Meticulous Care for Electro-pneumatic Pipe Organs

Conversion of a Möller Pitman chest to Unit EP actions...

Built in 1946 by M. P. Möller of Hagerstown, MD, their opus 7,161 was installed in the First Presbyterian Church of Athens, GA and served there until the organ was replaced by an Allen Renaissance Organ. We aquired the chest last fall (2005) and have set about converting the action from Möller’s standard Pitman (straight) actions to our standard Electropneumatic Unit Actions.

The chest has space for a 73 note Diapason (with the lowest 8 notes offset), a 73 note Dulciana (with no offsets) and an 85 note Melodia. The Melodia utilized Möller’s complex shifter system allowing this rank to play at two pitches (8' and 4') from the same manual.

The first three photos show the shifter mechanism; #1 shows the double action bores, one for the 8' pitch and another for the 4' pitch. The “shifter” moves from side to side between the two smaller bores and transfers the pneumatic impulse to the appropriate pouch via the small bore lead tubes shown in the second and third photos. The third photo shows the top octave “extension” wherein the action actually passes through the top board of the chest, between the feet of the treble pipes planted there and back into the chest connecting the top 12 notes (nrs. 74 — 85). All of this works fine as long as the connections are perfectly air tight... with the potential of 146 connections (one at each end of the 73 tubes that carry the pneumatic impulse for the 4' stop) to “spring leaks” it’s easy to see the potential for trouble! The last photo shows the Möller exposed primary actions that often result in a dramatically shorter lifespan when compared to the interior chest leather.

The small scale of this chest (overall length of 7' 10") coupled with its layout (chromatic with the lowest notes on the left side of the chest) makes this an ideal chest for a voicing machine for my own studio in the shop.  This chest has now been gutted of the original pitman actions, all the lead tubing has been removed and new electro-pneumatic actions will be provided to replace the 1946 actions.

Check back in the coming weeks to see ongoing progress and the completed project in late spring!