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Wirsbo manifold gasket replacement & air purge?

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LilyM
LilyM Member Posts: 19
Hi there,

I have a 20 year old Wirsbo manifold system that provides radiant floor heat in the house. I noticed small leakage around the union connection nut (pointed by the red arrow in the picture at here ). The rubber gasket inside this nut is probably worn out and needs to be replaced. I have already ordered the new gasket.

However, I haven’t figured out the steps to refill the manifold to get the air out after the gasket replacement. Could someone with experience of this old Wirsbo system share some light?

Suppose I first shut off both levers on the upper line and bottom line (the two red levers shown on the right edge of the picture). Then I unscrew the leaky nut. I imagine, during this disconnection, I will lose some water that is sitting in the lower line/manifold - the horizontal section specifically, I hope the water level in the 8 vertical pipes and in the upper line/manifold won’t be affected. Am I right about this water loss? I can catch this water using bath towels. Then I replace the gasket with new one, and screw back the nut.

Now there are some air introduced in the lower manifold. Is it okay for this air to stay in the closed system? How to purge the air out? Any idea?

Thanks a lot!

Comments

  • rick in Alaska
    rick in Alaska Member Posts: 1,457
    edited December 2020
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    You should be ok doing what you described. I think your water loss will be minimal enough that it shouldn't be an issue. Just do it fast as you can.
    Did you try just tightening the nut?
    Rick
  • LilyM
    LilyM Member Posts: 19
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    Yes, I tried tightening the nut which didn't help and actually made it a little worse. That's why I suspect the gasket is failing.

    There is one thing I don't understand about the so called "closed" system. Is there a desired pressure maintained inside this closed system? If the leak had been around/undetected for a while, is the system gradually losing this pressure? Has the outside air sneaked in to take the place of the lost water, or has somewhere been automatically replenishing the water, or no refill has happened and the water in the system just lose pressure and start to flow slowly?
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,844
    edited December 2020
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    To get an idea of Static pressure in your system look at my earlier post here. https://forum.heatinghelp.com/discussion/comment/1634318#Comment_1634318

    This will give you an idea of what pressure you may find at different levels of your system.

    If you lose too much water and a loop or two become air-bound, you will need to purge air out of the loop. You can check this by turning all the thermostats up to 85° and let the floors get warm. (at least 40 minutes) Any loop that does not return hot/warm will most likely be air locked.

    To purge a loop

    Look for a purge valve at the end of the manifold opposite the supply or return pipe. it is indicated at the top left of the photo.


    This is where the water /air comes out, so connect a garden hose here and run it to a drail somewhere. A toilet will work fine but the water will leave a stain in the bowl.

    Now increase the water feed pressure to about 25 psi for the purge process. You can do this manually with 2 people or you can adjust the auto-fill pressure for the procedure if you don't have a helper.

    Now close the top manifold valve (red handle on the top left) and close all the manifold actuator valves by removing all the actuators (mark them 1 to 8 so to remember where they go when you are finished). Now you can open the purge valve and one of the actuator valves to let the water push the air from the problem loop. It may take a minute or two to push water thru 200+ feet of tubing. Do only one loop at a time. You may not need all the loops purged. Only purge the loops that have no heat in them.

    Once you have all the air out of the loops, close the purge valve and restore all the actuators. Open the manifold valve that was closed earlier (Red handle top right) and set the pressure back to 12 PSI on the auto-fill and remove water pressure from the system until the gauge reads about 12 PSI now operate the heat and see if all the loops have flow. You can check all the tubes at the manifold to see if they all return hot/warm to the return manifold.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • LilyM
    LilyM Member Posts: 19
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    Wow, thank you very much for all the details, Ed! I will go back to study your earlier post multiple times, it’s so educational! In the meantime, let me ask a couple more questions.

    It sounds like the purging process can take a while, and the amount of air might get introduced during this one gasket replacement might be okay. If I hire a professional to do this Job (just replace one gasket), there could be a great probability that he might also choose to skip the purge because it takes too long - am I right?

    I noticed two months ago that some of my actuators didn’t fully close the flow when thermostat instructed so. Retightening the actuator rings helped. But the serviceman also commented then that the manifold is old and it’s time to get it replaced. I have additional two questions here: 1) the new uponor manifold he quoted me seems to be plastic, is it really better material-wise than the current copper manifold? 2) if I end up to hire the serviceman to replace the whole manifold, purge is probably necessary, he won’t skip it, right?

    Thanks again!
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,844
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    On the gasket change, if you lose a minimum amount of water and get a small air bubble in a loop or two, the purge will be unnecessary. the pump should be enough to move the air thru the loop gradually until it finds its way to an auto vent (assuming there is one). On the manifold change, you will need all loops purged. So far you scored A+ on this exam.

    If more air is trapped on the gasket change it will probably affect only one or two loops. Those are the ones you will find having no heat returning after an hour or so of operation. Then you purge only those problem loops.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,844
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    Regarding actuators that don't close completely,

    1. The manifolds you have are solid brass. In the summer you (or someone else) can take them apart and clean any debris or build-up on the valves and just put them back. The tube connections are reusable.

    2. The plastic valves are plastic. They will also get build-up on them over time and depending on how the connections are made, (mostly one-time rings of some sort) you will need to cut them out in 15 years or so to do the same maintenance. This will make the tubing shorter and the new manifold may not fit. But that is the next guy's problem.

    3. Before you go to all that trouble, check that the actuators are not at fault. This can be done by swapping a "known good" actuator with one that is not closing completely. If the problem follows the actuator, then the actuator is the cause. If the problem stays with the same loop then that manifold valve is the issue. If the problem is resolved then don't mess with it. it's fixed.

    I believe those valves are closed when the actuator is fully released or completely removed. you need to depress the silver pin in the middle of the manifold valve to open the valve. to reduce the flow in a loop that may have less resistance, you adjust the actuator by loosening the actuator. You may have increased the flow on those actuators that were not screwed down all the way.

    It is probably fine, but be aware of your adjustment if you notice problems with overheating and underheating in some areas.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • rick in Alaska
    rick in Alaska Member Posts: 1,457
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    "I believe those valves are closed when the actuator is fully released or completely removed. you need to depress the silver pin in the middle of the manifold valve to open the valve. to reduce the flow in a loop that may have less resistance, you adjust the actuator by loosening the actuator. You may have increased the flow on those actuators that were not screwed down all the way."
    Actually, when the actuator rises up and the pin comes up, then the valve is open. On those actuators, when you see the colored ring pop up on the top, then you know they are open.
    I have found if you take the actuator off and dribble some light oil on the pins, and then bounce the pin up and down a few times, that it will loosen them back up and work ok. In the worst case scenario, you might have to replace the individual valves.
    Rick
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,844
    edited December 2020
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    Rick, You may be correct. That makes my purge instruction incorrect. In order to close the valves, you need to set the thermostats to the coldest setting to close all the valves, then remove the valves actuators one at a time to open each loop valve.

    @LilyM You will need to verify if Rick is correct. I'm sorry if my instructions are Bass-Ackwards, but it has been over 20 years since I last handled those manifolds. (I will file this under "He forgot more about Hydronics than you'll ever know")

    This is why it is good to put more than one head on a problem.

    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • hot_rod
    hot_rod Member Posts: 22,157
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    correct when the actuator is removed, pin up, the port is open.

    if you have a plastic cap, you can thread it down to close off a port manually.

    I need to check everytime to make sure i have this correct :)

    Second to a failed actuator is the stem sticking from dirty or scaling fluid.

    Here is an example of a rusty, sticking valve, and a disassembled version. I did lose the tiny snap ring :) that goes in the groove on the stem.

    You can get replacement o-rings at automotive or hydraulic repair shops, probably metric size.

    A few folks over the years have rebuild these actuator valves. The brass or stainless manifold body should last many years, and is either has rebuild valve stems, or rebuild them yourself.

    Top quality manifolds will have stainless steel stems. Some chromed brass, if the chrome is worn off, a new o-ring may not seal.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • LilyM
    LilyM Member Posts: 19
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    Hi Rick, you are right about the moving direction of the pin and its impact on the flow.

    Two months ago we found 4 actuators not completely closed as instructed by thermostat. We were able to fix two of them by re-tightening the rings, but not the other two. We tried the black caps, they were able to fully close the two loops. We figured the black caps must have generated greater force than the gray rings. So we tried inserting a small cardboard piece between the pin and the actuator, that fixed the problem. Thanks for sharing your idea of dribbling oil on the pins, we'll give it a try next time.

    Anyway, according to our serviceman, he thinks the ceramic disc inside the valve might have been worn out over the years, which is why he suggested us to get the whole manifold replaced.

    To me, the valves and the manifold look like one whole piece. I'm not sure right now if I can replace the individual valves and reuse the main pipe of the manifold, of course, I haven't looked at them closely yet.
  • rick in Alaska
    rick in Alaska Member Posts: 1,457
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    You can unscrew them and replace them. Unfortunately, that manifold has been discontinued, so they are harder to find. The only time I have had to replace them is if they start leaking out the stem, as I do not have time to try and change the o-ring, or to find them. They are also not cheap, but cheaper than replacing the whole manifold.
    You might try taking one out and just see if there is any crud stuck to the seal on them. You might just be able to clean it off and get them to seal properly.
    Rick
  • LilyM
    LilyM Member Posts: 19
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    Thanks all for the replies! I’m reading them multiple times to digest the info!
    I took a picture of my end cap with purge valve. I have only one of this kind, on the left end of my upper manifold with isolation valves. The other manifold on the bottom is valveless and it has a plain end cap. I’m trying to understand the purging process Ed mentioned.

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,844
    edited December 2020
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    The top is known as a coin air vent. used on old cast iron radiators to vent the air manually. The small "pin" is actually the opening of the valve where the air/water will vent when you open the valve with a coin or key https://www.supplyhouse.com/Matco-Norca-CK-100-Coin-Key-Air-Valve-Nickel-Plated

    The "missing valve handle" is not actually missing anything. There is a slot for a screwdriver to open and close the valve. A 90° turn should be fully open.

    example of slot operated valve:

    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • LilyM
    LilyM Member Posts: 19
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    You’re a great teacher, Ed! I’ll come back with more questions on the purging process later :-)
  • rick in Alaska
    rick in Alaska Member Posts: 1,457
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    I can't tell by the picture, but if there is a protrusion on the cap on the drain line, you will find it has a square "socket" inside that is used to open the valve. Just take the cap off and turn it over and use it to open the valve.
    I am still pretty sure you won't need to do any bleeding though.
    Rick
  • LilyM
    LilyM Member Posts: 19
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    I opened another wall panel where the manifolds there are better accessible and I took some more pictures of the purge end cap. The top looks like a nut, can it be screwed off counterclockwise using a regular wrench? Once off, would water or air coming out of the top during the purging? The center of the top is a square shaped brass column, do I need to do anything to it?
    I just want to understand how things are supposed to behave. I have no plan to bleed the system. Rick, thanks for confirming that if I just replace one gasket!

  • rick in Alaska
    rick in Alaska Member Posts: 1,457
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    That top silver piece with the square fitting inside is the air vent. Do NOT unscrew it! It uses a special tool that fits the square head. You loosen the screw a little bit and if there is any air, it comes out of the little round fitting with the hole in it that is pointing toward you, on the side. The drain/ purge valve on the bottom of the manifold has a cap on it that sometimes has that square head tool as part of it.
    Rick
  • hot_rod
    hot_rod Member Posts: 22,157
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    The key looks like this, usually zip tied to the manifold when shipped.
    A small vice grips can also work, the long pointed nose type.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • LilyM
    LilyM Member Posts: 19
    edited December 2020
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    Thank you very much, Bob, for posting the pictures of the isolation valves and the special key! I haven’t seen this special key anywhere in my house.

    Glad I posted pictures and asked about this air vent. Thanks to Rick again for the detailed explanation, otherwise my first impulse would go unscrew the silver piece if I choose to do the bleeding.

    There are two boilers in my basement mechanic room. Each one has a gauge, one shows 14 psi, the other shows 22 psi (at another time I saw one at 12 psi the other at 24 psi). There is a pressure reducing valve (FB-38) nearby, its lever is rest at the auto-fill position (note there is no gauge associated with FB-38). Next to it, is a backflow prevention valve (Watts 1/2” 009 QT RP).




    None of my manifolds is in the mechanic room. They are scattered around the house, 5 in total, each behind a wall panel. The leaky manifold is behind a wall panel on the top floor which is 21’ above the basement boilers.
    Behind each wall panel, only the upper return pipe has an end piece with a purge/drain valve, the bottom pipe has a simple end piece, as in the photo below.

    If I’m going to bleed this top floor manifold panel, I’ll follow these steps as Ed suggested:
    1. Connect a garden hose to the purge/drain valve, drain the hose somewhere. Assume I have already put on the missing tiny red handle (borrowed from another panel) to this drain valve.
    2. Shut off the upper return pipe (the big red level on upper right corner of my original photo).
    3. Send a helper to mechanic room to raise water pressure to 25 psi - but how to do that? Lift the lever of FB-38 to “fast-fill” position? Note there is no gauge associated with it. How do I know its pressure?
    4. Cap off (close) all loops except the one I’m going to purge.
    5. Turn on the tiny red handle of the purge/drain valve.
    6. Wait until no air bubbles coming out of the garden hose, then turn off the tiny red handle.
    7. Repeat step 4~6 to purge the next loop.
    8. After all loops are purged, get the helper in the mechanic room to revert back the water pressure.
    9. Turn on the upper return pipe (the big red level on upper right).
    10. Disconnect the garden hose. All done!

    In this process, do I need to do anything to the square air vent, that is, use the special key to unscrew it a little bit? If yes, when to open & when to close it?

    Again, thank everybody for your expertise! I have learned quite a lot from you.
  • hot_rod
    hot_rod Member Posts: 22,157
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    If in fact you do need to purge, I suspect you may not? You can purge with the fill valve set at 12 psi, just do a loop at a time.
    many times when you move those valves to fast fill they tend to not want to regulate again, accurately.
    When you do replace the fill valve, the Caleffi Autofill is always a fast fill valve, set the pressure you desire and it fills at 5 gpm. Set it to 12-15 psi and walk to the manifolds and purge.
    valved properly you should be able to do all the purging in the mechanical room, don’t bother with manifold purging
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • LilyM
    LilyM Member Posts: 19
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    I have no plan to purge it right now, just try to understand the steps in case I need to do it in the future.
    It sounds like as long as both gauges of my boilers stay above 12psi I don’t have to mess with my FB-38 fill valve. That’s good for me to know. The fewer items to touch, the more comfortable I will be.
    As for the square air vent of the purge/drain valve, I think I should open it before purging the 1st loop (at step 3.5) and close it after all loops are done (at step 7.5). I’ll shop for that special key.
    Thanks to everyone for chiming in! Learned a lot here!
    Happy New Year!
  • LilyM
    LilyM Member Posts: 19
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    Hi there, I replaced the gasket tonight, I didn’t purge the panel, the leak is fixed now. However, I lost about one cup of water in this process, now there is water bubbling sound inside the manifold pipe. The bubbling sound currently stays near the gasket I replaced (the air is currently trapped in this section), I don’t know if the bubbles will travel to other places over time or not, such as, loops of this panel, or even to other panels. If I open just the air vent (without connecting the garden hose to the drain valve), will the trapped air come out from the air vent?
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,844
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    Depending on how the near boiler piping is designed, that air may eventually get adsorbed into the water as it circulates thru the system, then get vented out at an automatic air vent in the boiler room...OR... the air will find its way to a loop and cause that loop to reduce or completely stop heating. If the latter happens then you will need to purge it.

    @hot_rod ... That is an awesome radiator vent key. As I said before you have really cool toys!
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • LilyM
    LilyM Member Posts: 19
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    Can the air travel to other panels? I have 5 panels in the house, located in different places. It’ll take a while to track down which loop/panel needs to be purged.
    Is the air vent bleeder key interchangeable with the fireplace gas valve key?

  • hot_rod
    hot_rod Member Posts: 22,157
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    I'd close all but one port on the manifold, let the circulator push a good, high velocity flow, that should purge all the air. Maybe one loop at a time that way.

    Is there a good microbubble type purger at the boiler? That would catch any air that goes from the tube or manifold into the boiler piping.

    What pressure are you running? Sometimes you can temporarily increase the fill pressure to rid a pesky air bubble. The increased pressure squeezes the bubbles smaller and the flow moves them back to the boiler air purger.

    Remember to drop the pressure back down to the expansion tank pressure, or where you started.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream