I have a problem that may be new to TOH. It involves three Hurst steam boilers, an air compressor, and pneumatic thermostats. This system has Johnson Controls thermostats that operate with compressed air. The steam valves are controlled by pneumatic actuators. We currently have construction going on in the particular building, and it was said that the contractors severed a compressed air line. Everything was repaired and the pneumatic pressure is back up, but the thermostats will not respond. The boiler's burners don't fire because of this, and there are fluctuating and uncomfortable temps. The boilers are Hurst LPW's and the burners are Gordon-Piatt model R's. (gas fired) any suggestions as to why these thermostats don't work? Most the equipment is from 1995 up.
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