New shower will not get hot

[getback]

Hi,

I have just replaced our our Gainsborough shower with another Gainsborough Ambassador Thermostatic shower. We have a combi boiler system.

The water just will not get hot. The hot pipe went hot for around ten seconds but then cooled down.

Could this be because the cold water pressure is too high? Will I need to fit a pressure reducing valve?

I just don't understand how the previous shower worked and this one will not. I replaced the shower as the cartridge could not be replaced and it was constantly dripping.

 

[Softus]

Is this the same at any flow rate?

If not, then at what flow rate are you measuring the temperature?

 

[meldrew's_mate]

...I have just replaced our Thermostatic shower. We have a combi boiler system.

The water just will not get hot. The hot pipe went hot for around ten seconds but then cooled down.

When the hot water starts to come through the thermostatic element in the shower will mix cold with the hot, thus reducing the hot water flow. If your combi is triggered by hot water flow the lower flowrate may cause it to go off. Try it set to the highest flow at the highest temperature, with the shower rose off (open Pipe). Any better?

 

[kevplumb]

I just don't understand how the previous shower worked and this one will not. I replaced the shower as the cartridge could not be replaced and it was constantly dripping.

are you sure you replaced it the right way

 

[getback]

Hi,

thank you all for replying.

I have tried a fair few things since.

I adjusted the stop cock valve so the water was faster and the water partially warms up. However it gets no hotter and the pump/valve makes an awful noise.



Regarding whether or not I have I tried turning it around yes, but that was pointless as the valve is set for hot and cold and the water just continuously flowed when turned around.

I have looked at the Bolier at it says 0.5 and temperature is just under 30C

 

[Softus]

I have looked at the Bolier at it says 0.5 and temperature is just under 30C

If 0.5 is in units of bars, then your central heating system is riding for a fall.

That doesn't affect the hot water of course, but 30°C is woefully inadequate as an input to the hot side of a shower mixer valve.

Consider that the average human skin prefers a shower water temperature in the range 36°C to 38°C - if the hot water is merely 30°C, before being mixed with cold water, then it's no surprise that you can't get a hot shower.

It would be more normal to set the boiler output to 60°C.

Or have I misunderstood your post?

 

[getback]

The boiler is one of those old elm leblanc boilers.

Everything to adjust is numbers. So how I would adjust the temperature to 60C I am not certain.

I have adjusted the number to 6 for the water but I do not want that to make our hot tap dangerous to my daughter.

It already gets hot enough. Kinda makes me wonder if the thermostat is right as it does not change.



I still think the water pressure is one of the main problems.

 

[doitall]

Am I Missing something

Pump/valve-Combi-mains water.

Is that allowed

 

[Softus]

Everything to adjust is numbers. So how I would adjust the temperature to 60C I am not certain.

I have adjusted the number to 6 for the water but I do not want that to make our hot tap dangerous to my daughter.

I don't know what the number range is on your dial, so "6" means nothing to me, but if you assume that the temperature setting ranges from 40°C to 65°C, you probably won't be far wrong.

I don't see how the water can be 30°C and be "hot enough" - I'm sure it would feel distinctly luke warm. Have you measured the temperature at the tap, using a reliable thermometer?

If hot water entering the shower really is hot enough, and the outlet temperature doesn't change when you move the temperature dial, then the shower valve has a fault.

I still think the water pressure is one of the main problems.

Has the pressure changed recently? Do you know what the pressure is? Have you measured the flow rate (into a bucket for example)?

 

[doitall]

Am I missing something else

Always thought the numbers were for the heating temperature.

For domestic hot, the boiler raised the temperature through 35C irrespectively.

 

[Softus]

...and the pump/valve makes an awful noise.

Am I Missing something?

Pump/valve-Combi-mains water?

Is that allowed?

Hm, yes. I'd missed that point.

getback - do you have a shower that includes a pump? If so, stop using it and remove it, because you have a combi boiler and you cannot (both legally and technically) pump the output from it.

If not, then can you explain why you used the word "pump"?

 

[getback]

Pump was wrong that is valve. Sorry.

I'll take a picture of it all and show you the boiler and the shower connections.

 

[Agile]

I may be wrong but I did not think your boiler had any HW adjustment.

Try running a hot tap half on while you use the shower and tell me what the effect is on the shower.

Tony

 

[getback]

Here is the picture of the boiler, the part I think you need to see.

http://img235.imageshack.us/img235/7929/boilersm8vq.jpg

The range only goes from 1-8 but the temperature doesn't change on the boiler?

I could not take the temperature fully as I only have a digital thermometer. However before it cut out and the water was really hot is said 39.9C.


I tried the Hot Water thing Agile, and as soon as I turned on the shower the hot water tap nearly died out. The hot water temperature is adjustable but only slightly. But it is a showerable temperature.

I have managed to get the noise right down too, I took the Cartridge out and put it back, in. And if I turn the shower fully on the shower makes less noise. If I only turn the knob halfway the noise is loud.

I have also tried having the cold tap running when in the shower and this also calmed the noise right down, but is obviously wasting water.

The stop cock is turned on more now than it was for the previous shower, but this is the only way I get warmth from the shower.

The shower is powerful, which leads me to think the cold water in one way or another is overpowering the hot and possibly why the noise occurs!?!

Thanks all for your continued efforts in helping me.

 

[Agile]

I am not convinced by your boiler knob.

Why do you think that it is for the hot water only ???

Suppose I told you that its for the central heating ??? ( And thats why it makes no difference to the hot water temperature ! )

Is there any reason why you should not have the stop cock fully open ?

Tony