Posts Tagged ‘Grundfoss’

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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