Abstract: Multiple coil fittings are connected in series to a closed loop single pipe circuit. Each coil fitting provides a paralleled chilled water flow to a fan coil servicing an enclosure. The coil fitting has a housing enclosing a first tubing for directing chilled water to the fan coil and a second tubing for directing return water to the pipe circuit. A baffle is mounted radially on the end of the second tubing proximal to the pipe circuit causing a portion of the chilled water in the pipe circuit to flow into the first pipe with the return water entering the pipe circuit below the baffle so there is no mixing of return water with the chilled water entering the first tubing regardless of the direction of flow in the pipe circuit. A humidistat mounted near the load coil farthest from the chiller sends a relative humidity signal to a diverter valve that changes the direction of chilled water flow in the pipe circuit.

Abstract: A hydro-pneumatic expansion tank is provided in a water pipe circuit. The hydro-pneumatic pressure vessel is in the form of a water/air expansion tank communicating with the pipe circuit by means of a conduit and a float valve is provided in the conduit. The expansion tank includes air under pressure and the water. A barrier liquid is provided as a barrier layer between the water and the air, the barrier liquid being made of a clear polyalphaolefin fluid which is impermeable to water and does not readily absorb oxygen. The float valve has a float member having a specific gravity less than the specific gravity of water but greater than the specific gravity of the barrier liquid such that when the barrier liquid is being drained from the expansion tank, the float member in the valve will sink onto the valve seat when the barrier liquid is in the valve chamber thus closing the valve.