System design is a critical element of system efficiency. The hydronic heating system must be designed correctly to take full advantage of a high efficiency high turndown boiler. It makes sense that a high efficiency boiler will never perform at a high level in a system designed for an atmospheric boiler. The physics is just against performance.
Let’s review the main points to great performance from your condensing boiler:
- Low return water temperature. No higher than 135ºF back to the boiler.
- Pay attention to the minimum flow rate available at the boiler. The boiler just wants to get hot, it needs some cooling to keep from damaging itself.
- Make sure the boiler is the correct size for the application. This is one case where bigger is not better. An oversized boiler will not be able to take advantage of turndown and it will simply shut off.
- The system flow must be considered. Piping layout needs to be correct to optimize flow and performance of the boiler.
All of these issues are system level concerns. But, what if you have a large hot water system already in place? The options to improve performance are limited by the system parameters. In some cases, the only real solution is a complete system redesign. As expected, system redesign is prohibitively expensive in most cases.
If your system is performing poorly or the boiler needs repeated maintenance, there is a cost-effective option to increase performance and/or protect your boiler from any further damage.
Replacing the existing burner on a boiler with a high performance modern burner will create a performance gain and increase system efficiency.
Three benefits of a high efficiency burner:
- More complete combustion. Complete combustion means fewer exhaust issues, better use of the fuel, and better control of the flame.
- Higher efficiencies at part load in any boiler! The performance and controls of the modern burner create increased efficiencies at full and part load, whether the existing boiler is condensing or non-condensing.
- Reduced boiler cycling. No losses from phantom drafts, purging, etc. and no damage to unit from slamming on and off too frequently.
A new burner will improve the performance of an existing boiler and the entire system. In some cases where the system is less than ideal, the new burner will protect the boiler from short cycling and extract the best performance possible from the existing equipment.
Click on the button below to download a one-page PDF about condensing boiler systems.