Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Boiler runs too long for Hot Water.

I have system 2000 with heat exchanger for hot water and a 40 gallon tank.
Water is heating fine and is good if showers are spread out.
Also after stopping hot water use the boiler runs for about two hours before the hot water in tank is full to the temperature it should be at.
Heat exchanger was replaced 9 years ago as it was clogged due to well water issues.
I have back flushed the heat exchanger on the domestic side and the water is clean.
Circulator seems to be functioning fine. Might have been replaced once 14 years ago.
Water tank is as old as the boiler say 20 years.
What can be checked or done to resolve this or is this normal?
Thank you.


  • kcopp
    kcopp Member Posts: 4,303
    Sound like your HX is not transferring the heat to the tank. When its running feel the piping to and from the tank...is it hot?
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,373
    Heat exchanger was replaced 9 years ago as it was clogged due to well water issues.
    9 years with untreated well water is where I'd look.
  • dafy
    dafy Member Posts: 19
    On this same topic, I also have a system 2000 that has a lot of air in the domestic hot water side and the water does not heat up to what it should be. I also backflushed the plate heat exchanger and it looks ok. The heating side (hot water radiators seems to be working fine) What would cause the air to be in the domestic hot water side?
  • zaveri001
    zaveri001 Member Posts: 12
    Thanks for the responses. I am not a professional in this so terms I use may not be technically correct.

    "Bold">Reply to kcopp: the pipes to and from the tank are hot. One to the HX is cold in the beginning, but after a while it is a bit warm too. So, let me ask this. When we use hot water cold water needs to replenish what is used to the capacity of 40 gallon tank. So the HX takes the cold water and warms it and send to water tank. But it may not get to the required temperature right away, so then the water from the water tank keeps circulating via the HX until it becomes hot. Is that right? Awaiting more insight from you.

    Reply to Hatterasguy: You are right. When I say runs for 2 hours, no the burner stops and starts many times.
    When I say "stopping hot water use" I mean no request from house for more hot water. Now the tank has to do its job to get to the 40 gallon water capacity and to the temperature that it is supposed to be at. This is what is taking the around 2 hours for a 40 gallon tank. Should it take this long? I think it used to be much less before, but I never paid attention to it until now.
    When I see no more request from the tank and the burner finally stops that is when I am assuming that the water in the tank is to capacity and temperature. Awaiting more insight from you.

    Reply to STEVEusaPA: Thanks. I have thought about this and will probably do this. But just replacing things without knowing the exact cause is like just replacing everything and may not finally resolve the issue. I do not see black water when I back flush. When the HX was replaced last time, it had actually stopped working due to being clogged. And may be the long time to heat water is showing indication of clogging and will eventually stop working. Yes, I want to avoid that and proactively resolve this. Also, last time the well motor had issues and it was bringing up more dirt in the water and right now I do not see that. Awaiting more insight from you.

    Reply to dafy: I am not an expert or professional on this so cannot reply to this. May be others can.
  • rick in Alaska
    rick in Alaska Member Posts: 1,441
    There is also a spring check valve on the line going in to the storage tank that might be partially stuck closed. That one can be really difficult to figure out without taking it out and looking.
  • zaveri001
    zaveri001 Member Posts: 12
    Thanks again for all the comments. I checked the comment about spring check valve visually only as commented by rick in Alaska. I will be looking into the HX replacement as suggested by Hatterasguy, that sounds like the most logical thing to pursue. Thanks for all the comments and help.
  • billtwocase
    billtwocase Member Posts: 2,385
    I would also check the dip tube in that aquabank
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,520
    I would bet that 006 has no impeller left...
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • billtwocase
    billtwocase Member Posts: 2,385
    That too perhaps
  • zaveri001
    zaveri001 Member Posts: 12
    Request billtwocase (dip tube in aquabank) and Robert O'Brien (006 has no impeller left) to explain there comments in detail. I am not a professional in this field so need things spelled out clearly in non-technical terms (in plain English). Thank you.

    I also had to ask a question about hot water bleeding over. When only water tank is requesting heat to heat the water, should the pipes to the other zones also become hot even though they are not requesting heat? I see that the pipes do get warm and water may also be circulating a bit even though the zones are not requesting heat. The zones and the HX pipes are all connected so I would assume water flowing into the zones even though no heat is requested. Is this normal or needs to be fixed?
  • zaveri001
    zaveri001 Member Posts: 12
    Ok, so the problem is resolved. The Taco 006-BT4 has no impeller left was fixed by replacing that by paying $300 to oil company. This part I can get online for $120.

    This did not resolve the issue and the HX Model 14U
    part#:10-0416 needed to be replaced. Energy Kinetics has it listed on there website for $238.

    But they do not sell directly to customers and have to go through dealer so I had to pay $500 to oil company to do this.

    Now the problem is resolved, and I would say it was the HX as now the time of two hours to get a 40 gallon tank of water heated is reduced to 20 minutes.
    This part Model 14U part#:10-0416 for system 2000 was not available anywhere on the internet or through energy kinetics directly to customers.

  • rick in Alaska
    rick in Alaska Member Posts: 1,441
    This is the reason prices are not discussed on this forum. People who want to compare prices from the internet as a general rule, do not have any idea how much it costs to keep a business open. These costs have to be added on to the parts price in order to stay in business, so the customer will have some one who can come out to do the work they need. And the internet store will not come to your house and install it.
    Many times, the price you can get on the internet is actually lower then what the retailer with a store front has to pay.
    And Energy Kinetics does not sell to anyone but dealers because they like to support the trades people who use their products, which is admirable.
    Either way, you managed to get it fixed, which is great.