Electric Water Heating. British Vintage Documentary

that's about all I think oh except that young Johnson asked me to call in last week Johnson yes the chap in Elm Drive it seems he'd had a bit of a shock that morning a bill the electricity bill well now don't forget the emotion he said was your idea well tell me the worst nothing like as bad as I expected Tom's bill was terrific when he pitted either you've seen the heater in Tom's kitchen you'd know why could have a girl it was probably badly installed I'll get that check from the electricity board who pitted ours and take him down there of course she was dead right George the conversion of this fellow Tom's ancestral up water system to electricity was one of the worst layups I've ever seen what you gonna do with it I shall fit a self-contained e-town should have been fitted in the first place of course it's shorter you know a practical case like this makes my lecture tonight a bit silly Oh what's the subject planning the ideal solid fuel installation for conversion to electricity hmm very sensible I'm all for it would you ever get it read it yes no you read it try it on the dog buildin have to imagine me doing the demonstrations Oh try chip in if you got any suggestions right the heart of the solid-fuel hot water installation is the boiler it can be an independent boiler usually placed in the kitchen or a back boiler behind a kitchen range or behind a living room fire or behind a stove but one and all they must be sited near a flue so the position of the boiler is fixed next we need a storage vessel in some districts a copper cylinder is used in others a rectangular galvanized iron tank now where should we put this storage metal must it be close to the boiler to keep the flow and return pipe short answer prevent heat losses and not necessarily for in winter these pipes will help to heat the house and in summer when we use electricity there'll be no hot water circulating in it's much more important to avoid a long pipe between the cylinder and the sink for every time the sync tab is used and that's more often than any other tab in the house heat will be wasted you see the hot water left in the pipes leading to the sink will cool rapidly and it must be run off before more hot water can flow I've seen pipes in which you have to draw six pints of cool water before they run out yes and if that happens let's say 10 times a day it means 50 gallons of hot water are lost every week as I say the amount lost depends on the length of the draw pipe to the sink so let's put our cylinder beside the sink you better warn them about a long horizontal flow pipe engine I was just coming that when the boiler is idle and electricity is being used the water in the vertical length of flow pipe will be colder and heavier than the water in the cylinder this may set up a back circulation of water through the boiler the longer the horizontal length of flow buyed the colder the water in the vertical portion and the greater the risk of this heat wasting back circulation it can be entirely prevented if the flow pipe is kept at nearly the same temperature as the hot storage either by enclosing the pipe under the installation of the vessel or by running it up inside the vessel as a stand pipe or as in some districts by taking the flow pipe into the storage vessel immediately above the return pipe so finally we've found the best possible place for the storage vessel but we may not have the last word why cut it off my kitchen rise the housewife put it in my airing cupboard so upstairs it goes well fortunately for us the position of the chosen cupboard is not too far from sink or boiler wherever we put the vessel we must leave room for the immersion heater and three inches all run for installation do you really need three inches yes please three inches of good insulation if possible if a 30-gallon cylinder is left bare about 85 units of electricity a week can be lost with only a one inch of lagging we can reduce this to about 16 units lost but with three inch lagging we need only lose about six units a week and what do you call a good insulating material I always recommend granulated cork slag wool or glass fiber all of which are better insulators and easily applied by surrounding the vessel to the container well ready-made jackets very simple of course but they're still damn much more than one inch thick personally I'm not fond of magnesia cement for this sort of job it's a bit messy to apply not easy to build into a three-inch jagged in summer sufficient heat for airing will escape through the insulation however good we make it in winter when the boilers alight the extra heat needed to air clothes can be provided by a small heating loop from the flow and return pipes unless of course the vessel is high up in the cupboard when the flow and return pipes themselves will supply the extra yes next we must supply the cylinder with cold water so we must fit a system and this must be fitted with a ball valve we placed the cistern at a high point even in the loft of its permissible and from it we lead a cold water feed pipe down to the cylinder the cold water must enter the storage vessel at a low level in such a way as to give good stratification mm-hmm I think I put that more simply ah all right then so that the entering cold water does not mix with the hot water in the cylinder now with a cylinder the cold feed pipe will be taken to the bus provided at the side so the cold water will enter horizontally without mixing unduly with the hot water in the upper part side entry is also the best arrangement for a tank but in some cases the cold feed is brought through the top and down an inverted stand pipe this prevents mixing but may cause loss of heat through single pipe circulation you're going to explain single pipe circulation I hope certain a hot water in any vertical pipe will rise up the center of the pipe and the cooler water will flow down the walls causing single pipe circulation which may waste a lot of heat yes but this happens to be a cold feed pipe true but when no water is being drawn off the hot water in the tank will raise the temperature of the stand pipe and the water in it so causing single pipe circulation sometimes the cold feed to a tank is taken in at the bottom but mixing will occur unless a tee is fitted as a baffle obviously the cold feed pipe must never have a smaller diameter than the main draw pipe because cold water must flow into the cylinder as fast as the hot flows out well having maneuvered the cylinder near the sink don't throw away this advantage by taking the draw off pipe all around well there's the high-level draw of pipe which branches to the sink and then runs to the bath taps and the others then there's the low-level draw off from an internal standpipe which branches as before or again a combination of the two where the stand pipe serves the sink and the high-level draw off serves the rest of the house of course all pipes must be the right size or in feeding one you'll starve the rest I should add but don't make the sink pipe larger than necessary right the vessel also needs a vent pipe to get rid of air and steam but here's where you always get heat losses through single pipe circulation so the vent must be run horizontally for at least 18 inches just above the vessel while the top of the vent pipe should run up to discharge over the system and yes I'll write that in vent discharge over system good now having lagged our storage to conserve heat in summer we may find it overheats when using the boiler therefore let's circulate this excess hot water through radiators and towel rails but we must be careful for if they're connected to the draw piping or to the flow pipe a to higher-level electrically heated water will pass wastefully through them in summer this we must avoid at all costs we must connect them with a lower level or better still provide a separate circuit from the boiler and that completes our solid fuel system now let's add a thermostatically-controlled imagine heater thermostatically-controlled a what about the 3/8 which as an alternative mmm don't like him then alright with a thermostat anyway thermostats don't cost much more and a very reliable besides they give you a constant hot water without the bother of switching on and off the heater can be fitted vertically through the top of the vessel in this case a layer of hot water will collect at the top of the vessel the depth of this layer will gradually increase a circulator with a tube around the element to restrict circulation produces a similar effect even if the heater is not placed vertically in any case the link determines the total amount of water heated it can also be fitted from the side where it'll heat all the water above the element gradually and from the bottom where it will give a compromise between the other two positions and incidentally wear a shorter element will heat all the water in the vessel are you going to say anything about hard water ah yes that's a good point if the water's hard don't use a circulator because scale will soon clog the outlet hole and the element will burn out this will give you an idea of what scale can do while you're about it George say a bit about mixing copper and galvanized iron a metallic corrosion yes I've got a pretty good sample pretty bad you mean don't be tempted to fit copper pipes in connection with a galvanized hot water storage vessel and avoid whatever possible mixing copper and galvanized iron in one installation you may get away with it but you have been warned lastly a word about thermostats they're usually combined with the heater to avoid cutting two holes as the thermostat is affected by the average temperature along its length when placed vertically it should obviously be as long as the heater to register the mean temperature in the vessel whereas when horizontal its length is not critical because it lies in a water layer of even temperature but it must be at more or less the same level as the heater finally to recap here are the vital points in our system storage vessel near the sink no back circulation through the boiler a well lagged vessel the draw off pipe to the sink is as short as possible the cold water feed does not mix with the stored hot water no single pipe circulation in the cold water feed or in the vent pipe electrically heated water cannot circulate wasteful it through the tower rails and radiators the right type of immersion heater is fitted in the most suitable position the heater is controlled by a thermostat yeah in DES that's it [Music] for an outline of first principles George I think that's pretty good mmm-maybe what more do you want Hank well it's all theory hearing about that Elm Drive case reminded me Isle to give them some practical applications yes I suppose you should but now it is well let's have a look at the old case book yes here's one foil the house was an elderly Victorian mansion in the suburbs the basic installation wasn't much younger than the house and generations of plumbers professional and well not so professional and tried to keep it up to date the range have been replaced by a fairly modern independent boiler in the kitchen with flow and return piping leading upstairs the storage vessel had tank was in the linen cupboard and not too badly cited being next door to the bathroom and above the kitchen space heating consisted of a radiator on the landing and a towel rail in the bathroom miss Bennett the consumer had asked for an immersion heater were there any snacks the first thing that sprang to mind were the space heaters how were they supplied unfortunately from the flow and return pipes in the airing cupboard well that just wouldn't do I explained to miss Bennett that if the boiler was out the electrically heated water would circulate through the radiator and towel rail I should like to have run fresh piping direct to the boiler down in the kitchen but she wouldn't stand to the expense so low I didn't like to do it I advised fitting a valve to shut off the space heaters when the immersion heater was in use I hope you wrote to her saying you wouldn't be responsible to the bill if the valve was left open while the heat was on I most certainly did next I carried out a routine check on the installation the boiler was alight so first I tried the sink tap it ran cold for a long long time I collected nearly 6 pints in all a pretty big dead leg considering the vessel was only just overhead so I started to trace the jaw off piping it ran up to the bath across the landing to the bedroom basin and all the way back under the floor and down to the sink now why on earth shouldn't we take a half inch pipe direct from the drawer down to the sink I asked myself too expensive again I suppose not in the long run as I told the consumer savings in losses would soon justify the cost and she agreed to have it altered Miss Bennet was also worried because the bathroom coals of quickly now this was odd because the tank has obviously been meant to provide baths for a large Victorian family still everyone has different ideas about the size of a decent tub so I decided to check up sure enough it ran tepid after a few minutes I found the cold feed enter the top of the tank which implied a dip pipe inside perhaps the trouble they there sure enough later we decided to take off the manhole to fit the heater and we found some idiot had forgotten to fit the dip pipe at all the cold feed was pouring straight into the top of the hot storage as usual I warned my plumber not to leave in the tank any of the steel chippings he'd made while cutting a hole for the heater steel chips are bound to cause corrosion in a galvanized tank yes that's an excellent example bimetallic corrosion effect don't leave steel chips behind after cutting holes in tanks here's another job in an old house one which is being altered into flats on the upper two floors with a maser net below the boiler and cylinder in the basement that have be used by the maisonette the cylinder is fixed horizontally under the kitchen ceiling making good stratification most unlikely which is one good reason against the use of an immersion heater but furthermore the sink tap is taken from the flow pipe between the boiler and the cylinder which as you know was an old idea to provide a quick supply of hot water at the sink it won't work with an immersion heater of course because some of the water will run to the tap the long way around via the return pipe and the boiler and will be so cold that we only get tepid water at the tap so in a case like this I recommend the fitting of some type of self tane dieter for use in summer by the way you said nothing about them so far all right then self-contained heaters are factory assembled insulated vessels containing an electric element and a thermostat which are fitted as complete units these heaters may be of the one point non pressure type controlled at the inlet and they may be supplied by direct from the mains if they do not hold more than three gallons for the larger multi-point pressure type supplied from an external system the latter type includes the popular two-in-one heater with two thermostatically-controlled elements below which need switched on when a lot of hot water is needed there's also a cistern heater which is a fresh type containing its own cold water cistern and bulb this type may be connected director the mains however large its capacity well in the case of this maisonette on my advice the landlord decided to have a two-in-one heater fitted close to the sink under the draining board connected in series with the old draw pipe with a bypass and two fouls fitted at a and B a new vent for the heater and a new connection to the sink tap when valve a shut the electric heater can boost hot water from the cylinder or heat cold water from the cylinder if the boiler is not a light or when valve is shut the hot water from the cylinder goes direct to the taps the flats had no solid fuel system in the top one the main system was lower than the taps so he connected a system type heater direct to the cold water main in the middle flat we couldn't get a two in one under the draining board so we fitted an ordinary pressure heater as near the sink as we could yes flats are interesting here any problems with large blocks I've got one now where there's no central up water system and that needs its own leader it's a bit tricky for instance here's a case of a block of flats with several flaws we could fit two in one heaters but it will be on economical to run miles of individual cold feed and vent pipes a common feed pipe with a stop at the top is preferable but even so if the stop is closed and a tap in the bottom flat is opened hot water may be drawn from the upper flats even if we take each branch pipe off the main at a higher level in the heater it serves hot water might still be siphoned from the higher flats so we vent the down feed pipe below its stop and admit air to prevent siphoning as I suppose each flat really need to turn stop yes but not the loose jumper type huh why because it will prevent expansion from a heater from traveling up the cold feet and would force it up the vent pipe causing a discharge of hot water into the system and the wastage of heat I see the same sort of thing happens if the upper flats are starved do two wrong sizing of the pipes variations of pressure in the system may then calls surging through the vent pipes what happens if the cold feed freezes near the system then the main vent can't function and again siphoning may occur worse if the other vent pipes are frozen as well a partial vacuum may occur in the upper storage vessels which might collapse them we guard against this by fitting an anti vacuum valve alongside each branch pipe stopcock and against excessive pressure in the vessels by fitting each one with a safety valve in any case the heaters must also be strong enough to withstand the pressure due to the head of the building naturally but standard heaters are okay for anything up to 60-foot head another method is to fit small cold feed systems in each flat and from them feed two in one heaters the installation in each flat being vented to its own system or better still at birth use system type heaters yes but don't forget they can't be fitted as near the sink taps as the two-in-one heaters under the draining boards because the system part of the heater must be sufficiently high above the taps to give a reasonable head of water yes till contain either seem to be the answer to most problems well quite a few for instance here's a case in point an indirect job that reminds me in direct systems now it's no good I have to draw one the boiler is not connected to the storage vessel direct but to a heater inside it this primary circuit is not separate from the draw system and the same water simply circulates round and round thus saving the boiler from firing up in hot water districts now has a clean bowled now have you finished interrupting the job in question was a pretty palatial residence with an elaborate indirect system the cylinder was a new one on me and I couldn't tell at first glance if I could fit an immersion heater or not I was just debating whether to take off the manhole cover all wait and write to the makers when I realized that immersion heaters were out in any case why the depths were so far from the cylinder that the draw pipe was a circulating loop which would have wasted a lot of heat if we'd fitted an immersion heater to make matters worse there were various radiators and towel errors which would also have wasted electricity here again self-contained heaters seemed most suitable and our main problem was to know where to put them two bedroom basins in the small bathroom lay directly over the downstairs lavatory in the kitchen so we decided to use a multi-point heater for that group a two-in-one fitted under the draining board we were left with the main bathroom and upstairs lavatory and the three bedrooms in the other wing which we supplied from a 30 gallon self-contained heater fitted near the bathroom in that case of course the cost of conversion was one of the last things to consider but more often it is a prime factor yes I was talk about costs for instance only last week I was called one of those small houses on the Newtown estate housewife was dead keen to have constant hot water but didn't want to light the back boiler in the living room all the year round the case seemed to cry out for an immersion heater but there was a very long run to the sick also there was only room around the tank for an apology for insulation which would mean I costs if the heater was left switched on under thermostatic control so we fitted a sink heater to give it all the hot water she needed for household chores now she only has to light the boiler for baths and on washing day eat any more cases no I reckon I've got enough for one lecture good how are you going to finish ready for a pint ice thing yeah I feel probably given a problem you know what would you do it jumps fine and if teacher doesn't know the answer you probably find it in here you

Channel: Bill Parsons film archive

Views: 2,857

Rating: 4.9024391 out of 5

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Id: uLcfWmXxT2A

Length: 26min 46sec (1606 seconds)

Published: Mon Dec 11 2017