Rhemglas 101 Water heater help!

[fixa24]

Howdy folks..
the house i've just bought has a rhemglas 101 electric water heater. we got an electricity bill for our first 20 days in the house and it was $60!. I have suspected the water service as the culprit... the hot water is extremely hot.. far too hot with our young child around. I was under the impression that HWS was an off peak electricity user, but during the day i was down at the meter box and noticed the dial thing spinning madly. knowing i had nothing much switched on inside, i switched the HWS circuit breaker off, and the dial stopped. I had a look under the cover of the HWS and there appears to be no thermostat, as backed up by the info on Rheems website. apparently it has a thermostat that can be adjusted by "a qualified person".
Any ideas?
I don't want to imagine our 3 month bill if this continues...
Cheers!

[Markw]

First up
When you looked at the meter board do you have a seperate hot water electricity meter - if so then chances are you have off peak service.

Next - What sort of off peak is it?
In Sydney we use 2 types:

Off Peak 1 is designated for small systems of about 30 litres where it will reheat immediately if you run out of hot water and it reheates every time it gets the signal.

Off Peak 2 is for the larger storage systems of about 200 litres and above where if you run out of hot water then its too bad until the next hot water signal comes down the line.

Your electricity bill should tell you which system if any your on.

Lastly, just because you saw your OPHW meter spinning around in the day time doesn't necessarily mean that your not on off peak 1 or 2. In Sydney they quite often send an off peak signal during the day on weekends or public holidays. I suspect this is to actually drag more dollars from the customer rather than being generous by supplying more hot water. Lets face it if you can survive a whole 24 hr period during the week without "topping up" the heat, why do you need weekend top ups?

[lnt9000]

There is a thermostat on the hws, generally near where the main electric cable enters the hws, yes you are supposed to be an authorized person to get a small screwdriver and back off the thermostat, I think they put that in because some might crank it down too far and then bacteria starts to breed in the tank, as markw stated If you look into your meter box you will generally see a revolving disc for peak usage and a separate one for off-peak if fitted, and also a switch to either switch it off altogether or On now or on offpeak, I believe the storage tank has to be a minimum size of 150ltrs to be elligable for off-peak.
If the pressure relief valve is leaking then hot water is tipically going down the drain and can have a direct effect on your bill.

[Markw]

If the pressure relief valve is leaking then hot water is tipically going down the drain and can have a direct effect on your bill.

Just a quickie on leaking overpressure relief valves.

If a valve is leaking, it will leak continuously. Don't mistake this for the short periods of leakage when new cold water enters the hot water tank, especially when large amounts enter. What happens is that the new cold water heats up from the existing hot water in the tank and expands from this elevated temperature. The added volume needs somewhere to go and thats out the relief valve. The same thing should happen when the existing water in the tank is being reheated. Higher temperature gives more expansion, extra volume dribbles out the relief pipe.

This is normal and should be expected, if it doesn't happen then operate the valve override a few times to clear the valve. If it still doesn't dribble after reheat or large amount of use then think about talking to a plumber. You may have a more serious problem.

[China]

You also need a timer to switch it on in off peak and off in peak periods your elctrition should have told you that

[Markw]

You also need a timer to switch it on in off peak and off in peak periods your elctrition should have told you that

China
We haven't used timer switches since Noah was a cabin boy. Your electricity distributor sends a high freqency signal down the power lines which is picked up by a little control box on your meter board. The control box just changes the direction of the switch every time it hears the hi-freq signal.

You might find an old timer style OPHW control on an old terrace house in inner Sydney but most of these controls were replaced decades ago as they have long exceeded their expected service life.

They were mostly replaced cause when you have a blackout, the timer doesn't reset to the correct time therefore the off peak system could be operating during peak times.

[China]

plenty of em here in South Oz