Understanding the basic control signals of a hydronic boiler

[EffectaBoilerUser (USA)]

I am working on a control system for my effecta boiler system that will turn my Burnam boiler on/off depending on the tank temperature in the 1000 gallons of storage.

I understand DPDT relays and temperature setpoint controllers and such but have a question regarding the signals that come from the zone valve end switches and boiler t-stat itself.

Its my understanding that the end switch on the zone valve is normally wired so as to complete the 24V circuit if any zone/valve calls for heat, thus sending this signal to the relay on the boiler which will start the circulation pump.

Its also my understanding that the thermostat signal going to the boiler is also a 24V signal.

Not being an experienced HVAC guy I would appreciate any information which will help me to better understand the signals that the hydronic boiler receives from the thermostat and end switches on the zone valves so that I can integrate them with my temperature setpoint controller and relays.

Thanks,

Brian

 

[ewdudley]

https://www.hearth.com/econtent/index.php/forums/viewthread/61198/


Skin that one, pilgrim, and I'll get you another!

Cheers --ewd

 

[mikeyny]

It took me several tries to get mine to work right. You have posted a most sought after question for information I have seen here yet. When I did mine I had more trouble with the 24 v going the wrong way at the wrong time causing problems. That was quite some time ago so I cant actually answer your questions unless I really look mine over again, in fact, I m not even actually sure how mine works now, but it works great. I hope someone explains this concept in plain english for some of us to understand a little easier. I think I may have used a neutral switching relay (110 v) to actually make it work. I have a diagram somewhere in my notes if I can find them.