Feed Water Pump

Make: DAMPF & COLBEN HSP-PS -18 for RXA-02
Make: DAMPF & COLBEN HTP-PS -16 for RXA-03 to RXA-06

The pump is a reciprocating single acting pump. It is driven by a 3-phase electric motor through pulleys and V-belt. Pump & motor are mounted on a platform. Adjusting bolts on the platform allow adjustment of belt tension.
The pump has water chamber and crank case. The crankshaft mounted on ball bearings drives the pistons (HTN 1). The piston suck water on return stroke and push water on forward stroke. Gland washers (HTN 8) and oil seals (HTN 5) prevent the pressurized water for entering the crankcase. Control valves ( HTB 3 to 6) in the water chamber prevents flow of water from pressure side to suction side.
A control valve consists of valve seat (HTB 3), valve disc (HTB 4), spring (HTB 5) and valves cage (HTB 6), all held together with the Teflon washers. Control valves are fitted between the suction chamber (HTB 8), and valve chamber (HTB 1) and between the valve chamber and delivery chamber (HTB 7).
The surge suppressor (HTB  11) is a pressure vessel mounted on the delivery chamber. It  serves to dampen the pressure fluctuations caused by the reciprocating pump.
To access the water chamber, open the two vertical bolts holding the suction, valve and delivery chambers together. The control valves can be simply lifted from their sockets. For dismantling the control valve, stretch the rubber washer gently and pull out the valve cage with seat. Check for cracks in the washer. Check that the valve disc & seat are not worn. They should seat on each will allow water flow in reverse direction under pressure,  resulting  in reduced water supply to the boiler. Replace if necessary.
Remove  the two horizontal bolts holding the crankcase (HTC 1) & valve chamber together to access the piston, oil seals, gland washers etc. Examine the gland washers for cracks & wear. Replace if necessary. While reassembling tighten the oil ring (which holds the gland washers) properly. On the water chamber side, carefully clean   the surfaces on which the control valves sit & then place the control valves in the their sockets.
The crankcase side usually does not require frequent maintenance. SAE-40 oil should be used (up to the indicated level) for lubrication. Drain off the oil and fill new after 3 months as indicated will not be dampened properly.
Unscrew the surge suppressor, empty it off water and fit it back. If it is full of water the pressure fluctuations will not be dampened properly.