For closed hot water systems, particularly in HVAC applications, Parker Boiler engineers have seen any number of hot water piping schemes and control systems. In many instances, while out in the field, they have encountered systems in which the design engineer and contractor did not coordinate properly to provide a proper system for the end user, which can result in problems down the road.
Some of the common problems that we see are relief valve pressures too low, particularly on make-up water systems. A 30 PSI relief valve in the make-up water line in the basement does not remain closed in a five-story application as the water can be 80 ft higher than the relief valve thus creating a static pressure of 80 FT HD or 34 PSI.
One of the things we recommend for any design engineer is to provide a water meter on the water make-up line for a closed hot water system. This way, the owner can track water usage, balance chemicals and spot a problem before it becomes costly. On many systems, we recommend the make-up valve be closed during normal operation. The cost of these water meters are under $150 and can save thousands of dollars.
Another problem Parker encounters are systems designed so that they can go into a no-flow condition when all control valves shut down. We always recommend flow through the boiler, which can be accomplished either by providing some 3-way valves or end-of-main bypass, or a bypass valve in the hot water loop. Another solution to add a runaround pump to maintain minimum flow.
We also are seeing a wide diversity of requirements when it comes time for the boiler to communicate and integrate with the building's automation system.
When designing your system, we recommend contacting design sales engineers at Parker Boiler for consultation on the proper piping design and integration to building management systems. With the proper setup and operation, Parker's boilers can see a life of 30 to 40 years or more.
For more information, go to www.parkerboiler.com.