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1

If you are measuring the pressure inside the duct, before the diffuser, the pressure should be detectable. The velocity pressure is given by Pv = pV^2/2 where Pv is velocity pressure, p is the density and V is the gas velocity. Taking a wild guess at a velocity of 5 m/s, gas density of 1.29 kg/m3, then Pv = 16 Pa The static pressure should be equal to ...


0

The brace you refer to was probably put there to keep the house framing square until all exterior sheathing was installed. The sheathing now serves as bracing long as it was nailed to code. Cutting a notch in the bracing seems a fine alternative long as you inspect lint buildup in venting at regular intervals. After the install you can put hurricane straps ...


0

Although the installing contractor should perform load calculations and make recommendations based off your existing conditions (like iLikeDirt stated), a mechanical engineer can also provide the services you seek, but will likely charge more than if the contractor were to include it in his bid.


0

I would remove the register and pour ready-mix concrete into the channel to seal the old "ducts" and fill up the hole in the floor. Shouldn't cost you more then $20, if that.


9

In theory this is what HVAC professionals are supposed to do. In practice, most of them rely on antiquated rules of thumb to size equipment and use existing ductwork, even if it has major problems. A certified energy rater is who you're looking for and who will be able to definitively tell you what you need to know, but you can learn a lot yourself to be a ...


0

2nd vote for having the service guy fix the pipe. He has a bag of tools and couplers all the right size (you won't find what you need at Home Depot), and will have done this kind of thing a couple of hundred times. Your main expense will be the service call and the gas, they might not even charge for the 5 minute repair. Don't touch it with solder - solder ...


0

If you're going to pay and HVAC tech to refill the system for you, then why not have them do the copper repair, too? But why an HVAC tech? Call a refrigerator repair company.


1

The fan in an air handler is typically stated to have a flow rate at a given static pressure (e.g. page 7 of the Lennox CBX25UH air handler specifications here). In my experience, almost all pressures in HVACR are stated in terms of gauge pressure; as you suspected, 0.5 in w.c. is a gauge pressure (generally noted as in w.g.). Some fan flow rates are stated ...


0

No, not really. The work you're describing doesn't sound remotely cost-effective, or effective at all for that matter. Running a huge duct from the basement to the attic will choke off the airflow. Not to mention that if you're going to to that, you're already doing half the work necessary to redo the ductwork properly to connect the two zones. It sounds ...


1

The Tee was left open as a means of a clean out. Start by using a shop-vac on that Tee and hold your finger over the other end, in the pump (you may have to get the pump out of the way). Next, snake it out, going into the machine: (e.g., the brush that comes with an EZ-Trap; johnstonesupply.com) Followed with another vacuuming. Ideally the first go ...


0

The hard part actually isn't pumping down the vacuum on the AC, the hard part is recovering the refrigerant. Auto parts stores will loan you a vaccum pump that will work on a house AC, but this won't allow you to recover the refrigerant. Recovering the refrigerant requires specialized equipment that's quite expensive. Discharging the refrigerant to the ...


1

Unless you are an abnormally equipped layman, no. Even then, there may be a legal requirement (depending where you are) for this to be done by a licensed A/C service person, as regulations around refrigerants have become much more stringent over the years, trying to limit uncontrolled releases to atmosphere.


0

Sometimes if the pipes are frozen might cause this. just turn it off for couple of hours (at least 3), and turn it again and see if this well help. AC INSTALLER.


0

The difference between the setpoint and the activation temperature is called the "Deadband". 3° F is not uncommon for generic thermostats. Your thermostat probably calls for cooling at 79 and runs until it's at or near 76, right? This is its strategy to prevent turning the AC on and off too often, which is called "Short Cycling" and causes increased wear ...


0

Check that the coils aren't frozen. Also look for water clog in the drip pan. Or could need a shot of freon. Where are you located? Is the problem new? Recently working suddenly not? Has AC been on a lot lately?


0

The schematic image you've attached is difficult to see, so I can't say for sure. Based on the wiring, I would say that the B terminal would work as C. Since I'm not there and can't test things, I have to make some assumptions. Based on the wiring, it looks like the one cable goes to the thermostat and another goes to the outdoor air conditioning unit. ...


1

I think the outdoor unit fan turning off while the AC is still running is normal - I know that happens quite often in my own home (and my previous home), and the AC has always worked fine. As for the temperature, how new is your thermostat? In my current house, I have a thermostat from about 30 years ago (one of those dial-style thermostats), and while it ...


2

Mine was freezing over and not cooling the house. I had recently replaced the filters so I made sure all the vents were open. I noticed there was no airflow so I checked the A/C coil up in the attic... I pulled the panel off and it was completely blocked by lint. I used a wide vacuum brush and sucked all the crud off and now there's airflow again and the ...


1

After checking with the building maintenance, the super said, because the building's main system is in "heating" mode and haven't switched back to "cooling" mode, the HVAC will automatically override and turn off the compressor. The building officially switched to "cooling" mode yesterday and my HVAC is operating as normal again. As it turns out, it is the ...


1

A MERV 13 filter should not let much if any pollen get through. If you still have pollen getting past, it is likely leaking around the filter. I would check that the filter is secured tightly in the HVAC system and that there is no place for air to bypass the filter. To increase filtration of existing plain filters, you can also spray it with a tackifier. ...


1

You'd need an air-handler somewhere downstairs, taking up the same amount of space (and nearly the same cost) as a furnace. I can only assume that the increase in efficiency is due to having the unit being within the building envelope, instead of on the roof. Do a full, new split system downstairs. I might endeavor to have the old unit remain as a back-up, ...


2

Is this a heat pump with supplemental gas heat? Sounds like the shuttle valve is stuck or something in the cycle reversing has failed, heatpumps do both AC and heating. Why double the misery by having two systems to fail and not having the current one repaired/replaced? As to new systems, you can get very efficient heat pumps with supplemental gas heat, ...


0

Having a take-off at the end of the plenum doesn't allow the other take-offs to maintain equal pressure - the end take-off will steal all of the airflow because it has a straight exit path. This doesn't allow the plenum to pressurize as effectively as when the direction of the airflow is impeded. You can actually visualize this by taking two styrofoam ...


1

IMHO: I don't believe the position makes any difference. The pressure in the main duct, for all practical purposes, is uniform. There is a slight loss at each exit duct along the main duct, but the original main duct should have been designed to handle this. However, if you added the duct to the end of an existing system, and the duct is comparatively too ...


0

Something similar happened to my gas boiler. It was a problem with the ignition electronics. Every night, when the thermostat was lowered, the circuit board would cool down and a solder connection would come loose. Sometimes the board could be wiggled to make the connection again. Eventually I opened it up and identified and fixed the loose solder ...


4

It should be fine. Air conditioners remove heat and dump it outside; sounds like the heat got dumped into the cover. Remove the cover, let the unit cool down, and don't do it again. If it stops working, call a service tech.


0

Nest states their thermostats do not require a Common 24 volt leg of control power to be provided to the Nest, However there are some situations where the Nest will not stay charged after a bit thus requiring a Common leg of the 24 volt power sent to it, they allege the Common leg back feeds to the thermostat by unused circuits and it does in many if not ...


0

In the heat mode the larger copper pipe going to the AC unit outdoors should get very hot, if not then the refrigerant might be low or the reversing valve which switches modes from Cool to Heat may be bypassing. the fact it shuts down tells me its getting overheated likely due to low refrigerant level.


0

Your pictures have no 24 volt wires going to an AC unit, you show 4 wires at the stat and the 4 wires at the air handler with the G jumped to Y and the Green wires used for Common that looks ok, but nothing from the air handler to any AC unit outdoors as in Yellow and Common. You have a direct short in heat or cool modes yet for cool mode nothing is ...


0

The thermostat you posted has no Common terminal the blue wire that should be wired to Common at the thermostat is cut of and wrapped around the harness. You show Red, White Yellow and Green wired to R,W,Y,G terminal on the thermostat, but there is no Common terminal on that thermostat and the blue wire that should be wired to Common is unused at the ...


0

If the outdoor fan comes on and the compressor does not, you need a "hard start kit" this is either a potential relay and start capacitor as in my diagram or a PTC thermistor solid state start assist device that piggy backs onto the run capacitor. This is assuming your compressor is cold to the touch and has not been starting. If your compressor has been ...


0

n here]1 This is a Heat Pump wiring diagram, if you only have an AC unit then the AC unit outdoors will only require the Yellow and the Common wire as far as the 24 volt control circuits go. Common is the side of the 24 volt control circuit that every 24 volt circuit returns to, to complete the circuit, this is why it is called Common, cause every circuit ...


1

You could always put some sort of planter box in front/over it, like an upside down window valance. Something like a brick planter box


2

Give the ivy a few more weeks, and some compost to help it along. Wrap the bundle in a mesh to give the ivy more purchase. or put a short section of trellis in front of the bundle/wall for it to grab onto. Disappearing bundle, like magic. Shrubs if you feel you must, but given the ivy is already working the area, let it work.


1

There are a few options. You can get some brown gutter downspouts, cut out the back end and mount it over the pipes. I think the downspout will look better versus the gutter because of it's uniform shape. This is commonly done in my area but it is installed at the same time as the pipes so that the pipes can run through it without having to cut the ...



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