Our shower knob will turn all the way to hot, but the water won't get hot. The rest of the house has hot water. Think something inside the knob is not turning over to hot. How would I fix this??

There is an adjustment knob to control how hot the water can become. There might be a problem at the tap (however, if this is the case, you would still get hot water everywhere in the house). If the entire house isn't getting hot water, and the knob is set at the hottest water, you probably need to get the hot water tank replaced.

If this is a thermostatic shower then it sounds like the cartridge inside is failing, it a fairly common problem, but easily replaced, they will look something like this and are housed in behind the knob/dial, these can be purchased here Steam Shower Parts Spares Cabins Enclosures Parts or from here http://www.thermostaticcartrdges.co.uk/

There should be a hot water limiter behind the knob on the shower - shingle handle, undo the handle and move the adjustment to allow more hot water. Not familiar with mira discovery mixer

If you turn it to left or right (hot or cold) and get water out of the shower head,we'll elimate cloged shower head.If it just doesnt work in the middle ,probily a washer is stuck in your diverter,or to better understand>a part inside your shower knob assembly is clogging the water that goes up to your shower head. If you get water out of the shower head in the just cold possition or just hot position,then you will have to dissasemble the unit to repair. If you get no water in the cold or hot position could just be a clogged shower head.If you dont know how to disasemble a Shower diverter ,I wouldn't recommend taking it apart. Hope this helped!

When shower faucet apart make sure hot is getting 2 & coming out faucet ***. did you turn off stop integral w/ faucet or outgoing shut off valve on water heater.. May have rust or lime in small orifice leading to faucet ***. does your balancer/ piston move freely..good luck..

Hi im Rossouw

The rest of ur house water in the showers fine?
If not they must install a prv (Presure reducing velve) on the cold going to the house and geyser befor it t,s of to the house and even if the rest of the house water is fine u must ask ur plumber who intalled it if he took the cold water going to the new shower strait of the mains if so he must corect it by t-ing in at the right cold water supply or put a velve on the cold water to ruduse the cold presure . then u will have more hot presure and that means lovely hot shower

plz vote and rate my advice thanx

that pump is likely to be a hot water return pump not a booster pump. it sound like a large property so its likely the hot water system requires balancing to get the hot water to the extreme areas. If all the hot outlets have some form of isolation valve try closing all but the affected areas and see if hot water comes out. If so only open the closed outlets enough to give you reasonable flow. This hopefully will force the hot water to the affected areas.

Your hot water must come from your coil in boiler and not from a seperate hot water heater - more then likely furnace hasn't been on for heating your house nor has it been on for any draw of hot water. You have to wait till it goes on and brings the water temperature up to your setting or get a hot water tank put in or a new type wall mounted gas instant hot water unit.

To clean it, shut off the discharge valve at the water
heater. Then, you shut the valve off of the main water supply. After which, you can start cleaning the single
knob shower cartridge. After the cleaning job, you can
open the discharge valve of the water heater, then, the
valve of the main water supply.