RobC

MJ clamps have been around for a very long time. With a DWV designation, they can be found throughout the plumbing system, in drains, waste and vents. They can be very helpful in renovations in the transitioning of different size and composition pipes such as cast to plastic, copper to plastic and even cast to cast where a coupling is not available. I remember combing the city for the better part of a day looking for a 5x4 to connect a 4" ABS line to an existing 5" clay line without that coupling I would have been in deep trouble. Personally, I would have used an ABS/Copper coupling and changed the trap arm and P trap to ABS cuz I like plastic and the parts are readily available. I'll guess that the basins were upgraded and the location of the new tail piece didn't line up with the old drain system so the owner either didn't know about the coupling or was given unprofessional advice at the big box store. Regardless, I would call the repair permanent but unconventional something I wouldn't loose sleep over.

That would be a concern with Chicago winters. I don't think I've ever seen a stack 4 or 5' above the roof, but besides that, correcting this won't be easy. Not necessarily, if the attic is accessible, I'd relocate the vent down wind if there's such a thing and then connect it to the sewer stack. Remove the old flashing and patch the hole...voila! In the first place, that vent doesn't look right to me. Did you take your mirror and look inside and around the flashing?

Over extending a stack vent can create a frost closure condition and affect appliance performance.

.......and a missing clean out

Upstream or downstream of the trap?

I don't want to leave folks thinking that I'm suggesting the size of the ducting is inadequate. What I'm referring to here is the method in which the return was channeled through the framing, particularly to the second floor. Second floor returns are problematic and can sometimes take a lot of jogs and turns that are unseen until the walls are opened. While I'm on the subject Gary, you might want to test the returns on the second floor with a sheet of toilet tissue. Get back to us with your results.

Hi Gary, If I understand this correctly, your furnace was shutting down on high limit in December, so you hired a 'Tech' to offer a remedial course of action a few days ago. His advise was to replace the furnace cuz it's too big. [:-bigeyes Is work that scarce that trades have to resort to that? My first advise to you, DO NOT sign anything until we have this little discussion. The size of the furnace has NOTHING to do with high limit switches. The size of a furnace is determined by calculating heat loss of a building. It considers such things as size of house, type of construction, insulation levels in walls and ceiling, type and location of windows-sliders, sealed or casement, house orientation and exposure and the list goes on. Once we know how much heat the box looses then we can determine the amount of heat required to keep the box at an acceptable level at a specific outdoor temperature. Or We can rely on historical experience and make an educated guess as to size. So for us to opine on your furnace size is absolute folly, we neither have the information nor the experience to advise you. In my market, I would expect to see two furnaces in a home that size. The main floor/basement around 90MBTU and top floor 75MBTU with the possibility of a small radiant system for the basement floor. The high limit switch is a safety device that protects the furnace from running wild. It shuts off the gas valve generally around 200 degree F to prevent the furnace from overheating and causing a possible fire. It has NOTHING to do with size of furnace or house. Assuming the safety switch is functioning properly, the causes are generally a blocked passage in the throw and return loops in the form of: Blocked returns- undersized openings, carpet or flooring in the return, convoluted pathways etc. Dirty air filter Contaminated A/C coil (evaporator inside the furnace) Blocked heat runs Closed register dampers From my experience I'll bet the A/C coil is plugged with drywall dust. Here is my recommendation to you. 1. Determine if the switch is in fact ok. Find a hole in the heat plenum near the appliance and insert a probe cooking thermometer, turn on the furnace and observe the temperature as it rises. If the furnace shuts down on high limit (200 degree F) then the switch is doing its job otherwise get back to us with your observation. 2. Search out the cause of the blockage from the list above. There is a product that is specifically designed to clean A/C coils. It comes in a large spray can that dissolves crud without scrubbing the coil. If you want to go one step further you can also buy a special 'comb' to loosen difficult residue. However, DO NOT touch the coil with your fingers, it damages easily. If you don't feel confident with that, hire it out. 3. Repeat No. 1 and hopefully that will make the switch happy. Good Luck,

How about if you delete this post and start another thread.

Hi Randy, Here's what my decoder ring is telling me. Expect more frost Your flags are not telling you anything Your furnace has nothing to do with the 4" 'vent' Your clothes dryer has nothing to do with your furnace Run this test Remove the 5 gal pail and hold a paper towel under the 4" 'vent', under the following conditions: House static-no fans running that includes the kitchen hood and water heater. Dryer on Dryer on and kitchen hood Get back to us with the result But not so fast, I need you to come back with words like combustion air, fresh air and hoods. And where exactly are the icicles (picture). Am I giving you a hard time, you bet cuz you need to understand the mechanics of what's happening. Unfortunately, I won't hand you a fish but I'll be glad to give you a fishing pole.

I'm surprised we're recommending Noalox as an oxide inhibitor. Click to Enlarge 24.2 KB 38. Other brands, including the one, NOALOX made by Ideal and used in their #65 connector, ignite readily and burn vigorously.

Static electricity would be a concern.

As a Masters Electrican/Control Tech, perhaps you could tell us.

The 'box pattern' refers to the way it squares off to the wall as opposed to terminating into a smooth curve. I use the box pattern if I have a choice, they have nothing to do with couplings.

Over sized in what way? How does a direct vent furnace blow up? I don't believe for one minute, that you screwed up, there is more to this story...care to elaborate. You're not running some kind of covert psychological response subliminal test...are you? I know it's only Tuesday and all. [:-paperba

So what did you tell your client?

I have both Use both

Yes you will and that's the reason we want to remove insulation from the VR to keep the pipe warm. Condensation will occur on windows but I've never seen it on FA/CA Flex. Nearly every home in the Calgary and surrounding areas I inspect have this system without condensation. Remember, if the pipe, the VR, is exposed to indoor air it will remain warm enough to prevent condensation. As we speak, my humidistat is set at 40% and my office reads 54%, window are clear.

Hi Randy, Let me say the last thing you need at the moment is an HRV. In simple terms an HRV is a complicated system added to your FRESH air duct. In light of your past experience with your HVAC contractor I'm guessing they wouldn't have the expertise to install it right in the first place. Save your money and further aggravation, besides your problem is NOT related to improving fresh air efficiency. But, I have a concern with this photo Click to Enlarge 38.44 KB There is clearly condensation on the flex vapor barrier which would suggest the moisture is coming from the inside of the house and not from inside the pipe leaking out. What has me concerned is the presence of the additional insulation, the white fiberglass insulation, I suspect you peeled back to expose the duct. By adding insulation over your vapor barrier, you've effectively tampered with the location of the dew point. A vapor barrier MUST be on the warm winter side of the envelope. Here is what's happening. Mother Nature Rule No. 14. - Warm travels to cold. As warm moist air moves across the insulation toward the flex, its temperature drops. And as the warm air cools, it also looses its ability to hold water vapor. Somewhere in the gradient (insulation) the vapor turns to water or condenses, that point is called the dew point. The function of the vapor barrier is to prevent warm moist air from reaching the dew point. We don't want warm moist air at the dew point. By adding insulation you've effectively placed the vapor barrier beyond or downstream of the dew point, if that makes sense. In other words the vapor barrier is now on the cold side of the envelope. I would suggest you expose both ducts by removing the additional insulation and make the necessary repairs to the plastic and duct insulation, the silver pipe. The exterior wall connection is equally important and I'd bring the plastic as close to the wood framing (rim joist) and foam them in place to seal any air leakage. With regard to your comments above: You DO NOT need more insulation, you need LESS You DO NOT need an HRV You DO NOT need new ducts, the one you have are just fine. You DO NOT need caulking at the exterior You DO NOT need to service your exterior hoods, they're ok. You DO NOT need to shut off your humidifier, it has nothing to do with your problem. 40% RH is normal. Let us know how you make out.

on medication

Dew point can occur at any temperature dependent on RH Not sure how an HRV would solve a leaking fresh air duct.

I have to agree, you do have a 'choice' system and you shouldn't have moisture problems. Let's take this one step at a time. You have two corrugated pipes that should be insulated and wrapped in black plastic (vapor retarder). One pipe is attached hopefully to the return plenum called a 'fresh air' duct. This duct provides fresh air for the occupants. Judging by its size you must be referring to the other pipe, the 4inch one. This duct provides combustion air for possibly your two water heaters, boiler or another gas burning appliance, it's called a 'combustion air duct'. Here is what you need to check and then get back to us for more problem solving. 1. Determine exactly where the leak is coming from. 2. Check both ducts to ensure the black plastic is completely sealed, especially at the joints. Any warm moist air will condense on the cold pipe and cause a drip. 3. Make sure the pipe is continuously insulated and the straps are not too tight. 4. Locate the intake hoods and determine if they are exposed to wind driven snow. How far above the ground are they? Submit a photo. If the moisture is not coming from condensing warm inside air, then it must be coming from outside. Additionally, where is your humidifier located, directly on top of the furnace or on the other plenum? This is unrelated to your problem... just curious. Finally, measure the combustion air pipe, it might be 5 inches and not 4. Visit a big box store of your choice and get a combustion air termination fitting. The ‘boot’ contains the cold outside air and prevents it from dumping or flowing freely. It's inexpensive, around $35.00 and you can do it yourself.

Now that's scary. Your time is very much appreciated Thank you,

hamsters..aquariums.....and Loki

I don't have to read any further than this. What is Ozone? Ozone is a molecule composed of three atoms of oxygen. Two atoms of oxygen form the basic oxygen molecule--the oxygen we breathe that is essential to life. The third oxygen atom can detach from the ozone molecule, and re-attach to molecules of other substances, thereby altering their chemical composition. The words 're-attach and altering their chemical composition' would scare me enough to advise you to consider an alternate method of air filtration. I wouldn't rely on recommendations from the Chinese or the EPA. The RGF device purportedly does its job while keeping the ozone level below the danger level of .05 ppm. But . . . of course how can they know that will occur if they aren't calculating the cubic footage, air changes, etc.? The unit is currently unplugged till I find the time to perform more research. It does/did work like a dream. That's a dangerous thing to assume. What if the sensor fails? If the sensor is at the unit and shuts off at limit of .05ppm then what is the actual reading in the living space. Furthermore, who determined that the danger level is .05 ppm....the EPA!@#$@#? I don't need anything altering my chemical composition..thank you...at any ppm. Then, what happens when the third O molecule is floating around and can't find anything to 'alter'? Does it loose interest (self destructs) or does it keep on searching for more stuff, like occupants, hamsters..aquariums..... Question is: What is the life expectancy of the third O molecule? There is no question the use of ozone for disaster restoration work has proven very effective. But I don't see its application on a continuous basis in an occupied residence. I like the switch/timer idea as mentioned above, however, before doing that, you should answer the third molecule life cycle question.

I don't have a problem with deodorizing vacant houses. It's the occupied ones I'm talking about.