Baseboards hot but thermostat disconnected

Discussion in 'Boiler Forum' started by bentz69, Nov 14, 2018.

  1. bentz69

    bentz69 New Member

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    Hello everyone.

    I will try my best to explain the situation but please bear with me since I really dont know much about boilers. If I leave any important information out then please tell me.

    To start, I moved into a new home over this past summer. I have a older Burnham boiler that uses oil, has 3 heating zones (basement, 1st floor, 2nd floor) and heats the hot water. I turned on the heat in every zone about a month ago to make sure all the baseboards in the house were functional. During this time, I heard a lot of gurgling coming from a few off the baseboards. I figured there was a lot of the air in the pipes so I needed to the bleed the system. Fast forward to several days ago.

    I turned on the heat in each zone at the same time and waited about 20 minutes to get everything hot. I started with the basement zone, then the 1st floor and finally the 2nd floor. I connected my hose to the drain for the basement zone, closed the valve before the pump then opened the drain valve to let the water out. For each zone I needed to open the fill valve to allow more pressure. Each zone was done the same way. byt BTW, there are no zone valves on this system. There was a lot of brown/black water and substantial amount of air coming out the of the hose for each heating zone.

    When I was done bleeding each zone, I noticed the water pressure was almost 30psi. Since the hose was still attached to 2nd foor zone, I opened the valve to allow some water out to lower the pressure and I set the water pressure to the same 21psi that is was set to before I bled the system.

    So heres my problem that I never noticed before. The second floor has 4 bedrooms and 2 bathrooms. The 2 baseboards in my bedroom and the 1 baseboard in a seperate bedroom are constantly warm/hot no matter what. All the other baseboards are cold. At first, I thought the thermostat went bad so I completely removed it from the wall. That didnt work and those same baseboards are still warm. Then I figured something happened to the pump. I connected the multimeter to the pump but its not pulling any volts. So its definitly not running. The only way I can stop these baseboards from giving off heat is to close the valve on the rear of the boiler that goes to the second floor.

    I dont understand how these baseboards can be giving off heat if there is no thermostat connected and the pump is not running. What is pulling the water through the pipes?

    Thanks for the help

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  2. NY_Rob

    NY_Rob In the Trades

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    Sounds like your flow check valve for the problem zone isn't closing and you're getting "ghost flow". I don't know which zone is which in your photos... but the bottom photo has a flow check valve in it on the left hand side. The problem zone should have a similar looking device. Sometimes rapping it lightly with a metal object will free it up. But it may need to be replaced.

    Not related to the flow check valve.... what happened in that basement to cause all that corrosion?
    Is it even safe to run that boiler? The exhaust venting looks terrible with rust all over the damper.
    I would have the whole system looked at ASAP!

    You do have CO and smoke alarms in the basement correct?
     
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  4. bentz69

    bentz69 New Member

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    I was wondering what that little fitting was in the bottom photo. Glad you told me. However, that flow check valve is for the basement zone. There is only one in the entire boiler room. Is it possible that these flow check valves would be installed elsewhere instead of the boiler room? Doesnt seem to make sense

    The wall area around the exhaust sometimes get water that leaks in from very heavy rain. Yes I agree the venting is bad and needs to be fixed. And Yes, I have a Co2/smoke alarm approximately 10 feet from the boiler room door as well as every bedroom in the house. Thank you
     
  5. Dana

    Dana In the trades

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    When other pumps on the system are active it causes back flow on any zone without a functioning check valve.

    Those green Taco pumps usually come with an check valve at the pump (that gets installed integral to the pump), and most of the red Grunfos pumps do too, but the installer doesn't always install them. The Grundfos driving the misbehaving second floor zone looks shiny-new, so I'm suspecting the installer tossed out the "FC" integral check valve, or that the valve is defective. It's available as a spare part for about $25 at internet stores (could be cheaper or more expensive from a local supply house) but be sure to get the right one.

    It doesn't really matter where on the loop the check valve is, as long as it's oriented correctly. I've seen seen systems with separate check valves on the return manifold, and pumps on the supply manifold.

    I agree with NY_Rob that the vent stack shows signs of copious exhaust condensation, which could be from operating the boiler at too low a temperature. If it's going into a masonry chimney without a stainless liner the chimney is at high risk of being damaged by acidic exhaust condensation, especially if the flue is oversized for the boiler's heat output.
     
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  6. bentz69

    bentz69 New Member

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    Thanks for the info Dana. A buddy of mine has a lot of experience with boilers and he is going to help me install 3 zone valves. Im sure that solve my flow problem.

    Regarding the boiler exhaust, yes its in terrible condition. This is the 2nd time in a week after heavy rain that water has started to drip out of that crack. Upon closer inspection this is what I found. I pulled off the entire exhaust from the boiler and removed it from the wall. As you can see then entire section of pipe in the wall was gone. If you see that picture with the red arrows, that is where the water is coming from. So to respond to comment Dana about condensation, I hope its safe to say that ground water leaking in is the cause of the pipe rotting away.

    I cleaned up all the dirt/debree etc and right now Im the process of fabbing up a new exhaust. Ill post some pics when Im done.
     

    Attached Files:

  7. bentz69

    bentz69 New Member

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    more
     

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  8. Dana

    Dana In the trades

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    I take it there is no stainless liner in the chimney. What size is the terra cotta flue liner, how tall is the chimney, and what is the BTU rating of your burner?

    It could be the case that chimney is leaking copious ground & rain water due to mortar being totally rotted out by years of excessive exhaust condensation.

    BTW: The pumps all seem to be oriented pumping toward the return side of the boiler. If it's a failed or absent check valve the pipe directly above the red pump would start to noticeably rise in temperature when either of the other pumps started running. If there is a lot of crud built up in the system a piece of grit could be keeping the valve from closing completely. Grundfos pump-integrated replacement check valves are pretty cheap ($30 from Home Depot), so if the symptom looks like a leaking or absent check valve on that pump it's worth having one on hand and seeing if installing/replacing the check valve fixes it before investing a zone valves. Zone valves aren't cheap, and they too can be kept open by crud in the system. It may be worth installing a crud trap /filter on this system.

    If the problem turns out to be forward convection due to the return side being tall and much colder than the supply side that's more powerful than the spring in the pump-integrated check valve that may be stopped by plumbing in a big U that drops at least a foot below the return manifold (or in your case, the pump) before connecting to the manifold (or pump.)

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    This diagram shows the pump on the supply side of the circuit in a primary/secondary plumbed system, but it's not any different if the pump is on the return. The deeper the U, the more effective it is.
     
    Last edited: Nov 16, 2018
  9. bentz69

    bentz69 New Member

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    There is no SS liner. Without getting on the roof, I would say the clay liner is either 8x8 or 10x10. A safe guess on the chimney height is 30-35 feet. I dont know the BTU rating of the boiler. The spec panel doesn't list the model number. Can you tell me what the "Jacket Length" is? Or the number of "Sections" so I can find out the model number to look up the specs? Check the pictures.

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    There is no water in the base of the chimney (the section that is even with the ground level) and the inside walls look dry. This is based on what I can see when I put a flashlight in there. I cant see upwards into the chimney though. The water leaking in was discovered when I removed the boiler exhaust. The water is coming from underneath the base of the chimney that is roughly 2 feet under ground level. In the picture below I made a red mark where I always had this gutter drain positioned. I just moved it yesterday thinking that the water was saturating the ground. The green mark is the approximate location of the boiler exhaust BUT another 18-24 inches lower. I hope this was the problem.

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    Yes the pumps are oriented to pump towards the return side. YES!!! The pipes directly above the pumps all get HOT when when one zone is on and the others are off. When I bled the system there was A LOT of brown/black water and sediment coming out. Since the previous home owner told me that he has never noticed the baseboards being hot when the thermostats were off, hopefully its safe to say that I clogged the valve when I bled the system.

    How do I go about cleaning out the pump? Does it have to be removed and disassembled?

    Great Idea. Any recommendations on brand/type and where is the ideal location to install it?

    This could be a cheaper option then installing 3 zone valves. However, if my problem is a clogged check valve, then perhaphs this method or the zone valves are not even needed?

    BTW, here a few pictures of the exhaust I built last night. My buddy told me that it wouldn't be a problem if I increase the exhaust size after the 90 from 6 inches to 8 inches. I did this take up more volume inside the hole in the foundation. That hole is 8.5 inches. I re-used the dampener that was from the original exhaust and did my best to measure the holes so the dampener reacts the same way.

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  10. bentz69

    bentz69 New Member

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    so for the longest time Ive had this little black plastic part in the boiler room and never knew what it was. :mad::mad::mad::mad::mad::mad::mad::mad:

    After I read the manual for the pump, I see this peice is the check valve that was removed from the pump for whatever reason. Hope this solves my problem

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  11. Dana

    Dana In the trades

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    The Burnham V8x series are all the same height & width, but as they add plates the depth from the burner to the back side gets deeper, the "A" dimension on p3 of the brochure.

    The nozzle model # in the burner would be another way to tell, which may be marked on a tag from the last tune up (?)
     
  12. bentz69

    bentz69 New Member

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    here is a picture of the tag for the last tune up. I dont know how to read it. I spoke to a tech at Armstrong Pumps and they said I shouldn't install the check valve in a system with hot water because the check valve is plastic and may deteriorate over time. That sucks. I Guess zone valves need to be installed instead

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  13. bentz69

    bentz69 New Member

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    Using the measurements tells me this model is the V84
     
  14. Dana

    Dana In the trades

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    The V84 can take either a 1.05gpm or 1.35 gpm nozzle. Per the brochure at a flue height of 15' the minimum size clay liner for that model is 8x8" independent of which nozzle is used, about 64 square inches but that's also good for up to roughly twice that burn rate. With the 1.05gpm nozzle it can get by with a 6" round (28 square inches), but wiht the 1.35gpm it needs to be 7" (38 square inches.) It looks like your flue is at least twice that high which will have stronger draw, but it's also on the exterior of the house, which delivers a lower draw (due being colder), but height still winds. With the taller stack you can probably do fine with a 6" round even with the 1.35 gpm nozzle, but the 1.05 gpm nozzle will be better, since it delivers longer burn cycles, raising the average temperature of the flue (and higher as-used efficiency).

    The tag indicates it's been down-fired with 0.85 gpm 60 degree B type nozzle (smaller than what was shipped with it when new) which has even lower BTUs, and with the lower temperature, slower stack velocity, making it more like the V83. in output. Even with the 0.85gpm jet it's still probably 2x oversized for your heat load, but at least it's not 3-4x oversized. This is good for efficiency, but increases the flue condensation potential.

    If the flue is a 10 x 10 or larger it's too oversized, delivering sluggish stack velocity, and more cold surface onto which the exhaust can condense, and would likely be suffering at least some condensation damage already. As the acids eat away at the mortar it becomes more porous, and will draw more rainwater into the chimney, accelerating the process. If it's any bigger than an 8x8 it's time to have the flue inspected and take corrective action. If the chimney is being destroyed from the inside by condensation, by the time it becomes apparent from the exterior it's too late, and an expensive re-build would be required.

    A 6" stainless flue liner would prevent that, stopping any further damage- any condensation would be on the liner, not on the masonry. If there's room inside the clay liner to pour loose rock wool insulation between the stainless liner & clay liner it will improve stack velocity even further, reducing the amount of condesate that might dribble down the stainless to attack your shiny new B-vent from the inside out.
     
    Last edited: Nov 19, 2018
  15. bentz69

    bentz69 New Member

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    Excellent information. That certianly explained a lot. I measured the flue and it is indeed 8x8. The tag lists the last service which was 2 years ago. I was planning on buying a new filter anyway and have my buddy swap out the electrode. He certainly knows his stuff when it comes to boilers but maybe I should get a professional out here to check everything. Not sure yet

    Regarding the stainless steel flue liner.....does this liner simply slide into the flue from the top of chimeny and gets connected to the boiler exhaust? If so, looks like a simple install. Is the insulation mandatory? I found this site real quick

    https://www.firesidechimneysupply.com/flexible-chimney-liner-kits.html
     
  16. Dana

    Dana In the trades

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    The 316Ti liners of the type used with wood stoves are legal to use for oil & natural gas flues, but AL29-4C alloy liners are more acid resistant and for that reason more commonly used for oil-burners, which has higher acidity than wood/natural gas/propane exhaust. It looks and installs about the same as other stainless liner types.

    If it's an 8x8 clay liner and it doesn't show any signs of exhaust-acid erosion with a camera inspection you can probably skip the liner. If it were a 10x10 or bigger there would be no question. I believe in MA a stainless liner is now required for ANY new oil-burner installation, not sure if that's the case in NY, but installing it just to be sure would be something of an insurance policy against having to rebuild (or demolish) the chimney if you stay there for another decade or three. The 8x8 tile liner is the manufacturer's specified size for an even smaller 0.60 0r 0.75 gpm burner, so you're probably OK.

    It's worth figuring out your oversize factor too. Down-fired to 0.85 gpm the boiler's output is ~95-100,000 BTU/hr. If your 99% design heat load is less than 55-60,000 BTU/hr (probably is) it's probably going to be worth installing heat-purging economizer control such as an Intellicon HW+ or Hydrostat 3250, bypassing some of the aquastat controls on the boiler. This is especially true since you have three separate zones on the system, none of which are likely to be able to emit the 95-100,000 BTU/hr of boiler output into the rooms. If you measure up your radiation zone by zone you can figure that out to a practical certainty. At an output temp of 180F it takes at least 50' of typical baseboard or 575 square feet EDR to emit the full 100KBTU/hr. If the major zones are a lot shorter than that the boiler will cycle on/off during continuous calls for heat from a single zone, and possibly even short-cycle. (Don't sweat the basement zone too much- they're always under-radiated, but there's enough thermal mass in the boiler to keep it from going nuts on short cycles.)

    To figure out the actual 99% heat load, if you're on a regular fill up service that stamps a "K-factor" on the slips and a ZIP code (for 99% temperature bin purposes) we can work backward from a few wintertime fill up K-factors. If not comparing local weather data against exact fill up dates & quantities can get you there using this methodology. So keep track and report back.

    Using only wintertime fuel use for these calculations reduces the inherent error from daytime solar gains which can be pretty high even in late winter/early spring, and domestic hot water use. Those errors tend to offset one another to some degree, but it's never perfect.
     
  17. bentz69

    bentz69 New Member

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    It has been about 3 weeks since I sealed up the leak with cement and Im happy to say there is no more water making its way through. I never sealed the section of the foundation wall where the exhaust enters through because I wanted to make sure the water wasnt leaking.

    Today I removed the exhaust and noticed a fair amount of flakes at the bottom most section of the chimney. Im assuming these are pieces of the clay liner that are flaking off? Does that sound right? When I removed the original boiler exhaust 3 weeks ago there, there was rather large pile of this flaky material on the bottom most section of the chimney. Is the clay liner starting to deteriotate? If this is material is the clay liner, what are my options here? Would a stainless steel liner be the best option now?

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    Swapped out the oil filter since its been 2 years and this is what I found...
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    Last question, is there anyway to adjust the barometric damper without a manometer? If not, how can I get it in the ballpark before I get a gauge?
     
  18. Reach4

    Reach4 Well-Known Member

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    Put clear tubing into a clear jar of water. The water level in the tubing will match the water in the jar at 0 WC. If the water in the tube is 3 inches lower, that is 3 inch water column of pressure. If it sucks 3 inches higher than the water in the jar, that is a 3 inch vacuum.
     
  19. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    You mentioned that the purge water looked grungy...that's normal. When you add tap water to fill the system, that water will have some dissolved oxygen in it. Lots of components in the boiler system are ferrous. That oxygen will cause rust. Once all of the oxygen is used up, the water itself is pretty inert. If your system leaks, constantly adding fresh water will cause continuous corrosion. the system should be well sealed with no leaks.

    The acidic exhaust will gradually eat away the calcium in the cement mortar, and damage the liner as well.
     
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