Shower not giving me hot water

itgirlinuk

My shower was working fine up until a week and now I can't seem to get it
run hot water. The other taps in the house are fine and runs hot water

I did 3 things:

1. I have a combi boiler and I switched off the heating and left it to run only on hot water.

2. I cleaned the shower head and put it back on

3. I moved the dial to completely cold water and few days later wanted to have a hot shower, so turned all the way up.

I am not sure if any of these 3 things has had an effect on the hot water. As you can see, I dont know a lot about boilers and heating systems - hence the lengthy explanation.

Can anyone guess what's gone wrong? And maybe how I can fix it? Please help....

WestonDave

Is it an electric shower (i.e. instant heat - pull cord switch etc) or is it fed from your main boiler?

If its electric it sounds like something has tripped - check that its actually switched on (sorry but worth mentioning!), check that the fuse/tripswitch hasn't blown on that circuit, and if both of those are OK then only two possibilities remain - one is that the element has blown and the other is that the thermal cutout has operated but not reset for some reason (if you turn the power off and back on it may do but should have done when it cooled down). If you are in hard water area you need to expect an electric shower to have a relatively short life as the scale gets on the element and causes over heating.

If its fed off your water boiler you may have an airlock or blockage in the hot water pipe - not a lot you can do about that unless you can track it by feeling where the pipe stops getting hot. A tap with your hand on the pipe - gently - might be enough, but otherwise I'd get the plumber out.

itgirlinuk

Thanks for this.

The shower is fed off the boiler. But how come other taps in the house work fine? The shower pipe is the closest to the boiler, but the basin taps that are further away work fine.

Can something wrong with the heat control knob on the actual shower have a problem?

And if I have home emergency cover, will it be covered under that? Getting a plumber out is going to cost right?

WestonDave wrote:

If its fed off your water boiler you may have an airlock or blockage in the hot water pipe - not a lot you can do about that unless you can track it by feeling where the pipe stops getting hot. A tap with your hand on the pipe - gently - might be enough, but otherwise I'd get the plumber out.

moneysavingplumber

Try taking the shower head off completely and running the shower on hot setting. If this fires the boiler and hot water emerges, then you can blame the shower head for creating too much resistance. It sounds more like the thermostatic mechanism on the shower valve has stuck in the cold position, and the remedy depends on what shower you have.

boots_babe

We've had this a couple of times before with our shower. Following advice on here the first time it happened, we unscrewed the shower hose from the wall and hot water was coming out so some kind of pressure/airlock problem. Just screwing and unscrewing did the job - perhaps worth a try before you pay out for a plumber?

itgirlinuk

I have taken the shower head off and then run it. Boiler fires fine, but only tepid hot water comes through. I feel as if there is a stream of hot water (not as hot as it should be though) and a lot of cold water comes through. And the boiler fires.

And the other thing I noticed was that the water pressure is high. The shower wasn't this powerful before. So, as you say it could be the thermostatic mechanism.

I don't know what types are available. What I have is a round knob control, which moves temperature from 0c to 50c and a bit more. There is a red button, which I think helps you get over the "locks" and turn the knob all the way high. There is a separate knob to turn the tap on/off. And both these are set into the tiles. Does this make this sense?

moneysavingplumber wrote:

Try taking the shower head off completely and running the shower on hot setting. If this fires the boiler and hot water emerges, then you can blame the shower head for creating too much resistance. It sounds more like the thermostatic mechanism on the shower valve has stuck in the cold position, and the remedy depends on what shower you have.

mistergrumpy_2

Hello. Having just seen your post I've decided its time I registered as I'm pretty sure I know what this is but just to confirm first. Do you have an electric shower. You can tell as it is usually a plastic box type and has just one pipe running to it. I'm guessing it is. I'll explain now to save keep batting backwards and forwards and hope I'm right with my assumptions so far. Switch off the electric to the shower to be safe, either on the pull cord or at the mains, take the cover off the shower and where the pipe goes into the shower then turns at an angle to enter the gubbins inside there should be a plastic bit/nut thing. Undo this (remembering to turn off the water to it first) and you'll find that its actuallt a small filter. This is usually gunged up with dirt etc and causes the thermal trip to trip. Just clean this off then put it all back and job should be a good one. Hope this helped.

djohn2002uk

mistergrumpy, didn't you read the last post?

She turns the shower on and the boiler fires up.;)

moneysavingplumber

It sounds like a Trevi Therm shower or of that style. Has there been an increase in water pressure generally in your house? Trevis are designed with 22mm inlets and use a high volume of water, it may that when the shower valve is opened then more water is passing through the combi than it can heat. Some combis have an adjustment mechanism on the inlet to set the flowrate to what the boiler can cope with. If the hot side of your shower is drawing 20 litres a minute then no combi will be able to keep up with that and you'll get a maximum of about 25 degrees. Depending on the combi, the hot flowrate shouldn't be any more than 9-12 ltrs/min, although some deliver as much as 16/18 but it's less likely you have one of these.

If the flowrate hasn't changed then it's worth giving the manufacturer's technical helpline a call, some showers are manually serviceable, some require cartridge changes when they go wrong. If it has a white 'T' on the control in a black circle then it's definitely Trevi which is made by Ideal Standard.

mistergrumpy_2

That last post weren't there before mine! Honestly I'm not making it up

Martini

mistergrumpy wrote:

That last post weren't there before mine! Honestly I'm not making it up

We all believe you as the posts are only 1 minute apart so you were typing at the same time!