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Thermostat Calling For Heat, Boiler Not Kicking On

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GregHayes
GregHayes Member Posts: 3
in Strictly Steam
I have a 2 zone split system. Zone 1 is functioning properly - when the thermostat calls for heat the boiler kicks on. Zone 2 is not functioning properly - when the thermostat is calling for heat the boiler does not kick on. I replaced the thermostat in Zone 2 thinking that was the culprit, but no luck. My Zone valve controller has power as indicated by the LED in the photo and my Zone 2 indicator LED is green and orange which indicates the Zone is calling for heat and has an open valve. 

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  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,524
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    So on zone 2 the zone 2 light turns green when the thermostat is calling and the same light changes to orange when the valve opens and the end switch is calling?

    I read the instructions for the control and that's the way it reads.

    I am not clear on what the problem is could be the control or the zone valve. What type of zone valves do you have, 2 wire, 3 wire or 4 wire.

    The dip switches in the control have to be set properly for th e type of zone valve. Did they get changed perhaps by accident?
    GregHayes
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
    edited October 2021
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    Are you allowed to put that boiler on a combustible floor? I know the right side clearance is wrong.
    steve
  • HVACNUT
    HVACNUT Member Posts: 5,835
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    Where are the actual zone valves?
    If they're Honeywell V84, there should be a lever. See if it moves freely or if there's resistance. 
    GregHayeswlgann
  • GregHayes
    GregHayes Member Posts: 3
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    EBEBRATT-Ed said:

    So on zone 2 the zone 2 light turns green when the thermostat is calling and the same light changes to orange when the valve opens and the end switch is calling?

    I read the instructions for the control and that's the way it reads.

    I am not clear on what the problem is could be the control or the zone valve. What type of zone valves do you have, 2 wire, 3 wire or 4 wire.

    The dip switches in the control have to be set properly for th e type of zone valve. Did they get changed perhaps by accident?

    EBEBRATT-ED. Yes, the zone 2 light turns green/orange when calling for heat. I have 4-wire zone valves. I haven't changed anything in the control valve. We just moved into the home last year. Last winter, the zones were functioning properly. This fall, the zones were functioning properly for a couple of weeks.
  • GregHayes
    GregHayes Member Posts: 3
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    HVACNUT said:

    Where are the actual zone valves?
    If they're Honeywell V84, there should be a lever. See if it moves freely or if there's resistance. 

    HVACNUT. The zone valves are located in the crawl space directly below the unit. The zone valves are Honeywell V84. When I move the lever to manual it does have some resistance from the zone valve motor. I also took the zone valve motor off of the valve and was able to move the valve from "open" to "close" with my hand. I replaced the motor on the zone valve controller, thinking maybe I had a bad motor. When I replaced the motor and reinstalled the zone valve controller, I had the same problem. Calling for heat but the boiler is not kicking on.
  • Ironman
    Ironman Member Posts: 7,376
    edited November 2021
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    Here’s any easy way to check if the zone valve is opening and signaling the zone panel:

    1. Have the thermostat set high enough to establish a call for heat
    2. As mentioned, move the manual operating lever. There should be no resistance in moving it. If there is, then either the valve motor is bad or it’s not getting power from the panel.
    3. If the lever moves freely, then place a jumper between the top two end switch terminals of the valve or the two red leads if it doesn’t have a terminal block. If the boiler kicks on, the end switch in the motor is bad or improperly wired. If not, the there’s a problem with the panel or the wiring between it and the zone valve.
    4. If you follow the wiring from the zone valve end switch to the panel and jump it there, if the boiler kicks on, the wiring is the culprit. If it doesn’t, the panel is.
    5. Again, all of this assumes the zone valve is opening when the stat calls.


    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    wlgann
  • Ironman
    Ironman Member Posts: 7,376
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    By the way, the Honeywell number is 804, not 84.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,836
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    I wonder if the end switch is not working or not connected properly.

    The fact that the zone valves are not near the control sucks. The idea of watching the valve operate and the LED lights are one of the great features of using zone controls. putting them in different rooms was a bad design idea.

    Now this becomes a 2 or 3 person job with cell phones (if you get service in the crawlspace.) Person 1 sets the thermostat to call for heat and person 2 watches the valve operate. person 3 watches the lights on the control to see if they indicate that something should be happening (like the valve opening or the end switch closing) and it does not happen, then you have found the problem.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,836
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    GregHayes said:



    EBEBRATT-ED. Yes, the zone 2 light turns green/orange when calling for heat. I have 4-wire zone valves. I haven't changed anything in the control valve. We just moved into the home last year. Last winter, the zones were functioning properly. This fall, the zones were functioning properly for a couple of weeks.

    Does the LED turn green on a call for heat then about 2-4 seconds later turn orange? or are you saying the LED looks like both at the same time Green/Orange.

    There is a difference. The LED should look completely orange to indicate the end switch is activated. You picture looks mostly green. Here is a simple test. In the Zone Control, on the problem zone, set the DIP switch to ON (in the upper position) to see if the problem is resolved.

    And your clearance to combustibles is probably OK, but you should actually measure the right side to see if there is a full 1". And don't store any sheet goods or paper bags in that small area. it must be open for the fill 1" air gap and free air flow.

    No mention of Combustible floor clearance in the entire IO manual. That usually means 0" clearance or it would say "NOT APPROVED FOR INSTALLATION ON COMBUSTIBLE FLOOR" somewhere in the specifications. but it does say "do not install on carpet." also indicating that it is approved for a combustible floor installation.

    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • wlgann
    wlgann Member Posts: 14
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    I've had something similar happen in the past at my house. Note that the boiler may not fire if the system is already hot enough, but I imagine you've thought of that. If the boiler NEVER fires when zone 2 calls for heat, well...

    When the zone 2 thermostat calls for heat, does the circulator pump come on? Not that I think the pump is bad (it works for zone 1), but if it's not getting power when zone 2 is on then the boiler also won't come on because the boiler passes power to the pump.

    Basically, you need a signal that goes thermostat-->zone controller-->valve motor-->boiler. You know the boiler itself works because zone 1 works. Within the boiler itself the wiring for the two zones is common. So that's not a possible cause of your problem.

    Now you need to figure out which of the other three devices, the thermostat, the valve controller, or the valve, is faulty. Ironman's post earlier goes a long way, but here's some supplement.

    Swap your zone 1 and zone 2 thermostats. You know your zone 1 thermostat works, so swapping them eliminates the zone 2 thermostat as a possible culprit, as long as swapping the two doesn't suddenly cause zone 2 to work as expected and zone 1 to fail. I think it's very unlikely the thermostat is the culprit, but it's going to be pretty easy to eliminate it, so what the heck?

    Next, you can eliminate the "zone valve control" device as a possible culprit. Pull the thermostat from the wall and wire it directly to the zone valve (I know, it's real a pain to do in your case). But that will allow you to eliminate the zone valve controller as a possible issue. It might be lighting up as expected but still not giving the signal to the rest of the system.

    The next thing to examine is the zone valve itself. You've manually turned the valve stem and found that it isn't stuck, which is good. You replaced the motor, and it's likely good. But I recall having a real hard time getting a replacement valve control installed just so. It was a really fiddly job. You may have started out with a bad valve control and now have a good valve control that's not PERFECTLY aligned on the valve itself. If you pull the valve control off the valve body and leave it wired in, you can watch it turn when the thermostat calls for heat. The boiler should kick on when the valve motor has fully turned (if the system is cold!) because the valve motor will not pass the "fire" signal along till it's fully turned. Manually turn the valve itself when you do this test so that the circulator pump isn't throwing water against a closed valve!

    My advice is do a mashup of these three steps plus the stuff Ironman said, whichever you find easiest, so as to locate which of the devices is faulty.

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