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Boiler troubles

Jim_47 Member Posts: 244
Larry, try disconnecting the thermostat wires from the aquastat. Watch the boiler then. I should not be constantly banging off the hi limit if no one is calling for heat. Only the aquastat photo came out, and I could not see of you had anyzc/zr contacts coming from another zone relay. Is there water pressure in the boiler? are both zones when calling for heat circulating and returning hot water?
where are you located?


  • Larry_54
    Larry_54 Member Posts: 7
    Boiler Problems

    I have an oil fired hot water baseboard system in my home. Most components in the system were 60 years old from what I could tell. Two weeks ago I noticed the house wasn't warming up so I checked the circulator pumps, we have two one for the main house one for the addition. The circulator for the main part of the house wasn't running (I checked by both thermostat and relay) so it was replaced along the other circulator, the flochek valve and pressure regulator. The 60 year old thermostat was replaced in the main part of the house with a digital. Here’s the specs on the furnace. It’s a Burnham boiler # V-73 T. The aquastat is the only thing not replaced on this thing and it is a Honeywell with the settings of 140 degrees HI, 120 Degrees LO and a Diff of 20. With neither thermostat calling for heat (positively) and the gauge on the furnace showing 20 PSI the furnace comes on and runs for about 3 minutes and then stays off for about 12-13 minutes faithfully and the furnace gauge shows the temperature is 180 degrees when it shuts off and 170 degrees when it fires up. This means the temperature gauge on the furnace drops 10 degrees in 12-13 minutes. From the information given can someone tell me what’s wrong with this furnace? Could this be a bad aquastat? Could this be a cracked heat exchanger? If it is the heat exchanger how do I check it and what do I look for? There’s no water on the floor. Any other advice or guidance will be immensely appreciated.
    Thanks in advance, Larry (the unhappy home owner)
  • Jim_47
    Jim_47 Member Posts: 244
    boiler troubles

    Please tell us if you have zone valves, the model number of the aqua stat or a photo of the aquastat(cover off). Also when you replaced the thermostat, how many wires was the original and how many on the new one? thanks
  • oil-2-4-6-gas
    oil-2-4-6-gas Member Posts: 641

    Larry its called a Boiler
  • Larry_54
    Larry_54 Member Posts: 7
    Thanks Jim

    No zone valves Jim and only two wires going to the thermostat. This thermostat operates the boiler only (soon to be consolidated with the A/C thermostat). The Honeywell aquastat is called a Triple Aquastat-Relay, type L8124A, C under that is another #, L8151A. Jim I've included a photo of the aquastat and Boiler for your viewing pleasure. Thanks again Jim.
  • Larry,

    Looks as though you had your hands-full trying to purge the system.
    That aquastat is a triple-control unit as it is screwed into a domestic coil located within the boiler, but I can`t see if it`s still in use. Do you have another WH?
    When the stat calls for heat, it starts the burner & that circ (relative to the "diff" setting) & the boiler water temp rises(if allowed) to the "high" setting.
    When the stats are both satisfied it maintains a "low" temperature setting for the domestic HW needs.
    Now you have 2 circs, and if you have another source for your DHW, that is the wrong control and should have been changed.
    Copper vent-line on the OT?, certainly a new one on me.
    I would get a "pro" in there who knows what they are doing as some serious re-piping & wiring is needed on this unit. Trying to adjust that draft control would really make my day.

    BTW-How`s the fishing?

  • Larry_54
    Larry_54 Member Posts: 7

    Disconnecting the thermostat wires was my son-in-laws (industrial HVAC man) next step in determining the problem. He's efficient in everything but boilers, just my luck.
    Only the main part of the house is tied into the aquastat the addition has a seprate relay.
    Yes there is water pressure in the boiler and it maintains a steady 19-20 PSI. Yes both circulators are circulating and returning hot water. Both are brand new and you can check the progression of the hot water through the pipes as it circulates. I'll try another photo of the boiler. I may have exceeded file limitation size on this site.
    Located in Northern MD.
  • Larry_54
    Larry_54 Member Posts: 7

    No other hot water heater in the house this boiler supplys it all. Dave all the pipeing in this house was like this when I bought it. When I make a repair here I just replace the copper with copper and the steel with steel. It's funny you would say that, I had a plumber come here once and shake his head at what I have.
    Haven't had a rod in the water for over eight years now but I know a charter captain that fishes the upper Chesapeake, I hear it's still good.
  • I meant no insult

    Larry, so please don`t take-it that way!
    So this boiler is still making your DHW?, then it seems you`ll need at least 2 things to make that aquastat work, a boiler control "savvy" electrician, and a second relay like a Taco 502 to allow the circs to operate independently of each other and still maintain the function of this control for the 2 heating zones and the domestic.
    The "wet" side is another matter.

  • Larry_54
    Larry_54 Member Posts: 7

    Dave thanks for the advice and I'm not a plumber but I know whats in my basement is one of cluster $#@* things. This boiler is driving me to drink. I'm replacing the pressure/temperature gauge because the one on my well pump was clogged solid and I don't think the one on the boiler is giving me a true reading. It's probably clogged also and for 10 bucks it's piece of mind that at least that is working correctly. My son-in-law is bringing a temp probe up and we're going to check the cycling problem again. I'll let you all know what we find. Thanks
  • Larry

    Try to take it easy,, things may not be as bad as you think.
    Look forward to hearing from you!

    Good luck, & if you do,(Christmas is coming anyway), have a drink on me!

This discussion has been closed.