when my heatpump goes into defrost mod the back heat is kicking in why?

[mike 6661]

have a fridgeair 16/17 seerrunny r 410 refridgerate with the matching varible speed airhandler and 15kw electric back up.whats happening is when the heatpump goes into defrost mod the backup heat isnt comming on andy body no why??if i bump therostatup 2 degrees the aux heat kicks in ,if i change thermostat to emercency heat mod it comes on all works good !i remeber that what used to happen is when it went in defrost mod the emergency backup used to kick in for that period of time ,now the therostat just says on heat mod and when it goes int defrost mod it stays the same emergency doesnt start blinking therefore it blows cold air until the defrost cycle is finished ?does anybody no what is causing this ?somthing faulty?any info would be great thanks !

[mike 6661]

first line is backup heat isnt kicking in mod can you fix that thanks

[mike 6661]

bump thanks

[nike123]

bump thanks

Do you have electrical diagram?

[mike 6661]

i could draw you a diagram but nothing has come loose all exact same all that has happened is that now the backup heat doesnt kick in when in defrost mod ,its either the therostat or the heat pump board ,iam leaning toward the therostat only 2 years old it is a total line it seamed to of happened after a power outage maybe fried somthing not sure though iam a plumber hear and havent come across this and dont wont to pay for some dud to come and trouble shoot !all help is much appreciated!!!

[nike123]

What would you say for guy who is electrician and recently have noisy and vibrating pipes, doesn't have tools and knowledge to fix that and he came on plumbers forum to ask how to fix that noise .

Then you, as member on plumber forum, ask did he have piping diagram of house.
He answers no, but he could draw a diagram, but none of pipes has come lose, and only what happens now is that when he switch boiler ON, noise disappear. And he conclude that it is either boiler thermostat or hydro pack, and that, because he is electrician and he hasn't come across that before, he don't want to pay for some plumber dude come and troubleshoot that.

How would you proceed in this case?
I ask this because I need example how to proceed in your case.:rolleyes:

[mike 6661]

on the therostat from right to left yellow wire is hooked to Y1, green to G,white

[mike 6661]

on the therostat from right to left yellow is hooked to Y1,green to G, white to W2,orange to OB/WI,red to RH,black to C . like i was saying before it used to work just fine now when in defrost mod the emerency heat is not kicking in blows cold air ,the more and more i think and look at it i thinking it is the therostat ,but i will wait for proffesional answer first ,i have checked all connections everthing is like new ,board on outside unit looks like new aswell ,and everthing works if i use individually like emergency heat aux .heat hope this little info on how it is wired might help you nike

[mike 6661]

bump thanks not sure if i should try just replaceing therostat?

[james770]

how often does it defrost? Reason why it defrost is because the outdoor condensing coil ices up.When it is defrosting you would not get heatig unless you`ve got a hot gass bypass

[CarolinaCool]

Sounds like the outdoor tstat is locking it out.

[mike 6661]

mine is wired so that when it goes in defrost mod the emergency heat kicks in, in this short period of time .we had a major power outage and i havent noticed it working after that,i have checked all connections ,therostat works in individual mod like if i put it on emercency heat good if i bump up therostat aux. heat works fine looked in advance setting all is good .this why i am thinking it is a faulty therostat but could be wrong .thanks for help

[icecube51]

if i am testing stuff like that, i use lightbulbs,so if there is power and contacts,i now it by the shining of lights.

just a way of doing things.....i guess.

Ice

[THE WOMBAT]

When the unit goes into defrost it starts to cool the air. the Aux heat comes on to boost the supply temp.

Power outage: if you where on electrical boost heat when the power cut, this can cause electric heaters to trip on over temp stat inside the duct. This is a final safety , say if the contactor became stuck on and the supply fan failed.

[mike 6661]

ya my backup heat isnt kicking in anymore when in defrost cycle so it blows cold air trying to figure out why it stoped would the outside unti board cause this ?or should i try replaceing thermstat first?or how can i tell ?thanks