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Endurance installation manual question

Okay, my best guess for the amount of pipe used in my 4 zone hot water heating system is 500 feet. Plus the 20 gallons of boiler water.

What size Expansion Tank should I have?



  • Chris AlonzoChris Alonzo Member Posts: 9
    Endurance installation manual question

    I guess this is a question for Laars, but just in case anyone else knows the answer:

    On page 15, Figure 19, there are two notes. Note 2* says "Required when model EDB/EBP 110 has 3 or more zones". I have 4 zones. But I don't see anywhere in the figure what they are referring to.

    Anyone know?

  • BillMarchantBillMarchant Member Posts: 9
    Endurance manual correction

    Hi Chris Alonzo,
    Its not worded correctly, typo error. The endurance must be installed primary/secondary when you have more zones then the internal pump can handle. Basiclly, that piece of pipe labeled #1. We are telling you it is required if

    a) you have a system pump, or

    b) your 110 has 3 or more zones, or 175 has 5 or more.

    In either case, you will need a system pump because the internal pump is not enough to handle the load. Piping it this way will decouple the endurance pump with the system pump. Hope this helps.

    Bill M.
    Applications Advisor
    Laars Heating Systems.
  • Chris AlonzoChris Alonzo Member Posts: 9
    I do have an external circulator

    Thanks again for the quick response.

    I do have an external circulator, so I guess it is correct.

    Now, in relation to the PRV dumping water in my system - Since there is a circulator in the Endurance, AND I have an external circulator, could this combine to make the pressure even higher than normal? Would I need another x-tank?

  • Not due to the pumps.

    The expansion tank isn't making room for increased pressure, but for increased volume of heated water.

    The tank size is determined by total system volume and temperature rise.

  • Chris AlonzoChris Alonzo Member Posts: 9

    So the next step is to calculate the feet of pipe in the system? And by temperature rise, do you mean the difference between the highest and lowest temperature in the furnace? Not the cold water, right.

  • Chris AlonzoChris Alonzo Member Posts: 9
    Regarding 1* and 2* in the manual


    I reread the manual with your corrections. Now I understand it a bit better. It is saying I need a 'bypass', which I do not have. Can you explain a bit more what this is?

  • JoannieJoannie Member Posts: 115
    Expansion Tank

    And don't forget that the EBP units (the ones that do heating and hot water) have a 20 gallon BOILER water tank built in, so you need to include that 20 gallons, as well.

    Alot of people assume that the tank in the EBP holds domestic water, but it is boiler water. The domestic is made through the plate heat exchanger.
  • Bill M......Bill M...... Member Posts: 2
    No problem

    Hi Chris,
    That section of pipe that joins the system supply and return together, creating a loop for the boiler. That piece of pipe should only be 4 pipe dia. long, with tees. If you give me your email, I'll send you a print showing how to pipe it.


    Bill M....
    Applications Advisor
    Laars Heating Systems...
  • Chris AlonzoChris Alonzo Member Posts: 9

    I think I get it now, but it would be good to have your print out to show the plumber.

    [email protected]

    BTW - When I search for a message, it shows everyones email address. But not when viewing the whole thread.
  • SpichettySpichetty Member Posts: 1
    Have Laars endurance, have ?'s Please help

    You sound like you know the system. This is actually not Seth, but is wife. I'm posting this for him, so excuse that it may sound weird. We have the laars endurance. We run 3 zones from it. We are having a problem tho. We have 2 thermostats turned off, but still are getting hot water pumped to them. We have bleed, and purged. When we turn those 2 zones off, then the third gets whacked with hot water and its 82 degrees in there. We had someone come and put a circulator with a built in flow valve/check for the third zone and some new air bleeders. No luck. All zones are still getting hot water. The laars internal circulator is running, but no thermostats are calling. We checked the wiring with multi meter. the external circulators are not running( which tells us the thermostats are not calling). Is there any way to turn off the internal circulator in the boiler?
  • toni59toni59 Member Posts: 1
    endurance tank

    This might sound crazy but i am woman that don't know what she's doing. I need to turn my tank back on it was turn off due to frozen pipes i work out of state and now i'm home .The tank was drain and turn off I need someone to tell me step by step what to do to turn it back on the manual is confusing to me
  • heatpro02920heatpro02920 Member Posts: 991
    I would

    start a new thread, include pictures of your system so people can tell you exactly what you are looking at since no systems are done the same... And it will make instructions much easier, ie: turn the blue valve counter clockwise and open the red faucet, ect...
This discussion has been closed.


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