Plumbing Question

Dishwasher = issues with choosing hot supply over cold

Hello
I have just bought a dishwasher and have decided to link this up to a Hot supply rather than Cold due and would like clear advise on what could possibly go wrong if I do based on the following circumstances =

Details:
1) Dishwasher = Miele G5620 SC clst
2) Dishwasher's manual (with installation instructions etc) for reference:
http://www.miele.co.uk/Resources/OperatingInstructions/G%205620%20SC.pdf
3) Water hardness (according to Thames Water) =
14.959621 °dH (German degree of hardness, 10 mg CaO/l)
267 ppm (mg CaCO3/l) = Range 242(min) to 267(max)
2.66767379 mmol/l (millimol per litre)

I quote from the manual:
Page 63 =
a) The dishwasher may be connected to a cold or hot water supply, max. 60 °C. We would only recommend connection to a hot water supply if it is economical, e.g. a solar powered supply. When connected to a hot water supply all programme stages which would otherwise be arried out with cold water will be carried out with hot water.

b) The Without heater programme (if available) requires a hot water supply of between 45 °C (minimum) and 60 °C (maximum). The higher the water intake temperature, the better the cleaning and drying results."

c) Page 59 = Reduced cycle times if using Hot supply

Reasons for connecting to a Hot supply over Cold:
1) I have a gas Combi boiler, I believe this will be more efficient in heating water than using the electric heating within the dishwasher.
2) I am going to mainly only use the 'Sensor Wash' program which needs 45-65C and my hot water temperature is set to approx 50C. Page 66 of the manual lists that the dishwasher can take a Hot water connection with Max. 60 °C

Is there anything that can go wrong? e.g. water hardness clogging pipes quicker with Hot supply?

Thanks all.

1 Answer

Best Answer

Personally, I would keep the number of hot water draw off points from a Combi to the minimum, plumbing in a dishwasher will draw hot water inevitably whilst your having a shower or drawing hot water elsewhere, reducing the flow rate. I would put a water softener on the incoming main and connect the dishwasher to a cold feed. As for the cost, you'd have to do a lot of working out to calculate the gas cost versus electricity and as your model is A+++ rated I would trust it to be economical with its own heater utilised.

Answered 8th Apr 2013

CPHG Services

Member since 5 Apr 2013

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