HTST Holding Tubes. Heating surface area: 18.22 sq. ft. Holding tubes are equipped with a Balston Steam Filter, Type: 23/75 SR, Element No: 200-75 SR, maximum pressure @ 353 °F: 125, filtering retention: 98% at 0.01 micron, application: culinary steam. Unit uses a Fisher Actuator, Type: 513, size: 20, with a travel of 3/4 in., and an open range of 3-15 sec. Also equipped is a Fisher Electro-pneumatic control, type 646 and TCI Superior Flowmaster flow diversion valve. Inlet: (2) 2 in. dia. S-line fittings. Outlets: (1) 1-1/2 in. dia. S-line fitting. Overall dimensions: 9 ft. 8 in. L x 28 in. W x 66 in. H. XM