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Boiler fires up, but no circulator pump (new) no 24V at pump

Forrest_2
Forrest_2 Member Posts: 35
Gas National Boiler, 2 zones, Belle and Gossett pump, Honeywell Aquistat L8148 G

I did a lot of updates to my old system Gas National Boiler, 2 zones, Belle and Gossett pump, Honeywell Aquistat L8148 G , last year had a plumber/heat specialist in as well last year. So this year the boiler starts does its thing, but the circulator pump is not coming on, I am not detecting 24V at the pump. I have 2 zone valves, one seems to pass 24v from terminal one to three, the other does not. I have another zone valve but have not installed it.

I'm guessing the aquistat is bad, The Honeywell L8148 G doesn't seem to be available any longer, I can't find any info on it either.
thanks
-Forrest

Comments

  • hot_rod
    hot_rod Member Posts: 14,552
    Most often circulators are 120V? Should be a relay that takes a 24V signal switches 120V to the circulator pump.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Hvacman23
  • JUGHNE
    JUGHNE Member Posts: 8,175
    You should be looking for 120 volts at your pump, not 24 volts.
    It would come from a relay most likely in the L8148 G aquastat.
    Check for 120 volts there first.
    Hvacman23
  • Forrest_2
    Forrest_2 Member Posts: 35
    I had the voltmeter set AC V, just got no reading at all 24 or 120.
  • Forrest_2
    Forrest_2 Member Posts: 35
    I could use some bare wires from an extension cord to see if the motor spins right after disconnecting the leads from the aquistat? The pump is almost new.
    SuperTech
  • GBart
    GBart Member Posts: 753
    You could also call a pro and not electrocute yourself. - sarcasm
    SuperTech
  • GBart
    GBart Member Posts: 753
    Seriously tho', aquatstats rarely go bad, it could be almost anything but probably not the aquastat.
  • JUGHNE
    JUGHNE Member Posts: 8,175
    You could have 2 sources of 120 volt power.
    Possibly one of them feeds the transformer where the zone valves and your boiler gets their power.

    And possibly another will feed the aquastat for the pump relay.

    Possibly.
  • Forrest_2
    Forrest_2 Member Posts: 35
    Don't know if pics help, better here it is.





  • Forrest_2
    Forrest_2 Member Posts: 35
    Circulator pump runs fine from direct ac.
  • hot_rod
    hot_rod Member Posts: 14,552
    120V to the control with your test meter?
    Disconnect the t-stat from TV & T, jumper across those terminals. Does the relay click?

    Looks like that control has been hot, black discoloring around the transformer?

    You may need to replace the entire control, they are not really rebuildable.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    SuperTechHvacman23
  • Forrest_2
    Forrest_2 Member Posts: 35
    Hot Rod: By saying "T-Stat" do you mean disconnect the 2 wires?
    When I turn on the switch, the relay moves that top plate that says "Honeywell" out. That black soot is from below.
  • hot_rod
    hot_rod Member Posts: 14,552
    Either have someone move the thermostat up and down while you watch that relay, or disconnect those two small wires and jumper across TV & T. that eliminates the t-stat from the circuit. The silver lever should move in and out and send 120V to the pump.

    Beware there is 120 voltage inside that box and shock hazard, or worse. If you are not comfortable or versed in line voltage troubleshooting play it safe and call a HVAC service-man, or woman :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Hvacman23
    Hvacman23 Member Posts: 1
    If you don't have 120 volts at the pump, something somewhere is not sending it there. If you're not rather well-versed and relays controls and electrical, I would definitely call a professional in to do it. That's what we do for a living. You could cause damage to the entire system if you don't know what you're doing. I say this because I've had three DIYers alone this week that tried to work on their boiler and they were not at all happy with the news that I had to give them. One smoke through a aquastat, the other person fried a Transformer, and the other person had their boiler kettling so bad I almost ran out of there
    SuperTech
  • rick in Alaska
    rick in Alaska Member Posts: 1,160
    If the relay clicks and pulls down, you should have 120 volts between c1, and c2. If you don't, the control is bad and needs to be replaced. If you do, then follow the wires going to the pump and see if there is something else that it goes to first. There might be another aquastat in line that keeps the pump from coming on until the boiler is up to a minimum temperature.
    Rick
  • HVACNUT
    HVACNUT Member Posts: 3,800
    I dont know if that control is still available.
    If not you'll have to get an L8148 for gas and a separate 24v, 40va transformer for the zone valves.
  • Tim McElwain
    Tim McElwain Member Posts: 4,445
    You can replace that relay with an L8148J relay.
    SuperTechForrest_2delta T
  • unclejohn
    unclejohn Member Posts: 1,700
    edited November 2018
    The one you have was made in the summer of 1978. C1 & C2 should have 120v across them. Also as I look again you have some soot on the boiler. The boiler is 40 years old or older if thats not the original aquastat. I would consider a replacement.
    SuperTechForrest_2
  • SuperTech
    SuperTech Member Posts: 1,579
    > @unclejohn said:
    > The one you have was made in the summer of 1978. C1 & C2 should have 120v across them. Also as I look again you have some soot on the boiler. The boiler is 40 years old or older if thats not the original aquastat. I would consider a replacement.

    How did you know the date of manufacture? I gotta know!
  • unclejohn
    unclejohn Member Posts: 1,700
    On the tsat above the red wire is a date code 78 31. Thirty first week of 1978
    SuperTechForrest_2Solid_Fuel_Man
  • Forrest_2
    Forrest_2 Member Posts: 35
    I tried Hot Rods suggestion of turning the two thermostats by setting up a video cam (I live alone). Might give a better idea of what is going on.
  • rick in Alaska
    rick in Alaska Member Posts: 1,160
    At 24 seconds in, the relay opens to fire the burner. At this time, the pump should be running, and should have 120 volts to it. The reason the boiler shuts off and the relay is still open is because the thermostats are still calling for heat, but since the pump isn't running, the boiler got up to its max temperature and shut off. The relay is still open trying to to get the pump to come on though.
    There should be 120 volts on C1 and C2 as soon as that relay clicks. Assuming there is no quirky thing going on between the C1 and C2 terminals on the aquastat and the pump, such as a bad wire, then you have a bad aquastat and needs to go.
    Also, you have Taco zone valves, and as such, it takes up to 3 minutes for them to open up and send a signal to the aquastat. So, moving the thermostat is not an instant response at the boiler.
    Rick
  • Grallert
    Grallert Member Posts: 491
    You really need to look at C1 and C2. Look for 120V. I've got my money on a bad control.
  • Forrest_2
    Forrest_2 Member Posts: 35
    Looks like we got nothing at C1 and C2. So I guess this means a new Aquastat is the call.
  • Forrest_2
    Forrest_2 Member Posts: 35
    Made the call to my Plumber/heat guy, but thanks for all the Help and Suggestion, much appreciated.
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