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Second Floor Radiators are Cold In Near 100 yr old home.

Hello everyone. Ive been reading post after post about issues similar to mine but not finding answers yet & may not be able to find answers since the pandemic has been hard on cash flow, so I can't hire a good plumber. To the problem & I have photos that probably explain better what's wrong than I can.

We have a 2 story home with an old asbestos covered coal burner converted to gas some decades ago. Little work had been done to it since my wife & I have been married 30 years ago. We never had much of a problem with it until now. 1st floor rads get hot & the 2nd floor rads are totally cold. I blead both upstairs rads, after the initial air escaped nothing else came out. No water at all. I can leave the valves open & nothing happens. My boiler hasn't needed to run for a few days but a winter storm is almost here. I tried to add water to the boiler but it doesn't seem to flow in. It appears that the boiler pressure is under 5psi. I may be doing everything wrong as i'm the type of guy that creates leaks not fixes them. I'm a bad plumber but i've been forced to learn over the last decade. I know a little & can follow instructions.. usually lol. Thank you for your help. We appreciate it. Btw there's now 8 people living here including my 3 grand kids, Two boys & a girl. 4 months, 4 years & 2 years old. It's going to get cold.


  • Zman
    Zman Member Posts: 7,587
    Your second to last picture shows a pressure-reducing valve with 2 isolation valves. Are the valves open? The pressure-reducing valve is what normally keeps the system at the correct pressure. If it isn't working, it needs to be replaced. In a pinch, you may be able to fill the system through a drain using a female-to-female hose like the ones on washing machines.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • retiredguy
    retiredguy Member Posts: 919
    edited February 2022
    That item in the 4th picture down, is a PRV or pressure reducing valve. It is supposed to keep a minimum water pressure in the heating system. For you, the minimum pressure should be 12PSI. The pressure keeps the radiators completely full so they will heat. To find your minimum system pressure you would measure from the top of the highest radiator to the pressure gauge on the boiler and divide that measurement by 2.3. For example, if the measurement is 20 feet divide the 20 by 2.3 and get 8.69 and add a safety factor of 2-3 psi. Resulting pressure would be about 11 psi. Those PRV's come preset at 12 PSI and will work on almost every 2 story house. You need a new PRV which you can purchase at supplyhouse.com. Until you can buy a new PRV, a quick fix would be to attach a garden hose equipped with a double female end similar to a wash machine hose to the hose faucet in the bottom picture and slowly add water until the cold pressure is about 12 psi and then bleed all the 2nd floor rads. Do not go much above the 12 PSI pressure . I would strongly recommend that you have that boiler inspected by a competent HVAC company ASAP for your safety.
  • WMno57
    WMno57 Member Posts: 1,383
    I disagree you need a PRV. I have a system identical to yours. I do have a PRV, but leave it valved off. You do need to get the pressure in your system up to 12psi to get heat on the 2nd floor. That means get more water in your system. Either through the connection to your domestic water system, or with a made up temporary connection with a washing machine hose.
    It would be a good idea for you to find a boiler tech who could check your system for safety. And if the heat goes out you will then have someone to call. Check HeatingHelp's Contractor tool here: https://heatinghelp.com/find-a-contractor/
    Please buy another CO detector. You should have more than one in your home. They only last 5-7 years. I buy a new one every fall.
    Have you ever drained the expansion tank in your ceiling? If not, you may need to do that at some point. You will know it needs drained if you start seeing a large rise in your system pressure when the boiler heats up. Don't drain it now if it doesn't need it.
    You really need to get a tech that knows these old boilers to give your system a lookover. If the Find a Contractor tool doesn't show anyone in your area, someone here may know someone local to you.

    I DIY.