WWW. LOW PRESSURE SYSTEM.CO.ZA INSTALLATION GUIDE Important: The VENT pipe must be OPEN, else the tank will burst when water boils. Fill tubes with water before inserting Cold water in Hot tubes will shatter tubes. Lubricate glass tubes with soapy water before inserting. DO NOT use grease, vaseline, oil, etc.
The vent pipe on the top of the geyser tank must always be open to the atmosphere. These systems boil easily, and the steam must escape. Do not use any valve or restriction on the vent pipe. This will void any guarantee. When connecting inlets and outlets, remember that the stainless steel tank is only 0,41mm thick. Do not over tighten. Tips when installing low pressure systems: Remember that the system works best when facing north. The optimal angle for the glass tubes is latitude +10o. For the Pretoria area it will be ± 35o.The stand is designed for 38o, so the stand can be used without any modification. When installing on a 26o pitch roof the short leg with the right angle end is not installed. The angle of the roof plus the remaining angle of the stand will give the required ± 35o. How to assemble the stand: The tank holders, thus the parts on which the tank rests, are in the box marked water tank. All the other parts are in the long, thin box marked bracket If the stand is mounted on a 26 degree roof, the rear upright foot is not installed. The white plastic washer is fitted on the side of the nut. There are three horizontal bars (J profiles): One has only the two holes at the ends: Always fitted at the rear of the stand, in the lowest hole (for horizontal or 26 degree roofs) The one with the two holes closest to the middle is always to the rear, under the tank, together with the long cross struts. In the 100 litre systems, when fitted on a 26 degree roof, the cross struts actually cross. The horizontal bar with the two holes the farthest from the middle, goes in the front of the stand, under the glass tubes, together with the two short cross struts. Glass tubes: To insert the glass tubes, take a mug of water and add some dishwasher liquid. Wet the open side of the glass tube by dipping into the soap water. Insert the tube in to the hole, using a screw in motion. Take care not to make the angle between the stand and the tube too big, as it may cause the tube to break. Pull the tube back to fit into the hole in the stand.
Anode: Like any geyser, these solar geysers must also be fitted with an anode. Made from magnesium, scale and rust will first deposit on the anode. Yearly inspection of the anode, and replacement when necessary, will make the geyser last much longer. The anode has a plastic connector which fits into a glass tube, and gets inserted into the tank together with the glass tube. To remember on which tube the anode is fitted, we try to put it as close to the inlet/outlet. When connecting vent: The vent pipe is connected to the inner tank with a silicon washer. Use a spanner or vise grip to hold the pipe in place. Be careful not to force the vent pipe into or out of the tank, or not to turn the pipe axially. If this happens, it will feel as if the pipe breaks loose, and you will be able to turn the pipe axially. It will not leak, because only the bond between the metal pipe and the poly urethane insulating foam breaks. With no electric element installed: Manual filling: Connect a pipe to the bottom male thread (marked Outlet ). This pipe can then act as both an inlet and outlet pipe. A Tee coupling is connected in the pipe. One end of the Tee gets connected to a valve and the cold water supply. The other end of the Tee gets connected to the hot water outlets. In the morning, while the hot water taps are closed, open the inlet valve and let the water fill the tank until it runs out through the vent. Close the inlet valve. The tank is full. Let the water heat during the day. In the evening or early morning, when the outlets are opened, the tank runs empty without cold water entering, as happens with the automatic filling methods. This way, there is more available hot water. There will be no damage to the geyser if it runs empty, because the tubes stay full of water. At installation, or when the vacuum tubes are allowed to boil dry, (usually after the tank was empty for a few days), do not pour cold water into the geyser in daytime, because adding cold water into hot, dry tubes will shatter the glass tubes. Notes: This method can be automated using a day/night switch together with a Latco valve or auxiliary tank. Using a GEYSER WISE controller, this can be done electronically, but the sensors are not stable under the high South African water temperatures.
Bottom of supply tank just above geyser tank: The top of the vent pipe must be at the same height as the top of the supply tank. The water level in the vent pipe on the geyser tank will be the same as in the supply tank. No Latco valve or auxiliary tank is used. Pressure will be balanced at the shower. The 22mm inlet is at the top and the 22mm outlet is at the bottom, as marked on the tank. The cold water runs out first, but the outflow is better, because the tank can run empty. There is still hot water available when the supply tank is empty. There will be no damage to the geyser if it runs empty, because the tubes stay full of water. At installation, or when the vacuum tubes are allowed to boil dry, (usually after the tank was empty for a few days), do not pour cold water into the geyser in daytime, because adding cold water into hot, dry glass tubes will shatter the tubes. 1. If the bottom of the supply tank is 3 to 5 metres above geyser tank: (when the vent pipe is longer than 1.5m, and thus too long to be stable) or 2. the pressure difference will be so small that it will not significantly effect the mixing at the mixing valve, or 3. if there are no mixing valves, and a difference between cold and hot water is acceptable, there are two options: 1. 3 litre Auxiliary (feeder) tank: It is a 3 litre tank with a ball valve, like a toilet cistern, used to bring down the pressure and keep the geyser tank full. The auxiliary tank cannot be used to balance pressures for the mixer valve (shower) If you have no mixing valve in the house, and differing pressures at the hot and cold outlets is not a problem, it can be used to install where the inlet pressure is high. If the hot/cold pressure difference (difference in head) is small, there should not be serious problems at the shower. Using a 22mm to 15mm reducer, the auxiliary tank can be fitted on the inlet, with a short vent pipe on the 15mm vent. (if you do not have a reducer, the two pipes can be switched.)
The 22mm inlet is at the top and the 22mm outlet is at the bottom, as marked on the tank. The cold water runs out first, but the outflow is better, because the tank can run empty. There is still hot water available when the supply tank is empty. There will be no damage to the geyser if it runs empty, because the tubes stay full of water. At installation, or when the vacuum tubes are allowed to boil dry, (usually after the tank was empty for a few days), do not pour cold water into the geyser in daytime, because adding cold water into hot, dry glass tubes will shatter the tubes. 2. 100kPa (Black an white) adjustable Latco valve : It can be bought from The Sun Pays or from the local hardware store. A Latco Valve can be used to equalise the pressure for the mixer valve (shower) If the valve is used to equalise the hot and cold pressure, the cold water is taken off on the low pressure side of the Latco Valve. The 22mm inlet is at the top and the 22mm outlet is at the bottom, as marked on the tank. The cold water runs out first, but the outflow is better, because the tank can run empty. There is still hot water available when the supply tank is empty. When the Latco valve is installed, adjust the white ring on the Latco valve so that the water runs out at the top of the vent pipe, and then back, so the water level is in the vent pipe. There will be no damage to the geyser if it runs empty, because the tubes stay full of water. At installation, or when the vacuum tubes are allowed to boil dry, (usually after the tank was empty for a few days), do not pour cold water into the geyser in daytime, because adding cold water into hot, dry glass tubes will shatter the tubes. With electric element installed: 1) Bottom of supply tank just above geyser tank: The top of the vent pipe must be at the same height as the top of the supply tank. The water level in the vent pipe on the geyser tank will be the same as in the supply tank. No Latco valve or auxiliary tank is used. Pressure will be balanced at the mixer valve (shower). The inlet is at the 22mm male thread (marked Outlet ) at the bottom of the tank. The outlet is at the 22mm male thread (marked Inlet ) at the top of the tank. This way, the tank cannot run dry, and the heating element will not be damaged.
2) 100kPa (Black an white) adjustable Latco valve : Latco valves can be bought from The Sun Pays or from the local hardware store. A Latco Valve can be used to equalise the pressure at the mixer valve (shower) If the valve is used to equalise the hot and cold pressure, the cold water is taken off on the low pressure side from the Latco Valve. The inlet is at the 22mm male thread (marked Inlet ) at the top of the tank. The outlet of the geyser tank is at the 22mm male thread (marked Outlet ) at the bottom of the tank. An anti siphon loop, about 12cm higher than the outlet, must be connected to the breather pipe to protect the element. When the Latco valve is installed, adjust the white ring on the Latco valve so that the water runs out at the top of the vent pipe, and then back (½ or ¼ turn), so the water level is in the vent pipe. This way, the heating element cannot run dry, and will not be damaged.
3) 6 Litre feeder tank (black and white) with high flow ball valve: The high flow ball valve valve can be used to equalise the pressure at the mixer valve (shower). If the valve is used to equalise the hot and cold water pressure, the tank is installed right above the cold water take off (to the mixer valves). The inlet is at the 22mm male thread (marked Inlet ) at the top of the tank. The outlet of the geyser tank is at the 22mm male thread (marked Outlet ) at the bottom of the tank. An anti siphon loop, about 12cm higher than the outlet, must be connected to the breather pipe to protect the element. The breather pipe on the anti siphon loop must be as high as the top of the feeder tank. This way, the heating element cannot run dry, and will not be damaged.