Just taking the advanced HVAC system course and I wondered how heat pumps avoid liquid slugging in the compressor when it’s cold outside. Also, the instructor recommends testing the check valve on condensate pumps by adding water. If the discharge line has water in it, isn’t that proof that the check valve works? Thanks, Paul
There may be a check valve on the drain side of the condensate pump. If the check valve sticks the pump may not be able to open it. Ours has one that way, and it can stick closed after long periods of no use.
#1 an accumulator. And a crankcase heater.
#2 Robin, it’s that the water in the pump discharge line flows back to the pump at shut down. Looses capacity of the pump and it short cycles. If you have a sticking valve, you need to service your equipment more often.
Ah ha is that crankcase heater a built in or a wrap around and what does a accumulator look like???
Must I teach you everything Charles? 
BTW: You left out the bleed resistor type…
Is it just me or do you wish David’s and Charles’ brains could transfer to mine like a jump drive!? Especially since most HVAC systems are installed wrong and most HVAC techs look at me like I’m an alien when I ask them certain questions. So David and Charles I’m gonna be asking lots of dumb questions this year!
After just spending 8 hours on a new construction inspection its a wonder I still have a brain. The home had 3 split system carriers. The 3 upflow furnaces were in the attic the first one I inspected had 3 burners and only one of them would ignite and then fail on a safety. All three had the condensate drains piped to a plumbing vent stack that had a P-trap that was not a wet trap and this was installed by so called professionals.
Will,
If you get in a jam, I work in Nashville.
I also work in collaboration with a PE from Franklin (not Home Inspection; Building Science, Testing Adjusting & Balancing, HVAC System Design, Air Barrier Testing, Industrial Hygienist, Aeroseal etc.).
When you get beyond Home Inspection, we can pick it up from there.
Yeah David I would love to work you some. I talk to B Westbrook a bunch, we went to Atlanta for our combustion training last month.
I’m sure this happens everywhere but it seems like the installs get worst every year. I’m going back to an Energy Star home later today for the 5th time just for the HVAC. The contractors make things entirely too complicated when it can be so simple. The duct work is starting to look more like spider webs and they wonder why they aren’t getting any air flow and their static pressure is twice to three times higher than the manufactures recommendations. I got into it yesterday with a guy because he just wants me to pass stuff. He argued with me that he did all the balancing and testing, I had rooms off over 100 CFM and an air cycler ventilation system installed with an exhaust dampener installed on the outside so 0 CFM actually ventilated the home and there was no filter on the intake. After I pointed all this out to him I asked him how big of a dumb @$$ did he think I was. Now I have to get him to redo all the paperwork, fix everything, and resubmit it. It pisses me off when these guys fill out paperwork, sign it, and they never tested anything!! 8 out of 10 systems I completely test fail and this all on new construction and Energy Star for the most part!
Ah, the old CAZ class…
Do you do AHJ test outs for Brentwood - Murfreesboro etc. on new construction?
If you do, I’ll pass off all my calls to you. It’s not worth the drive for me, unless I have other stuff to do. And as you pointed out, dealing with idiots is not my cup of tea any more…
Yes I do. Thanks I would appreciate it.
Yeah I just had to fail ole genius again. I’ve got everyone pissed because the house can’t close until I pass it. He argued with me again that he got 70 CFM through his intake that is attached to an exhaust only dampener!! I told him he was magic then, I had to take a picture of it and draw a diagram of how there is no way in hell he’s getting any airflow. Then take a picture of my balometer with a big fat 0 CFM on it. Hopefully he’ll figure it out and I can get this builder off my back and pass this house