Coffee with Caleffi: Water Quality in Hydronic Systems

Mechanical engineer leads technical webinar for plumbing contractors, designers and wholesalers
Coffee with Caleffi: Water Quality in Hydronic Systems

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John Siegenthaler, mechanical engineer with Caleffi Hydronic Solutions, leads an online webinar, “Water Quality in Hydronic Systems,” from noon to 1 p.m. CT on Thursday, March 10.

There is no cost for the complimentary education series, Coffee with Caleffi, but registration is required.

Topics include:

  • What are the consequences of poor water quality?
  • What is demineralized water?
  • Why demineralization is better than softening.
  • How to demineralize water – using Hydrofill.
  • Procedures for commissioning water in new systems.

The following is a question-and-answer session from February’s webinar, “Zone Relay Controls for Hydronic Heating,” led by Mike Schreiner, engineering and operations director for Caleffi Hydronic Solutions:

Q: Can we use the Caleffi relay control to feed the DHW and hydronic systems with one boiler?

A: The short answer is “yes.” Our controls have the ability to prioritize the DHW demand and they also have the ability to operate a specific pump for the DHW demand.

Here’s an example using the ZSR zone pump control:


Q: What is the exercise function on the ZSR zone pump controls?

A: The control operates the exercise on each pump individually. After the pump’s last power cycle, it will wait for about 72 hours of inactivity and cycle the inactive pump for 30 seconds.

Q: If you’re using two wire actuators on the ZVR zone valve control, is it required to jumper the end-switch contacts?

A: Yes, you will need to jumper the end-switch contacts on the ZVR if you’re using two wire zone valves. The board looks to the end-switch closure to initiate the call for heat to the boiler as well as turning on any connected pumps.


Here's an example using the ZVR zone valve control:


Q: Regarding LED for each zone: Is it on when TT is called? Does it wait for the end switch #3-4?

A: On zone valve control it will wait for the end-switch terminals to close the XX terminals to tell your boiler to turn on. If you’re using a two-wire zone valve, you will need to jumper out the end-switch terminals.

Q: Boiler pump output is system pump, not primary pump, right?

A: On the ZSR you will have a pump output for each zone. The primary pump output is for your primary (boiler) loop pump.


Last month’s webinar, “Zone Relay Controls for Hydronic Heating,” can be viewed below:




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