Pump group options

We recommend installing the Worcester GB162 with either the modulating or 3 speed pump group accessory. The high quality pump groups ensure quick, easy and reliable connection of the boiler to main flow, return and gas headers. The Worcester pump groups are correctly sized to ensure that the flow rate through the GB162 heat cell never exceeds the limit of 4300I/h @ ΔT 20K. Our pump group options will also help to prolong the life of the boiler by minimising wear and tear on the appliance and its components. As a result, system efficiency is improved and running costs and installation time are reduced. When using our pump groups a low loss header should also be used to simplify hydraulic design of the heating circuit.

3 speed

The 3 speed pump group for each GB162 boiler is supplied with a Grundfos pump, 1” gas pipe with isolating valve, flow and return isolating valves, pressure gauge, pressure relief valve, drain valve, non-return valve, connection for the expansion vessel (expansion vessel not supplied) condense trap and a fully insulated cover. Thermometers are not supplied with the 3-speed pump.

Modulating pump

The modulating pump group includes flow and return connections with valves and thermometers, a pressure relief valve, a gas valve, a modulating pump, condense trap and custom-fit insulated casing.

Both pumps can be directly mounted under the boiler to feed a low loss header or supply the system directly when possible. Due to different flow resistances inside a heating system, the modulating pump can decrease or increase its pressure. This lowers power consumption and helps to reduce noise.

Positioning and termination of the condensate drain pipe

The condensate pipe should be routed internally to prevent freezing. If an internal routing of the condensate pipe work is not possible then to reduce the prospect of freezing we would advise the use of a trace heating device or an auxiliary syphon.

The condensate pipe should run and connect to the internal sewage pipe in the building or waste pipe. Alternatively, the condensate can be discharged into the rainwater system if connected to a foul water draining system, or into a purpose-made soak away (condensate absorption point) refer to local building requirements.

All connecting drainage pipe work should generally have a fall of at least 2.5º to the horizontal, or approximately 50mm per metre of pipe run. If this can not be achieved, consider the use of a condensate pump. It should be noted that the connection of a condensate pipe to a drain may be subject to local building control.

GB162 pump group

Key to components

1. Condensate drainage point
2. Pressure relief valve
3. Pressure gauge
4. Flow isolating valve - red
5. Flow connection
6. Screw fitting 1¼” connection set (optional accessory 5 584 552) when using boiler without cascade frame
7. Return connection
8. Return isolating valve - blue
9. Connection for expansion vessel (not supplied)
10. Modulating or 3 speed pump
11. Gas isolating valve - yellow