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One zone not getting heat

HTM
HTM Member Posts: 22
Hello all. I am trying to narrow in on a solution to a zone problem in a hot water baseboard system that is otherwise
working well.
Thirty year old WM model P566E-W boiler, indirect hot water heater. Older Taco zone valves, five separate zones.
This year, one of the zones (two bedrooms and a bathroom) is not getting heat. At the boiler, pipe on each side of the zone valve is cool to the touch. Since replacing a very old thermostat this same pipe warms up and we can now hear muffled "pinging" inside the baseboard. Not heard with the old thermostat. But still no heated water coming in.
Could the issue be zone valve related or something else? Appreciate any guidance. Thank you.

Comments

  • HVACNUT
    HVACNUT Member Posts: 4,015
    What model zone valves? Are there levers on them to manually open? When the valve is open the lever should move freely. 
    The new thermostat is for the same problem zone? Is the thermostat wired correctly?
  • unclejohn
    unclejohn Member Posts: 1,730
    Could be air in system. Pictures are worth 1000 words maybe even 2000 here. Post some of the zone valves boiler piping ect.
    rick in Alaska
  • HTM
    HTM Member Posts: 22
    HVACNUT,
    Thank you. Answers:
    1. Zone valves are Taco 572-2 (one zone) and 571-2 for the others
    including the problem zone. Power heads are all 555-102.
    Levers on power head allow manual or auto. Problem zone
    lever does move. Sometimes there is resistance. Currently
    moves freely. I have had lever in auto and manual positions.
    Either way, no water coming into this zone's baseboard.
    2. Problem zone new thermostat Luxpro 521 (replaced a much older Luxpro). Two wire RH and W1. Followed same wiring as
    the old thermostat. Found 24V at wire leads prior to buying
    the new thermostat. Believe it is wired correctly. With other thermostat temps turned down, boiler does respond to call for heat from new thermostat. Baseboard remains cold.
    3. For my skill level, new thermostat was easiest first step.
    "Popping" noise in the baseboard was encouraging. Sounded
    like the lead up to water coming through. Ultimately nothing.
    4. As a next step, I picked up a new power head early today.
    A model 555-050RP listed as current replacement. I don't know
    whether it will be the cure - I couldn't get the pins to slide fully into the slots for a proper upright fit against the valve. Might
    work if I were a better mechanic but didn't want to force it.
    I removed the valve's slotted plate for better access to check fit. Pins on the new head seem to be slightly "off" relative to the old slotted plate. Would not slide into the fully secure design position. Re-secured the slotted plate as water started to leak from the valve. The old power head went back into place easily. Ran the boiler, no leakage.
    Thanks for reviewing. I welcome more advice.
  • rick in Alaska
    rick in Alaska Member Posts: 1,209
    My bet would be air in the loop. Most likely it just needs to have the air bled out. Post some pictures of the piping and we can maybe guide you on how to do it.
    Rick
  • HTM
    HTM Member Posts: 22
    Hello Guys,
    Appreciate everyone's input.
    Photos attached. The light green zone valve furthest to the left
    is the problem zone. Let me know if I've shown the piping area
    detail you need. Thank you.
  • HTM
    HTM Member Posts: 22
    I'll have to try again with photos............
  • rick in Alaska
    rick in Alaska Member Posts: 1,209
    If you close the valve below the drain valve with the red handle, and manually open up the problem zone, then you can bleed the zone by opening the drain vale with the red handle until air comes out. You would wan to make sure the other zones are off while doing this, and make sure the boiler pressure stays up. Run it until no more air comes out.
    Rick
  • HTM
    HTM Member Posts: 22
    Hello Rick,
    1. If I were to change the settings on all the house
    thermostats to "off" - excluding the problem zone thermostat -
    is that the best way to make sure the other zones are off?
    2. With the other zones "off", I'll start the boiler. Problem zone
    valve lever in open position.
    3. Close brown handle valve (this is the one below red handle
    drain valve).
    4. Gradually open the red handle drain valve. Should it be fully opened during air bleeding?
    5. What boiler pressure range should I be looking for to be maintained?
    I'll look for your reply and then head to the basement.
    Thank you.

  • unclejohn
    unclejohn Member Posts: 1,730
    Turning all tstats off and manually open the zone valve should do it. I like to get at short hose like from a washing machine for the drain and put it in a bucket and keep bleeding until no air bubbles are present. Try and keep boiler pressure above 10psig. If you can maintain pressure with it fully open fine. I did not see a bypass or fast fill on the reducing valve.
    rick in Alaska
  • HTM
    HTM Member Posts: 22
    unclejohn - thank you for clarifying the procedure.
    I'll hunt down a hose and try in the morning.
    As for the water lost during air bleeding, I'll find out
    whether it's a lot or minimal. I expect it should be
    made up?
  • unclejohn
    unclejohn Member Posts: 1,730
    As you bleed air water should flow through the reducing valve and if that is working properly when you shut the bleed valve the water pressure will rise to 12psig or so. If you open the bleed valve and do not get a continual flow of water make sure the valve to the reducing valve is open, if it is and no flow you have a bad reducing valve.
    rick in Alaska
  • HTM
    HTM Member Posts: 22
    unclejohn - I was out of pocket a couple of days, now back in action. Fortunately it's warmer here in PA this week.
    Thanks for explaining water replenishment. I located the reducing valve and the valve in the line above it (blue Amtrol visible in two photos, lower right).
    One more thing on the tstats I'd like to double check.
    Before starting the air bleeding, are all of them to be in the "off" position or the problem zone tstat "on" and all the others "off"?
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 2,188
    edited November 2020
    Use your mind's eye to visualize the water coming in from the fill valve, every time the pressure from that valve comes to a Tee it needs to make a decision where to go. it will take the path of least resistance. If a valve is closed at one of the tee outlets then the water flows out the other. By closing all the valves the water stops.

    Now open only the valves that direct the water to the problem zone piping. that water pressure will push the air out of that zone piping and when it gets to the valve with the hose on it the water will leave the system forcing the air out with it. The valve just below the drain valve with the hose must be closed so you only get water that goes thru the zone piping to exit at the drain valve. this water pressure is what is forcing the air out of the pipe.



    Try to imagine just one of the zones at a time. Red arrows indicate no flow green arrows indicate flow the water fill valve on the red pipe (top left) is water pressure from your house. if the valve is open the pressure will cause water to flow in until it hits a reason to stop, like a closed valve.
    Now, by opening only the valves that will allow the water to flow thru the problem zone (the upper zone in the picture) and closing the valves to the other zones (represented by the lower zone) by closing all the other valves. water can only exit the system by the drain valve that is open. Bu closing the valve just below the drain valve, the water cant short circuit thru the boiler and out the short way.

    I hope this illustration helps.

    So, zone valves or other valves closed will do what you want. But the zone valve for the problem zone must be open in order to let the air and water out. The zone valve can be opened by the manual lever. this way you are sure the valve is open.

    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
    SuperTech
  • HTM
    HTM Member Posts: 22
    Hello Ed - Your comments shift my focus to valves/zone valves as opposed to tstats. Let me know whether I am understanding your example, and everyone else's input, as they relate to open and closed valves for bleeding air from the problem zone. Also, thank you for everyone's patience. My father handled all kind of electrical and mechanical repairs around the house when I was growing up. I was the flashlight holding kid who often wishes he had taken more of an interest and learned more.

    Problem zone: Taco zone valve lever in "on" position. Brown handled supply valve closed. Red handled drain valve open.
    Adjust drain valve to maintain about 12 psig boiler pressure. Watch for air and water to drain until air bubbles are gone.
    Drain valve can then be closed.
    As a side note - with boiler not running, pressure gauge
    shows 10 psig. Is that considered normal?

    Other zones: There are four. Three are next to (in line with) the problem zone. The fourth is less visible in the photos. You can see larger diameter newer copper piping (1") added to far left
    end of the black pipe manifold and risers just above the boiler.
    A blue handled lever operated supply valve is just below a newer
    Taco zone valve (out of the picture) specific to the kitchen.
    Added to the system by previous owner. Not in the same line
    as the circulator serving the original four Taco zones, including
    problem zone.

    To keep these other zones closed, I was going to temporarily shift their controlling tstats to "off" position. If it's more effective to use valves to close off these zones, would sliding the zone valve levers to the "auto" position reliably do the job? Or do I temporarily close the supply valves below each of these four zone valves? While bleeding, the boiler would be pushing water
    against valves closed to all five zones. One problem zone with
    drain valve open.

    I know this is long winded. Hoping to cover all bases that come
    to mind. Thanks.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 2,188
    WOW. Sorry, I did not see this a week ago. Hope you have the problem solved by now.

    IF NOT

    1. turn off electricity to boiler and zone valves.
    2. open all zone valves with the manual handle. This way you are sure they are all open
    3. close all the brown valves
    4. connect a hose or put a bucket under the red valve on the zone you want to purge
    5. increase the boiler pressure to about 25 psi by lifting the auto-feed lever to allow more pressure in the system. (This higher pressure will force the air out of the system at a higher rate of speed because of the higher pressure)
    6. now open the red purge valve and let the water and air fast flush out.
    7. keep an eye on the pressure gauge to keep the pressure near 25 PSI. if you are getting over that put the auto-feed handle back to automatic. if you are dropping below 20 then close the red valve purge valve to build up pressure. your goal is to have enough force to move air from upstairs to go down the 3/4" pipe and come out the purge valve.
    8. if you stop the water flow and the air is still in the pipe... the air will bubble back up the pipe to the second floor. If you don't have enough pressure to force the air down the pipe, the lower pressure water will just flow by the air and the air will bubble up the pipe while the water is trickling down the pipe.

    You need to see it in your mind's eye. A fast gush of water will push the air in front of it. A slow-moving flow of water will just travel under the air leaving it in the pipe and cause you aggravation forever.

    9. once you have all the air out of the zone loop, then you can move on to the next zone and repeat. (if you need to do more than one)
    10. once you are finished with all the purging put the auto-feed valve back to automatic.
    11. allow the water pressure to return to your cold static pressure. Usually around 12 PSI
    12. Close the red handle valve you are purging once the pressure is back to normal.
    13. now you can put all the other valves back to normal... Zone valve handles to automatic, brown valves open, check that all the red handle valves are closed, let the system pressure settle at the cold pressure.
    14. Now adjust all the thermostats to the lowest temperature and turn on the electricity. No pump should be operating and all zones closed.
    15. Turn up the thermostat to 90° for the problem zone and wait to see if the heat circulates thru the loop. If yes, then turn down that thermostat and go to another thermostat and see that it also operates properly. Continue this test on each zone.
    16. once you have all zones verified, then set the room temperatures as needed and go have a beer.
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
    SuperTech
  • HTM
    HTM Member Posts: 22
    Ed - I saw your last post yesterday. Work sometimes takes me away for extended periods. Sorry for appearing to "disappear", especially given the extensive guidance offered. I am grateful for the help from you and others on the HH site. I've noted to friends how HVAC professionals on this site generously share their knowledge. Nice to see in this day and age.
    I did not have a chance to try purging the problem zone. Before I left, I picked up a couple of Delonghi electric, oil filled portable radiators to tide us over.
    Since returning home, I've noticed another zone with weak output, so there will be two zones to purge. I follow the
    principle of higher than static boiler pressure to aid purging.
    The PRV in my system has a thumb screw fast fill feature. An old paper tag wired to the valve reads "turn the thumb screw down tight" for fast filling or purging. I assume that means turning the thumb screw clockwise in order to obtain the pressure rise noted in your post. Was unable to confirm this with Amtrol. Their tech service guy I spoke with was not familiar with this type of fast fill, it not having been offered in many years.
    One other point concerning the red handled drain valve and the correct time to close it when more than one zone is purged. I am referring to items 9-13 in your Nov. 13 post. Presume it's required to secure first purged zone by closing its drain valve before moving on to purge another zone. Otherwise, water would continue to drain out of the first zone while trying to purge another zone. One hose at a time into the bucket. Am I understanding the procedure correctly?
    Also, do you recommend the boiler be shut off several hours allowing the water to cool down somewhat before attempting to
    drain/purge?
    Many thanks.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 2,188
    edited December 2020
    I have done this on boilers that are up to 180°F without a problem. the shock of the cold water entering the boiler system is not as bad as many on this site will make it out to be.

    If you have a boiler that is steaming and all the water is leaving the boiler... and it has not cracked yet... then you don't want to put cold water in that until the metal temperature has dropped below 150°,

    But cold water from a zone that is room temperature often is pumped into a hot boiler when another zone has already raised the water temperature. Just be careful because the water coming out of the purge valve may be very hot.

    To answer your question about closing valves before going to the next zone... You are absolutely correct. You want to make sure that the fast fill feature does not exceed the pressure relief valve pressure during the process. if it does the relief valve will discharge and you will have a mess to clean up. I know from experience. filling the boiler with the fast-fill and getting distracted doing something else often results in the relief valve discharge. then I run around trying to figure out what is going on and remember that I left the fast-fill engaged.

    After I correct that oversight, Then I clean up the water from my tools and the floor. Then get back to work on the purging process. and try to focus on just that. "Men and Multitasking, never a good combination" Quote from my wife
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
    HTM
  • HTM
    HTM Member Posts: 22
    Ed - Your wife is a wise lady.
    I was thinking of water temperature only as it relates to drain
    water safe handling. There's much more to get a handle on.
    1. Starting with fill water ....... If from the house supply, then it's coming from our well. Estimated winter water temperature maybe mid 40's. Is that the temperature entering the
    boiler? Should I try purge and fill when boiler water temp is on the low side? When the boiler hasn't run a few hours, gauge reads around 150 degF.
    2. When a zone is purged, is the drain water coming only from the lines supplying the zone? Our problem zone heats a few rooms directly over an uninsulated crawl space. Radiator supply pipes in this crawl space are not wrapped. Since the zone hasn't been operating, supply pipe and any baseboard water temp is low.
    Drain water temp also low, or does it become high by somehow mixing with boiler water?
    Thank you.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 2,188
    @HTM
    I don't recognize some of the terms you are using. specifically "Drain Water"

    Basic terms are as follows:
    Closed system: the heating system that includes the boiler the emitters (Radiators) and the pipes that connect them.
    Supply: Where the hottest water is in a heating system. it is the opening in the boiler where the hot water leaves. it is the opening on a radiator or emitter where the hot water goes in.
    Return Where the coldest water is in the system. The opening on the radiator where the colder water leaves the radiator. It is the opening on the boiler where the colder water enters the boiler.
    Boiler Drain this is an opening on a closed system where water can be removed. usually has a garden hose threaded connection so you can direct the water leaving the closed system to a place where it will be contained or discarded appropriately.
    Feed or Fill (valve or pipe) the place where a closed system is connected to the building potable water (domestic water supply) in order to add water to fill the system and maintain pressure for operation. This opening may be closed off to isolate the closed system from the "OPEN SYSTEM" of the building plumbing piping. A BFP is required by code to prevent water from the closed system from contaminating the open system
    Back Flow Prevernte or BFP A device that prevents the reverse flow of a fluid. Usually used to prevent contaminated liquids from a liquid handling system from reversing flow if the pressure from the source drops below the pressure of the target system.
    Open System A water system that is open to the atmosphere where water may enter and leave or the atmosphere can come in direct contact with the water in the system. A bathtub full of water is an open system. A Domestic hot water heater connected to the home plumbing piping is an open system because the water leaving the water heater will be discharged to an "OPEN" faucet or tap where it is degraded. The water does not return to the water heater to be reused. If there is a recirculation pump on the water heater system it is part of the "OPEN SYSTEM"
    Recirculation Pump Is found on many commercial snd some residential hot water systems. This pump is designed to move hot water thru the piping system to maintain a desired warmer or hot temperature in the Domestic Hot Water System so there will not be a long waiting time for heated water to reach the tap or faucet that is located a substantial distance from the DHW source
    DHW This stands for Domestic Hot Water. This is the water that is heated by a water heating devise or system. It is contained in an "OPEN SYSTEM" This is the water you will take a shower in or wash your hands with among other things.

    With an understanding of these terms, please repost your query.

    Thank You
    Merry Christmas
    Ed
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 2,188
    edited December 2020
    HTM said:

    Ed - Your wife is a wise lady.
    I was thinking of water temperature only as it relates to drain
    water safe handling. There's much more to get a handle on.
    1. Starting with fill water ....... If from the house supply, then it's coming from our well. Estimated winter water temperature maybe mid 40's. Is that the temperature entering the
    boiler? Should I try purge and fill when boiler water temp is on the low side? When the boiler hasn't run a few hours, gauge reads around 150 degF.
    Answer: Yes it is ok to purge the / add water from your well system to the boiler at 150°F
    Follow-up: The water may or may not enter the boiler depending on the location of the fill location and the purge drain location.

    2. When a zone is purged, is the drain water coming only from the lines supplying the zone?
    Answer: That also depends on the location of the valves in question. The idea of purging is to direct the high pressure of the well water system to the piping that has the air in it, then force that air (with the higher pressure) out of the piping, allowing the air to exit by way of the purge valve that is open to the atmosphere (or garden hose that is open to the atmosphere).
    ...Our problem zone heats a few rooms directly over an uninsulated crawl space. Radiator supply pipes in this crawl space are not wrapped. Since the zone hasn't been operating, supply pipe and any baseboard water temp is low.
    Answer: once you get the ar out of the closed system, then you will close the system to operate the boiler. Close the purge valve, open the isolation valve, and set the feed to automated or close the feed valve as your system is designed. The circulator pump will then gently force the flow of the heated boiler water from the boiler supply to the baseboard radiators. Once the boiler water is warm enough the baseboard radiators will start emitting the heat into the room. The water will drop in temperature as the heat is released into the room. The return water will be hot or warm to the touch but it will be somewhat lower in temperature than the water temperature in the supply pipe.

    I don't understand this statement
    ...Drain water temp also low, or does it become high by somehow mixing with boiler water?
    Thank you.

    In Dan Holohan's teachings, he often refers to "thinking" like the water or the air in the system. If you were water pressure entering a Tee fitting, which way would you go. You would take the path of least resistance. so if a valve is closed at one of the outlets of a tee fitting, then you can only leave the tee fitting by way of the other outlet opening. Keep following the flow until you get the air to move out of the purge opening.
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
  • HTM
    HTM Member Posts: 22
    Ed - Thank you for the much needed Basic Terms and your latest comments. You have gone above and beyond assisting me.
    I will review our supply and return piping. Back to you when I am better equipped to discuss.