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What is the steps to replace a Watts ET-30 expansion tank? What would be a good replacement?

Vginotes Member Posts: 1
I'm a DIYer that recently soldered a busted water pipe in my crawl space so I felt confident I could replace a dripping stop and waste valve in my heating system. After replacing the stop and waste valve with the newer ball valve I noticed my thermostat took a long time to heat up the house and there was a constant gushing sound in the pipes. I figured I needed to do some bleeding at the valves, but after an hour, I still kept hearing the gushing sound, but the heat was on so I thought it was ok...Well after I came home today I found water gushing out of the pressure relief valve in back of boiler!! I turned off the power, I tuned off the water coming into the system as well as the valves on the supply and return pipes into the boiler, but the relief valve kept dripping..it finally stopped after I flicked it up real fast a couple of times.

To make a long story short..I checked the pressure of my expansion tank and there was no pressure evident..only a drop or two of water came out so I'm thinking it is the problem..:(

I was reading some other post about the expansion tank, but mine does NOT have a shut-off valve between the tank and the boiler. I do have that automatic air relief thing in between the expansion tank and boiler.

Boiler is a Peerless WBV-03-WPC

Expansion Tank is a Watts Regulator ET-30



  • heatpro02920
    heatpro02920 Member Posts: 991
    edited February 2013
    Get a tech out there

    Your expansion tank if it was bad would have the same pressure as the boiler gauge reads.....

    and it would be full of water {heavy and not hollow sounding at the 3/4 to bottom range}...

    If you were my customer I would start by replacing the pressure relief valve {it may be holding now but what happens next time it pops}... checking the water feed, expansion tank, air removal system{high vents and air scoop most likely, and tankless heater {if applicable}...

    Then when everything was proved to be in working order, I would refill the system and purge all of the air out with the psi relief valve in place so it would replace the air gap. Only allowing the boiler to get to a min. pressure {depends on how high your highest zone is}, then I would run the burner until it was up to temp and allow the pressure regulator to operate as normal... make sure the pressure is around 18psi {depending on height again}hot and take off...

    Anyway to replace the tank, shut off the power and water feed {1/2" cold line feeding the boiler}, open the boiler drain {shutting any zone valves or purge valves, making sure not to isolate the tank with it}, when the water stopped coming out, confirm the boiler is pressure free via the boiler gauge, unscrew the tank and screw the new one in with thread sealant... Then close the boiler drain and open all the valves except the purge isolation valve, let the boiler come to pressure stop and open the purge valve with the iso valve still closed until all the air is out of the zones 1 by 1....
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