amtrol in my garage on an open loop system - supplying hot water for radiant slab, domestic hot water for 2nd floor bathroom & laundry and also supply a hot water coil in the HVAC system.

   System has been running for about 5 years.  So far so good....

2. 
   rich1 | May 28, 2008 07:23am | #2

   Uhhhh, isn't the ST the round one? 

    

   Which one is cheaper? I've changed both and FWIW, I'm willing to bet the guy who dreamed up stacking a cast iron boiler on top of a water heater never had to change one.

1. 
   jurassicjet | May 28, 2008 02:57pm | #4

   Yes Rich1, the Amtrol is the round one. They are both about the same price so that is not really a factor, I think they are within about $100 of each other.
   Not sure I understand the comment about cast iron and stacking. Both of these units sit on the floor with the associated plumbing coming from my wall hung Buderus boiler. The boiler is made out of some combination of aluminum and stainless I think. It is around 98% efficient.The boiler I have is "tankless". I utilized a boiler like I have because of the in floor heat that I have installed. Not sure if the Renai is made for supplying heat for that type of system. I feel that I need a storage tank (they are quite efficient, losing only about 1/2 degree per hour) because we have a large whirlpool (72"x42") and also 4 bathrooms.

1. 
   rich1 | May 28, 2008 05:57pm | #5

   The square tanks can have a cast iron boiler stacked on top of them to save space.

   Looks good on paper.....

    

   Don't worry about the tankless, you will have the best of both.

1. 
   RBean | May 30, 2008 01:48am | #6

   We've used a brazed plate exchanger as a preheater for an off the shelf gas fired tank type on a number of projects. 

   Allows one to shut down the boiler in the summer and shut down the water heater in the winter. 

   Provides for:

   Temporary redundant heat source in the event of failure in either system

   Allows for serviceabilty of heat exchanger without losing DHW or space heating

   Is less painful if/when replacing the water heater is required.

   Helps reduce or prevent cycling of boiler.

   Just another option to consider...

   piping schematic (Ignore the funding solicitation...meant for non industry personnel)

    

   Edited 5/29/2008 6:53 pm ET by RBean

3. 
   ChicagoMike | May 28, 2008 02:17pm | #3

   I hope I am answering this correctly, I have the Buderus GB142 wall hung boiler and I love it. When it came time for hot water, I chose the buderus tank. I am know regretting this. The tank and all the pipe and control w/ pump was almost $900. I have no problems with the system but I would have gone with a tankless system like rennai. It cost about $1100.

    

   "It is what it is."

1. 
   NRTRob | May 31, 2008 08:35pm | #9

   you would have lost efficiency.standby losses are low in tanks, and that gb142 is more efficient than the rinnai, and you're getting better hot water delivery characteristics with your current setup.-------------------------------------
   -=Northeast Radiant Technology=-
   Radiant Design, Consultation, Parts Supply
   http://www.NRTradiant.com

1. 
   ChicagoMike | May 31, 2008 11:50pm | #14

   Cool! Thanks! I no longer feel buyers remorse! 

   "It is what it is."

4. 
   DDay | May 30, 2008 03:14am | #7

   How about option number three? A megastor, http://www.crownboiler.com/products/indirect/mega_stor.asp

   My buddy installs HVAC equipment for a living and has put in over 100 buderus boilers over the past 3 years. The have only used the Buderus indirects a handful of times. They are nice equipment but he does not like the glass lined tanks and to get the warranty you need to have it documented that you replace the anode rods every year. They almost always use megastors for indirects. The tanks are stainless steel and the circulation tubes. I put one in my house with a buderus 115 boiler a few weeks ago. I know he really doesn't like Amtrols either, that's not the best equipment.

1. 
   jurassicjet | May 31, 2008 04:08pm | #8

   Dday:I appreciate your link to crown boilers. It is now the front runner for me with the Buderus a close second.
   The stainless steel interior and heat exchanger without the anode rod and having a lifetime warranty is a real plus.
   The only downside that I see so far is the fact that stainless is not "real" efficient with heat transfer and the fact that the foam in the unit appears to be polystyrene. Why on earth would they use polystyrene? It is one of the most worthless types of foam out there IMHO.
   Now I just have to figure out sizing. I might start another thread on that one. I was going to get a 40 gallon version but was told it will not be big enough considering I have a whirlpool (91gal full, 59 min.). I don't plan on filling it every day (maybe once or twice a week or so) but what they are telling me is I will run out of hot water. How can that be with a 85000btu boiler and the indirect water heater having a continuous rating of somewhere around 140 gph?

1. 
   NRTRob | May 31, 2008 08:36pm | #10

   what's your problem with polystyrene? also, the amtrol is pretty much a bargain basement indirect. weak recovery due to small coils, if my memory serves.-------------------------------------
   -=Northeast Radiant Technology=-
   Radiant Design, Consultation, Parts Supply
   http://www.NRTradiant.com

2. 
   NRTRob | May 31, 2008 08:41pm | #11

   also, 140 GPH is only 2.3 GPM. Maybe if you install a flowsetter on the jacuzzi, and you're willing to wait a half hour to fill it, it'll work out. Of course, you're losing heat out of the tub that whole half hour.. might take longer to get it to a temp you want.you either need a slow fill, a very large amount of storage, or more output for the DHW. and you'd need to make sure your coils won't scale up over time.-------------------------------------
   -=Northeast Radiant Technology=-
   Radiant Design, Consultation, Parts Supply
   http://www.NRTradiant.com

3. 
   woodway | May 31, 2008 09:21pm | #12

   Just sitting on the sidelines here but I have the same question about your opinions regarding ss and polystyrene that the other post does...please outline your concern regarding heat transfer with SS and quality of polystyrene foam, I don't quite understand. Is it open cell or closed?

1. 
   jurassicjet | Jun 01, 2008 06:33am | #15

   Polystyrene is less efficient that Polyurethane foam. Polystyrene has an R-value of anywhere from 3.3 to 5.0, depending on the forming process.
   In my opinion, the water heaters that use polyurethane foam maybe show a little more inclination to higher quality. Polyurethane foam has an R-value of nearly 7.
   http://www.roofhelp.com/Rvalue.htmI didn't think about ICFs and SIPs utilizing polystyrene so I guess I am probably going to take some heat on that.As far as stainless goes, it has a significantly lower thermal conductivity than nearly all other metals. If your really wanted to transfer heat, make the heat exchanger out of silver. Copper is the next best one.
   Check out this chart and you will see what I mean..... Stainless steel thermal conductivity is 14 k(W/m*k) whereas copper has an outstanding 401 k(W/m*k). Looks like a copper heat coil would be best for heat transfer, not sure how long it would last though.
   Check out this sight and read the problem about the cooking kettle. It is rather enlightening.
   http://hypertextbook.com/physics/thermal/conduction/

4. 
   DDay | May 31, 2008 10:58pm | #13

   Check out the spec's on the megastor indirects, the heat is off for the summer now, so the boiler is only running for the hot water. The heat loss is so little on those megastors, that you never know the boiler is even working. That insulation and the design, they are very efficient.We have a two person whirlpool, the one below. It takes 95 to fill to the over flow but with one person its 76 and with two its 50 something. So yours will be similar. We have a 53 gallon megastor, and i think the boiler is set up to make 140 water and with the mixing valve, the 53 is plenty. We also have a shower with body sprays and a hand shower that uses a decent amount of water andthe 53 is fine for tha tas well. http://www.aquaticwhirlpools.com/products.py/startModel=LUXEAIR%2021/seriesSearch=9

2. 
   dedema | Dec 21, 2014 09:04am | #18

   Nowadays these boilers - is the best choice for central heating. Useful information about crown gas boilers - http://gasboilerguide.com/crown-gas-boilers/

   AFUE of boilers very high. And you can setup it yourself. I think, that its good variant.

5. 
   iamsteelpath61 | Jun 16, 2013 08:19am | #16

   Buderus vs. Amtrol Indirect hot water

   In my case Amtrol (spam link removed) seems to cary a weight here since its popular and the quality seems no one beat it! That just my thoughts..

1. 
   rich1 | Jun 16, 2013 08:16pm | #17

   While you are a little late to the party, I would really question that Amtrol is the best quality.