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New expansion tank less heat

toni66 Member Posts: 2
Plumber installed new water heater and replaced the boiler expansion tank also. I now have to turn my thermostat up at least 5 degrees higher to be warm. I used to keep heat set at 72 during day and turn down to 70 to sleep. Today is very cold so I had it up to 76 just to be warm. I've been reading about the gauge on boiler and the pressure is about 20. It used to be 12. The other one is 110. It used to be 140. Is the 110 reading the cause for my heat not working the same? Is there a gauge to adjust that temp? If not, what could have gone wrong? I'm so upset, as all this was done preemptively because WH was 20 years old. I swear I'll never fix it if it ain't broke again. Thank you in advance.


  • BillyO
    BillyO Member Posts: 276
    Boiler Make? did he happen to touch aqua stat?
  • kcopp
    kcopp Member Posts: 4,188
    Did you call him back to see what has changed?
    HVACNUT Member Posts: 5,025
    Post some pics of the boiler and controls. Not too close.

    Seems for some reason the plumber lowered the temperature setting(s) on the boiler.

    If you typically see the boiler limit at 140° @ 12 psi, and now see 110° @ 20 psi, he might be trying to hide something.

    I'm tempted to say to raise the limit back to 140°, but in doing that, it could also raise the boiler pressure above 30 psi.
    There should be a 30 psi relief valve somewhere on/ near the boiler, with (hopefully) a discharge pipe terminating near the floor. If the pressure on the boiler reaches 30 psi, the relief valve (again, hopefully, annual maintenance is important) will, guess what? Relieve pressure. Maybe really fast.

    So post some pics so we can see what we're looking at.

    Also interested to see if he left the valve to the PRV off. Not that that's a bad thing in itself, but a clue nonetheless.
  • SuperTech
    SuperTech Member Posts: 1,919
    The thermostat is a switch, not a gas pedal. You can turn it up twenty degrees above room temperature, it's not going to make your boiler work any different than if you turn it up one degree above room temperature.

    The boiler water pressure should not affect the way it heats the home. But I would definitely call back the guy who replaced the expansion tank and have him address the pressure. 12-15 PSI is normal for a two story home.
  • toni66
    toni66 Member Posts: 2
    Ty for responses. I did call plumber and initially was told that hes been getting calls like mine due to weather fluctuations and last night was cold. Reason why I like to have SOME insight before I call. After 32 years, I've experienced many cold nights. I know my house and my heat. He said he did not touch aquastat. It's set at 190. Good. He said the pressure at 22 was good. My old burnham has no high low I can set and he does not feel 110 is problematic for low temp because it is getting up to 180. He does not know why it's so low. Okay, so why am I freezing???? He called dad plumber and got right back and said I'm coming to purge the system. Dad was not there for job and son was supposed to let the air out. There was a lot. So idk if that always needs to be done when changing out expansion tank or just cuz I was air bound before that it made the problem worse, (I mean now i had water sound rushing through baseboard), but my pipes are hot now in basement and while I have not been home am thinking this should help with heat. And Maybe even bring pressure down. I dont know because plumber said the gauge is the water pressure in exp tank and has nothing to do with it. Not sure. But ill keep an eye on pressure and temp. Thank you again!
  • mattmia2
    mattmia2 Member Posts: 7,733
    you have to open the system to replace the tank. depending on where there are valves you might let in a little or a lot of air doing that. you have to purge or bleed it out.
  • GroundUp
    GroundUp Member Posts: 1,573
    edited February 2020
    72 degrees is 72 degrees. 76 degrees is 76 degrees. Unless your thermostat somehow malfunctioned and is reading the wrong temp, the comfort problem is in your head. If the boiler is set to 190 but the water temp is 110 (or 140 like you say it used to be), there is a problem there and the tech should have never decided that was okay. Sounds like a plethora of issues that he needs to repair
    HVACNUT Member Posts: 5,025
    I gotta stop posting before my second cup.
    Yes, by replacing the expansion tank, air was probably introduced into the system but never purged. Ideally you shouldn't hear the water rushing through the pipes but there are numerous causes of that. A good purge and an operable air eliminator usually does it though.
    Without knowing your climate zone, or heat loss, its impossible to say what temperature the limit should be. 190° IMO is too high except on maybe the most extreme days. Between 160° and 180° is typical. Factory set pressure on the extrol is (should) be 12 psi. That matches the factory setting on the PRV. There will be rises and falls depending on temperature between 12 and 20 psi.