Advice on new heating system: TT | Munchkin | Crown

mc118

Hi,



  I'm looking for some advice on a natural gas, high-efficiency heat/hot water boiler (~100k BTUs) purchase. I've chosen an installer who comes highly recommended from a variety of people, but I am struggling to decide on a system.



Background: My home is about 1500 sqft and I would guess we use a little above the average amount of hot water. We have two small children, so the laundry, dishwasher and bath/shower are often running though only occasionally do they run simultaneously. Also, we live in a fairly cold climate.



Of the five bids I received, a majority recommended the TT Prestige Excellence. I found good reviews and bad reviews, which any amount of online searching will produce. I understand as well that the installation plays a vital role in how well a boiler operates.



The installer I am going with mentioned that we would have a noticeable loss of water pressure and an increase in lag time (already 18-30 seconds for hw) in the upstairs bathroom by going with the TT. This is the furthest point from the boiler. If I followed his reasoning correctly, the TT slows the water down to heat it quickly and this results in a lower pressure and slower moving water to the source.



Did I understand him correctly and is this accurate? What role does the TT's 14 gal internal water heater play in the system? Does it fill the call for hw and allow the boiler time to start heating more hw?



He recommended using a Munchkin Contender or Crown Bimini along with a 40 gal domestic storage tank. He feels this would keep the pressure consistent with what we have now and have ample hot water.   



None of the other installers who recommended the TT mentioned a change in pressure/lag or suggested going with an external tank for hot water. I gave them all the same details about our water usage and all had the same access to the house.



If the tankless system isn't the right way to go, then I would choose between the Contender and Bimini boilers. From what I could tell, the major difference is in the heat exchanger. The Contender being stainless steel and the Bimini aluminum. I like the efficiency that aluminum provides, but I worry about corrosion resistance. I tested my city water tonight and got a pH level of about 5.7, which is not terribly acidic, but still acidic enough. Total alkalinity was about 80, not sure about mineral levels. Is annual maintenance enough to combat the scaling that would occur, given my water conditions, without damaging long-term performance? Or, is stainless just a safer bet with this pH level?    



Does any have thoughts with either of these boilers or their heat exchangers?



Did I miss any important details?



Any guidance is very much appreciated!



<span style="color:#666666">Thanks</span>

bob eck

new boiler

I sell and have a Triangle Tube Prestige Excellence PE110 in my house. I love it. No they do not slow the water down to make domestic hot water. This model is a 110,000 BTU input gas 95% condensing boiler with stainless steel self cleaning heat exchanger plus it has a 14 gallon stainless steel indirect water heater built right in the cabinet. On the domestic side you will get 3 GPM (180 GPH) and when there is a call for domestic hot water that gets priority over heating the house. If you install ALSONS 1.6 GPM shower heads you can run 2 showers at one time. If it takes 20 - 40 seconds now to get domestic hot water to the second floor what ever new boiler or water heater you install it will still take that long to get the hot water to that bathroom. If you think you need more hot water install their Prestige Solo 110,000 BTU boiler with their Smart 40 gallon or 50, 60, 80 gallon stainless steel indirect water heater. To solve your long wait time to get hot water to your bathrooms look at installing a Grundfos comfort pump system that recirculates domestic hot water so when you turn on the faucet you get hot water right away. This Grundfos comfort pump goes on the water heater and has a timer so you do not have to run it 24/7 have the pump come on 15 minutes before you get up in the morning. if no one home during the day have ti go off when going to work have it come on 15 minutes before getting home off at bed time. Up under the sink in that bathroom there is a small cross over tee that gets installed so when the pump comes on the hot water will go out the hot lines to that cross over tee and the hot water will slowly go into the cold water line so there is no need to run a return line all the way back to the water heater. any other questions send me a email.

CMadatMe

Advice

I feel that a 100,000 btu boiler is grossly oversized for a 1500 sqft house.  I would tend to say loss is more likely between 40,000 -60,000 dependent on a heat loss. Some may argue that the extra btu's is required for the domestic but I would increase the storage capacity of my indirect to overcome that. With that in mind I would not be quoting a PE110. I more than likely would be looking at a PS60 with a 50 or 60 gallon indirect. I would choose that indirect based on the gpm requirement you need and the capable recovery based on the 60,000 btu's.



Did the contractor you plan on choosing do a heat loss? What are the heat emitters, fin-tube baseboard, cast iron? Did he do a comparison of a room by room heat loss to the capable output of the emitters to select the proper heating curve for the condensing boiler? These practices would be necessary to properly size and set-up any condensing boiler.



I would be more concerned with the design and installation first before worrying about the equipment. The boiler you choose will only perform to how it was sized and installed.

Jean-David Beyer

boiler is grossly oversized

I am not a contractor, but since my (former) contractor did not do a heat loss calculation, I did one. My house is a Cape Cod with about 1150 square feet between the  two floors here in New Jersey (Design day 14F). I calculated 35,000 BTU/hr. I have an indirect (38 gallon) hot water heater that runs less than 10 minutes a few times a day (I guess three times on days I do laundry). Since the smallest boiler I could get in the product line I was interested in was 80,000 BTU/hr input, I did not even have to consider the domestic water heating load. So if your house were next door to mine, and heating load is proportional to floor area, you would need about 46,000 BTU/hour.



Now my boiler is, as a practical matter, oversized for my house. I define "oversized" to mean that the boiler will not modulate down far enough to manage the system at low load when only the upstairs zone is calling for heat. As a result, even though it is a mod|con with outdoor reset, it goes into bang-bang mode to keep its heat output low enough when only upstairs calls for heat on a cool day. Mine modulates down to 16,000 BTU/hour, but the upstairs needs only 6500 BTU/hr on a 0F day.



The only way I could imagine your needing 100,000 BTU/hr would be if you were in Verkhoyansk (Siberia) or some such place. "The lowest monthly average low temperature is -52 °C (-62 °F) in January."

I believe they do not have natural gas, and you would probably have to heat the oil to get it through the pipes in the winter.



http://www.climatetemp.info/russia/verkhoyansk.html#imperial



If you are as fussy as I am, be sure to have a good heat loss calculation made and get the smallest boiler you can get larger than that calculation produces.

TonyS

TT excellence

is an excellent choice. The boiler is modulating and will turn down to 25,000 btus and of course on warmer days even low fire may be to much and the boiler will cycle a little.... That being said, you will never save more energy by going to a smaller boiler and using a larger indirect! Heat loss in a indirect is given in degrees per hour and that is based on the delta t of the water inside the tank and the ambient air temp surrounding the tank. Total btu's lost are per pound of water and a sixty gallon tank has a lot more pounds than a 14 gallon tank. It is simple math 60 x 8.33 =499.8 lbs x heat loss per hour times 24 gives you btu,s lost per day. Now those days are every day all year long as compared to a winter season with a few days that a 25000 btu boiler is too big and will cycle. Its not even close!!!! The TT Excellence is a really nice boiler and if your hot water demand can be satisfied with it...you cant go wrong.

mc118

Thanks to all

Thank you all for taking the time to post. They give me more ideas to explore and plugged more than a few holes in my knowledge. I am still curious about the consensus on the two other brands; Munchkin and Crown. What tier level are they quality-wise; low, mid or high?



My field of expertise is in documentary photo and video production. If anyone has questions on still or video cameras I am happy to try and answer any questions outside this forum. Just trying to repay the sharing of knowledge one of the few ways I can.



Thanks again!