On 8/19/2011 3:56 PM, Colbyt wrote:
"Home wrote in message ...
Colbyt wrote:

A friend of mine is buying a house with a heat pump. The sellers
bought a new outdoor unit, but *left the original old indoor unit
intact.

Be sure to read James post. All that need be changed is the A-coil.
The rest of the old unit should function fine.

What else is there when it comes to the "indoor unit" other than the
A-frame coil?


I suppose in some places the indoor part is just an air handler. Here back
up heat strips are required so you have those, the controls, the air handler
part.

Why replace all of that if the proper coil will fit in the old shell?

I just replaced my unit here this year. I sure did not buy a new furnace.
We just replaced the A-coil and the condenser unit.

The average homeowner looks at the old shell and does not see the new coil
inside the unit so they think nothing was done inside.



We have changed out systems and converted the old gas furnace to
emergency heat for the new heat pump. There is a control mod on
the market to do just that. The pressures for the new R410a
refrigerant are much higher than the old R22 systems so it's not
likely anyone will try to reuse an evaporator coil but the line
set could be OK. I would flush the line with nitrogen and internal
system cleaner if I reused it to get rid of any mineral oil and
contamination. As long as the old air handler produces acceptable
CFM for the R410a evaporator, there is no reason to have to replace
it unless it's worn out.

TDD