Shower temperature drops off then back to hot

googler

What's the distance between boiler and shower? Where does the hot water pipe go in between? Any garage or loft spaces where heat could be lost?

googler

breaking_free wrote: »

Whenever I take a shower the water comes out nice and hot, then about 30 seconds in it goes lukewarm, then back to hot again and stays hot for the rest of the shower. So to be clear, the temperature drops exactly once during each shower. The exact same is true of the ensuite shower.

Is it impractical to suggest that you start the shower and don't enter it until 30 secs later?

Rain_Shadow

breaking_free wrote: »

Hi all.

I have a Potterton Heatmax combi boiler and two mixer showers (one's an ensuite).

Whenever I take a shower the water comes out nice and hot, then about 30 seconds in it goes lukewarm, then back to hot again and stays hot for the rest of the shower. So to be clear, the temperature drops exactly once during each shower. The exact same is true of the ensuite shower.

My shower, pumped from a traditional HW tank, does this too when it hasn't been used for a while.


Although the reason is different can I suggest you do what I do to overcome the problem? I start the shower and then wait 30 seconds before getting in. Much easier than faffing with clueless engineers.

Loanranger

Is it sludge in the system?

Bubblecat

Silly question but do you start the shower and whilst waiting for it to warm up you use the toilet, flush it and then get straight into the shower? If we do this with our shower the temperature will drop when the cistern finishes filling as it causes a sudden surge of cold water until the shower thermostat regulates the temperature again.

breaking_free

Bubblecat wrote: »

Silly question but do you start the shower and whilst waiting for it to warm up you use the toilet, flush it and then get straight into the shower? If we do this with our shower the temperature will drop when the cistern finishes filling as it causes a sudden surge of cold water until the shower thermostat regulates the temperature again.

Nope, can't say that this applies.

For the suggestions that I wait an extra 30 seconds before getting in the shower, that's a heck of a waste of hot water over the long term and not very money saving :eek: I'd rather get this sorted if possible. British Gas engineer number 4 is due tomorrow...
N. B I pay for Homeserve so callouts and parts cost me nowt extra.

fezster

What's the route and length of hot pipe from boiler to shower? Is it lagged? Sounds to me like some of the water in the pipe is either cooling down (i.e. the water nearest the shower remains warm, but prior to that the pipework is exposed and goes stone cold), OR being a combi, the water in the pipe actually remains warm, but new cold water flowing through the boiler takes a few seconds to warm up before the boiler has a chance to fire up. This is then quickly followed by hot water which remains until you turn the shower off.

breaking_free

Here's the thing. The running shower is the very first bit of hot water that goes through the system in the morning so I can't see that there would be any residual warm water. Specifically when I turn the shower on it is stone cold (as would be expected), then it heats up, then it goes cold again before returning to heat.

Before the morning shower no hot water has been used for anything at all.

Route to shower is a long one but I couldn't give you a measurement except to say that it goes from kitchen, is routed round a bedroom, then into the bathroom. As for lagging, no there is none.

fezster

Get somebody else to turn the shower on and monitor the boiler. Does it turn on and stay on? Or does it perhaps go off before turning on again. This will at least help you identify if the boiler is the issue or not.