Can anyone help with why a solar hot water service would be using a large ammount of power for boosting over summer?
A householder has a 1000kwh per quarter "J" tarrif bill, 3x what I would normally see for homes with standard electric HWS. Any assistance would be appreciated thanks
Benny
Member
does the booster even need to be turned on over summer ? I have a 20year old flat plate system here in Perth and ours hasn't been on for months.
I don't know what a J tariff is, but is it an off peak overnight one ? If so maybe the family are all having evening showers, so using up all hot water. Then overnight the booster heats the whole tank up. Then during the day the sun can do no more - effectively it becomes an electric storage system.
dymonite69
Member
Very bizarre. We have a similar system. I have monitored our off-peak electricity consumption fortnightly. We have a 302J Solarhart (300L two plate system). Up here in the Adelaide Hills there is often a lot of cloud cover particularly during winter.
Over the summer the boosting requirement has not exceeded 1 kWhr/day. In fact it can be turned off without losing hot water. It may be very well that we aren't depleting the tank in summer.
FYI it takes about 16.4 kWh to heat up a 300L tank from 15 degrees to 60 degrees. The inlet water temp obviously changes this a little (and how how much hot water was 'left over' from the day before).
So the worst case scenario is heating a fresh 300L of cold water every day resulting in a quarterly consumption of about 1500 kWh.
I measured about 1000 kWh for our winter quarter. This suggests that the solar component contributes no more than third of the energy)
I am wondering if the solar system failed or the household is consuming double the capacity of the tank in hot water. The best diagnostic test is to turn off the off-peak booster switch at the meter box at the beginning of a sunny day and also record the reading on the meter. You should be able to get enough hot water to last you the next morning.
Now if the off peak meter keeps ticking then you have a electrical connection/metering problem.
LanceTurner
Key Master
Also check for water leaks. Sounds obvious, but have heard of situations where bills were much higher than expected because of hot water pipe leaks under the house. I had a similar problem, where the PTR valve was leaking and was venting hot water to the outside. The outlet of the pipe was hidden in rocks and no water was visible as the soil was very porous. I only found it when I discovered the pipe was hot all the time.
Enviropoint
Member
i have seen in the past that the tank sensor cable is not in the corrcet loaction, ie it could be lose or not touching the tank. if so it will be sensing the atmosphere temp, rather than the tank. this will cool the tank every evening.
Thanks everyone, the family believe that they have been able to turn the booster off in summer, but the high bill suggests something is badly amiss. Will pass on all of your thoughts - it seems we need the plumber/electrician to re look.
Cheers
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