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Phantom hot water heater on slant fin

SK_19 Member Posts: 1
So I live in an apartment that is heated by a Liberty II model #LD-30 PZT Slant Fin boiler/hot water heater combo. Last year our hot water heater started leaking so the landlord cut it off and put in a separate gas hot water heater. Our boiler is oil-fired. Our heating bill last winter seemed very high -- the guys upstairs have the same setup, but with a hot water heater, and theirs was like half of ours. And we don't keep it warm at all.

Anyway, we shut the thermostat off in April or something and there was like an eighth of a tank of oil left. A month later, the tank was dry. I noticed when I was in the basement once that the boiler was running which struck me as odd.

So I think that when the landlord cut the hot water heater off that's all they did. They didn't alter the control logic at all. So the boiler doesn't know that the hot water heater isn't there any more and keeps kicking in to heat it up.

Anyway, this is very frustrating because the landlord isn't convinced there's a problem. I'm getting oil put in the tank today and getting the boiler primed. How costly an issue would this be to resolve? Am I correct that a boiler with no hot water heater attached only needs to be turned on when there's a signal from the thermostat? The landlord said something like the boiler needs to stay hot all the time even if it's not heating the house at the time, which sounded like BS to me. But I know little about this stuff.

Anyway, thanks in advance for any help anyone can give me.


  • Jamie Hall
    Jamie Hall Member Posts: 23,442
    Sounds like a control issue

    If your boiler isn't hooked up to the hot water heater, there is no reason for it to run except when either its own aquastat (hot water) or thermostat (steam -- you don't say which) is calling.  And if it's hot water, the aquastat will only call if the thermostat is asking for heat and the boiler is cool.

    Therefore... in the summertime, whether it's steam or hot water heat, the boiler shouldn't run at all.

    If the modification didn't change the control wiring for the boiler, though, it could well be thinking that it still needed to heat the domestic water.  Check your controls.

    The idea that it needs to stay hot all the time as your landlord suggested is simply not true -- but landlords can be hard to convince.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,099
    Summer winter Hook up

    Summer winter hook up is what the oil company would call your original system. It runs in the summer to maintain hot water for your Domestic Hot Water (DHW) Once the water heater section is removed from the oil fired boiler you no longer need a Summer Winter Hook Up control.

    Many homeowners that had this work completed would shut off the oil burner switch in April and turn it back on in September. With the price of fuel today you may want to change that "Logic" and it is usually a simple wire removal. if you have a Honeywell L8124 Control see the post from jstar October 12 2010


    if you have other controls you will need a tech that can decide what is best for you. if you landlord won't got for the service call cost.... you may want to pay for it anyway... it will save you on fuel

    use an oil heat tech not a plumber.... Some plumber may know what to do but most are good at piping and leave the controls and wiring to others.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

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