Effecta 55 Operating Pressure

[HeatFarmer]

I finally fired my new system up after a year of working on it.
The starting pressure was 20psi. I used around 80lbs of pine to raise the temp of the boiler, 900 gallons of water and another 50 gallons of piping and radiators—so 1000 gallons give or take—from 54* to 95* in about 5hrs. The pressure raised to about 26 psi. I checked the boiler at 7pm and it was winding down at around 186* and a 4” bed of coals. I checked again at 10:30 and the boiler was off, sitting at around 170* and just a bit of embers.
Sometime around 12 the temp spiked over 200 and apparently the pressure relief valve opened. When I checked the system at 7 am the pressure was 3. Temp 145.

So what pressure should the system be at? Cold ? Hot? I have a 60gal thermal expansion tank. And another 6gal expansion tank on an air scoop. The primary loop pump was running the whole while.

 

[salecker]

It may take a bit to find the sweet spot.
After a couple years of juggling i added the small expansion tank that came with my boiler and that made the difference. I had a 60 gallon one in the system.
I haven't had the pressure relief go off in over 10 years. I just make sure the pressure needle is off the peg before i start the system for the year and it is all good.

 

[HeatFarmer]

Among my many mistakes was not checking the pressure of the expansion tank before filling with water. I refilled the system today and have been chasing air all day and high full pressures. So I checked the bladder on the tank and it was reading 26psi at 20 psi cold boiler pressure. I’ve backed it down till the boiler pressure is 12psi.
I’m going to refire the system tomorrow early enough to try to catch when in the boiler cool down the heat spike occurred. Seems to me the pump shut off early but there isn’t any setting for that. It’s all pretty automatic coming from an EKO.