30 psi vlave blows daily

Eric_31

I had the same problem. I had to replace the cold water fill valve and it solved the problem. I also added a pressure gauge to the fill valve to see exactly what the pressure of cold water coming in was.

jeff_96

30 psi valve

my 30 psi boiler pressure valve blows daily. I have a buderus G124, with a Logamatic control set on automatic. the aquastat L8148E is set for 185 degrees. It feeds multiple zones of radiant via a 2 way mixing valve, a 50 gallon buderus hot water tank and manually mixed cellar floor radiant. any help would be greatly appreciated. Thanks:)

adambuild

Blow

How is your expansion tank, waterlogged? Is fill valve leaking to boiler raising pressure? Is relief valve bad? At what psi is it blowing?

Bob_86

Jeff, Does your system have a diaphram expansion tank? They usually charged to at least 12 psi. If it is low in pressure or if it is full of water it will not be able to absorb the pressure the boiler creates during a run cycle. Usualy what happens is that the relief valve will blow off during a run cycle, and when it cools and the pressure drops the vale will close.

jeff_96

30 psi valve

I will check the expansion tank tomorrow( haven't done so yet). I would say no. the relief only blows when the boiler is firing. Dont know if relief valve is bad. seems to blow at about 190-195 degrees and around thirty psi. I stood around while the boiler fired. Thanks for helping:)

Brad White

Could also be

an undersized expansion tank or the line connecting it to the system is valved off or plugged in some way. Any number of things, but in short, no room for thermal expansion.

Weezbo

interesting ... very interesting..

try this for a day, set the boiler pressure down to 12 psi,

dial the honeywell down to 165.

if it bounces over again, record the temp and pressure.

come back here and we will come up with another tactic.

guaranteed *~/:)

Joannie_12

Working

You have a 30psi relief valve that is blowing at about 30 psi. That's not the valve being broken. That's the valve working properly.

MikeL_2

Do you have a makeup valve on the circuit attached to city water ? If the pressure setpoint of the makeup valve is too high (say 25 psi), then your expansion tank is already too pressurized and when the boiler starts heating it can't deal with the expansion and the safty valve pops. The makeup valve should be set for 10-12 psi, the same as your expansion tank bladder.

Bob_95

same problem

I have the same problem with the pressure relief valve discharging at 30 psi. When cold the boiler water pressure is at ~14psi and gets to 30 psi by the time it hits 175F. I replaced the expansion tank (12 psi) and relief valve but still the same thing. The expansion tank gets hot to the touch near the fill inlet and a few inches down, so I'm guessing there is flow to the tank. And I'm flummoxed.
My system has A 7 year old Buderus G234X-64 boiler feeding Weil Mclain built in radiators with a two pipe (supply and return) feed to each radiator.The expansion tank feeds off the air scoop downstream from the boiler. I bleed the radiators twice a winter and normally there is air in just one of the 35 radiators. Which makes me wonder- how do I calculate the thermal expansion in the system? I replaced the expansion tank with the exact model that was attached. It turned out to still have an air charge of around 12 psi and no water inside. Maybe I need to gang on another tank?

jp_2

start a thread,

bob I would start you own thread on the main 'wall' page.

sounds like the original exp tank was too small to begin with?

any estimates as to water volume of system?sounds big?

ALH_4

sizing

Unfortunatly, from what I have seen, there is frequently a one-size-fits-all attitude to expansion tanks.

Estimate your system volume and check the size of your current tank against the Amtrol chart.