Ween two 15mm bidet pipes which are about 3 inches apart and slightly at an angle

If you can stand washing in cold water there is no reason why it should not be connected to only the cold supply though if the bidet is fitted with a combined hot/cold tap (faucet) the hot water inlet should be plugged.

It should be possible to run hot water to the bidet and would be worth the effort. Modern flexible plastic pipe and associated fittings will carry hot water and overcome many plumbing problems.

English? Would that be approximately 3 feet of 1/4 inch pipe? 3 feet of 3/4 inch pipe?

It's your choice.There's only a single supply hose and with most dishwashers that means cold fill only, but as this is a compact basic worktop model the manual supplied suggests that users connect to a hot water supply.

In real-life situations though, the water drawn from the hot supply often isn't instantly hot so all you do is drain cold or tepid water from the supply pipe and let it get replaced with wasted hot water which then cools in the pipe! If the machine features condenser drying like many dishwashers, then cold water is essential for it to work. A final consideration is that unless your hot water is supplied at mains pressure (such as in a combi-boiler or megaflo system) then the water pressure from a hot water storage tank will not often be high enough and you'll have to use the cold supply.

There are advantages and disadvantages to both pipe sizes. Typically, most houses utilize 3/4 inch or larger to supply high volume circuits like the circuit from the meter (or well) to the hot water heater, outside spigot, or water softener. Distribution from water heaters is usually 3/4 for the main branch but this is reduced for the runs to the sink, dishwasher, washing maching. The reason for reducing the size is to reduce the volume of water in the tube or to reduce the amount of cold water you run down the drain before it turns hot.
Since your house seems to have 1/2 inch supply to the current water heater, I would suggest staying with the current size. The option is to enlarge the tubing from supply to distribution which can be a major plumbing task. If your current water pressure (at the faucet) is ok, then go with what you have.

You have clog in the water line.
Since all hot water pipes are involved, clog is probably near water heater.

Buy pressure gauge at hardware store that threads onto hose connection.
Brady BTG 100 at Amazon
Picture of gauge

Check outdoor pressure for baseline pressure in your home.
Turn off electricity to hot water heater for an hour or two so there is not scalding water.
Open drain valve on water heater to see if water heater is clogged with sediment.
http://waterheatertimer.org/Water-heater-will-not-drain.html

Put pressure gauge on drain valve and compare with outside pressure.
Open hot water spigot on bathtub and see if tank pressure drops ... if tank pressure drops significantly with bathtub spigot on, then clog is on incoming cold water before tank, and could be on outgoing hot water pipes too.
If tank pressure stays about the same, then clog is on outgoing hot water pipes.

Clog can be sediment caught in cold water shut off valve located above tank. Open and close valve and test pressure again. Take apart incoming cold water pipes above tank and check for sediment. Replace valve. Look at condition of cold water nipple on top of tank.

Sediment caught at hot water elbow near tank.
Sediment can fill up old pipes. Take apart hot water pipes above water heater and see condition.
Look at condition of hot water nipple on top of tank.
You may have to take apart pipes up to first or second elbow.

Pipes can decay at joint where copper pipe connects to galvanized pipe. Check for copper to galvanized connections on cold or hot pipes and replace section of galvanized pipe. Copper pipe will probably be good, the galvanized pipe will deteriorate. Replace copper-to-galvanized joint with 3/4" non-conducting union from hardware store

This is usually the result of long hot showers and lack of ventilation. Open a window, or install an exhaust fan that runs whenever the light is on or kick those kids out of the shower. Another (maybe silly) option is to run a detour in the supply cold water-- that is, make the water supply that feeds these toilets run through a long section of 3/4 inch copper pipe in the basement so that the water can warm up a little before it fills the tank. 50 ft of 3/4 inch pipe holds about a gallon. (That would run you about $75 plus fittings.)

Hello,
You aren't the first to run into this dilemna.

The size of thhe pipe will affect your system in this way.
If you start 85lbs of pressure in the water main, The meterhas a 1" pipe inlet and a 3/4" outlet. The meter reduced thhe pressure to60 psi and then it is reduced again at the point of entering the structure dropping to 1/2" pipe. By resucing the pressure is upped approx 5-7 lbs. The point of regulator and pipe size is the only time the pressure changes. The lowest pressure will drive a rainbird spribkler,actually several. But too many rainbirds won't affect by pressure as much as volume. The pressure will push whatever is available.By reducing the 3/4 to 1/2" didn't affect your pressure as much as it did your volume.. The reason your hot water starts to run cold sooner is that now you do not have the volume ratio between the cold and hot.It 's 1:1 now instead of 1.25:1. Hot more than cold. It takes more hot water to heat cold water than ittakescold to cool hot. Plus, the hot water you use is being replaced by cold water and that water is cooling what hot water is in the tank as the heat moves to the cold. The heater cannot heat al that water fast enough, but the cold water line is happy as can be.No pressure changes and no temperature changes. Before, you had to turn up the cold to bring the temp down to comfortable or safe. I just had my shower redone and everything is the sme size. Here is something to think about. Ck the shower head. They clog up and cause poor mixing over time. Yoou should be ok. How old is the water heater? Over time they get a build up of calcium and lime which is very detrimental to the heaters efficiency and recovery time. I hope this all made sense to you. At times when we have things done right it seems to be wrong because we are accustomed to the way it was. You will get accustomed to it and find your water heater gobbling less energy. Good luck and I hope it all works out, There is no need to fret. Sincerely -Ned-

I would try PLUMBER'S GOOP (hardware store) on the copper pipe. Remove it and put a liberal amount of goop on the end about a quarter inch back from the tip -- insert and smooth the goop around the connection -- let it cure for 24 hours -- turn water back on.

Charlie

To get the water to the dishwasher, it depends on your plumbing setup. If you have shutoffs under your sink(1/2" X 3/8" compression angle stop), you will need to buy a 1/2" x 3/8" compression double stop. This will be easy to change.

#1 Drill a 1 1/2" hole in the back bottom of the cabinet to run your water, drain line, and power cord through.
#2 First turn off the water at the Hot Water Tank, or the House supply, and turn on the sink to relieve the pressure.
#3 Next remove the Hot supply stop, and install the double stop.( The nut and ferrul do not have to be removed, as they will attach to the double stop. Reinstall the hot supply to the sink to one of the connections on the double stop.
#4 Install a 3/8" x 3/8" x 48" braided flex with the 1/2" MIP
x 3/8" compression ell at the dishwasher.
#5 Install the drain hose supplied with your dishwasher at the bottom of the dishwasher.
#6 Install a 6' pigtail power cord to the power box under your dishwasher.
#7 Feed the drain line, power cord and water supply through the hole in the back of the cabinet at the bottom. As you push the dishwasher back into the enclosure, you will need to feed the 3 lines into the cabinet under the sink.
#8 Attach the water line to the open connection on the double stop.
#9 The drain line will attach to your garbage disposal.(If you have one) Be sure to knock the small piece of plastic out of the drain connection, and retrieve it out of the disposal, before connecting the dishwasher drain line.
#11 Raise the middle of the drain line as high as possible under the cabinet under the sink, preferably attach it to a screw to the bottom of the counter top. This will keep the dishwasher from drawing a back siphonage and getting a bad odor.
#12 Plug in the dishwasher. Assuming you have electrical under your sink. Otherwise an electrical outlet may need to be installed.
#13 Balance the dishwasher using the front legs. After you adjust the depth of the dishwasher, and the level. Use the 2 mounting screws included with the dishwasher to fasten the 2 clips above the door to the bottom of the counter top.
#14 Remove the installation manual and styrofoam from the tray, and turn the dishwasher on. Inspect for leaks as you run a cycle.
#15 Attach the bottom kick panels

You are done.

If you have any questions, please let me know.