D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
(OP)
Blast. Goofed on the house furnace/HVAC filter the other day. Regular schedule said the filter didn't need replacement, thermostat timer switch said it didn't need replacement, but it was seriously clogged anyway.
(Painting nearby? Weld fumes in the adjacent basement? Painting upstairs that clogged the fi;ter with "wet varnish" that then trapped particles? Don't know. It was solidly clogged thoguh - way before we expected to replace it. We don't smoke, no fires, no fireplace. Odd. But the filter was solidly clogged.
Sop we needed a service call, nothing else to fix the heating problem. Regardless, I could have done it myself - should have done it myself, and saved the 89.00 fee.
Installing a d/p gage across the 16 x 25 inch x 1 inch filter would be easy, but what differential pressure is expected for a house HVAC fan? Alt: A vacuum gage on the fan suction side?
(Painting nearby? Weld fumes in the adjacent basement? Painting upstairs that clogged the fi;ter with "wet varnish" that then trapped particles? Don't know. It was solidly clogged thoguh - way before we expected to replace it. We don't smoke, no fires, no fireplace. Odd. But the filter was solidly clogged.
Sop we needed a service call, nothing else to fix the heating problem. Regardless, I could have done it myself - should have done it myself, and saved the 89.00 fee.
Installing a d/p gage across the 16 x 25 inch x 1 inch filter would be easy, but what differential pressure is expected for a house HVAC fan? Alt: A vacuum gage on the fan suction side?





RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
B.E.
You are judged not by what you know, but by what you can do.
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
For Diesel exhausts, I use them with a range around 50 inches of water, but they are available in much lower ranges, which are not correspondingly more delicate. I'd guess 5 inches of water would be all the range you'd need for HVAC, and still have sufficient sensitivity.
For only a little more money, Dwyer offers Magnehelics with relay contacts that you can use to light an LED. You could probably power such a circuit with an AA cell or two, and not have to change the cells more often than you change smoke detector batteries.
Mike Halloran
Pembroke Pines, FL, USA
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
Suspected a bad thermostat in the 3rd stage of the house (upstairs = 1, basement = 2, upstairs back bedrooms = 3.) That didn't work either. To run the heater for a while, turning it off completely did let it turn on a run for awhile, but that was only because by turning it off manually with the power cutoff switch, I was -resetting the HVAC controller completely. So that reset the high temperature alarm condition, which let the fan and controller restart the furnace heater. After a while of heating, the clogged filter closed off too much air flow again to the fan suction, which overheated the furnace, which alarmed the controller, which promptly and correctly secured the burner.
My fault. Did everything right except suspect the real source of the problem: A clogged filter. We had replacements right next to the furnace, I just never thought of replacing them.
Blah ..........
SO, use oil in a manometer rather than water? Because it evaporates less? Is that the rationale? Cooking or a lightweight non-combustible one? If it leaks out or gets sucked into the furnace inlet, that would cause a bigger mess than a water leak, wouldn't it? (Fan suction side is heated ventilation air, not combustion air, but the two are not a perfect isolation from each other. )
If I expect a max of 3 inches water d/p, does that equate to a manometer depth (height ?) difference of 4 inches, since oil will be lighter than water?
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
... But I'd buy a Magnehelic with relay contacts so I wouldn't have to remember to check it, and I wouldn't have to worry about the liquid evaporating or being surged out in a transient.
Mike Halloran
Pembroke Pines, FL, USA
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
May not stand up to DMAIC scrutiny but there you have it, until you have a history of events related to this failure mode I'd be inclined to mitigate by adding to the troubleshooting check list.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
The wires, Kenat, not the batts ... have wondered the same thing - why do they eat the batteries so fast?
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
The other obvious advantage of being AC powered with battery back-up is that even if you ignore the battery, they'll still work most of the time.
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
We have the reminder set as a timer selection on the HVAC thermostate, but the clogged well before the alarm (3 month timer setting) was 'supposed' to off. My error - I didn't think to open, inspect and replace the dumn thing before troubleshooting.
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
As a chem eng/metallurgist the first part of any answer I give starts with "It Depends"
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
That's what I would expect, too. But after 1 year, they chirp until the battery is replaced. And in that year, we've lost power twice, once for 8 minutes, once for 2 minutes.
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
As a chem eng/metallurgist the first part of any answer I give starts with "It Depends"
RE: D**m. Furnace (HVAC) Filter Overloaded, Caused on Unneeded Svc Trip. What D/P gage is needed?
http://www.alpinehomeair.com/related/G-99.pdf
However my cheap HVAC system has a built in alarm that lets me know. about 2 seconds after the fan cuts off, I hear a "pop". the walls of the inlet duct poping back out since a high dP pulled them in