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Questions about oil fired boilers

nick_f22
nick_f22 Member Posts: 3
Looking at purchasing our first home and the inspection brought up a few plumbing and heating issues. The home is equipped with a relatively new (<5 years old) Peerless oil-fired boiler (model unknown) equipped with a tankless coil to provide domestic hot water. Water supply is a private well.

We noticed that the hot water seems to have a rotten egg / sulphur smell. I'm unsure if this is just the hot water or both hot and cold, however our well water testing (on cold water) brought back "not detectable" on the odor test. So for now I am assuming this is only an issue with the hot water.

From what I've read this is common on well water homes. The remedy seems to be to change our the sacrificial anode in the hot water heater from magnesium to aluminum. As far as I can tell though, oil fired boilers with tankless coils do not have sacrificial anodes. Is this correct? If so, what are my other options?

The second issue we've found is temperature and pressure regulation. Running two showers (one on the 1st floor, one on the 2nd) shows a significant drop in both water pressure and temperature. The well pump is providing ~55 PSI to the house. Could this then be due to blockage in the plumbing? Are there any options to provide better temperature regulation with a tankless coil?

Comments

  • STEVEusaPA
    STEVEusaPA Member Posts: 5,689
    Yes there are no sacrificial anode rods in a tankless. Second, probably no way you run 2 showers with a tankless and expect constant hot water.
    As far as pressure drop, what size shower heads are you using (flow rate)
    Your options:
    1 shower at a time.
    Indirect storage tank
    Separate hot water heater.
    Also keep in mind, with a well, your tankless might be plugged, or partially plugged, further limiting your hot water transfer, and dropping the pressure, or limed up on the boiler side.
    I have a customer on well water, she only listens to her plumber, and only gets about 4 years out of a boiler.
    You have to treat the water that goes in the boiler and treat the water that goes thru the boiler.
    The rotten egg smell has nothing to do with any boiler.
    steve
  • Jamie Hall
    Jamie Hall Member Posts: 18,951
    Welcome to more rural living!

    The slight rotten egg smell is hydrogen sulphide in the well water. It's more noticeable in hot water than cold. It's a nuisance, but not harmful at those levels. There are a number of treatment options to get rid of the problem; my preference has always been manganese greensand filters, but there are a number of other approaches.

    The best solution to the temperature regulation problem is using the tankless coil to supply a hot water storage tank, and drawing the hot water from that rather than hoping the tankless coil will do the job by itself -- which it probably won't, given modern water usage styles.

    The pressure problem is related to the plumbing and the well pump. It may be that the pipes are a bit small; it may also be, if they are old iron pipes, that they are rusted. That will cause a pressure drop from the pressure tank on the well to the point of use. On the other hand, it may simply be normal behaviour of the pump and pressure tank. Most well pump installations do not deliver constant pressure, but rely on the pressure tank to control the pump, with the pressure moving between 30 to 50 psi (typically) or sometimes higher (40 to 60). If the rate at which water is being drawn is greater than the pump can manage at the higher pressure, the pressure will drop to the point where the pump can keep up (or the lower pressure causes lower flow and the pump can keep up!) if the use goes on long enough.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • nick_f22
    nick_f22 Member Posts: 3
    Great, thanks for the feedback Jamie and Steve.

    So, sounds like the odor can most likely be remedied with filtration and is hopefully not indicative of a larger well issue?

    Also sounds like going to an indirect storage tank is our best option for temperature regulation, assuming the boiler is in good repair.

    I'm assuming that if the pump is supply adequate pressure to house (54 PSI), that either the tank is undersized or it's indicative of a piping issue (blockage, size, etc). We ran a first floor sink and as soon as we turned on a second floor sink the water slowed to a trickle.

    Thank you all! This has been a huge help.
  • Jamie Hall
    Jamie Hall Member Posts: 18,951
    nick_f22 said:

    Great, thanks for the feedback Jamie and Steve.

    So, sounds like the odor can most likely be remedied with filtration and is hopefully not indicative of a larger well issue?

    Also sounds like going to an indirect storage tank is our best option for temperature regulation, assuming the boiler is in good repair.

    I'm assuming that if the pump is supply adequate pressure to house (54 PSI), that either the tank is undersized or it's indicative of a piping issue (blockage, size, etc). We ran a first floor sink and as soon as we turned on a second floor sink the water slowed to a trickle.

    Thank you all! This has been a huge help.

    Your description of the water pressure behaviour is classic partly plugged pipes. If the pressure tank were undersized (unlikely, although it could have lost its charge -- it would be worth checking that) the change would be gradual, not abrupt.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • nick_f22
    nick_f22 Member Posts: 3

    Your description of the water pressure behaviour is classic partly plugged pipes. If the pressure tank were undersized (unlikely, although it could have lost its charge -- it would be worth checking that) the change would be gradual, not abrupt.

    Thanks Jamie, that makes sense. Will investigate further.
  • hvacfreak2
    hvacfreak2 Member Posts: 500
    Amtrol makes a digital pressure switch that has helped me with my water pressure issues. Of course this is after new piping in the house , new poly from the house to the case and down 275 and new wire. I ran plastic conduit in the ground from the house to the case for the next time.



    hvacfreak

    Mechanical Enthusiast

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