It is a BLENHEIM 15/30 Balenced Fule Boiler. What can i do apart from call in a plumber person?

My home was repaired for water damage a my dishwasher was removed to install new cabinets. When the “plumber” came he changed the hoses underneath the sink. He reinstalled the dishwasher and now there’s no hot water coming to it. I noticed that the water intake was connected to the cold water valve under the sink. My dishwasher is at least ten years old and came with the house when I purchased it five years ago. Shouldn’t the dishwasher water intake hose be connected to the hot water?

I am selling my house through a realtor and had an offer, accepted. She asked for 3 repairs to be made I agreed to repair one. Her inspector said there was a sewage leak that would cost $300 to fix. (I am providing a home warranty that she would only have to pay $60 to get it fix.) I have never noticed or smelled a leak in the basement so my realtor hired another plumber to inspect. He said that there was no leak and $300 would not touch the cast iron pipes i have since it is an older home so he was not sure what the other plumber saw. My realtor and the buyer’s realtor scheduled a meeting with the buyer and another plumber to inspect again and the buyer did not show up. Now she is backing out because of unreconsilable differences and my realtor says i need to release the earnest money. Is this right? My realtor also tried to call the plumber who originally did the inspection and he is conveniently no longer doing inspections two weeks after the initial inspection. What should I do?

All the brown pipes from my combi boiler are on show there are about 12 altogether. Is this dangerous. They get very hot and are covered in limescale. My landlord says this is fine but a plumber said they should be I think the term he used was earthed.

My toilet bowl is filling up with rust-colored reddish water. I’ve flushed a few times. Every other faucet is clear as can be. The city is doing some repairs one block over… and I suspect it’s water related. Could this possibly be a city plumbing issue, or is this my pipe that needs immediate attention? Is there a way I can check before calling out a plumber?
Update: Minor rust color coming out of the shower too… but the toilet is getting lighter in rust color. Saw some sediment build-up in a black tube behind the toilet. Thanks for all feedback, I’m not going to worry too much unless it continues for another day.