heat pumps

[wayne123]

I am installing the electrical supply to heat pump furnaces in a new house i am wiring.There is a 4 ton furnace unit under the house that has two 60 amp breakers instaleed in it.The max breaker size on the furnace is 90 amp @ 240 volts.Will it be ok to just install a pull out 100 amp disconnect beside the unit for disconnection or should i install a 100 amp panel with a 100 amp 2 pole breaker?

 

[bennie]

Re: heat pumps

This appears to be an 18 KW electric furnace. Are you sure it is a heat pump?

 

[frenchelectrican]

Re: heat pumps

hey bennie i belive that the electric furance is a back up source for heat pump ( when the weather get too cold for heat pump to run then switch over to alterntive heat source ) but i am not sure what is your local code admendment requried for secondary disconnet switch at the heating /cooling device

btw if the label say max breaker size 90 amps that mean use 90 amp breaker not a hundred amp breaker (100A ) the other reason that if i recall that you meantion 2 60 amps breakers i bevlive that is 2 stage heating elemnts and i know each stage cant draw over 45 amps each section i dont have the nec part with me but i do recall it pretty clear

merci marc

 

[bennie]

Re: heat pumps

Marc: This is one big back up heater. 18 KW should heat a 2500 square foot house.

Some of the furnaces are set up for one 90 amp feed or two 60 amp feeds.
There is a link that has to be removed when two feeders are being used.

 

[wayne123]

Re: heat pumps

Good morning guys.Yes bennie I am sure this is a heat pump furnace.It is one of three heat pumps going in this 4000 sqft house.I asume that the breaker sizes in the furnace are 60 amps each because the manu.of the heat pump (Rheem)has sized them accordingly @125%.Is a 100 amp pull-out disconnect allowable for this? All I am looking for according to the code is a disconnecting means within sight of the equipment.In the past I have seen and have wired heat pump furnaces that do not have OCD's included with them and I have installed sub panel sized accordingly.

 

[frenchelectrican]

Re: heat pumps

wayne if the furance is located near the load centere then the ocpd is not nessecary BUT from my experanice it is very good idea have ocpd or disconnetion device right next to the furance but the other part of nec code say withen sight of ocpd( breaker box etc) then dont need one if that loacated in other room or large number of items obstructiong sight then it is recmoned to add disconneting means

i hope i get it right

merci marc

 

[wayne123]

Re: heat pumps

Two furnaces are under the house an one is in the attic space.These furnaces are not withen site of the panels. I have installed pull out disconnects for the units. I will find out today if it is OK, inspectors coming.

Thanks, Wayne123