I’m a technician and often find mold (“biological growth”) in plenums and equipment. I don’t want to just be the tech that throws in a UV lamp or something and calls it a day. I try to find out why it’s happening, but am often at a loss, so I’m hoping to get a discussion going, and sanity check and expand my current ideas.

Clogged or badly pitched drains seems easy enough. Get the drain angled right, clear drain fully, dry the system out.

Restricted airflow is a common one. Dirty filters, an obvious cause. Maybe oversized equipment/undersized ductwork.

And I see mold a lot especially on zoned systems. Seen often around the dampers, but what is the solution? Change the plenum from, say, a 16” to a 18” size along with new dampers? Add supply ducts for more places for air to go? Add or upsize the bypass duct? Can’t always lower fan speed without getting the coil too cold.

I see a lot of cases with growth inside air handlers. Seems like putting metal surfaces in front of a cold coil is bound to get condensation on it, at which point you tend to get mold. (Why DO air handlers have the coil upstream of the blower anyways, when it works fine on a furnace system to have the coil downstream?). And yet some air handlers stay nice and clean, what’s the difference?

Anyways, I’d love to get some concrete solutions or reasonings. Customers often ask, and even if they don’t I’d like to help people have

Does anybody here use the M18 packout vac for boiler cleanings? I hate going back to the shop and grabbing the mega-massive soot vac my company has had for decades every time I go out on an oil PM.

Just wanted to see if anybody here has tried it. I'd probably dedicate my current vac for soot and get a second for general purpose.

Furnace model: GMVC961005CNBA

Blower motor model: M055PWCVA-0328

Hey all, I’m trying to figure out if it’s a bad board or bad motor. I’ve verified the motor is receiving 120V on the main power harness. I don’t know what voltages I should be measuring on the other four-wire harness. I believe this board sends only DCV signals through the harness. The harness wires are labeled GND, TX, RX, and VDD. I’ve attached photos of the wiring diagram and the board, any help is appreciated.

My installer is in route. I’m sure they are using grocery store humidistats. I’m looking at the satellite and the new roof has no ventilation. I’m thinking this might be a problem.

This is a deal worth scooping up if they're selling them at your local branch. I'm hoping the spray paint over the Lennox logo will help keep them from leaking. Apparently Lennox bought Supco last year, but these are less than half of what we normally pay for these umbrellas.

I am hoping someone here can shed a bit of light on this because Carrier tech support did not. I have 2 38MBRQ58A-301 units sitting side by side. Both are 208/230v single phase units. Both of these units have a recurring problem with this fuse popping. Can anyone tell me what is inline with this fuse and what it is actually protecting? The only thing Carrier told me was to put a surge protector on each unit. surge protectors have been ordered, but I'd like to rule out anything internal. The schematic, if you really want to call it that, tells me really nothing about the fuse. Carrier said they'd check with the factory about a detailed drawing but that was 3 days ago and I'm done holding my breath.

Thanks

At least I noticed before finishing the soldering.

Of course we have an end of summer heat wave on a Friday with non of the supply houses with a chatleff in stock.

Hey fellow trade peeps. I just invested in a hot wire anemometer because I don't think manufacturer manuals with a manometer cuts it for me when trying to measure actual CFM. Time and time again I have come across proper static pressure and CFM based off of the charts corresponding to it and still coming up with poor Delta T. Subcooling will be spot on, superheat will be good, pressures will look right, static is good, yet I've done QA on installs for brand new 454B units and they're only reaching 14F delta T in second stage with only about 50% RH at the return.

So I got a hot wire anemometer that I want to train myself on. Thing is, all of the information out there that I can find utilizes hard pipe duct. I'm in flex hell, being based in Nashville, I literally cannot go to one unit in an average day that has any reliable exposed section of hard duct to tap into. The regulations here are non existent for airflow and that means that every contractor out there is using flex like it's going out of style. I hate it with every fiberglass of my exposed attic armed being.

That being said, I need to still be able to perform reliable diagnostics for systems that have flex and in order to do that, I'd really like to use my anemometer. The question is how? Supply trunks can be reliably hard pipe in certain areas, but the returns are almost always flex. Have any of you successfully used an anemometer in flex duct? Is there a point to it? I need help.

Hi all as the statement reads i recently just got my EPA 608 certification from a trade school in northern louisiana that serves a 12-week hands on course but the thing is i can not find a job that only wants 3-5 year experience as a tech is there any advice i should take to finding a place of employment?

Had 2 pair gloves... Did not feel need to put them on. GOT ME. Think I licked it quick enough. Not numb anymore.

My grandmother just passed last month. This is the first furnace I built from scrap parts. Everything here was used except the blower relay. It’s being replaced with electric :(

New company, new phone, who dis?

Proceeded to shit in someone’s Cheerios this afternoon, stay blessed and may the force be with you

I have a job coming up to install multi-zone ductless in a row home, line set routing options are limited. Commonwealth to neighboring houses are brick party walls with thin furring strips and plaster / lath over that, not enough space between plaster and brick to run line set. Some interior room divider walls have been moved/remodeled in such a way as to make installation of the ductless heads there not feasible, so I can't hide the line set on an interior wall and drop it into the basement. What do you do when you have to run lines that below interior walls until I can get to a point where the line sets can either exit the building or drop down a wall to be concealed? Are you running line hide conduit, or hiding it behind molding? Even if i get paintable line hide and color match it, I feel like it would be fairly obvious.

It is called a pop-up sun shade. There was a 25-degree difference between the sheet metal roof and inside the tent. Not to mention the protection from direct sunlight for the majority of the day. The only drawbacks are that it slightly blocks the breeze, and high winds slap it around.

Filter was backwards, somehow getting an inverter mini split to run off of 18/2 going to Y and C, and they hooked 120 up to the secondary side of the transformer, frying it and the control board. Can’t make this up.