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What looks wrong with current boiler installed

bubbafatbubbafat Member Posts: 5

I moved into a new home. There are 2 levels, the finished basement and the floor above. I looked at the boiler. The boiler is a Weil Mclain P-WTGO-4 series 1. Please tell me what looks piped wrong or should be changed. Let me know if i'm correct or incorrect in what I see.
I noticed there is no damper. Also, the expansion tank is connected to the supply line after the circulator. Shouldn't it be connected to the return line? Should there be an air eliminator added and would that go in the return line as well? There is no check valve before the pressure reducing valve. The copper pipe that runs past the expansion tank runs down the back wall and blocks a little black door on the wall from opening. I believe this black door is the clean out for the chimney. There is no isolation and drain valve on the supply line. In the manual, it shows zone valves go on the supply line. Does it matter the zone valves are located on the return line?
On the tankless heater piping side, I noticed there is no flow regulating valve and no automatic mixing valve. Are those necessary? Please let me know if I missed something, if i'm wrong or what else should be changed.

Thank you,



  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 5,715
    1 No barometric damper in flue pipe

    2 Circulator pumping toward expansion tank. It will work the way it is but should be changed if you do any re piping.
    3 zone valves can go on supply or return
    4. isolation valves to isolate zones & boiler make service issues easier
    5. I would like to see the oil lines protected or at least tucked in closer to the boiler
    6. tankless heater needs a mixing valve (this is very important)
    7. vent on top of boiler looks like it has been leaking

  • bubbafatbubbafat Member Posts: 5
    I looked at yellow service card. The last service was in March-2018. Seems they put a new pressure/temp gauge, new pressure reducing valve, new relief valve, and new automatic air vent. Maybe that leak was from the old automatic air vent. The auto air vent was also changed in Dec-2015. When I first looked at boiler, i thought pressure gauge was bad because it read zero, yet house was warm. Then 3 weeks later I touched the manual lever of the pressure reducing valve for a second and water started flowing and gauge went up to 12psi. So it ended up valve was stuck and not the gauge. I don't see why if a specific company was servicing this boiler for 23 years, why didn't they correct the plumbing or add a damper? I'm thinking when the summer comes, I would like to redo the piping so it's proper.
    1542 x 1876 - 2M
    1698 x 3012 - 3M
  • ZmanZman Member Posts: 4,855
    edited January 3
    If you are going to dump that much labor into it, you might want to consider replacing the boiler. It is almost certainly oversized for the heat load (unless you are living in a 2 zone 6,000 square foot home). The tankless coil is not a very efficient way to heat hot water in the summer.
    A new properly sized boiler with a small indirect would be a huge upgrade. By the time you repipe what you have, you would probably cover the labor to install a new boiler.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • NY_RobNY_Rob Member Posts: 1,369
    Where is your pressure relief valve?
    I see the new feed water pressure regulator but no relief valve.
  • Solid_Fuel_ManSolid_Fuel_Man Member Posts: 1,492
    A 3 pass oil boiler is a very nice upgrade from that pin boiler.

    Master electrician specialising in boiler and burner controls, multiple fuel systems, radiant system controls, building controls, and universal refrigeration tech.
  • bubbafatbubbafat Member Posts: 5
    The pressure relief valve is located behind the boiler. You can't see it from the photos angle.
  • NY_RobNY_Rob Member Posts: 1,369
    ^ gotcha!
  • bubbafatbubbafat Member Posts: 5
    700 sq feet downstairs. 1400 sq feet upstairs. However, you can see the pipe after the upstairs zone valve splits with a "T" and goes through the ceiling at 2 different locations. The previous owner installed a lot of sliding glass doors, where walls would have been. The bedroom wall is all glass and the kitchen wall is all glass and a dining room wall is all glass.
  • Alan WelchAlan Welch Member Posts: 140
    Underground oil tank? Don't see what good the oil safety valve is doing. I'd also be concerned about the corrosion where the basement zone enters the ground, and the corrosion at the coil behind the control. Also no backflow preventer, don't know if required where you live.
  • bubbafatbubbafat Member Posts: 5
    The oil tank is above ground in the garage. Two oil lines are coming out from the top of the oil tank. It is also well water and there is no whole house sediment filter. There is a water softener, but I think previous owner might have had the valve in the wrong direction, bypassing it.
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