Coffee with Caleffi: Multiple Temperature Regulation in Hydronic Systems

Manager of engineer education leads technical webinar for contractors, designers and wholesalers
Coffee with Caleffi: Multiple Temperature Regulation in Hydronic Systems
Jody Samuell

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Jody Samuell, manager of engineer education for Caleffi Hydronic Solutions, leads a free webinar “Multiple Temperature Regulation in Hydronic Systems” from noon to 1 p.m. CT on Thursday, Jan. 21. Registration is required.

He will explore the various methods and emitter types used in providing multiple water temperatures.

Topics include:

  • The first water temperature: What is actually delivered to the building with primary/secondary piping?
  • Indirect water heaters: How do you achieve good performance with outdoor reset control? Additionally, is priority a good option with an indirect water heater?
  • How many different water temperatures do I really need?
  • What are the methods of providing a second water temperature for priority staging, proportioning mixing valve, thermostatic mixing valve, motorized mixing valve and injection pumping?
  • What are the effects of secondary water temperature on system performance?

The following is a question and answer session from last month’s webinar, “Part 2: Proper Component Selection for Boilers and Application Fundamentals,” led by Bob “Hot Rod” Rohr, training and education manager for Caleffi Hydronic Solutions.

Q: What is the best placement of a DIRTMAG; before or after mod/con boiler circulator?

A: Generally, you want to place the DIRTMAG before the mod/con. If your circulator is pumping into it, you would want to place it before that as well.

Q: Regarding solar thermal system piping, how do you allow for piping expansion?

A: The Copper Tube Handbook has some good info and formulas for tube expansion. For long runs, some installers hard-pipe in an expansion loop with four ells. I have used some stainless steel braided expansion couplers, also. Just be sure they are rated for solar temperatures. The pipe mounting also needs to allow for some movement. Click here for more information.

Q: Shouldn't the largest pipes be connected to heat source, not the buffer tank?

A: I think you may be referring to the 2-inch pipe buffer tank piping? The large diameter piping at the tank is to allow multiple flows to pass one another and allow varying flow rates without pump interference. The concept is hydraulic separation, where a large pipe or chamber allows a low flow velocity zone. Piping at the boiler should be sized to handle the gpm flow rate that is required by the boiler manufacturer. The 15th and 17th edition of idronics are great resources for further information on this topic. You’ll find them on our website.

Q: What material do you use for your HX?

A: Porcelain glass-coated, cold-rolled steel.

Q: How do your compression fittings compare to SharkBites?

A: The fitting has a collar that screws down, causing a grip ring to dig into the PE and the O-ring to compress against the tubing for tight seal.

Q: Could you send me the manufacturer’s rep contact information for any biomass boilers and biomass feed systems you are familiar with, especially those mentioned in the webinar?

A: Three of my favorites are the following:

These are all good products with great U.S. support and manufacturing. Marc at HydroHeat has some really interesting “parlor” boilers. They are nicely styled gasification stoves and he can custom size an HX to do some radiant or DHW. He has a nice line of wood and pellet hydronic kitchen stoves also. On my wish list for sure!

Last month’s webinar, “Part 2: Proper Component Selection for Boilers and Application Fundamentals,” can be viewed below:


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