Puzzling immersion heater question

[luke1081]

Hi there, hoping someone can help. Bought a timer for my Megaflo immersion heater a couple of weeks ago and it was installed by an electrician. Woke up the last couple of days to find the immersion heater had not warmed the water overnight. It was set to come on from 5am-6am. But waking up at 7am, the water was cold.
However, when the timer is over-rided and simply switched to "on", the water heats up as it should. We tried this this evening and it worked.

So my question, simply, is the timer faulty or could there be any other possibilities - like the electrician didn't install something correctly?

NB: The flat was formerly on an economy 7 circuit but this was changed a couple of weeks ago to a standard tarrif. This shouldn't make a difference, should it? The timer is wired between the fuse plate on the wall and the bottom tank (ie. not the boost tank at the top).

The timer swtich is this one:
http://www.diy.com/nav/fix/plumbing...ay-Electronic-Immersion-Heater-Timer-12758608

Any help much appreciated - I don't want to call an electrician back, only for him/her to tell me the timer i simply broken.

 

[EFLImpudence]

Well - if it works when you 'switch' it on it must be wired correctly.

Does it show it is on when it is the set time?

Set it for on in a couple of minutes and see if it works.


I suppose you are setting it to 'timed' and not 'off'

 

[luke1081]

Yeah, that's the thing - on the timing function, the timer does come on (there's a red light on the timer itself), but it just does not warm the water at all. On the manual "on" setting, it does warm the water. I cannot, for the life of me, think why this is the case, unless the timer itself has a faulty...well, timer.

 

[EFLImpudence]

Mmm. If the light comes on but not the heater I'm afraid it would seem to be faulty.

 

[PrenticeBoyofDerry]

I think the quality of the timer should be put into question, return it, ask for refund and purchase a better one!
They have a history of packing up after very little use!

 

[DaftPunk]

Do you have two immersion heaters in your cylinder?

 

[Gutterball]

when you say it is set to come on 5am to 6am do you mean it's only on for an hour? if so that's not long enough.

 

[luke1081]

Yes, there are two immersion heaters in the megaflo we have. One is the boost heater and works fine. It has been on from 4am-6am this morning and water is lukewarm at best, certainly not warm enough to shower in. The electrician had a look and said the electricity is definitely "flowing" to the heater from the timer switch, and could only point to the timer function being broken. Is 2 hours really not enough to heater the tank completely?!

 

[Gutterball]

the main heater should run overnight on the cheap rate electric. it will heat the tank until the thermostat reaches temperature then stops. the boost is for when you feel the water getting colder during the day and should be on the normal day rate. is the boost on a runback timer,ie do you set 2 hours and it runs back to zero?

 

[luke1081]

the main heater should run overnight on the cheap rate electric. it will heat the tank until the thermostat reaches temperature then stops. the boost is for when you feel the water getting colder during the day and should be on the normal day rate. is the boost on a runback timer,ie do you set 2 hours and it runs back to zero?

Except we've now changed from the economy 7 tarrif onto a standard tarrif. The electricity company took the E7 radioswitch out (and we removed all the storage heaters to be replaced by electrical panel heaters.) I am guessing I may need to just try time it on for longer than two hours and see what happens...if anything - I just presumed 2 hours would be more than enough!
The boost - I dont know about runback timers - all I know is that the boost is not connected to the timer and you simply switch it on, on a seperate switch (for a separate tank) and it provides almost-immediate hot water.

 

[PrenticeBoyofDerry]

There a few issues regarding how long a cylinder will take to heat up.
Volume of water, temperature of incoming cold water, the thermal lagging of the cylinder. But I would expect a cylinder to heat up within 90 minutes and I believe there are regulations in place that should satisfy that time scale!
Like I have previously mentioned, that particular switch has a history of short term failure!

 

[viewer]

Set the timer for, say, 7pm to 8pm when you are at home to find out if it's working.