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Corrosion is an electrochemical reaction involving the transfer of electrons. For the reaction to take place a 'cell' comprising an electrolyte (liquid that conducts electricity), an anode (positive electrode), a cathode (negative electrode) and a conductor circuit are all required.
Corrosion is accelerated by impurities in the metal surface and by the presence of acids or other ionic compounds in the electrolyte (central heating water). Differences in temperature can also create anodic and cathodic areas, where the hotter part of the metal (steel) is usually the anode whereas with copper the hotter part is the cathode. Corrosion inhibitors form a 'passive' protective layer on the metal surfaces, thus closing down the corrosion cell.
Is System Inhibitor compatible with Fernox and Sentinel inhibitors? It is not recommended to mix inhibitors from different manufacturers. Drain down before using System Inhibitor.
Can Salamander products be used with stainless steel components? Stainless steel is a form of steel containing a high percentage of chromium, a low percentage of carbon and often other elements such as nickel and molybdenum. Because stainless steel does not rust or stain its gaining popularity as a construction material for central heating systems, but the presence of chloride (flux) increases the susceptibility of pitting attack. It is therefore important to clean and inhibit systems of this type with Cleaner and System Inhibitor.
Can Salamander products be used with under floor heating? Under Floor Central Heating (UFCH) is gaining popularity in the UK. It uses a network of under floor polybutylene (PB) barrier piping to radiate heat from under the floor. Although the pipe system itself will be "corrosion and scale free", this will be connected to metal components such as the boiler, manifold system, circulatory pump, or possibly integrated with existing radiators. Polybutylene pipe fittings are often of the "push-fit" type and as such are susceptible to air ingress. Untreated, this will lead to an unwanted increase in the resistance of the network due to the formation of corrosion and sludge debris. It is therefore important to clean and inhibit systems of this type with Cleaner and System Inhibitor.
How long will System Inhibitor last? We recommend that inhibitor levels are checked annually. If for any reason the system is drained, it will be necessary to re-treat with System Inhibitor. As overdosing is not detrimental, it is good practice to add a new bottle of System Inhibitor every one to three years.
How often should I have my boiler serviced? Have central heating boilers and heating appliances serviced regularly; at least annually. While water treatment chemicals will extend the life of your system, they should not be regarded as a means of extending service intervals. The burner will need regular servicing to ensure that no hazards to health arise from combustion products such as odourless and toxic carbon monoxide (CO) gas. Small doses can cause drowsiness, headaches and nausea, whereas large doses can be fatal. [All businesses or individuals that undertake gas work (natural gas or liquefied petroleum gas) must by law be registered by CORGI or in the case of oil fired, be registered by OFTEC. For solid fuel domestic heating appliances, the SFA in conjunction with HETAS operate a registration scheme for heating engineers]. To find a local qualified plumber follow this link: www.registeredplumber.com Ask your plumber to provide an "Installation, Commissioning & Service Record Log Book" which you should retain. Make sure that it is updated, recording any service work that is carried out, together with details (including dates of installation) of water treatment chemicals.
My boiler is operational but my radiators are cold. Why? There are a number of possible reasons:
If this last diagnosis solves your problem you are advised to contact a qualified plumber and have your circuitry checked out, as all control components should be electrically interlocked to prevent boiler cycling when no demand for heat exists.
Some radiators are hot and others are cold; how do I balance the system? The following instructions are for correctly installed two-pipe (parallel) systems. One-pipe (series) systems can be very hard to balance due to reducing water temperature.
The procedure for balancing the system is as follows:
All radiators should now get a proportionate share of the heat, rather than the early radiators returning hot water before it has even had a chance to reach the later ones. Room comfort adjustments can be made with the radiator wheel valve. Remember to replace the covers on the lock shield valves, as the exposed valve stems can be hazardous.
Can treatment be added to my system type? Whether your system has a regular boiler, combination boiler, is condensing or non-condensing, is 'low water content' or has an open or room-sealed flue, as long as it is a fully indirect system, then water treatment products can be used. (Excepting those with Primatic cylinders). However, what is important to determine, is whether your system has a feed and expansion tank (also known as open vented systems) or whether it is sealed, as this will affect the methods of installation available to you. If you have a feed and expansion tank, then treatment can be added via the tank or easily via a radiator. If your system is sealed (no feed and expansion tank) the function of the header tank (system pressure) will be provided by an expansion vessel. This may be integral within the boiler casing or may be external. The presence of a pressure gauge on the boiler is another indicator that the system is sealed. Water treatment products can be added to sealed systems but this work is best completed by a qualified plumber. Dosing vessels (akin to lawn sprayers) are available from builders merchants which allow treatment chemicals to be added under pressure via the radiator bleed valve or the filling loop.
Can Cleaner be used in power flushing machines? Yes, as well as using cleaner for a conventional flush, it can be used in flushing machines to clean central heating systems. Circulate for minimum 1-2 hours with warm/hot water for best results.
How long can I leave Cleaner in the system? The table below shows the duration that Cleaner should be left in a circulating system. Match to the nearest description of your circumstances. For optimum cleaning, ensure that no parts of the system are closed off.
Cleaner contains inhibitors and can be left in for longer in an emergency, however we strongly recommend that the system is flushed to remove the debris that Cleaner will mobilize, and that the system is protected with System Inhibitor at the earliest opportunity.
Should I use my domestic water softener to fill my central heating system? No! Artificially softened water should not be added to your central heating system. Base-exchange softeners replace calcium and magnesium ions with sodium. This has a tendency to increase the corrosiveness of the water because when sodium carbonate is heated it decomposes to carbon dioxide and caustic soda. Use normal 'mains' water which has not been processed through the water softener, together with System Inhibitor.
My Feed & Expansion tank contains 'foulant'. Will System Inhibitor remove this? System Inhibitor is a mild biocide, but if your feed and expansion tank is contaminated with a jelly-like substance that smells (which could be bacteria, algae, fungal growth or yeast formation) then you should bail out the tank and rinse with a 10% solution of household bleach. Observe good personal hygiene practice. The expansion of warm water into the feed and expansion tank, together with the ventilated loft space means that the ideal environment has been provided for airborne bacteria and spores to thrive. Although one might expect the natural 'pasteurization' effect (15-30 minutes at 60°C) within an active central heating system to kill off these bugs, their effect on water quality can be detrimental. Its therefore important to remove this contamination. Organic matter in their metabolism produce change in the composition of water; algae remove carbon dioxide and give off oxygen while other organisms consume oxygen. Decay of organic matter may also generate corrosive amino-acids. Sulphite Reducing Bacteria (SRB's) for example which produce hydrogen sulphide cause corrosion directly but are only active during periods of inactivity. (Over the summer for example). There are, however, mesophillic and thermophillic SRB's which can survive and grow in hot water. Treating a clean system with System Inhibitor and covering the feed and expansion tank with a close fitting lid should prevent reoccurrence of the contamination.
How do I add treatment via a radiator? Best performed on open vented systems (those with feed and expansion tanks) to avoid pressure loss in sealed systems: You will need a short length of hose/tube, a funnel, a radiator key and an assortment of spanners. Keep a rag handy to mop up minor spillages. This procedure should be performed when the system is off and cold.
Adding treatment via a radiator is an effective way of getting all the treatment into the system with the minimum amount of lost protection time.
My bleed valves are located behind the radiators; how do I add treatment? If your bleed valves are located behind and directly within your radiators you will have to add treatment via the feed and expansion tank, or in the case of a sealed system we advise you to contact a qualified plumber.
Does my water quality affect my central heating system? In a word, YES! Hard water tends to be scale forming, whereas soft water tends to be corrosive. Either way, an inhibitor is beneficial. Levels of calcium and magnesium in the domestic supply vary throughout the country. There is no UK maximum limit for hardness. Higher levels of hardness will be found in areas where rain-water percolates through limestone rock. Granite or surface water supplies will tend to be softer. If white deposits form on your kettle element, or white scum floats in the bath, these are indicators of scale. Heating causes dissolved bicarbonates to form solid carbonate limescale and is more likely to happen when temperatures exceed 60°C. A simple test can be carried out with vinegar. Scale will fizz slightly and give off bubbles. Because your central heating system re-circulates the same water, there is little opportunity for new hardness salts to enter the system, unless you have a leak! Unfortunately the small amount of hardness will tend to deposit itself on the hottest part of the system, resulting in irritating noises. Hardness is measured in parts per million (ppm) of calcium carbonate (CaCO3). See table below for the description of hardness levels:
In soft water areas the installation of System Inhibitor will protect the metals from the corrosive nature of the water and in hard water areas, the scale inhibitor within System Inhibitor will control hardness. In very hard areas it is recommended to additionally install System Silencer.
My boiler makes knocking and kettling noises. Will System Silencer reduce these noises?
Scale forms because the solubility of its prime constituent, calcium carbonate decreases with increase in temperature. Scale is also a poor conductor of heat, hence heat transfer will be reduced while the temperature of the metal beneath will increase as scale acts as an insulator. System Silencer contains ingredients which will remove baked on scale and sludge from the heat exchanger and keep them in solution. Over a period of several weeks after installing System Silencer you should note a marked reduction in the noise emanating from the boiler. You can also make some minor adjustments to tune your system which will help reduce boiler noise; turn down the boiler thermostat (not to be confused with the room thermostat which should be situated some way from the boiler) and if your circulating pump has a multi-speed facility, increase the pump speed.
If I add System Silencer, do I also need to add System Inhibitor? Yes, System Silencer will prevent scale and should be left in the system permanently, however it is additionally necessary to add System Inhibitor to protect the metallic components. System Inhibitor also contains scale inhibitors, but in extremely hard water areas, or if your system suffers from knocking and kettling then System Silencer is recommended in conjunction with System Inhibitor. In summary, System Inhibitor can be used on its own, but System Silencer should be used with System Inhibitor.
My pipes creak and tick; will System Silencer stop this? No! If the noise emanates from under the floor or within the walls, away from the boiler, then the most likely cause will be that the pipe's free movement has been constrained and the noise is thermal stress. (Radiators may also be heard to creak in their brackets). Pipes expand when hot and contract as they cool. For example, each 1-metre length of copper pipe-run will increase axially by 1 millimetre over a 60°C temperature gradient. Adding treatment chemicals will not break the laws of physics! If you wish to eliminate the noise then you have little choice but to lift the floorboards or break into the wall and make provision for movement. Pipes that run parallel to joists should be secured with clips that allow movement whereas pipes that run across joists should sit in large enough notches to accommodate felt lagging to cushion against rubbing. Alternatively you might consider adjusting your programmer so that your system comes up to temperature (and cools) at times during the day when the creaking noises will be less obtrusive. Humming noises usually emanate from the circulator pump. Vibration noises of this type can be caused by an ineffectual mounting bracket or wear to the impellor shaft/bearing.
There are two tanks in my loft. Which one do I add the treatment to? The central heating feed and expansion tank is usually smaller than the main water tank; it holds only about 10 to 25 litres. If you are unsure which is the correct tank, turn on a hot water tap. The tank, which does not refill is the central heating feed and expansion tank.
There are three tanks in my loft. Which one do I add the treatment to? It would seem that your installer in placing three tanks in the loft, has considered your use of a shower unit. Run a hot water tap and check the tanks in the loft to see which one is refilling. Do not place treatment in that tank. Run the shower unit cold water side only, and check the tanks in the loft to see which one is now refilling. Do not place treatment in that tank either. Treatment should only be added to the header tank which supplies the central heating system. The water may appear stagnant, and is often discoloured.
How long does it take for sufficient treatment to enter the system via the header tank? Depending upon the size of the system, the design and the rate of expansion / contraction, it can take between 1 and 6 weeks for sufficient treatment to be drawn into the system. While this is an acceptable method for 'topping up' a treated system, clearly its not fast enough for Cleaner for example which should only be left in the system for a maximum 4 week duration! Nor is it advisable to add the first shot of System Inhibitor this way; better to follow this procedure:
If for any reason you want to completely empty your system, tie up the ball valve to prevent the feed and expansion tank from refilling.
A pinhole leak has appeared in a radiator. What should I do? Pitting corrosion usually causes pinhole leaks. The symptom would indicate that either the system was not cleaned and treated and that copper is in solution which has deposited onto the less noble steel radiator, or an aeration fault such as pumping over has caused oxygen pitting. The latter condition may be identified by the presence of orange coloured system water. As a temporary measure, isolate radiator, mop up spillage and attempt to plug the pinhole with epoxy or other suitable non-metallic plug. The failed radiator will require to be replaced. Observe colour of the system water. It is likely that pitting corrosion is also occurring in other parts of the system, so it would be wise to replace all the radiators to prevent a repeat of the incident. Investigate pumping over if orange coloured water was found. Rectify mechanical fault. Ensure the static head (vertical distance between pump and expansion tank water level) meets the minimum recommendation of the pump manufacturer. Drain and flush (with Cleaner) then treat with System Inhibitor for ongoing protection.
Pumping over occurs when water is pumped over the open vent pipe and into the feed and expansion header tank. This cannot happen in sealed systems. It can be caused by an incorrectly placed circulator, too high circulator speed, insufficient static head or incorrectly sited system components. Conversely, seesawing is where water is pumped up the feed and expansion pipe. In either case, if there is enough thermal contraction then re-oxygenated water will be drawn into the primary circuit which will promote corrosion. The first likely evidence will be pinholes in radiators. A correctly installed system will create positive pressure in as much of the installation as possible. The diagram below shows correct 'left to right' and 'right to left' installations. If the order in your system is different then we recommend you contact a qualified plumber.
B=Boiler
What is a WRAS approved formulation? WRAS (Water Regulations Advisory Scheme) approved formulations are tested against BS6920 (materials which have passed full tests of effect on water quality) and those products which pass are listed in the Water Fittings and Materials Directory under section 6030 "FLUIDS FOR INDIRECT SYSTEMS".
The SEDBUK (Seasonal Efficiency of Domestic Boilers in the UK) rating was developed under the governments Energy Efficiency Best Practice Programme to provide a fair comparison of different models of boilers and is a measure of the average annual efficiency under typical operating conditions.
Changes to the Building Regulations for England and Wales (part L1) which came into effect on 1st April 2002 to help reduce the United Kingdom's production of carbon dioxide, require domestic boilers fitted to new buildings to have a SEDBUK rating of A to D. Non-compliant boilers may be fitted into existing buildings until 31st August 2002. The use of Cleaner to commission new systems followed by treatment with System Inhibitor will ensure that the efficiency rating is maintained.
Does System Inhibitor contain mineral oil? No, System Inhibitor does not contain mineral oil. Furthermore, nor do Cleaner and System Silencer.
Does System Inhibitor contain nitrite? No, System Inhibitor does not contain nitrite, nor do Cleaner and System Silencer.
Does Salamander offer any field service testing facilities? Yes, we can provide comprehensive testing to support our products. Considering a move? Then why not use our laboratory analysis sample service to survey the central heating system prior to purchase?
For more information about testing, please contact us in writing, by phone or via the feedback form.
I can't find an answer to my question; can Salamander help? We have tried to answer the most common questions but in the event that you have not found a satisfactory response, please complete the feedback form and an expert will contact you shortly. Many thanks.
Last Update (dd/mm/yy hh:mm:ss): 13/06/03 11:09:07 |
