An engineer asked a question about using variable speed pumps for air temperature control in lieu of a two-way control valve. The question clearly makes you …
Hydronic Primary-Secondary Piping – How Important are the Two Close Tees?
Every year we get questions about the importance of primary-secondary piping rules around boilers and coils. Recently, I also received a call about using a …
Solving Minimum Flow in a Primary Variable System (Part 3)
The engineer is aware of the importance of minimum flow to the pumps in hydronic systems. The R. L. Deppmann Monday Morning Minutes Part 1 …
Minimum Flow in Variable Speed Pumps for Building Hydronic HVAC Systems (Part 2)
The HVAC engineer designing a hydronic system understands the need to protect the circulating pumps from a dead head or no flow condition. This week, …
Variable Speed Chilled Water Systems: Demand Reset
There are multiple methods to vary pump speed in HVAC chilled water systems. A common method is the use of a differential pressure transmitter at …
Cooling Tower Spring Startup Tips
The weather is warming, and our attention turns away from heating and toward system air conditioning. To protect the cooling tower pumps, we offer a …
Tis’ the Season to Start Your Air-Cooled Chillers
Many air-cooled chillers do not have glycol and are drained for the winter season. Most cooling towers are also drained for our cold winter months. …
Hydronic Expansion Tanks: Can I Pump into the Point of No Pressure Change (PNPC) to Reduce the Tank Size? (Part 3 of 3)
Can we pump into the point of no pressure change in a closed hydronic system? We gathered feedback on the proposed system by a local …
Hydronic Expansion Tanks: Can I Pump into the Point of No Pressure Change (PNPC) to Reduce the Tank Size? (Part 2 of 3)
We are gathering input from the last R. L. Deppmann Monday Morning Minutes asking for your feedback on the potential to “not follow the rules.” …
Hydronic Expansion Tanks: Can I Pump into the Point of No Pressure Change (PNPC) to Reduce the Tank Size? (Part 1 of 3)
We often design system after system and designate the sizing of expansion tanks to the newest employee on the team. It is just a matter …