What is a waterlogged "Extrol" tank?

Joseph_4

Can someone please help me regarding waterlogged extrol tanks. Something I saw today threw me for a loop. I get the call that a 30 lb pressure relief valve is leaking. get to the job. see the gauge on the boiler. its reading 20 pounds. so I figure the PRV is bad. so I drain the boiler to change the PRV. I figure once system is no longer under pressure, let me check the extrol anyway. Its an Extrol #30. I remove the extrol and it weighs a ton. Now here is what I don't understand. I put the extrol in sink and wait till all water drains out of tank (takes about 5 minutes) then I put a tire gauge to it. It reads zero lbs. so I figure must be the tank is ruptured. But then I ask myself then this guy's boiler gauge would have been higher than 30lbs and was only on 20. so i figure let me try to pump up the tank and see if its really ruptured. I pump it to 12psi and it holds at 12psi!

I do not understand why when I unscrewed the extrol it was at zero pounds and the extrol was full of water. I always was under the assumption that if I drain the water out of the system and shut the intake so now my system is empty, when I unscrew the extrol, it will be empty and will read 12lbs on a gauge [This was my procedure to check an extrol tank].  I also thought the opposite that if  I unscrew it and its full of water, it means its a ruptured tank. Now I don't know what is correct anymore.

JK_3

I think

You are correct in your understanding of it, but thinking to fast. First I never trust the guage on the boiler and put my guage on a drain valve or purge valve. If it weighed a ton and took 5 min to empty it is usually a ruptured bladder. If you waited a little while after you pressurized it more water would probebly come out from behind the bladder. any time I get that type of call the first thing I do is put my guage on the system then determin if its a releif valve, tank, PRV or sometimes a leakiy domestic coil.

Unknown

Josh,

depending on the manufacturer, some tanks lose their pre-charge faster than others.

Changing the PRV was a good move anyway, and the gauge could be-off, you protected everyone.



Remember,,, you MUST exhaust ALL system pressure to check the tanks pre-charge,,,,, if you did this, you did the right thing!