Dave Hannigan

30/03/09 Long Itchington to bottom of Hatton flight-no sign. Have not tried the Saltisford arm though, anybody there to confirm or deny??

Went from Calcutt to Long Itchington yesterday-no sign Dave

All back now, no mystery, all the signs along the M55 are being replaced at the moment. Don't know when they went back but spotted today. Dave

Certainly sounds good in principle. My initial thoughts are that these devices are fitted to boilers with fan assisted flues and only if approved by the boiler manufacturer that the flue fan can do the job. On a natural draught flue the temperature of the flue gasses contributes to the effectiveness of the flue and lowering this temp could stop the flue working properly, with obviously all sorts of nasty possibilities to do with CO poisoning. Also the flue above the condenser would condensate, which is acidic and could compromise the flue integrity. I have seen some condensing boiler installations where copper has been used as the condensate drain and has resembled a sieve within 18 months. Having said that, if you could get one to work properly, you could make a fortune. Dave

The only direct systems that I have come across are for hot water, with the boiler being a copper back boiler or gas circulator, they were never used for central heating. When central heating was added to hot water systems then the indirect cylinder came into being. I suspect what they are saying is not to use with a 'primatic' cylinder, or to give full title 'single feed indirect' cylinder. These used the cold water storage tank to supply the central heating circuit. They were designed so that when the system was full then the primary circuit (central heating) was separate from the secondary (domestic hot water) by an air bubble. Obviously with using the cold water storage tank then inhibitor could not be added. Dave

A cooker would not be regarded as a fixed appliance- they are will need to be moved for cleaning purposes. Personally I would rather a connection designed for that purpose than solid pipework that was not designed to allow cookers to be moved on a regular basis. I agree hobs and ovens meant to be secured in housing units should be solid pipework. Dave

28mm fittings will fit 1" imperial pipe compression or solder. Dave

There is also a certification specifically for boats, as the boat regs differ from other LPG installations. Dave

Sit back & enjoy

Not strictly true, it does not comply with the boat regulations, but is perfectly acceptable in domestic house pipework. Dave

Not necessarily the pump if you are fitting a modern boiler with pump overrun. Check with the boiler manufacturers instructions- the pump may be wired directly to the boiler. Dave

Lee Generally the red coloured are for heating systems, usually white for potable water, don't know if the difference is in the material used for the diaphragm or the material for the vessel itself. Presumably the potable ones are made of food grade materials. Also potable water is oxygenated whereas central heating water tends to be de-oxygenated and treated with corrosion inhibitors, so corrosion is not the same problem. dave

Hot water bottle, electric blanket or just snuggle up all cosy????? :lol:

Alan, Having reread some posts you gave an input pressure of 14" as against 14.8", are you able to measure the actual burner pressure and compare with the manufacturer's spec??. If this is down by the 0.8" or very close then changing the diaphragm probably wont help as the gas valve must be fully open. If you have a regulator and can pipe so you have the full 14.8" at the inlet and try rating the appliance again to see how much difference the 0.8" will make. The actual burner pressure is the governing factor in the heat output of the appliance and is the one thing to get right before looking for other faults. On these type of appliances the inlet pressure can directly affect the burner pressure at the full gas rate. If you get the inlet pressure right then if the burner pressure is low then look to the diaphragm or gas valve. If the burner pressure is ok then you will need to look at the heat exchanger. If doing the above is a pain, then a tenner on the diaphragm wont break the bank, and may save some work with the above and do the trick. If it doesn't the do the above. Feeding the Morco directly from a calorifier would be a no no, as if the engine had been running all day the calorifier could be around the 80deg mark and another 25deg would give you a steam shower-ouch!!! However as suggested feeding from a thermostatic blending valve set to 25deg would give you around 50deg. Although why use gas to heat the water thats already heated freebies???? It would I suppose make the calorifier hot water last longer, if there are a few aboard for showers. Good luck Dave

Alan, Is it possible to set the flow rate to Morco's spec and then measure the temp rise, so that you will know just how far off the spec you are??? Having been out last week the thing that we noticed was how much colder the cold water was than what comes from the tap at home. Could it be just very cold inlet temp thats causing the problem?? Dave

Signed

Chris, your EV is precharged to 35psi. When you put it into your system and turn thr water on but no pump, then (ignoring any head of water for simplicity as the head could only be a few ft of pressure in a boat) the air side is at 35psi (you set it), the water side is 0. When you turn the pump on the water side pressure climbs to 30psi (your figures). To do this the pump must force water into the system, that water can only be accomodated in the EV (assuming water is not compressible and no more air pockets in the system), therefore the diaphragm must move to accomodate this water, therefore its pressure must rise from 35psi. The water side is at 30psi as it is at the pump cut out pressure. When you heat the calorifier then the water will expand into the EV but the starting pressure for water side is 30psi while the air side is 35psi + increase due to the pump. The point I am trying to make is that the pressures will always be different with the water side being lower than the air side, with the result that although the EV is above PRV pressure it will not blow it. The water added by the pump could be measured by taking out of circuit any accumulators and, from cold, turn the pump off, open a hot tap and measure the volume of water that comes from the tap. This will give you the volume of EV filled by the pumps action and therefore the starting point for the expansion calculations. By the way according to Zilmet the design should be that the air pressure does not exceed PRV pressure. Just a simple way please point out all my flaws

Can I point out what I think is a flaw in many arguments and send you all off for another 12 pages??? An expansion vessel comes off the shelf precharged to an initial pressure-typically 0.5bar. Therefore the side to be connected to the water is at atmospheric pressure. Once connected it will initially be at the pressure given by available head of water. Forgetting expansion and heating, just the pump. When the pump is switched on the pressure of water will rise to the pump cut out pressure. The trapped air on the other side of the diaphragm will then rise from the initial 0.5bar, to what i dont know as I have a life and work to do so will leave that to others. The pressure on the water side is also free to fall back to the available head of water if the pump is switched off and taps opened. It does not matter what the initial precharge pressure of the EV is as the water side will always start from atmospheric go to pump cut out pressure and then to expansion presure, as I said I do not have the time to start working out volumes and pressures have to go to work now. It seems to me that everybody has missed the fact that EVs are precharged.

Hi Alan, from your figures it looks like 'thats as good as it gets'. The only thing that will make any difference is getting 14.8" instead of 14". Is it possible to measure the pressure at the regulator?? If you can and you get 14.8" at the regulator, then the 0.8" loss is due to pipework. If this is the case you must ask if the work to improve the pressure loss is worth the effort for the gain you would get. Without doing the maths I would guess ony a degree or 2- not the full 8deg at 2.5l per min

Hi Alan, Just some more thoughts for you. The pressures that you have measured are around normal, a little low but not low enough to make a significant difference. As you said the incoming water temp will have an effect but you should still be usable. Unfortunately on LPG it is not easy to measure the amount of gas used without some very accurate weighing and a bit of maths, so is not easy to guage whether the burners are overgassed. The air intake is set in manufacture so is unlikely to change and you have said is clear, likewise the injectors are brass and just passing gas are unlikely to alter radically in size If the flames are blue at the base with a well defined shape and (usually) a roar type sound then orange tips of flames could well be dust from the atmosphere or from the heat ex itself if you have just been cleaning it. If all the airways and flueways are clear then were you to do a flue gas analysis the I would expect the co reading to be below 10ppm quite often 0. The orangy flame may be a red (or orange ) herring. What is the flowrate of the water?? This can be quite easily measured, along with the temperature. According to Morco you get a 25degree rise at 5.4 litres per minute and 50 degrees at 2.7litres per minute, with the settings at max and min. If your flow rate is higher then you need to regulate to this and see what the rise is. I think you need to find out the flow rate through the appliance when it first fires. let me know the results

Hi Alan I have no direct experience with Morco so am working from a very bad diagram on the net. There will normally be another test point somewhere around the burners, which with the appliance off will read 0, so reads the actual pressure available at the burners. If this is lower than it should be then you will not be generating the heat required and could also account for the different flame picture you are getting. If the flames are fairly strong and blue at the base near the burners then orange tips could also be caused by dust from the atmosphere being drawn into the appliance. I'm assuming it is an open flue burner?? 13 years for a diaphragm, wish they could get domestic combi's and multipoints to last that long, I'm onto the third in my combi in 9 years, first one lasted about 6 and went on christmas day, the second one lasted 2. As I said I have no direct experience of Morco so am unable to advise on ease of change. You may be able to dismantle the water section from the rest of the heater, after that the diaphragm is usually straightforward. Some pictures may be useful Good luck

Hi, Alan Do you have access to a manometer ? If you do then measure the burner pressure, it should be 36mbar. If you have not got that make sure you have about that at the inlet side. If you have full pressure at the inlet but not at the burner, then my money would be on the diaphragm not opening the gas valve fully due to a hole. happy searching Dave

From the perspective of a CORGI registered installer, I can't see CAPITA making much more of mess than CORGI did. I was never one of CORGI's biggest fans, few have any sympathy for them. The obvious problem for most, of course will be letterheads, vehicle signage etc. The HSE appoint the company to run the gas registration scheme, but do not have juristiction in Northern Ireland, Isle of man, Jersey & Gernsey, so CORGI will continue to run the scheme there, now thats joined up thinking for you . The problem now is that the HSE allowed CORGI to run the scheme under their own copyrighted name so now the scheme is to be run by another company then a new gas safety brand has to be created. Whatever the name will be apparently will be owned by the HSE so another company could then run the scheme without the disruption that will occur come April One of the biggest critisisms of CORGI was the many ways they dreamed up to extract more money from the installer and used the database to flog everything from insurance to vans on 'special deals to CORGI installers' all of which could be found considerably cheaper with a quick internet search. CAPITA ,apparently will just run the gas registration scheme with no added extras. Personally I think there should be one central register with several competing companies operating the scheme, so that we would all be 'X registered' to the public but could choose from competing companies to register with. The one thing that we can safely predict is that the whole thing will be a complete cockup

Whats the flame look like when lit? blue with or with yellow tinge? Is this new or used? Looking at a blocked injector, misaligned electrode or blocked air intake, as you dont say which model I'm not sure how the air is supplied. Dave