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MCiCiR
12-08-2011, 05:26 PM
I am hoping to make a smart choice to complete an oil to gas conversion before the end of the year and could use some help. Because of the high rebates, I thought the best way to go was a high-efficiency boiler and water heating unit with an AFUE rating greater or equal to 90 percent and domestic hot water storage of 2 gallons or less, so a combi unit would be the perfect choice.

I've received quotes from two companies which came out and took pictures, etc. and also read all of the threads here that seem to do with this subject and my head is now spinning trying to figure out the terminology and what option(s) are going to provide reliable and cost-effective heating and hot water for years to come. Here are some questions I could use help with:

What are the advantages of going with a high efficiency tank less boiler if it will likely need more repairs because of the aluminum heat exchanger? Would changing that to a stainless steel one reduce the potential for maintenance?

Is the lower maintenance of a cast iron boiler worth sacrificing the higher efficiency rating?

These are the systems that have I been quoted. Are there questions I should ask or anything I should know about these?

Baxi Luna HT 380 Wallhung Condensing Boiler. This fully modulates up to 112,601 Btu’s and is up to 99% efficient. The Baxi Luna HT 380 is a combination central heating and on-demand domestic hot water boiler (with DHW flow rate of 3.9 US gpm @ (T80 F).

Navien Combo Gas Boiler vented with 3" pvc pipe model #CH240ASME

Lockinvar WHN155 Heating Gas Boiler rated at 96% with a 40-gallon indirect hot water tank.

Buderus G124X4-32 rated at 96,000 net BTUs aand 85% AFUE with a 40-gallon Heat-Flo stainless steel indirect hot water tank. An optional Buderus Logamatic Weather Sensing Control is also offered.

Are there other models I should consider?

Currently I have an oil burner that's about 25 years old with a tank less hot water, and there's plenty of hot water to go around. I have two zones in a 1800 sf slab ranch with 1.5 bathrooms. I know it has a bad mixing valve but my repair guys tell me I don't need to replace it - it just means the hot water is a little higher than code but since it's just adults here, it isn't all that important. I suppose I could just keep it but the cost savings of gas compared to oil are pretty attractive and I'd like to get a gas stove at some point.

One last question, I had a new oil tank installed about 6 months ago (and then got a free gas line installation offer from NStar), so I'm wondering whether I can sell my oil tank or if I just need to junk it (well, the installing company would take it away for me).

Many thanks in advance, this was a very interesting forum to read and I'm glad there are pros like you to help people like me figure these things out.

beenthere
12-08-2011, 09:49 PM
Check out the Weil McLain ultra.

platchford
12-08-2011, 10:44 PM
Does anyone else think those boilers btu ratings seem a bit low for the New England area? They were all around 100k btus I believe and while that seems plausible for heating the home, IMO it seems rather low when it is expected to provide DHW too. I'm no expert when it comes to boilers which is why I am asking rather than stating it for fact.

grasshopper
12-08-2011, 10:49 PM
Our company does the Navien Combi and the Peerless Triangle Tube Prestige Excellence. I am looking at putting a Triangle Tube in my own Mom's house. The Navien is good, but the triangle tube has a tank in it and is better I believe. They cost more but we have had far less warranty issues.



Prestige Excellence
High Efficiency Space Heating and Domestic Hot Water All-in-One
The Prestige Excellence Series combines a High Efficiency Condensing Stainless Steel Wall Mounted Gas Boiler with a built-in “Tank-in-Tank" Indirect Fired Water Heater.

In addition to the reliability and economy of a 110 Series Stainless Steel Condensing Boiler the Prestige Excellence Model's 14 gallon in-cabinet Indirect Fired Water Heater is capable of producing 180 gph of domestic hot water.
» 96% AFU Efficiency
» Abundant Domestic hot water with standard mixing valve
» Highest water content in the industry
» Ideal for small zones without short cycling
» Self Cleaning / Self Descaling
» Condensate washes combustion residue away when streaming down the tubes resulting in a constant efficiency and reduced maintenance
» Quiet operation
» Fully Modulating
» Built-in exclusive “Tank-in-Tank”
» Unparalleled resistance to corrosion
» Less sensitive to water flow
» Vertical Firetube Design
» 439 Grade Stainless Steel Heat Exchanger
» Impervious to chloride cracking
» Stable temperature control
» Low pressure drop
» Condensate washes combustion residue away
» Control panel with digital display
» Standard Outdoor Reset
» Digital Display
» Direct Vent / Sealed Combustion

Gross
12-09-2011, 10:29 AM
Our company does the Navien Combi and the Peerless Triangle Tube Prestige Excellence. I am looking at putting a Triangle Tube in my own Mom's house. The Navien is good, but the triangle tube has a tank in it and is better I believe. They cost more but we have had far less warranty issues.



Prestige Excellence
High Efficiency Space Heating and Domestic Hot Water All-in-One
The Prestige Excellence Series combines a High Efficiency Condensing Stainless Steel Wall Mounted Gas Boiler with a built-in “Tank-in-Tank" Indirect Fired Water Heater.

In addition to the reliability and economy of a 110 Series Stainless Steel Condensing Boiler the Prestige Excellence Model's 14 gallon in-cabinet Indirect Fired Water Heater is capable of producing 180 gph of domestic hot water.
» 96% AFU Efficiency
» Abundant Domestic hot water with standard mixing valve
» Highest water content in the industry
» Ideal for small zones without short cycling
» Self Cleaning / Self Descaling
» Condensate washes combustion residue away when streaming down the tubes resulting in a constant efficiency and reduced maintenance
» Quiet operation
» Fully Modulating
» Built-in exclusive “Tank-in-Tank”
» Unparalleled resistance to corrosion
» Less sensitive to water flow
» Vertical Firetube Design
» 439 Grade Stainless Steel Heat Exchanger
» Impervious to chloride cracking
» Stable temperature control
» Low pressure drop
» Condensate washes combustion residue away
» Control panel with digital display
» Standard Outdoor Reset
» Digital Display
» Direct Vent / Sealed Combustion

well...yea...but its not as shiny..so theres that.

Gross
12-09-2011, 12:12 PM
Removed quoted text

you can buy condensing boilers over the internet in the US.

i dont believe it comes with a licensed and skilled installer...

Gross
12-09-2011, 12:17 PM
removed quoted text

im thinking th qualification standards in the peoples republic of china are slightly lower than those of the United States

MCiCiR
12-09-2011, 06:46 PM
and advice. I'll look into the Weil and Triangle.

Do you know whether I can sell my 6-month old tank or if I have to junk it?

Mary

hearthman
12-09-2011, 06:46 PM
Jim1977, that's four illegal postings in one day.This is the Ask Our Pro's forum. In order to post responses here, you must have verified qualifications and have been approved by the AOP Committee. Please see my signature line for links to register and review the AOP Forum Rules. Thank you. Your post will now be deleted.

grasshopper
12-09-2011, 11:11 PM
and advice. I'll look into the Weil and Triangle.

Do you know whether I can sell my 6-month old tank or if I have to junk it?

Mary


You oil tank is worth whatever someone is willing to pay for it. I would think if someone needs a tank they would love to work a deal with you. Talk to contractors in your area that do or deliver oil.

platchford
12-09-2011, 11:24 PM
and advice. I'll look into the Weil and Triangle.

Do you know whether I can sell my 6-month old tank or if I have to junk it?

Mary

I dunno about the market in the Boston area but my suspicions would be that you could sell the tank via Craigslist perhaps or maybe even the contractor that replaces your unit may be willing to take it off your hands. If you were near me I'd offer to take it. I'm looking for an additional storage tank for a project. :grin2:

beenthere
12-10-2011, 06:56 AM
Does anyone else think those boilers btu ratings seem a bit low for the New England area? They were all around 100k btus I believe and while that seems plausible for heating the home, IMO it seems rather low when it is expected to provide DHW too. I'm no expert when it comes to boilers which is why I am asking rather than stating it for fact.

Boiler with indirect set as priority zone, no problem sizing the boiler to the heat loss. A 90,000 BTU boiler can recover 40 gallons 100 degrees in 20 minutes. 80 degrees in about 15 minutes. Not often that it would have to heat the entire 40 gallons by 80 o 100 degrees.

beenthere
12-11-2011, 05:42 AM
darkbeekeeper

This is the Ask Our Pro's forum. In order to post advice here, you must have verified qualifications and have been approved by the AOP Committee.

You can find the rules for posting and qualifications here (http://hvac-talk.com/vbb/showthread.php?t=957002).

Further infractions may result in loss of posting privileges.