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Boiler Wiring Question

Just bought house

Here is what I know

1964 American Standard Arcoliner  wideback with General fittings tankless (estimated  original cap 5GPM) 164,000BTU/hr Becket burner

Hi Limit Detroit Lubricator (Breaks burner line voltage on temp) Set at 185 Deg (Coasts up to 200+ ) Closes at approx 160 Deg

3 taco 007 circulators with 3 American Standard relays with terminals for TT and SS(stack switch is non existing but looks like they are wired and jumped)

3 luxon programable thermostats (new to replace old Honewell mercury round)

I assume thermostat controls circulators only but not sure.

Here is confusion.

SPDT American Standard aquastat in tankless well is wired  NC(normaly closed)

back to TT on burner relay (however, it is always closed, I am assumining it is malfunctioning.) it is wired in parallel with wires going back to circulator relays but not sure why. I think that it is just a complex (cobbled) way to jump TT on burner relay. Possibly an attempt to disconect circulator  and fire burner on low temp but not sure how. Not sure when NC opens( above or below adjustable setting)

On back is White Rogers 11d31-1 spdt wired to close on rise to break line voltage to circulators. Adjustable differential is set to as close to 0 as possible

If not set to 120Deg, circulators will not turn on and boiler will hang a few degrees above 160 deg on hi lim switch.

Is it normal to have such a differential from top (temp/pressure guage and lolim sensor? It seems like a rather primitive way to control.

Is boiler just bouncing between differential on hilim switch.

what about thermal shock?  Should of cracked a long time ago.

 30 deg outside with all 3 circulators calling for heat, boiler  drops  to 130degs and  I still have hot water for shower. Tankless does have 30 gal aqua boost with its own circulator and separate aquastat.

heating approx 3000 sq/ft (1000 perzone) Have not updated insulation yet.

any advice/insight   

 would Intellicon HW+ help  save $ or just lower differential on hilim? Would circulators ever turn on?


  • CMadatMe
    CMadatMe Member Posts: 3,086

    Boiler and system is 40 years old. Is it really worth even thinking about a fix? My advice, do a heat loss, plan a replacement strategy.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • FredH
    FredH Member Posts: 18
    Boiler Wiring Question


    High end boiler replacement quoted in the 10-12k range.

    I am investing $3,800.00 in insulation (with $2000 rebate fron NG)

    My replacement strategy is to save some money this winter and do heat loss calc after house is sealed and insulated.

    How about some insight into short term. Maybe take a stab at ansering questions.

    When does an adjustable  NC switch on tankless open. on rise or drop?

    Why would I even want it when the hi lim diferential comes on at 160Deg anyway? Boiler still makes hot water with all 3 zone circs pumping.
  • kcopp
    kcopp Member Posts: 3,990
    wiring on some....

    really old boiler can be VERY strange. The reason you have no hot water issues is mist likley due to the 30 gal aquabooster. They must have had issues w/ the boiler temp dropping so much and had no hot water.

    As to the control wiring...I don't think I would mess w/ it much.The Intellicon most likely would really be a waste for this system.  Wiring the boiler was done for  whatever reason that way... who knows the system may have had stack switch on it. You could spend a lot of money to get it "right" and not save any money on your heating bill.

    What type of radiation do you have? sounds like cast iron baseboard or radiators.....pipng in a bypass would help w/ the temp. drop

    The Arco liner is/ was a beast. It can take just about any punishment to thermal shock... needless to say it had it day. Insulation is a VERY good idea.

    Hope this helps...
  • FredH
    FredH Member Posts: 18
    Boiler Wiring Question

    Have fin tube baseboard baseboard.

    Stack switch was removed long ago.

    Heat loss calc came in at 77KBTU/hr

    New insulation should drop that to 71KBTU/Hr

    I am wonderinng is  the newer Becket flame retention burner increases the actual capacity of what the boiler was  originally rated for. I would asume it puts out more heat than what was installer originally.

    Running off the Hi Lim switch can not be best way to economize.

    Someone mentioned replacing old controls with Honeywell Electronic in the tankless well. Seems to be a good place to start.  $120-150 plus some wire and my labor.
  • kcopp
    kcopp Member Posts: 3,990
    well hey ...

    why not. What is the burner on it? What is the firing rate? Sometimes it may be best to start over..... but remember it is a 40 yr. old boiler. good luck.
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