New boiler on gravity system

hot_rod

https://forum.heatinghelp.com/discussion/comment/1843381#Comment_1843381

There is an approximately 18° hysteresis. So with a 115° element + 18° = 133° for the bypass to close off 100%

With a 130° element it takes 148° degree return to shut the bypass.

Screenshot 2025-02-18 at 2.17.12 PM.png

jesmed1

So a 115F element is correct for a system that requires 130F return temps…Why can't anything be simple? 🙄

EricPeterson

https://forum.heatinghelp.com/discussion/comment/1843408#Comment_1843408

In my system I have temperature sensors on the supply and return to the boiler return and supply pipes.
Spot-checking these, I rarely see the return temperature get up to 133F - which means that most of the time, the system is running with the valve only partially open. I must admit that initially this was a point of concern for me, however in practice it seems to work quite well. There has been no issue whatsoever in keeping the house warm.

—Eric

hot_rod

Maybe it has to do with cast iron boilers shrinking in physical size and thinner casting that thecast boiloer manufacturers are stepping up their warning about return water temperature.

A bold step on their part using the bold printing😉

Will it matter??

Maybe when equity companies take over manufacturing companies they look hard at block warranty expenses:)

Screenshot 2025-02-18 at 4.55.25 PM.png

EricPeterson

https://forum.heatinghelp.com/discussion/comment/1843473#Comment_1843473

I wonder why manufacturers of cast iron boilers don't simply partner with a company like Caleffi to provide what in my opinion is the best solution, namely a thermostatic mixing valve, as part of a turnkey system. Throw in a Grundfoss circulator while you're at it. Instead they leave it up to installers to do things however they want to do. But that's just me wondering.

—Eric

mattmia2

https://forum.heatinghelp.com/discussion/comment/1843495#Comment_1843495

the most common installations are low mass and don't need it.