Expansion and Compression Tanks Series – Part 1

Josh LooperHydronic System Design, History, Expansion and Compression Tanks, Expansion/Compression Tanks, Monday Morning Minutes, Tanks

We could entitle the next dozen weeks as: TANKS-A-LOT. (Sorry). Over the next few months, the Monday Morning Minutes blog will examine expansion and compression tank sizing. We will also tackle some more advanced issues in the selection and troubleshooting of closed system expansion tanks. Tanks are often selected using software programs such as the Bell and Gossett ESP-Plus™ selection program.

Griswold Chemical Pot Feeders

Norm HallHydronic System Design, Air and Dirt Control, Chemical Feed, Chemical Feed, Monday Morning Minutes

“An old friend with several new twists” Chemical feeders or “Pot-feeders” have adorned mechanical equipment rooms for decades. R.L. Deppmann appreciates the specification and purchase of the Griswold 2 and 5 gallon feeders. Today, I’ll present a couple of the benefits both owners and installing contractors may enjoy when using the Griswold Feeders.

Plumbing Topic: Domestic Water Recirculation Systems Part 8

Norm HallMonday Morning Minutes, Plumbing System Design, Domestic Water Recirculation, Mixing Valves

“Dual Temperature Systems and Mixing Valves” “Performance Conditions of a Mixing Valve” Last week the R L Deppmann Monday Morning Minute article examined the addition of a mixing valve. Today we will examine the re-circulation system with dual temperature requirements and answer questions about the term “Performance Conditions” mentioned in the Lawler literature.

Plumbing Topic: Domestic Water Recirculation Systems Part 7

Norm HallMixing Valves, Monday Morning Minutes, Plumbing System Design, Domestic Water Recirculation

“Addition of a Mixing Valve” During the last 6 weeks, the R. L. Deppmann Monday Morning Minutes concentrated on re-circulation systems where the supply temperature to the system was the same as the outlet temperature of the water heater. Today we will examine the addition of a Lawler master mixing valve in the system.

Plumbing Topic: Domestic Water Recirculation Systems Part 6

Norm HallMonday Morning Minutes, Plumbing System Design, Domestic Water Recirculation, Balancing, High Rise Systems

High Rise Considerations The last article, part 5, showed an example of a high rise system with pressure reducing valves (PRVS) and the importance of the correct setting of the balance valves. The example we used showed balance valves with as much as 18 PSIG across them at a low flow. When a design starts to incorporate

Plumbing Topic: Domestic Water Recirculation Systems Part 4

Norm HallPumps, Plumbing System Design, Domestic Water Recirculation, Balancing, Monday Morning Minutes

The last three articles outlined pump selection in domestic water recirculation systems. In general, these systems have low flow and low head pumps. What happens in a high rise with pressure reducing valves (PRV) in the hot water supply? The pressure reducing valve introduces a fixed pressure drop which must be added to the calculations.

Plumbing Topic: Domestic Water Recirculation Systems Part 3

Norm HallMonday Morning Minutes, Pumps, Plumbing System Design, Domestic Water Recirculation, Domestic Water Recirculation

The purpose of the domestic water recirculation system is to delivery hot water near a fixture during times when there is no draw. If someone is using hot water in the next room or apartment or process; the hot water is near enough to your fixture so the hot water is delivered in seconds, not minutes.

Plumbing Topic: Domestic Water Recirculation Systems Part 2

Norm HallMonday Morning Minutes, Plumbing System Design, Domestic Water Recirculation

Let’s assume the domestic hot water supply is a total length of 1000 ft. That is the entire pipe on all of the floors. Let’s also assume an average of 15 BTU/hr/ft of loss through the supply pipe insulation. Now let’s assume the recirc piping is 300 ft total at an average of 10 BTU/hr/ft of loss. What flow rate is required for a 10 degree ΔT? What flow rate is required for a 5 ΔT?