Posts Tagged ‘Viessman’

Boilers Part 17 – Restrictive Heat Exchanger = High Pumping Costs

November 30, 2010

The second disadvantage of most Direct Vent Condensing Boilers is their restrictive heat exchangers. Not all DVCB have this disadvantage however so you must make sure to ask your contractor about this. Let’s say that you have a 3,000 square foot home with an 80,000 BTUH boiler. You would probably need about 8-10 GPM or 8-10 gallons of water passing through your boiler per minute. Most boilers would have a pressure drop through your boiler of 8 feet of head. The best boilers have a pressure drop as low as 5 feet of head. This means that with the right boiler your pump will work half as hard. Pumping water around your house uses quite a bit of electricity. With a non restrictive heat exchanger, you will be able to keep this cost to a minimum.

Make sure that your contractor understands pump and boiler flow curves so that your system will be designed to run as efficiently as possible.

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Boilers Part 8 – Combustion Efficiency

November 9, 2010

Today I will discuss Combustion Efficiency.

Combustion Efficiency is the percentage of heat you get from your fuel. For instance, if your boiler has a combustion efficiency of 70%, you are getting 70 cents of heat for every dollar of gas that you are paying for. The rest of the heat is going right up the chimney. This is why you can burn your hand when you touch the hot chimney of a 70% efficient appliance. You are feeling the heat that is being wasted right up the chimney.

If you think about it, you are getting burnt even if you don’t touch the chimney because you are losing/wasting so much energy.

Compare this to a DVCB which has a 95% combustion efficiency and you will see that you are getting 95 cents for every dollar in fuel used. This is a great savings of almost 30%. If you feel the vent of a condensing appliance, it is just a bit warm because you are extracting 95% of the heat from the flu gases before you send them out the vent.

With today’s high energy prices and our concern for the environment, it is a crime not to invest in a DVCB.

Boilers Part 6 – DVCB – The Safest

November 5, 2010

In my last post I listed as the first advantage of the DVCB (Direct Vent Condensing Boiler) that it is the safest type of boiler.

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The reason for this is that the combustion process is completely isolated from the airstream of your home. All of the combustion air is drawn through a sealed pipe from outside and all of the products of combustion are vented directly to the outside in a sealed pipe. No matter what happens in the combustion process and no matter if the flame is producing CO (Carbon Monoxide), everything will be vented outside with no danger of anything entering your home. This is the best protection that you can provide for your family. The Direct Vent boiler is also the preferred boiler by the TSSA for this very reason. You can see this preference clearly in the language of their bulletin on replacing boilers.
Please see the advisory below.

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Boilers Part 5 – Direct Vent Condensing Boilers

November 3, 2010

Hello,
Today we will discuss the best type of boiler for your home. I say the best because it is
1. The Safest
2. The Most Efficient
3. The Most Versatile
4. The Most Compact
5. The boiler that will deliver the greatest comfort.

The Direct Vent Condensing Boiler.

There are so many DVCB’s to choose from so I will dedicate the next posts to the many options, features, pitfalls, and concerns you should be aware of when selecting the right boiler for your home.

Below is a photo of a compact DVCB system that we installed.

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