I have a Lennox Heat Pump and want to install a programmable thermmostat for a 2 stage heat pump. I have a 8 wire hook up. O-G-Y-R-B-Br-Bl-W. Which kind of stat should I get.

Umm... I would suggest... a programmable thermostat... for a 2 stage heat pump system. Not sure where I got this idea...

Lennox designs and nomenclature tend to be a little different that most, so assumptions are risky. It would appear that most of your terminal designations are standard (O-G-Y-R-W), the other 3 may not be. B is likely a low voltage common circuit, the others may be for indicator lights. Posting the thermostat and indoor unit model numbers may be helpful in clarifying what each circuit represents so as to avoid releasing any "Magic Smoke" or "Warning Sparks".

My model# is HP26-042-7P
Serial# 5800F56746
Wireing is O-orange
G-green
Y1-yellow
R-red
L-black
T-brown
C-blue
W1-white

Thank you for anything that will help me

Check the black and brown wires at indoor unit, post what terminals they are connected to, or if they are not used at all.

The brown and black wire are spliced to cable going to outside so I will have to go outside to check termation.