It seems winter is just around the corner (where did the year go?), and this practical article gives a time pertinent, blow-by-blow maintenance instruction in order to achieve the very best for your club in regard to its irrigation and water supply needs.
Before winterising the system, carry out steps 1 to 7:
- Check the operation of the isolation valves by closing and then trying the sprinklers with the system under pressure to ensure that it still isolates the supply
- Close and open every main line isolation valve. If they are gate valves ensure that once opened to the full extent the valve is turned back ½ a turn
- Check the manual hydrants to ensure they open and close tightly and that the hose couplers are in place
- Check and clean the suction pipe strainer at the pump if the system draws directly from a pond or river
- Check the water tank for leaks and inside for debris (leaves or even weeds that grow up through the bottom)
- Check that the ball valve shuts off when the tank is full
- Run each pump for a short time (not more than 2 minutes) on hand control against closed delivery valve and record the pressure. Check this against the record and if it is down by more than 10% consider having the pump repaired
- Winterise the system - See below
- Examine every sprinkler for damage
- If it is an open case design (impact or some older Toro series) ensure that the inside of the case is clear of debris (sand) which will interfere with the sprinkler popping up or down
- Reset the sprinkler height so that its top is not more than 6mm below the surrounding ground level. Ensure it is also vertical. Obviously watch out for sprinklers above ground that a mower would strike. Use some clean 10mm shingle to raise the sprinkler, as this will assist local drainage
- Look in every valve box to ensure it is clean and clear access is available (moles have a habit of filling valve boxes with soil)
- If boxes flood with water install a land drain to ensure it is clear
- Check the box has not sunk down until the lid is resting on the hydrant in the box or on the pipes. Dig out and re-support on bricks or a bed of 10 to 20mm mixed size gravel
- Check the valve box is not broken and replace with new as necessary
- If it is a decoder system make sure the decoder is supported off the bottom of the box. Plastic cable ties to the side is a good idea. Ensure the cables are clear of the hydrant and that the crimped connections are sound (no bare cable showing)
- Mark on the valve box lid with permanent marker pen the decoder number and what area the valves control
Winterise the system
The extent to which you need to clear the system of water depends on a number of factors - location in the country and the severity of the weather conditions experienced - depth at which the pipe system was installed - the elevation falls across the course - the pumping station building construction. In general, bear in mind that any system of equipment in constant use is likely to be more reliable than one left inactive.
Assuming that the weather is going to be severe and that your pipe system cannot be thought to be all buried deeper than 500mm (perhaps there are open section across ditches or maybe you just do not know), the following steps should ensure freedom from frost damage:
- Turn off the underground stopcock on the water supply and open the drain cock on the riser to the ball valve on the tank
- Switch the pumps off (if pumps fitted with Hydrovar speed control, set the units to off but keep the power on to keep the electronics warm as these units are sensitive to internal condensation)
- If your system has no tank but receives water to the tank from a borehole, then turn off the borehole pump and drain the tank feed riser pipe and any above ground borehole pipework.
- Pump sufficient water from the tank to lower the water level by 300mm in order that the ball valve arm drops sufficiently to clear water from it. Float some pieces of Polystyrene packing on the water to help prevent the formation of a solid ice layer that might have a tendency to jack outwards on the tank
- Close the underground valve (if fitted) between the tank and the pump house. If there is only a valve inside the pumphouse, then close that one but remember to cover the valve pipe on the tank side of the valve with some insulating material. Best action is to box it in permanently with plywood and fibreglass insulation (remember to leave the handle accessible!)
- Open the wash out valves on the system out on the course
- Crack open by just a tiny amount each manual hydrant (not wide open otherwise a mouse might fancy a winter home!)
- Run the system automatically (pumps still off) to ensure that the lateral pipes are as relaxed as possible
- Drain the water from the pumps and pipework by opening the drain cocks and by removing the drain plugs. It is safest to remove them for the whole winter. I suggest the plug is placed in a small plastic bag and tied to the pump motor. Wipe a smear of grease round the pump internal socket
- Fix a warning sign "Danger pumps drained down"
- Set the irrigation controller with a winter electrical run check programme. I suggest a 1 minute setting on each station set to run once per week. Do not set a longer time as the solenoid may over heat, as it is not passing water
Keep the door of the controller closed and the power on at all times, except in the case of severe electrical storm conditions when it is wise to switch of the power supply to minimise power circuit surge failure (if your controller is already fed by a surge protected supply this will not be necessary).
If you are in a country that experiences severe winters, such as in Continental Europe, Canada and the USA, the simple drain down procedures and insulation will not be sufficient. The system must be blown out with compressed air. To do this, instigate all the above for temperate zones but then connect a portable compressor (0.5m3/min size of not more than 6Bar is preferable) to a hydrant on the highest part of the course and then run until no more water is observed to come from the wash out valves. Then close all the wash out valves and run an irrigation programme of 5 minutes per station so that all the water in the lateral (sprinkler feed) lines is clear. Take great care as compressed air is much more dangerous than high-pressure water at the same pressure.
Go round and crack open the wash outs again.
Any section of pipe work that cannot be drained in the pumphouse must be heated either with pipe wrap heater cable or the complete pumping station should be heated throughout winter. Be careful of relying totally on heating to protect your pumping system because in severe weather it is just the time the power lines come down!
If there is a water tank, then it will be wise to drain it down but take steps to protect it from high winds as empty tanks present a large sail area and relatively low mass to volume ratio.
Author: Article first published on Golf Business News. By Bill Hawthorn MIAgrE ASIC GCA, the Irrigation and Water supply specialist Engineer for the Golf Consultants Association and a Director of 2iC Consultants Ltd.