Hot shower from combi - winter

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LiE

LiE

LiE

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Anyone else have issues with having a hot shower this time of year? I have a combi and I imagine part of the issue is the cold water temp is a lot lower coming into the boiler. This means the hot water coming out at any decent flow rate will be cooler than usual, and when mixed in the shower with colder then normal cold water = no hot shower.

Even cranking the temperature control on the shower to max and reducing the flow to half doesn't do it.

If I could control the hot and cold feed into the shower independently I imagine I could get the mix just right, but not with a mixer.
 
Not noticed any difference yet but last year the flow just dropped a bit as the water took a bit more heating up, certainly not as much of a difference as to when I had an electric shower and even at 10.5kw there wasn't much more than a "dodgy prostate" dribble
 
I'm still getting a scoulding hot dousing of water from my dual head shower. I'm glad I said yes when the boiler man asked if I would like the more powerful 40kw combi boiler. :)
 
My boiler is set higher than 55, not sure off the top of my head. It's only a year old.

One factor could be the water pressure is pretty insane here. I may have to dial back the cold water pressure to the shower.
 
It's why I'm holding off a combi until the day my old trusty boiler croaks it. A big cylinder full of red hot water on demand all day long? Yes please :p
 
RoboCod said:
It's why I'm holding off a combi until the day my old trusty boiler croaks it. A big cylinder full of red hot water on demand all day long? Yes please :p
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why heat all that water for it to sit in a tank all day? Combis are great we've saved a shed load of money from the gas bill.

Plus you're not waiting to heat up 40 gallons just to have a shower.
 
hornetstinger said:
why heat all that water for it to sit in a tank all day? Combis are great we've saved a shed load of money from the gas bill.

Plus you're not waiting to heat up 40 gallons just to have a shower.
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A shed load? My 250 litre pressurised tank is heated for 30 minutes a day. That costs me £7.80ish a month to heat.

Try reducing the cold pressure OP
 
hornetstinger said:
why heat all that water for it to sit in a tank all day? Combis are great we've saved a shed load of money from the gas bill.

Plus you're not waiting to heat up 40 gallons just to have a shower.
Click to expand...

Out of interest, did you pay to replace your old boiler with a combi? Or did you just move into a home that already had a combi installed.

Nathan said:
A shed load? My 250 litre pressurised tank is heated for 30 minutes a day. That costs me £7.80ish a month to heat.

Try reducing the cold pressure OP
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Indeed, I have mine heat for 30mins in the morning, 30mins afternoon and 30 mins early evening. It suits our lifestyle as the GF works from home. The tank stays hot throughout the day as it is well insulated. British Gas engineer tried to make me buy a combi off them, I told him I'll wait until my old boiler dies thanks...!


PS, our shower is Electric anyway ;)
 
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NoNameNoNumber said:
Our 30kW combi is keeping up fine with me having a shower whilst she's running a bath. Although I haven't tried that when the heating is on.
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With heating on should make no difference - a combi will prioritise DHW demand over CH :) When the DHW demand reduces, it will go back to CH.
 
No problems here and high water pressures present.

Consider turning up the hot water temp the boiler outputs, just remember everything else will be hot to.

Alternatively try turning on a cold tap to reduce the water pressure while having a shower and see if that helps!
 
LiE said:
Anyone else have issues with having a hot shower this time of year? I have a combi and I imagine part of the issue is the cold water temp is a lot lower coming into the boiler. This means the hot water coming out at any decent flow rate will be cooler than usual, and when mixed in the shower with colder then normal cold water = no hot shower.

Even cranking the temperature control on the shower to max and reducing the flow to half doesn't do it.

If I could control the hot and cold feed into the shower independently I imagine I could get the mix just right, but not with a mixer.
Click to expand...

I'm guessing you have a thermostatic mixer.

1) Turn on a hot tap (not shower) full, does the water stay hot ?
a) If yes then it's the thermostatic valve on the shower that is faulty - replace it.
b) If no then the boiler is faulty. My guess would be the demand sensor is turning off the boiler when it needs to be on. Is the boiler starting and stopping even when the tap is on ?
 
hornetstinger said:
why heat all that water for it to sit in a tank all day? Combis are great we've saved a shed load of money from the gas bill.

Plus you're not waiting to heat up 40 gallons just to have a shower.
Click to expand...

Costs me £12 gas a month to keep a 180L tank hot 24/7, which includes two showers a day. It's an insignificant cost when you compare it to running a central heating system.
 
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I am on a combi with cold water tank in the attic that feeds the electric shower. Yes I need to turn the thermostat up in winter compared to summer, but it is still more than hot enough to burn me if I turn it up too much.
 
My 35kw combi is a bit over specced for my single overhead shower but I guess that might be why I've never seen the temp drop when its cold.
 
Combis still can't run two 'generous' shows at once though. Fine for two bed flats, but unsuitable for a larger house.

Electric showers shouldn't even be called showers.
 
my shower is like that during colder winter time. I put it down to the incoming water temp is a lot lower so takes longer to heat up perhaps before it gets to the shower head.

perhaps try turning down the output pressure a little?
 
So it's fine now, I reduced the cold water pressure. I think since the cold water is a lot cooler now the mix is overall cooler. Hot comes out very hot still so no issues with the boiler.
 
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