Is it time for a new dishwasher?

My dishwasher keeps filling up (and overflowing) with water when it's not on, but the water drains away properly after a cycle.
We had the same problem 2 years ago and we had a 'repair set' and new inlet valve fitted at a cost of £120. The repair man also recommended that we change the supply to cold water as our water pressure is very low but we haven't done this.
Could anyone tell me if I should change to cold water, if I should pay another £120 for a new inlet valve/float switch, or is it now time to get a new dishwasher (it's about 8 years old)? Thanks

You should use the cold supply for your dishwasher. There are two types of inlet valve one for high pressure supplies and one for low pressure supplies. Most people dont beleive this but it is true. They are different inside and work in a slightly diffrent way. Before you renew your machine try a cold supply and see what happens. If all else fails fit a tap to the pipe and turn on when needed.

Thanks for your help. The pipe already has a tap so that's what we're doing now, but it's not ideal cos we have to pull the freezer out to turn it on and off.
It's quite a big job to get a cold water supply fitted (apparently) but we'll do it if it's worth it. I'll also get whoever comes out to check we have a low pressure inlet valve fitted. Thanks again.

If you have a standard inlet valve all you need to do is use cold water cos it will be at high pressure ( and will hold the valve closed with no power supplied ) The higher the water pressure the more the valve is held tightly shut. ( the opposite to what you might think ) The only other reason a valve might leak is if you have a bit of grit stopping the diaphragm from sealing properly. Make sure you have a fine mesh filter fitted inside the hose connector. If this is missing grit will pass into the vavle and cause it to leak.

Another Thought. You already have a supply to the dishwasher and so it must come from somewhere!!! Can you not cut and cap the hot water supply and connect it to the Cold water main?

Our house is a bit of a mish mash! It's a bungalow with a loft conversion so the tanks etc. are not in the loft (cos it's now a bedroom). Our water pressure on cold is also low (but not as low as hot).
We had someone to look at converting the supply to cold and he said he would have to take a pipe off the upstairs bathroom supply (cos it's mains) and run it round to the back of the house where the dishwasher is. He said this would cost £100 so we didn't do it at the time.
We can certainly look at the current pipework to see if we can change the current hot supply to cold, but is it worth installing something that would increase the water pressure overall?