Dealing with scale without using chemicals...Condensing boilers often have two heat exchangers as...
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I t is often a surprise to many plumbers and heating engineers that some of the more powerful electronic or electro mag- netic water conditioners can be very effective at clearing existing encrusted scale from heaters, appliances and pipework. Traditional methods of treating scale encrusted appliances can involve time consuming descaling using chemicals that then have to be neutralised and then disposed of. Apart from the down time and health hazards associated with chemicals, an undesirable side effect is etching of the metal, making the surface more conducive to scale formation in the future. The result is that each time the plant is descaled, the more quickly it scales up again. As an alternative to the traditional descaling methods, an electronic water treatment system, such as our Water-King system, is capable of rapid and effective descaling without chemicals and without any down time. The exact mechanism by which the descaling process is achieved is still not fully understood, but what is very clear is that it does not dissolve the existing scale. It actually reduces the bonding of the scale to the surface it is attached to so the scale comes away in chunks or plates. Perhaps the best way to describe the process is ‘exfoliation’. The result is a collection of scale particles in the plumbing, some of them quite big, but clean pipes and calorifiers. You would expect this process to take a very long time to remove all the encrusted limescale, but what is surprising is the way that the scale actually breaks down very rapidly, normally within a few weeks of treatment com- mencing. After a couple of months, it is common to find that all the scale has broken away from the surfaces previously en- crusted, leaving the under- lying surface almost entirely scale free. Taking the strain All this scale let loose in a domestic hot water system can cause its own problems. The larger particles get broken down and can eventually emerge as sand or grit, but this can play havoc with point of use strainers and some plant. To overcome this problem we recommend that con- sideration is given to fitting a hot water backwash filter, such as the Judo JRSF, on the hot water line. Installed on the hot flow, a filter will reduce the need to keep cleaning out local strainers fitted to blending valves. Where a hot water secondary return comes back to a direct fired water heater we recommend filtering between the circulation pump and the water heater. This is especially important in the case of direct fired water heaters where a sudden influx of old scale can result in the heater failing. The JRSF filter allows backwashing to be done without interrupting the supply of hot water. There is no need for a bypass or spanners, it is just a matter of turning a spindle through 360 degrees and opening the vent to let the waste material go to drain. It can even be set up to backwash automatically when the pressure differential reaches a pre set level. The backwash cycle can be triggered by time lapse or the pressure differential across the filter. This means that the whole filtering and backwash process can be carried out independently of any maintenance or service personnel whilst being monitored by the BMS. Shower power Modern shower mixers and thermostatic blending valves are highly sensitive to small particles of grit and scale, so most of them incorporate strainers to ensure safe and proper working. This in turn leads to increased maintenance to service these strainers. Area strainers may reduce the need for individual servicing but they in turn require their own regular maintenance which can result in an interruption of the water supply at in- convenient times. However, instead of having to go around cleaning every strainer in a shower block once a month, all that is necessary is a weekly backwash of the JRSF that takes about five minutes. The Judo JRSF backwash filter is a simple solution to the problem of servicing multiple point of use strainers. An example of a typical application is The Caravan Club site at Henley on Thames. Like most busy sites in the summer, the shower block is very popular and gets heavy continuous useage. The maintenance staff found that they were having to service the strainers to the shower blending valves about every four weeks to clean out scale particles that were lodged in the 500 micron strainers. With two strainers on each shower, it was a time consuming job and it also meant closing off the shower block, which was not popular with the guests. In June last year a Judo JRSF hot water filter was installed on the flow from the water heaters and the results have been dramatic. Since the installation of the filter, it has not been necessary to service the strainers at all, even through the peak summer holiday months. Backwashing of the filter is carried out once a month and only takes about five minutes with no in- terruption of the flow to the showers. The benefits of non chemical descaling are very considerable. It is a lot less expensive, safer and more convenient than chemical descaling and combined with strategically placed backwash filters, plant that would otherwise be con- sidered only for scrap can be rescued and have its effective life prolonged. Water-King installed with a JRSF Backwash filter fitted on hot flow protecting strainers at the Caravan Club An inside look at the JRSF A piece of scale found in the bottom of a ship’s calorfier two months after a Water-King had been installed Dealing with scale without using chemicals An electronic water treatment system, coupled with the installation of a backwash filter system, can provide an effective way of dealing with the problems of scale. Jonny Seccombe, MD at Lifescience Products, argues that such non-chemical solutions represent a better solution. 163 Hydropath issues condensing warning
Transcript of Dealing with scale without using chemicals...Condensing boilers often have two heat exchangers as...
44 March 2005
It is often a surprise tomany plumbers andheating engineers that
some of the more powerfulelectronic or electro mag-netic water conditionerscan be very effective atclearing existing encrustedsca le f rom heaters ,appliances and pipework.Traditional methods oftreating scale encrustedappliances can involve timeconsuming descaling usingchemicals that then have tobe neutralised and thendisposed of.
Apart from the down time and health hazardsassociated with chemicals,an undesirable side effect ise tch ing o f the meta l ,making the surface moreconduc ive to s ca leformation in the future.The result is that each timethe plant is descaled, themore quickly it scales upagain.
As an alternative to the traditional descalingmethods, an electronicwater treatment system,such as our Water-King
system, is capable of rapidand effective descalingwithout chemicals andwithout any down time.
The exact mechanism bywhich the descaling processis achieved is still not fullyunderstood, but what isvery clear is that it does notdissolve the existing scale.It actually reduces thebonding of the scale to thesurface it is attached to sothe scale comes away inchunks or plates. Perhapsthe best way to describe theprocess is ‘exfoliation’. Theresult is a collection of scaleparticles in the plumbing,some of them quite big, butclean pipes and calorifiers.
You would expect thisprocess to take a very longtime to remove all theencrusted limescale, butwhat is surprising is theway that the scale actuallybreaks down very rapidly,normally within a fewweeks of treatment com-mencing. After a couple ofmonths, it is common tofind that all the scale hasbroken away from thesurfaces previously en-crusted, leaving the under-ly ing sur face a lmostentirely scale free.
Taking the strainAll this scale let loose in adomestic hot water systemcan cause its own problems.The larger particles getbroken down and caneventually emerge as sandor grit, but this can playhavoc with point of usestrainers and some plant.To overcome this problemwe recommend that con-sideration is given to fitting
a hot water backwash filter,such as the Judo JRSF, onthe hot water line.
Installed on the hot flow,a filter will reduce the needto keep cleaning out localstrainers fitted to blendingvalves. Where a hot watersecondary return comesback to a direct fired waterheater we recommendf i l t e r ing be tween thecirculation pump and thewater heater. This isespecially important in thecase of direct fired waterheaters where a suddeninflux of old scale can resultin the heater failing.
The JRSF filter allowsbackwashing to be donewithout interrupting thesupply of hot water. Thereis no need for a bypass orspanners, it is just a mattero f turn ing a sp ind lethrough 360 degrees andopening the vent to let thewaste material go to drain.It can even be set up tobackwash automaticallyw h e n t h e p r e s s u r edifferential reaches a preset level. The backwashcycle can be triggered bytime lapse or the pressuredifferential across the filter.This means that the wholefiltering and backwashprocess can be carried out
independent ly o f anymaintenance or servicepersonnel whilst beingmonitored by the BMS.
Shower powerModern shower mixers andthermostatic blendingvalves are highly sensitiveto small particles of gritand scale, so most of themincorporate strainers toensure safe and properworking. This in turn leadsto increased maintenanceto service these strainers.Area strainers may reducethe need for individualservicing but they in turnrequire their own regularmaintenance which canresult in an interruption ofthe water supply at in-convenient times. However,instead of having to go
around cleaning everystrainer in a shower blockonce a month, all that isnecessary is a weeklybackwash of the JRSF thattakes about five minutes.
The Judo JRSF backwashfilter is a simple solution tothe problem of servicingmult ip le po int o f usestrainers. An example of atypical application is The
Caravan C lub s i t e a tHenley on Thames. Likemost busy sites in thesummer, the shower blockis very popular and getsheavy continuous useage.The maintenance stafffound that they werehaving to serv ice thestrainers to the showerblending valves about everyfour weeks to clean outscale particles that werelodged in the 500 micronstra iners . Wi th twostrainers on each shower, itwas a time consuming joband it also meant closing offthe shower block, which was not popular with theguests.
In June last year a JudoJRSF hot water filter wasinstalled on the flow fromthe water heaters and theresults have been dramatic.Since the installation of thef i l ter, i t has not beennecessary to serv i cethe s t ra iners a t a l l ,even through the peaksummer holiday months.Backwashing of the filter iscarried out once a monthand only takes about fiveminutes w i th no in -terruption of the flow to theshowers.
The benefits of nonchemical descaling are veryconsiderable. It is a lot lessexpensive, safer and moreconvenient than chemicaldescaling and combinedwith strategically placedbackwash filters, plant thatwould otherwise be con-sidered only for scrap canbe rescued and have itseffective life prolonged.
Water-King installed with a JRSF Backwash filter fitted on hot flowprotecting strainers at the Caravan Club
An inside look at the JRSF
A piece of scale found in the bottomof a ship’s calorfier two monthsafter a Water-King had beeninstalled
Dealing with scale without using chemicalsAn electronic water treatment system, coupled with the installation of a backwash filter system, can provide an effective way of dealing withthe problems of scale. Jonny Seccombe, MD at Lifescience Products, argues that such non-chemical solutions represent a better solution.
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Hydropath issues condensing warningWater treatment expert DrDaniel Stefanini of Hydropathwarns that, although theGovernment’s intentions tocut domestic CO2 emissions byenforcing the use of con-densing combination boilersmay be sound, these goodintentions could potentially bewasted.
Condensing boilers oftenhave two heat exchangers asopposed to the traditionalsingle exchanger. The firsttakes the flue gasses andcondenses them, the secondtakes heat from the gas flame,so therefore the water isheated through two stages,and scale will be precipitatedin both stages. The boiler willconsequently be doublycompromised by limescale.
Hydropath points out thatits Hydroflow system oflimescale prevention has beenproven over the past ten yearsto prevent scale deposits,including calcium carbonate,and removes existing scalethroughout the entire heatingsystem. The product works by
emitting randomly-varyingelectric fields throughout thesystem. This enhances theprecipitation of the bi-carbonates from solution tosuspension by introducingclusters of ions in the water toact as seed for suspendedcrystallisation. The resultingsuspension therefore does notadhere to pipework or internalsurfaces, but is merely‘washed away’ with the flow.
Dr Stefanini explains:“Large parts of the UK havehard to very hard water, andperhaps no other householdequipment is affected quite so
much by limescale build-up asthe gas boiler. Just 0.4mm ofscale build-up in water willwaste 40ft3 of gas per 1,000ft3.This is because energy iswasted heating up the scalebefore it can heat up thewater. This rises to 27%wastage with 4.8 mm of scale –not an uncommon level ofbuild-up. Not only are runningcosts increased, but theexpected lifespan of the boileris reduced. If condensingcombis are not protectedsufficiently, the potentialinefficiencies are doubled.”
With chemically softenedwater becoming an increasingissue to environmentalists,and health workers concernedwith the build-up of sodium inthe watercourse, plumbersand heating engineers areincreasingly consideringphysical water treatmentsystems. This, combined withthe impending regulations onthe requirement to fitcondensing combi boilers,which are more expensive topurchase than conventional
boilers, means that customersare keen to reduce theirrunning costs, reduceemissions, and extend the lifeof their investment.
Hydroflow is claimed tooffer certain advantages suchas treating the water bothupstream and downstream ofthe unit, and also protectsstanding water, and is notdependent on water flowingpast the unit. The productsare said to be easy to fit toexisting and new systems, andoffer low operating costs. It isparticularly beneficial fordomestic heating systems,because if the water supply toboilers is not conditioned,scale build-up increases fuelconsumption and the boilerdeteriorates rapidly throughthe external overheating ofthe plates and tubes. If wateris softened ( i .e . treatedchemically) sodium carbonatehydrolyses to produce freealkali that is aggressive toboilerplates and tubes.
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