Heat pumps

Unknown

Red wire is to give you 24 volts. In case the unit goes into defrost and someone shuts off the thermostat or the thermostat is satisfied; defrost period will continue until the the cycle is complete

david broome

Anthony Mobilio_3

I have a question, we just started to get more involved with heat pumps. The question I have is regarding the wiring on the board. There are 5 wires. On the cooling side there are black and yellow(y-c) for the contactor the orange wire pulls in the revering valve IM OK with that. On a call for heating the orange wire drops out the y and c pull in the contactor there are w2 and r left i know the w2 is for the second stage heat when its in defrost but the red wire IM iffy about,usally the electricians wire the up on the new installs I want to be prepared for the winter.just trying to get a better understanding. I thinks the red wire powers the defrost timer. But is this only on a call for heat.also when its in defrost does the w2 power the w2 terminal or is it a dry contact.

don_9

heatpump

r-hot side of transformer
c-common side of transformer
o-reversing valve-can be energize on heat or cool depends on equipment
y- for contactor first stage heat and cool
w2-seconds stage heat energize if you have a two degree diff from tempin house and setting on stat,also energize
when in defrost,
g-fan relay energize from heat or cool
e- for emergencey heat only
t for thermistor again depends on whos equipment
most defrost board or power 24/7 now days from r/c terminal.
now that you are in to heatpumps have fun and look forward to as we call it job security. don

Anthony Mobilio_3

Thanks, also when charging heat pumps is it best to use the manu. charging chart on the unit. what happens if its a old clunker with no info. some one was saying you can charge it by using a clap on amp meter on the run wire and charge it by the name plate amps.

don_9

dont do it

you better not go that route,are you over charge the system and be replacing that compressor. thats a myth,now maybe
with an r12 system you could but that the only system you could 12000 btu= 1hp,but that does not matter anymore r12 is beening phase out.If it a orfice you charge by superheat,
and if its a expansion valve charge by subcool, yes please go with chart on equipment.that is if its a match system.
If the chart is missing check with equipment manf,they can
get it for you.good luck,don