Q. L’ichvod Rav Bartfeld,
The president of our Shul is about to bring forward to the board the question of installing a Shabbos Stair Lift using the halachic principal of Gramma. The information given to me is shown below, attached as a pdf file and is to be found at http://www.zomet.org.il/eng/?CategoryID=248&ArticleID=87.
I’m being asked prior to the board meeting as to whether it is halachally acceptable for our shul. My personal opinion based on my knowledge of Halacha is that a Gramma with intended consequences is not permissible accept in a hospital pikuach nefesh situation. Our Shul operates under an Orthodox Charter. We therefore need the approval or disapproval of a recognized Halachic authority in Toronto such as Rav Miller. The consequences of not installing it is that some of our long standing Shul members who are finding stairs increasingly difficult may no longer be able to attend our Shul. Our building has many steps and even when in the building it is impossible to access the only washrooms without using stairs. 

A. Horav Shlomo Miller’s Shlit”a opinion is that although he does not personally endorse the use of any stair lift mechanism for Shabbos use, for those who out of need have to be lenient, there is a difference in the available products today.
The one you quote that has Zomet approval is based on a simple grommo heter. Namely, there is a time delay between the switch activation of the lift mechanism and the resulting starting of the lift motor activated.
Grama Chip Technologies (created by R’ Shmuel Glick, http://www.gramachip.com/home), offers a more Halacha advanced switch system, where the activation of the on control, does not turn on the lift motor. That is done constantly by a circuit that turns on and immediately off the power to the lift. Activating the switch merely removes the turning off part of the cycle, and the lift then starts moving and stays on, until it reaches the end of the normal trajectory. This system has the hechsher of a number of prominent Rabbonim, including Horav Heineman Shlit’a from Star-K.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a