Timer for Geyser

Discussion in 'General Electronics Chat' started by hal1964, Oct 14, 2011.

  1. hal1964

    Thread Starter New Member

    Oct 14, 2011
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    Hi,

    I installed a timer on my geyser, which worked fine and then quite suddenly burnt out, I replaced it and a month later this timer also melted. I spoke to an electrician whom adviced me to install a relay switch, any one got a wiring diagram and info on how to install the relay?
     
  2. John P

    AAC Fanatic!

    Oct 14, 2008
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    Do I take it that you're using the British term "geyser" to refer to a small hot water heater, often installed above a kitchen sink? Americans will be thinking of Old Faithful.

    Your heater probably draws more current than the timer you're using is meant to supply. I'm thinking of the kind that you can run an electric light from--that would be good for an amp or two, but a heater element is more than those things are capable of. The electrician probably meant run a relay off the timer, and the heater off the relay. It's workable, but you'd end up with a lot of wires, and it might not be very safe. Can you not find a heavy-duty timer? An electrical supply store probably has them.
     
  3. colinb

    Active Member

    Jun 15, 2011
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    You're lucky you didn't burn down the house.
     
  4. Adjuster

    Well-Known Member

    Dec 26, 2010
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    I'm sorry to have to say that this may come under the heading "if you have to ask, you do not know enough about the subject to do it safely".

    The relay would have to be correctly rated for the water heater, as would any heavy-duty timer that you might use instead. Do you know the ratings of your geyser (aka water heater)?
     
  5. colinb

    Active Member

    Jun 15, 2011
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    Actually, after giving it some more thought, shouldn't the timer be internally fused if it can't handle the 15 amps for which that the standard outlet is rated?
     
  6. Adjuster

    Well-Known Member

    Dec 26, 2010
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    Possibly not, as the manufacturer may assume that the timer will be used in a circuit which itself would be fused at an appropriate rating. I'm not certain if even all the plug-in types sold in my country have internal fuses, as here each plug normally has its own fuse, 13A maximum for 230V.

    If a fuse were fitted, this might have been expected to fail if the timer was grossly overloaded, unless the OP fitted one of higher rating, or a nail etc. :eek:
     
  7. colinb

    Active Member

    Jun 15, 2011
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    It seems a safety code violation to have such improperly fused receptacles. For fixed installation wiring you have to use appropriate wire (e.g. 14 AWG for 15 amp service) and use the correct circuit breaker or fuse at the central service panel. For instance, my house uses all 12 AWG wiring with 20 amp breakers. There is even a special variation of the U.S. 120 V outlet that is used for appliances needing up to 20 amps.
     
  8. Georacer

    Moderator

    Nov 25, 2009
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    Regulations differ from country to country. Over here, you don't need to have every outlet fused. Typically every outlet and light of a room is connected to one supply line to the central panel and fused with a circuit breaker of 10A to 20A.
     
  9. colinb

    Active Member

    Jun 15, 2011
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    I'm not saying that each outlet has an individual fuse.

    What I am saying is:
    Circuits must be protected according to the weakest downstream link. The central breaker at the service panel must be sized according to the lowest-current link in the system supplied by the breaker. If you have a 20 A breaker, your building wiring to the outlets on that circuit must be 12 AWG wire (or whatever the local code requires for 20 A service).

    For instance, you must not use 16 AWG wire for an outlet protected by a 20 A breaker or you run a severe risk of fire if an 18 A appliance is plugged into the circuit!
     
  10. Adjuster

    Well-Known Member

    Dec 26, 2010
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    The problem here is that the OP seems to have installed a wrongly rated timer, not faulty wiring calibre. If the manufacturer of this item expected that it would be used in an appropriately protected circuit, the timer may not have been built with an in-line fuse. (Proliferation of fuses in a circuit being a very mixed blessing.) The timer motor or electronics might have its own low-current protection, but that would not save the OP if he put it in too heavy a circuit. Alternatively, there may have been a fuse in the timer, but someone may have uprated it or replaced it with metal bar etc.

    Note also that the OP may be in a location where electrical codes are poorly enforced, and of course any references to awg and 120V, 15A etc. services may not apply to his region. My guess would be India, because although the word "geyser" is known in UK, it conjures up images of primitive and sometimes dangerous gas devices, more used back in the days when piped hot water was less common.

    These horrors were often open to room air - lit with a match or taper! :eek: They sometimes led to tragic accidents with carbon monoxide poisoning in ill-ventilated bathrooms. The use of coal gas and coin-operated meters in flats made these things doubly dangerous. Even short of that, losing one's eyebrows was a definite possibility unless the turning on of the gas and the approach of the flame was timed right.

    In any case, we will not be able to do much more about this unless we hear more from the OP.
     
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