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Oversized Boiler

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Bob_72
Bob_72 Member Posts: 7
in THE MAIN WALL
Hello. I installed a Crown TWZ125 oil fired boiler with a tankless heater in my home about 4 years ago. The problem is: I had a plumber friend size it for me, and it's capacity is 152,000/132,000 BTU net. I've since had a Manual J calculation done on my home, and the heat loss is only 74,000 BTU's... so I'd say it's a bit oversized.

My home is a 2,100 sq. ft. rancher with 2 zones, and Baseray cast iron baseboards. It works great, but short cycles. I've since become an HVAC service tech, but I work on gas, and heat pumps only. I'm comfortable servicing my own boiler, and I have a combustion analyzer, but what I would like to do, (safely, and if possible) is to lower the firing rate of my burner - a Beckett AFG.

Crown makes a boiler - the TWZ090 which appears identical to the TWZ125 model as far as dimensions, boiler sections, (4), and flue pipe, and its output is 111,000/97,000BTU net. the only difference I can see are in the Beckett burner itself. Here are the differences I've found: TWZ125 - 70MD air tube combo, while the TWZ090 uses the70MB. TWZ125 uses a V1 head, TWZ090 uses the L1 head. Static plate TWZ125 is 2 3/4, and TWZ090 is 3 3/8.

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  • Bob_72
    Bob_72 Member Posts: 7
    Oversized Boiler

    Hello. I installed a Crown TWZ125 oil fired boiler with a tankless heater in my home about 4 years ago. The problem is: I had a plumber friend size it for me, and it's capacity is 152,000/132,000 BTU net. I've since had a Manual J calculation done on my home, and the heat loss is only 74,000 BTU's... so I'd say it's a bit oversized.

    My home is a 2,100 sq. ft. rancher with 2 zones, and Baseray cast iron baseboards. It works great, but short cycles. I've since become an HVAC service tech, but I work on gas, and heat pumps only. I'm comfortable servicing my own boiler, and I have a combustion analyzer, but what I would like to do, (safely, and if possible) is to lower the firing rate of my burner - a Beckett AFG.

    Crown makes a boiler - the TWZ090 which appears identical to the TWZ125 model as far as dimensions, boiler sections, (4), and flue pipe, and its output is 111,000/97,000BTU net. the only difference I can see are in the Beckett burner itself. Here are the differences I've found:

    TWZ125 TWZ090
    Air tube combo ---- 70MD 70MB
    Head type --------- V1 L1
    Static plate------- 2 3/4 3 3/8
    Nozzle-------------1.00/45B 0.75/45B
    Pump pressure------ 175psi 140psi
    Shutter setting---- 10 7
    Band setting------- 1 0

    So, my question... can I alter my burner's setup and achieve a lower firing rate which would bring my boiler's output closer to the design of my home without compromising anything? If so, do I need to change all of the above items that are different, or can I just change some? If anyone can help, I would very much appreciate it. I'm going to include a link to Crown's boiler manuals in case someone would like to see what I've got, and what I'm trying to do.

    http://www.crownboiler.com/manuals/content/Residential_Boilers/Oil/TWZ Series Installation Instructions.pdf

    Thanks, Bob
  • Bob_72
    Bob_72 Member Posts: 7
    Oversized Boiler

    Hello. I installed a Crown TWZ125 oil fired boiler with a tankless heater in my home about 4 years ago. The problem is: I had a plumber friend size it for me, and it's capacity is 152,000/132,000 BTU net. I've since had a Manual J calculation done on my home, and the heat loss is only 74,000 BTU's... so I'd say it's a bit oversized.

    My home is a 2,100 sq. ft. rancher with 2 zones, and Baseray
    cast iron baseboards. It works great, but short cycles. I've since become an HVAC service tech, but I work on gas, and heat pumps only. I'm comfortable servicing my own boiler, and I have a combustion analyzer, but what I would like to do, (safely, and if possible) is to lower the firing rate of my burner - a Beckett AFG.

    Crown makes a boiler - the TWZ090 which appears identical to the TWZ125 model as far as dimensions, boiler sections, (4), and flue pipe, and its output is 111,000/97,000BTU net. the only difference I can see are in the Beckett burner itself. Here are the differences I've found:

    Air tube combo -TWZ125, 70MD the TWZ090, 70MB. Head type - TWZ125, V1, and TWZ090 L1. Static plate - TWZ125, 2 3/4, and TWZ090 3 3/8. Nozzle - TWZ125, 1.00/45B @175 psi, and the TWZ090 has a 0.75/45B @ 140 psi. Starting shutter setting - TWZ125, 10, and on the TWZ090, 7. Band setting - TWZ125, 1, and TWZ090 is 0.

    So, my question... can I alter my burner's setup and achieve a lower firing rate which would bring my boiler's output closer to the design of my home without compromising anything? If so, do I need to change all of the above items that are different, or can I just change some? If anyone can help, I would very much appreciate it. I'm going to include a link to Crown's boiler manuals in case someone would like to see what I've got, and what I'm trying to do.

    http://www.crownboiler.com/manuals/content/Residential_Boilers/Oil/TWZ Series Installation Instructions.pdf

    Thanks, Bob
  • Bob_72
    Bob_72 Member Posts: 7
    Oversized Boiler

    Hello. I installed a Crown TWZ125 oil fired boiler with a tankless heater in my home about 4 years ago. The problem is: I had a plumber friend size it for me, and it's capacity is 152,000/132,000 BTU net. I've since had a Manual J calculation done on my home, and the heat loss is only 74,000 BTU's... so I'd say it's a bit oversized.

    My home is a 2,100 sq. ft. rancher with 2 zones, and Baseray
    cast iron baseboards. It works great, but short cycles. I've since become an HVAC service tech, but I work on gas, and heat pumps only. I'm comfortable servicing my own boiler, and I have a combustion analyzer, but what I would like to do, (safely, and if possible) is to lower the firing rate of my burner - a Beckett AFG.

    Crown makes a boiler - the TWZ090 which appears identical to the TWZ125 model as far as dimensions, boiler sections, (4), and flue pipe, and its output is 111,000/97,000BTU net. The only differences I can see are in the Beckett burner itself. Here are the differences I've found:

    Air tube combo -TWZ125, 70MD the TWZ090, 70MB. Head type - TWZ125, V1, and TWZ090 L1. Static plate - TWZ125, 2 3/4, and TWZ090 3 3/8. Nozzle - TWZ125, 1.00/45B @175 psi, and the TWZ090 has a 0.75/45B @ 140 psi. Starting shutter setting - TWZ125, 10, and on the TWZ090, 7. Band setting - TWZ125, 1, and TWZ090 is 0.

    So, my question... can I alter my burner's setup and achieve a lower firing rate which would bring my boiler's output closer to the design of my home without compromising anything? If so, do I need to change all of the above items that are different, or can I just change some? If anyone can help, I would very much appreciate it. I'm going to include a link to Crown's boiler manuals in case someone would like to see what I've got, and what I'm trying to do.

    http://www.crownboiler.com/manuals/content/Residential_Boilers/Oil/TWZ Series Installation Instructions.pdf

    Thanks, Bob
  • Bob_72
    Bob_72 Member Posts: 7
    Oversized Boiler

    Hello. I installed a Crown TWZ125 oil fired boiler with a tankless heater in my home about 4 years ago. The problem is: I had a plumber friend size it for me, and it's capacity is 152,000/132,000 BTU net. I've since had a Manual J calculation done on my home, and the heat loss is only 74,000 BTU's... so I'd say it's a bit oversized.

    My home is a 2,100 sq. ft. rancher with 2 zones, and Baseray
    cast iron baseboards. It works great, but short cycles. I've since become an HVAC service tech, but I work on gas, and heat pumps only. I'm comfortable servicing my own boiler, and I have a combustion analyzer, but what I would like to do, (safely, and correctly if possible) is to lower the firing rate of my burner - a Beckett AFG.

    Crown makes a boiler - the TWZ090 which appears identical to the TWZ125 model as far as dimensions, boiler sections, (4), and flue pipe, and its output is 111,000/97,000BTU net. The only differences I can see are in the Beckett burner itself. Here are the differences I've found:

    Air tube combo -TWZ125, 70MD the TWZ090, 70MB. Head type - TWZ125, V1, and TWZ090 L1. Static plate - TWZ125, 2 3/4, and TWZ090 3 3/8. Nozzle - TWZ125, 1.00/45B @175 psi, and the TWZ090 has a 0.75/45B @ 140 psi. Starting shutter setting - TWZ125, 10, and on the TWZ090, 7. Band setting - TWZ125, 1, and TWZ090 is 0.

    So, my question... can I alter my burner's setup and achieve a lower firing rate which would bring my boiler's output closer to the design of my home without compromising anything? If so, do I need to change all of the above items that are different, or can I just change some? If anyone can help, I would very much appreciate it. I'm going to include a link to Crown's boiler manuals in case someone would like to see what I've got, and what I'm trying to do.

    http://www.crownboiler.com/manuals/content/Residential_Boilers/Oil/TWZ Series Installation Instructions.pdf

    Thanks, Bob
  • Bob_72
    Bob_72 Member Posts: 7
    Oversized Boiler

    Hello. I installed a Crown TWZ125 oil fired boiler with a tankless heater in my home about 4 years ago. The problem is: I had a plumber friend size it for me, and it's capacity is 152,000/132,000 BTU net. I've since had a Manual J calculation done on my home, and the heat loss is only 74,000 BTU's... so I'd say it's a bit oversized.

    My home is a 2,100 sq. ft. rancher with 2 zones, and Baseray
    cast iron baseboards. It works great, but short cycles. I've since become an HVAC service tech, but I work on gas, and heat pumps only. I'm comfortable servicing my own boiler, and I have a combustion analyzer, but what I would like to do, (safely, and correctly if possible) is to lower the firing rate of my burner - a Beckett AFG.

    Crown makes a boiler - the TWZ090 which appears identical to the TWZ125 model as far as dimensions, boiler sections, (4), and flue pipe size, and its output is 111,000/97,000BTU net. The only differences I can see are in the Beckett burner itself. Here are the differences I've found:

    Air tube combo -TWZ125, 70MD the TWZ090, 70MB. Head type - TWZ125, V1, and TWZ090 L1. Static plate - TWZ125, 2 3/4, and TWZ090 3 3/8. Nozzle - TWZ125, 1.00/45B @175 psi, and the TWZ090 has a 0.75/45B @ 140 psi. Starting shutter setting - TWZ125, 10, and on the TWZ090, 7. Band setting - TWZ125, 1, and TWZ090 is 0.

    So, my question... can I alter my burner's setup and achieve a lower firing rate which would bring my boiler's output closer to the design of my home without compromising anything? If so, do I need to change all of the above items that are different, or can I just change some? If anyone can help, I would very much appreciate it. I'm going to include a link to Crown's boiler manuals in case someone would like to see what I've got, and what I'm trying to do.

    http://www.crownboiler.com/manuals/content/Residential_Boilers/Oil/TWZ Series Installation Instructions.pdf

    Thanks, Bob
  • brucewo1b
    brucewo1b Member Posts: 638
    Bob

    Bob your best bet is top call Crown, but it is not uncommon to have one boiler to cover two or three size ranges with just burner changes, I would say that if it that is the case then you would have to do all the changes.

    B.S.

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