Overtemp protection aquastat on EKO 25

[Medman]

In setting up my boiler controls I had the following thought:

Why would I want to have the safety overtemp aquastat shut off all power to the EKO 25? Wouldn't it be better to have the aquastat simply control the power to the draft fan, so that if the boiler went overtemp the draft fan turns off but the controller stays on and running?

What do you think? I will be wiring this weekend.

 

[stee6043]

Your overtemp aquastat surely should not be shutting off power to the EKO. It is my understanding that your overtemp should activate a heat zone to pull heat away from the boiler. In my case the overtemp aquastat will turn on the circ pump on my heat zone as well as the blower fan of my forced air furnace. Thus removing excess heat from the system. Depending on how you have your main circ pump wired (ie. to the EKO) the last thing you want to do is shut off the EKO. The EKO controller should shut off the draft fan on its own once the water reaches 180 but you still need that main circ pump to run.

 

[Medman]

Right, this was my thinking. I want the controller on to run the circulator, but I want the draft fan off. The manual is not too clear on this and I wanted to know what others were doing. I will probably wire it to shut off the draft fan only.

 

[stee6043]

Someone else may chime in here but you really shouldn't have to do anything with the draft fan. The controls for the fan are internal to the EKO. It is set to turn off the fan on it's own when the temp hits a certain level (180F or so). Your aquastat should be used to remove heat from the water, not shut things down...