Geyser troubleshooting

Geyser troubleshooting: What you need to know

So, how can you as a homeowner trouble-shoot common problems and manage your hot-water system?

• Hot water and steam coming out of an overflow pipe: This indicates a release of very hot water because of excessive temperature (or pressure). The most common cause is the thermostat. This is a serious safety situation which should be attended to immediately. Switch off the geyser until it’s fixed and contact the insurance company or call a plumber.
• Faulty thermostat: Switch off until it’s fixed. Thermostats are designed to fault in the open or “off” position. In this case there is no hot water. However, sometimes the thermostat faults in the “on” position, in which case the water will eventually boil. This is a dangerous situation that must be attended to immediately. Switch off the geyser until the thermostat is replaced and contact the insurance company or call a plumber.
• Water leaking through the ceiling: If a geyser bursts or springs a major leak, immediately turn off the water supply to the house and open a hot water tap to relieve pressure. Remember to also switch off the power supply to the geyser at the distribution (DB) board and contact the insurance company or call a plumber.
• Poor hot water pressure: This could be caused by a number of things: very often it is a blocked or dirty valve, or simply low pressure in the area. Call a plumber.
• Hot water coming out the cold tap during a water supply failure: Hot water coming out of a cold tap happens because of a geyser that was installed or replaced incorrectly. It can also be caused by excessive cold water pressure or unbalanced pressure when cold water causes backflow into the geyser when opening a mixer tap. Correctly installed pipes and vacuum breakers around the geyser prevent this occurrence from happening which makes for a safe installation. This is a very dangerous situation which will drain your geyser during water supply failures. Don’t allow the geyser to drain dry without switching it off. If the geyser runs dry the element will most likely overheat and fail. This is dangerous and needs to be rectified; contact the insurance company or call a plumber.
• No hot water: Check the geyser circuit breaker on the DB board. If the circuit breaker has tripped you should only reset it once. If it trips again then call an electrician or plumber to investigate the cause. If there is power supply, but no hot water, then it is either the element or the thermostat which has failed. The element and thermostat should always be replaced at the same time. Contact the insurance company or Call a plumber
• Not enough hot water, or water not hot enough: This may be caused by the setting on the thermostat being too low, or it may be a sign that the geyser has reached the end of its useful life. Move the setting to 65 degrees Celsius. Geysers calcify over time and eventually need to be replaced. Modern geysers work better than the old ones. It is not recommended that a geyser thermostat is set at its highest setting. Call a plumber
• Water Hammering or pipe rattling: Unbalanced water pressure (between hot and cold-water supply) is often the biggest culprit, but this should not be the case in Tokara as the standard water installation is a balanced water system.
  The following list are some of the most likely causes of pipe rattling in order of importance that must be investigated:
  • Loose pipes in the ceiling. Also see the notice on geyser compliance. To rectify this, it is best to call a plumber.
  • Worn out ballcock assembly (toilet cistern). This can be a DIY fix or call a plumber.
  • Worn out tap washers, headgear or cartridges. This can be a DIY fix or call a plumber.
  • Faulty (installed) pressure valve (this can be reported to King Price insurance once all the above have been eliminated).

Geyser Installation

Geyser installations are often incorrect. In terms of the latest SOUTH AFRICAN NATIONAL STANDARD (SANS) 10254, 10106, 1352 and the National Consumer Protection Act; all owners or users of a maintained, replaced or repaired hot water heating system must comply to these standards. See the Geyser Compliance Checklist at the end of the page.

It is recommended that owners get their geyser installations inspected by a plumber certified with the Plumbing Industry Registration Board (PIRB) and corrected by a company registered with The Institute of Plumbing (SA) (IOPSA).

• Plumbing compliance SANS 10254: What is compliance (based on 2017 edition of the applicable standards)?
• Standards relating to plumbing – 2019
• How to pass your insurance geyser replacement audit 2019
• How to pass your insurance geyser replacement audit – Part 2 2019
• How to pass your insurance geyser replacement audit – Part 3
• Lagging – Part 1
• Lagging – Part 2

An incorrectly installed hot water heater is the most common defect discovered by HouseCheck inspectors in South African homes.  These defects can be extremely dangerous and is the result when untrained, or un-supervised workers are left alone in the roof cavity to do the geyser installation.
Below is a illustration of what can happen to a geyser with no safety measures .

It is a legal requirement for a Plumbing Industry Registration Bord (PIRB) Certificates of Compliance (COC) to be issued when plumbing work is done on a geyser, a solar water heater or a heat pump. See Certificates of Compliance: Compulsory or not?

Tokara houses have high pressure (400kpa) system geysers installed.

Components of a hot water heating system (see image below):

Drip Tray: The geyser sits in a tray made of plastic or steel. Since June 2001, the drip tray is not optional. The tray must be fitted with a 40mm PVC waste pipe that drains the tray by piping the water out the house.

Vacuum breakers: These are small brass components mounted at the 30cm length of pipe. The two vacuum breakers stand vertically about 30cm above the geyser. These are important. They prevent the water siphoning out the geyser when the cold supply is stopped. See “Hot water coming out the cold tap during a water supply failure” above.

Shut off valve on the cold water side: The cold water side is the side that directly connects to the drain cock.

Temperature and pressure safety valve (T&P Valve): Mounted on the geyser often on the opposite side of the drain cock, is the T&P valve. This is a vital component. This valve should have a 20mm metal (copper or steel) pipe connected to it and the pipe must lead directly out the building. This vent is an important safety feature of the whole system. It must be made of copper or steel – not plastic. The pressure rating valve must match the pressure rating on the geyser.

Multi-valve (pressure control valve – PCV): This is a water pressure control valve fitted to the cold water supply to the geyser. The purpose of the pressure control valve is to “balance” the water pressure of the hot and cold water supply to baths, showers and basins.   For a balanced system the cold water supply to baths, basins, showers etc. must be taken off the supply between the pressure control valve and the geyser.  The pressure control valve reduces the cold water pressure to the same pressure of the hot water coming from the geyser. At Tokara the 400kPa (Red top) pressure control valve is located outside of the house – where the cold water supply enters the house.   The pressure control of the multi-valve is designed to release excess pressure and may therefore drip via the discharge pipe when water is drawn through the valve.  Each geyser must also be fitted with a pressure control valve. As most geysers have a maximum working pressure it is vital that the pressure is controlled for the geyser to have a longer life span. If no pressure control valve has been fitted, then the geyser guarantee will likely not be honored.

Electrical isolator switch:  Should be within 1m of the geyser.  The geyser also has to be earthed.  There should be a cover over the thermostat and element. These are often just left lying next to the geyser.

Thermostat:  Regulates the water temperature inside the geyser.  A good temperature for household use is 60 degrees centigrade.  Legionnaires’ disease cannot live in water above 55 degrees centigrade. See article on legionnaire’s disease here.

Self-sacrificing anode:  Anode rods that come installed with geysers are generally made of magnesium or aluminium that is wrapped around a steel core wire. Water heater anode rods are screwed into the tank.  Because the rod is made with a higher current potential than other metals in the water heater, it will ensure that the galvanic current flows from the rod to other exposed metals, preventing their corrosion. In other words, the anode rod corrodes and not the tank or the element. The anode rod is “self-sacrificing.”  When there’s no sacrificial metal left on the anode, the tank can rust out. Anode rods generally last about five years but this depends on the quality of the water and how much water travels through the geyser. Not replacing a depleted anode rod will shorten the life span of the geyser.

Plumbing piping: The pipe into and out of the geyser must be copper or galvanised steel. The PCV and T&P vent pipes also have to be steel or copper, especially the T&P vent. The hot water should be carried in copper, steel or suitably rated (70 degrees) plastic or metal-sheathed composite pipe.

Correct Geyser installation (600kPa) – adapted from and courtesy of Kwikot

1. Anode.
2. Thermostat – SANS 181.
3. Element.
4. Flange Gasket.
5. Flange.
6. Earth stud.
7. Thermofused Porcelain Enamel Lining.
8. Urethane Insulating.
9. Vacuum Breaker (green top is for a 600kPa while the red top is for a 400kPa system) shall be installed on both hot and cold-water pipes to ensure that siphonage of the water heater is prevented. The vacuum breakers shall be installed with a minimum of 300 mm above the top level of the geyser and the vacuum breaker on the hot water outlet shall be piped a minimum of 200 mm away from the hot water outlet.
10. Safety Valve or Temperature & Pressure Relief Valve also called TP valve, shall have the same pressure rating as the geyser.
11. Draincock.
12. Kwikot Multi Valve (Cobra Masterflo) which shall have the same pressure rating as other valves used in the system and the discharge pipe not less than the size of the outlet of the valve with maximum two 45° bends.
13. Kwikot geyser Tray. The size of the drip tray shall be such that it will cover the total area of the heater and the associated water control appurtenance.
    The support structure for the drip tray and water heater, must be placed on tie beams that are supported on load bearing walls, at least grade 5 of SANS 1783-2, of a size 114 mm x 50 mm or bigger and may not be spaced more than 500 mm apart.
14. Distribution board.
15. Earth Leakage.
16. Geyser Circuit Breaker.
17. Cable Size, minimum 2.5mm².
18. Isolator Switch, 1m away from Electrical Connection to Geyser.
19. Copper Pipe for incoming cold water after main stop-valve. The pipes shall be thermally insulated and firmly anchored to prevent water hammering and the dislodgement of joints.
    • There shall be no stop valve (isolating valve, gate valve, non-return valve, or similar flow-control device) in the cold water supply line between the pressure control valve (also called pressure reducing valve or PRV) and the geyser. This is a key requirement to ensure the pressure relief/expansion function isn’t blocked, preventing dangerous pressure buildup in the cylinder. Multiple sources, including manufacturer guidelines, plumbing compliance explanations, and direct references to SANS 10254, confirm this explicitly—no valve of that type is allowed in that section, as it would void warranties and fail compliance (and could be unsafe).
    • If a stop valve is needed (e.g., for maintenance near the geyser, or in cases where the main pressure control valve is installed further upstream for balanced pressure systems common in modern installs), then a relief valve (specifically an expansion control valve or pressure relief valve) must be installed between that stop valve and the geyser. This additional relief valve protects the geyser from trapped pressure when the stop valve is closed, allowing expansion/relief downstream of any isolating device. It must be properly piped (e.g., overflow to a safe drain, often over the drip tray), as per SANS 10254 rules.
20. Discharge from valve
    The discharge pipes from expansion control and safety valves shall
    • be of a size not less than the size of the connection to which they are fitted with due consideration to the fact that the maximum length of run is 4m and for runs that exceed 4m, the sizes shall be increased over the whole length to a maximum of 9m
    • have three or fewer bends for each additional bend, the maximum drain pipe length shall be reduced by 600mm; all bend shall be a maximum of 45° or formed with a center-line radius at least five times the diameter of the drain pipe
    • shall be installed that
      1. they incline downward continuously to their outlet
      2. drainage of both valve and pipe is ensured
      3. blockage due to freezing or foreign objects is prevented
      4. when flow occurs from them the flow can be readily observed with the minimum risk of injury or damage due to steam or hot water
      5. they are never joined together
      6. each is led to a discharge point which is visible outside the building and in a position where the discharge from the pipe will not cause a nuisance and also cannot be blocked
      7. water traps which could prevent the free flow of air into the system do not develop
    • in the case of safety valves, always be of metal and be inclined downwards away from the valve
    • be used for conveyance of water resulting from the normal expansion of heated water and shall discharge to the atmosphere in a position where the discharge is readily discernable but shall not inconvenience the buildings occupants or cause damage to the building.
21. Hot Water Outlet and Copper Pipe for supply to the house. The pipes shall be thermally insulated and firmly anchored to prevent water hammering and the dislodgement of joints.
22. Kwikot 600 Dual geyser, 600kPa SABS Approved.
23. Cold Water Inlet.
24. Earth Connection.
25. Geyser Tray Overflow pipe to Exterior of Building. The discharge pipe shall be connected to the discharge connection of the tray and shall be sized, laid out and supported to comply with SANS 10252-1 and SANS 10252-2 and shall be led through an the external wall in order to discharge on the outside of the building in a visible position. The joint between the discharge pipe and the discharge connection of the tray shall be made leak tight.
26. Earth Bonding Strap between Hot and Cold Water.
27. Cold water supply to the house for a balanced hot- and cold-water system.
28. Thermal insulation of pipework
    Thermal insulation with a minimum thermal resistance (R-value) of 1,0 m²·K/W shall be installed on the relevant pipework in accordance with the requirements of SANS 10252-1 (Section 6, including subclause 6.7.5) and, where applicable, SANS 10254.  The insulation shall cover:
    • the first 3 m of hot water outlet pipework from the water heater connection;
    • the first 1 m of cold water inlet pipework to the water heater connection; and
    • the first 1 m of the temperature and pressure (T&P) relief valve discharge pipe from its connection to the water heater.
      (As illustrated in the image below.) 
      The insulation material shall: 
    • be suitable for the operating temperatures and conditions of use; 
    • resist water absorption to maintain its thermal performance; and 
    • be continuous over the specified lengths, with joints properly sealed.
      All exposed insulation shall be protected against degradation (including UV exposure, weathering, mechanical damage, and moisture ingress) by means of a durable waterproof barrier or cladding. Where installed in exposed locations, the protective covering shall be finished with a good-quality, weather-resistant coating (such as roof paint or equivalent UV-resistant paint).  The installed thermal insulation and protective covering shall be inspected annually and repaired or replaced as necessary to ensure continued compliance and performance.
29. Main water stop-valve of the unit.
30. Main water inlet to the unit.
31. Drain.
32. Water Meter.

Geyser Compliance Checklist – courtesy of IOPSA