Posts Tagged ‘Raypak’

Boilers Part 16 – High Efficiency Boiler Disadvantages

November 28, 2010

The Direct Vent Condensing Boiler is the best choice for any home. However, you must be careful when selecting the right boiler for you.

In order to successfully transfer the heat from the flame to the water as easily as possible, the vast majority of condensing boilers force the water through a very restrictive heat exchanger with many small passages. This can cause 2 very serious problems.

The first problem is that if one of these passages becomes blocked with debris or dirt from the system, the heat exchanger will quickly overheat and fail. A heat exchanger replacement on a high efficiency boiler can be in excess of $2,000. It would be a shame to lose all your fuel savings on a major repair like this. These restrictive heat exchangers require extensive cleaning annually. Since many people neglect to call for service, and many contractors don’t even know about this required cleaning, many people have suffered disappointment and heat exchanger failure. Life doesn’t have to be this complicated. If this boiler is installed with the proper flow design, dirt and air separator and cleaned as per the manufacturers’ instructions, it will last a long time.

In my next post, I will discuss the second problem with these restrictive heat exchangers.

Advertisements

Boilers Part 15 – Turndown

November 25, 2010

Hi Again, Turndown is the ability of a boiler to reduce its input to match the load. Imagine a home with 3 floors and a separate thermostat and heating zone for each floor. When all three floors require heat, the demand might be 80,000 BTUH. This would require an 80,000 BTUH boiler. If only the basement needed heat, the load might only be 20,000 BTUH. Firing an 80,000 BTUH boiler would be overkill and horribly inefficient. All DVCB have a turndown that allows the boiler to fire at the required rate for that time so the boiler would fire just at the 20,000BTUH that you need. Efficiency is enhanced once again.

Now that it is crystal clear that the best option for a boiler is the DVCB, Direct Vent Condensing Boiler, I would like to discuss the problems with these boilers and how to avoid them.

Boilers Part 14 – Low Water Temperature Operation

November 23, 2010

Hi Again,

Today I’d like to discuss the advantage of low temperature operation and how it enhances your energy savings. We have discussed in previous posts that most of the time, your radiators will give you enough heat with water temperatures between 90 Deg. F. and 120 Deg. F. If you have in floor radiant heat, your water only needs to be around 90 degrees all the time. In order to extract the most heat from your gas flame and get really high efficiencies, the water entering the boiler must be as low as possible. 90 Deg. F. water will suck so much more heat out of the flame than 140 Deg. F. water. The problem with most boilers is that such low water temperatures will shock the boiler and cause it to crack and leak. Complete destruction!! The DVCB is designed for low water temperature conditions. As a matter of fact, it works best with low water temperatures since it is able to condense and extract so much more heat from your gas dollars. This compounds your savings.

Boilers Part 12 – The Heating Cycle

November 18, 2010

Let’s say you have a typical 3,000 square foot home with cast iron baseboard or radiators. This is what happens in a typical heating cycle.
Your thermostat is set at 70 Degrees Fahrenheit. The temperature in your home drops to 69 Deg. F. and your thermostat sends a signal to your boiler to fire. Your entire piping and radiator system is at room temperature or 69 Deg. F. Keep in mind that the weight of all your piping and radiators is around 5,000 lbs. Your boiler fires and starts warming the water, all the steel piping and cast iron radiators to 140 Deg. F. This will take around 20 minutes to achieve since there is 5,000 lbs to heat up. While your house waits for heat, the temperature continues to drop. By the time tha radiators warm up enough to start warming your home, the temperature probably has dropped to 65 Deg. F.
Now your 5,000 lbs of steel and cast iron has reached 140 degrees and the temperature has reached setpoint at 70 degrees. The boiler shuts off but the 5,000 lbs of steel in your home is still radiating het and the temperature in your home continues to rise. By the time your heat peaks and the radiators cool down and stop emitting heat, your home is probably 75 degrees.
Now your house starts to cool and the cycle starts all over again.
What is happening is that yu are getting a very wide range on 10 degrees in your home. This will not be comfortable and as you het your home to 75, you are wasting loads of energy.

In my next post I will illustrate the heating cycle with a DVCB (Direct Vent Condensing Boiler) that is equipped with Outdoor Reset.

For more technical details about reset, see this article from John Siegenthaler

Boilers Part 10 – Modulation

November 14, 2010

One of the great operational advantages available with a Mod/Con (Modulating Condensing) boiler is its ability to modulate its heating power to match the requirements of your home. When your boiler is sized, it is designed to provide you with enough heat to keep your home nice and comfortable even on the coldest day of the year. However, most of the time your boiler fires, it is not quite as cold as it was designed for. As a matter of fact, the coldest temperatures only happen less than 3% of the time. All other times, your boiler is too big for your home. When your boiler is too big, it will run in short bursts called “short cycling” and will waste energy. See this video about oversized boilers.

The modulating boiler, however can adjust its heating power to match the actual requirements at the time. This is done in real-time adjusting the boiler’s power depending on weather conditions. Now your boiler is always just the prefect size for your home and is always operating at peak efficiency.

In next post I will discuss the advantage of Reset.

Boilers Part 9 – Modulating/Condensing Boilers – Operational Efficiency

November 11, 2010

Proud of a great furnace install.

The energy savings of a condensing boiler is compounded by its operating efficiency. Operating efficiency means that the boiler operates in such a way to maximize savings and reduce energy consumption due to this special sequence of operation. This is all in addition to the fact that its combustion efficiency is high. There a several ways in which the modulating condensing boilers offer operational efficiency and depending on which boiler you select, you will benefit from some or all of these operational advantages.

  1. Modulation.
  2. Reset
  3. Low water temperature operation.
  4. Turndown to support zoning.

In my next few posts, I will elaborate on these operational efficiencies and explain them in detail. Please feel free to ask a question if you require additional information.

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 4 – Power Vented Boilers

November 1, 2010

Proud of a great furnace install.

Hi,

Today I will discuss the Power Vented Boiler.  Power vented boilers can reach up to 85% efficiency which is a bit more than the old workhorse atmospheric. They are relatively reliable and are easy replacements for the old atmospheric. They look like the atmospheric with one difference, the atmospheric has the mushroom-shaped draft hood on top while the power vented boiler has an induced draft blower on the side of the boiler. Please see the picture below.

View this document on Scribd

These boilers have a blower that forces the flu products out of your home, so they are a little bit safer than atmospheric boilers. However, since they rely on air from inside your home for combustion air, they still present some dangers and their installation are also restricted by the TSSA as follows.

1. A dedicated and properly sized combustion air duct directly from the outside must be installed in the boiler room.

2. Carbon monoxide detectors must be installed in or adjacent to every sleeping area in the home.

See the Safety Advisory below. Again, when I hear that these boilers require such extensive carbon monoxide monitoring, I would not consider installing these types of boilers in my home and jeopardizing the safety of my family. To me it is like throwing my child overboard in rough seas with a life jacket.

In my home, I would only install a direct vented boiler that we will discuss in my next post. These boilers have no restrictions on their installation because they are inherently safer than the 2 boilers we just discussed.

View this document on Scribd