Oversized Boiler

Bob_72

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.

Bob_72

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

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

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

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

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

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.