Archive for November, 2010

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.

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.

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.

Premi-AirClimateCare Fall 2010 Campaign

November 21, 2010

Please see this video of our print ads and corresponding radio messages. Let me know what you think.

Boilers Part 13 – The Heating Cycle With Outdoor Reset

November 21, 2010

Today I will illustrate the heating cycle with outdoor reset.

Your thermostat is set for 70 deg. F. The temperature drops to 69 degrees and the boiler fires up. Based on the outside temperature of 50 degrees, your boiler reset controller determines that a water temperature of 100 degrees will provide the right amount of heat. The boiler starts heating your water until it reaches 100 degrees. Your home heats up to 70 degrees and the boiler shuts off, but the temperature doesn’t go up higher because your radiators are only 100 degrees. In order to maintain 70 degrees in your home, tha radiators must stay at 100 degrees so they will never cool down. Rather, they will stay at 100 degrees and maintain your exact set point of 70 degrees in your home. How efficient, How comfortable? As it gets colder outside, your boiler will automatically adjust the water in your system hotter and hotter to meet your exact heating needs. Imagine how comfortable it will feel in your home without temperature fluctuations? Imagine how quiet your system will be without the constant noise of your pipes expanding and contracting as they heat up and cool down. But most of all, imagine how much energy you will save due to this operating efficiency.

See this video to learn more about outdoor reset.

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

Atmospheric Boilers – Dangerous – TSSA Mandatory Annual Testing

November 17, 2010

If you own a boiler that vents up your chimney and is equipped with a draft hood, you must have it inspected by a licensed Gas Technician. The TSSA just renewed its mandatory annual testing requirement for this boiler. Even if your boiler was inspected last year, it must me re-inspected and a tag must be affixed to the boiler showing that it was tested. This year the TSSA added a worst case scenario depressurization test to the mandatory testing. The required test would cost from $300-$600 dollars. I would get rid of this potentially dangerous boiler and replace it with a Direct Vent Condensing Boiler.

See the TSSA Advisory below including a letter to homeowners describing the problem and a sample of the Tag that must be affixed to your boiler.

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View this document on Scribd
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View this document on Scribd

Beware of DIY Do It Yourselfers

November 17, 2010

Yesterday, one of our technicians attended an industrial storage space and found this unit heater that was vented into the tenant space. This would allow CO carbon monoxide to go right into the tenant space. The results could have been fatal. After investigating we found out that the new tenant who moved into this space modified the venting on their own. This could have been deadly. When it comes to gas appliances, always call a licensed and competent professional. It is a matter of life and death!

See a photo of this danger below.

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Boilers Part 11 – Reset

November 16, 2010

Today we will discuss RESET. Reset is the ability of a boiler to change the water temperature in your radiators to meet your specific heating needs in real-time as the outdoor temperature changes. A standard boiler will typically keep your radiators at 140 degrees Fahrenheit. On really cold days, this is great. For milder days however, your radiators don’t need to be so warm. When it is just a bit cool outside, 90 degree Fahrenheit radiators would be enough. As it gets colder outside, your radiators would need to warm up to keep your house warm. A boiler with the Outdoor Reset feature will constantly measure the temperature outside and adjust your water temperature to give you just the right amount of heat. Now that’s what I call efficient.
In my next post I will illustrate the typical heating cycle without outdoor reset.

The following video is a great simulation of what happens in my favourite DVCB, the Triangle Tube Prestige during a heating cycle. Check it out!