10 Things to Avoid When Designing a Hydronic System

Designing your first hydronic system or your 100th? Lessons learned the hard way are never forgotten. Cody Mack, Caleffi training and education manager, is eager to share his experiences in the field and on the road to help you steer clear of potential pitfalls when designing your hydronic systems.
You'll learn:
→ What happens when you pipe a mixing valve improperly in a hydronic system?
→ I can drink the water on site so it’s good to put in my hydronic system, right?
→ How do I determine the appropriate fill pressure in my system?
→ Should my customers require an engineering degree in order to operate their system?
→ What’s the real cost of setback thermostats?
Mack has nearly 20 years’ experience as installation contractor, service technician, application engineer and most recently training manager for Caleffi. He pounds the pavement educating Boomers, Gen-X’ers, Millennials and beyond. When not on the road, he’s often in the Caleffi lab experimenting with product design solutions. A family man, gear-head and motorcycle-enthusiast, our audience will appreciate his thoughtful delivery and common sense product approach.

[@DaleKlein]

Thanks for these great educational videos. A potential for the desired warm floors in a more efficiently insulated home: reduce the size of the radiant heating area. Say limit it to just in the actively used kitchen floor area, or just in bathroom floors, vs. the whole living room / dining areas.

[@AlinDRG]

Greetings! Excellent video! Looking forward to see that cloud based P&ID tool!

[@LobstaLOL]

I am sizing a small closed water loop for a university project - I have a rough schematic of what I need, can a Caleffi technician help me size/spec the right equipment for this job? Thank for all your videos, I've been learning heaps of info!

[@CaleffiHydronicSolutions]

Sadly, we don’t do sizing for applications. We encourage you to get an engineer involved to help you with proper sizing and system design.

[@theplumber585]

Hey I have a question regarding point 7. The thermostaticlly controlled by pass does that essentially act as a primary loop in a simple system. I am going to be re doing a simple boiler system. Its a super hot or ray pack style boiler and it currently has 3 zone valves that serves fin tube base boards. Oddly they are supplied by 1/2 in floor pex.... There is no primary loop just a ball valve. Since it is all one temperature is there any point to having primary/ secondary loops or would it makes the most sense to just have one pump with the thermo controlled by pass valve? Thanks!

[@CaleffiHydronicSolutions]

Thank you for your question, David. The thermostatic bypass temporarily acts as a small primary loop as it short cuts hot supply into the return to preheat the boiler. Once the boiler and bypass loop is heated up, the bypass closes and full flow continues through the piping and the rest of the system.

[@jamescecil4629]

Can you use collected filtered cistern rain water in a outdoor wood boiler

[@CaleffiHydronicSolutions]

Like any hydronic system, water quality plays a role in the longevity and reliability of the system. You would want to use the source with the best water quality.

[@nathanbarrington9574]

In a closed loop system. Does the height of the system create a static head or is this balanced from the water coming back down in the return and therefore net zero force?

[@CaleffiHydronicSolutions]

Nathan, you’re 100% correct. In a closed loop system, the height does not need to be taken into account when sizing circulators because “what goes up, must come down.” Where we were going with the comments on pressure is what it takes to fill a closed loop system from bottom to top. In that case, height does matter and the higher the building, the more head you’ll need to get water to the top. After it’s filled you’ll be smooth sailing just overcoming friction losses throughout your system and not worrying about height at all!

[@nathanbarrington9574]

@@CaleffiHydronicSolutions thanks for the reply! Do valves at the lowest levels in the system need to be rated only for the pressure created by the pumps or for the pump pressure and the height of the building?

[@CaleffiHydronicSolutions]

@@nathanbarrington9574 The dynamic pressures of your system caused by the circulators will be directly related to your fill pressure / height of the building. The pressure from the circulator should be added to the static pressure and you will want to make sure the components of your system are rated for that max system pressure at that point or height in the system. We hope this helps.