HVAC Shop Talk is a YouTube channel & podcast that celebrates the guys and girls in the skilled Trades – especially HVAC. #hvac #hvactraining #hvactech #hvactechnician #hvacpodcast
Join the HST Discord server –
Sign up for email notifications –
Sponsors
Beckett Corporation –
Yellow Jacket –
NAVAC –
Company Cam –
EWC Controls –
TruTech Tools (Use my “SHOPTALK” promo code)
https://www.trutechtools.com/
Contact me –
This video is brought to you by Beckett HVAC pump Solutions you can trust Learn more at beckettus.com forward Slash industrial so I had a comment that Was interneted to me 17 hours ago looks Like it's on an electric furnace video Where the Heat and the blower ran Constantly and the comment was from a Man named Eric when I shut off on the Thermostat it won't shut off So if you have an electric furnace that Is running constantly even in the off Position a lot of times that is because Electric furnaces include little relays Called sequencers now sequencers are a Special kind of relay instead of a Holding coil they have a bi-metal switch And that bi-metal switch gets low Voltage power and typically located on The base of the sequencers and the high Voltage switching takes place up high There's sometimes a couple rows of Contacts or at least one row of contact A five KW sequencer has one row a 10 Kwa Has two rows and if you go up to 15 or 20 typically it's two separate Sequencers in tandem But when these sequencers engage that Initial 5kw will bring on the blower Because sequencers have a timing so Let's say if you have 20 kW you might Have a sequencer where the first five Comes on at a certain point then the Next five to make 10 comes on a few
Seconds later and then so on and so on Until you get to 20. but whenever the Machine cuts off it works down in the Opposite way so the blower stays on into The last sequencer goes off now if that Sequencer is stuck Then it'll make the heat in the blower Run constantly so what happens is even Though the low voltage power to the base To that bi-metal switch is offline The high voltage is still getting Through because the sequencer is stuck Closed therefore the blower gets Constant power and the heat gets Constant power now you can shut off the Breaker to solve this problem that's one Way of dealing with it until you can fix The problem and typically fixing the Problem is as simple as changing that Sequencer and it's a pretty common Problem with electric furnaces because The sequencer relays have very high Amperage going through them all winter Long and if they're heat pumps they Still have the amperage going through During the defrost Cycles electric Furnaces are a little bit worse for this Because that's the primary source of Heating is the resistive Heat So they have a heavy load on them for Several months out of the year at least That being said they're prone to failure And it happens quite a bit so make sure You check those sequencer relays when
You face that particular problem next Time you visit an electric furnace
