Help with new boiler selection and install
Hello. I live in a 1800 sq ft house in lower CT that currently has an old WTGO-5 boiler with a Carlin EZ1 burner that I want to replace. The house has three heating zones controlled by individual zone valves, and a separate zone with a dedicated circulator for a 55 gallon Vaughn P55F indirect water heater.
Zone 1 has about 43 ft of copper fin baseboard
Zone 2 has about 34 ft of copper fin baseboard
Zone 3 has about 41 ft of copper fin baseboard
I have downfired the burner to a 1.10 nozzle, and have adjusted the Hydrostat 3250 for a high limit of 175 and a differential of 30. The longest the burner will run with all zones calling for heat is about 8 minutes before reaching high limit. The indirect is wired to be priority between the Hydrostat and the Taco single zone control relay for the indirect.
I believe this boiler is oversized for the house, and I want to replace it with something sized more appropriately. I also want to repipe the near boiler piping since the circulators are currently on the return piping.
I'm considering purchasing either a wgo-3 or a wgo-2 boiler with a Carlin EZ-1 burner. I want to keep the zone valves for the heating zones, and a separate circulator for the DHW.
I have attached a drawing of the near boiler piping I have created for the new boiler installation to see if anyone can help me with it, and give any suggestions.
I am currently looking for contractors to do the installation, but I wanted to see if I'm in the right ballpark with what I have come up with.
Thanks for your help!
Comments
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You can run 1" on the return instead of 1.25. Plenty for your heating load.
You should definitely run 1" for the indirect.
Most would like to see the tank on the supply side ahead of the circulator, but the pressure drop in the boiler is so low that it really doesn't matter.
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Happy New Year! Thanks for the suggestions.
The indirect is piped for 3/4" from the factory, so that's why we used 3/4" instead of 1"
I have called Energy Kinetics, and will get some estimates from their recommended installers.
I'm probably going to be in this house for only ten more years, so that is a factor as well with respect to budget.
I'd like to stay with a Carlin burner and a 3250 Hydrostat aquastat for the new boiler as I am familiar with these units and have spare parts for them.
I had the outdoor reset hooked up to the 3250 initially to try to save oil, but the burner would only run for about two minutes since it lowered the high limit for economy. This is when I switched to removing the outdoor reset, and set the high limit to 175 with a differential of 30 and economy turned off. I can now get the burner to run for about 8 minutes.Readings on the Testo 310 are as follows:
O2 - 5.2%
CO2 - 11.72%
Stack Temp - 432
Excess Air - 33.9%
CO - 1
I will also see if the Buderus G115WS3 is an option, and if it can be used with a Carlin burner and 3250 Hydrostat.
Are there any other issues or suggestions for the near boiler piping diagram I provided?
Thanks!0 -
@katman , if you multiply your gallons of fuel oil usage per year by 70, you will get a reasonable estimate of how many BTUs an hour your home is using on a design day.
The engineering basis for this is because nearly all cold climate locations use about 1% of annual fuel consumption on design day based upon design day heating degree days and annual heating degree days (1.2% is more conservative). This is estimate is higher than your actual heat loss because it includes energy required to make hot water and the energy that’s wasted based upon the efficiency of the equipment. Here’s the math:
1.2% per day / 24 hours/day x 138,600 BTU/gallon = 70
Examples: 1000 gallons of fuel oil per year is estimated at 70,000 BTUs/hour, and 2000 gallons per year would be 140,000 BTUs/hour.
When you calculate your gallons per year, make sure that you are looking at the gallons consumed. For example, if you have a full tank delivery of 150 gallons on September 1, and a full tank delivery of 200 gallons on November 1, your usage is 200 gallons from September 1 to November 1, not 350 gallons.
@SuperTech , thank you for your kind words about Energy Kinetics!
Best,
Roger
President
Energy Kinetics, Inc.0 -
The indirect is piped for 3/4" from the factory, so that's why we used 3/4" instead of 1"
The "factory" saved money by using 3/4" and compromised the flow rate. You have much further to go and return so you should NOT compromise it further!
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Thanks. Looks like I was using 850-1000 gallons per year, but that was with the outdoor reset in use.
I keep the house at 72 during the day, and at 68 overnight and during the day when I'm not home.
I like a warm house 😀
I just changed all of the thermostats to be set to 3 CPH.Current boiler is 175,000 BTU/ Net 152,000 BTU
Thanks. I'll add in a 1" pipe between the new boiler and the indirect, and reduce it down to 3/4" at the indirect.
I'll use a circulator with ifc on the indirect supply. Do I also need a flow check valve in the indirect return piping?0 -
@katman , I'd do a heat-loss calculation on your house to verify the proper boiler size. Any contractor worthy of the name can do this for you. For CT, go here:
Also try @Charlie from wmass , I understand he comes to CT as well.
All Steamed Up, Inc.
Towson, MD, USA
Steam, Vapor & Hot-Water Heating Specialists
Oil & Gas Burner Service
Consulting0 -
@katman I also highly recommend Energy Kinetics over Weil McLain and buderus. A few reasons why:
True thermal purge which other brands don’t have.
If you have multiple zones the EK energy manager comes with a standard 5 zone set so no need for a separate zone control.
The burner air box with air intake taken from the outside virtually makes the burner silent.
By far the easiest boiler to clean and service.
Boiler stand so need to put boiler on blocks and comes with adjustable legs to level the boiler.
Most of all the best tech and customer service out of any manufacturer in the industry.3 -
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You said:
55 gallon Vaughn P55F indirect water heater.
Zone 1 has about 43 ft of copper fin baseboard
Zone 2 has about 34 ft of copper fin baseboard
Zone 3 has about 41 ft of copper fin baseboard
Current boiler is 175,000 BTU/ Net 152,000 BTU.
Even with the indirect heater don't you think that with only 118 feet of baseboard that your boiler is quite oversized?
I am in Chicago with a -10 degree day design.
I have a 1954, 1250 sq ft home. I have around 100 ft of copper fin baseboard. My boiler is 100K BTU input 85K Gross and 73K net. My house will keep 70° at the -10 design. I haven't changed my envelope at all. I really really think you need to do a professional heat loss on you house before you make any more mods.
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Hi, yes the boiler is way oversized. It's from 2006, and was here when I bought the house.
I definitely need something smaller to stop the short cycling.
I'm hoping to find a good contractor in CT to help me with the selection and the install.0 -
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Thermal storage tank could be a stopgap until this boiler dies. It will also work with a newer smaller boiler.
Cost is what you spend , value is what you get.
cell # 413-841-6726
https://heatinghelp.com/find-a-contractor/detail/charles-garrity-plumbing-and-heating0
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