Nesbitt Cabinet heaters

Freezer

I have taken the position of Facility Manager for a half way house in Pa. It is a three story 1920s vintage elementary school building and had it's last major remodel in 1965. With that remodel Nesbitt classroom cabinet heaters were installed with a Johnson Control pneumatic control system. I don't have a good set of prints for the building but have been able to figure most of the system out. I have been researching the Nesbitt Cabinets units but have had limited success. The pneumatic system has been abandoned, a mistake in my opinion, and the Nesbitt units have not had maintenance in decades. The blower squirrel cages were completely clogged with dirt and debris. The heat exchange fins were flattened, clogged and damaged. Many of the motors are inoperable. They were depending on this botched system to provide radiant heat, it didn't. I have cleaned and repaired the system. I've located the air vent valves drained the air out of the system. On/off switches were installed for fan control but I don't have thermostatic control or any means to control the dampers. I also have two ceiling hung Nesbitt units in the Gym but I haven't started to repair or research them. This is a very sick building as it doesn't have any air exchange. Staff and residents have said this building is unbearable in the summer. With no air exchange it isn't hard to understand.

As I stated I don't have and can't locate schematics, drawings or operation manuals for the Nesbitt cabinets. Where can I get them? It's my understanding that these units were designed to provide 30% fresh air at all times which is desperately needed in this building to reduce communicable disease transmission.

Is it better or more cost effective to restore the old pneumatic system or replace it with electronic components in the cabinet? Many of the pneumatic motors and valves have been damaged and I haven't tried to figure out the electronic relays without a schematic. The wiring resembles a rats nest.

For the first time in my career I'm working for a major corporation and I'll have to submit a proposal for the repair of the systems in this dilapidated building. I will need to document everything well in order to justify the funds needed to get this building into a safe operating condition.

njtommy

As per the pneumatics. You may find it cheaper and easier to convert the rooms over to a Electronic control system. You could even do each room as a standalone system or put it on a building management system.

You could do it as simple as a Honeywell jade controller with a t-stat and dampers.