Will I regret getting a combi?

DiamondLil

There are two in this household, and since replacing the hot water tank and condensing boiler with a combi, the water pressure has been better. However the drawback has been when someone is having a shower and elsewhere in the house a toilet is flushed or the hot /cold water taps elsewhere in the house are opened. No problem if one is quick enough to jump out of the way when the shower suddenly runs ice cold or steaming hot.

ThisIsWeird

DiamondLil said:

There are two in this household, and since replacing the hot water tank and condensing boiler with a combi, the water pressure has been better. However the drawback has been when someone is having a shower and elsewhere in the house a toilet is flushed or the hot /cold water taps elsewhere in the house are opened. No problem if one is quick enough to jump out of the way when the shower suddenly runs ice cold or steaming hot.

It all comes down to each household's mains pressure and flow. Yours is seemingly ok, as you are happy with the improved performance from a combi over your previous stored type. 
Kitten's mains p&f are poor, so a combi would be just 'adequate' to begin with. Turn another tap on in K's house, and their shower would virtually turn off. 
Is your shower mixer thermostatic, Diamond?  

Albermarle

Most folk, with a stored hot water system, would manage with 20kW or a bit above, 

We have a 18KW system boiler and a hot water tank. 4 beds, 4 people, 13 radiators and it copes no problem.

DiamondLil

ThisIsWeird said:

DiamondLil said:

There are two in this household, and since replacing the hot water tank and condensing boiler with a combi, the water pressure has been better. However the drawback has been when someone is having a shower and elsewhere in the house a toilet is flushed or the hot /cold water taps elsewhere in the house are opened. No problem if one is quick enough to jump out of the way when the shower suddenly runs ice cold or steaming hot.

It all comes down to each household's mains pressure and flow. Yours is seemingly ok, as you are happy with the improved performance from a combi over your previous stored type. 
Kitten's mains p&f are poor, so a combi would be just 'adequate' to begin with. Turn another tap on in K's house, and their shower would virtually turn off. 
Is your shower mixer thermostatic, Diamond?  

@ThisIsWeird

Erm, I have no idea. I leave that stuff to the Diamond Geezer who sorts our heating and plumbing.

The mixer tap is just a simple wall mounted lever - swing left for hot, swing right for cold. Easy, simple and doesn't require a science degree to work out how to use it.

ThisIsWeird

DiamondLil said:

@ThisIsWeird

Erm, I have no idea. I leave that stuff to the Diamond Geezer who sorts our heating and plumbing.

The mixer tap is just a simple wall mounted lever - swing left for hot, swing right for cold. Easy, simple and doesn't require a science degree to work out how to use it.

A thermostatic version looks and operates pretty much the same, the only difference being that it has a thermostatic cartridge inside it. These maintain the set temp, regardless of what happens elsewhere. So if someone turns on a cold tap or flushes a loo during a shower, or even turns on another hot tap, instead of the shower temp soaring high or dropping to cold, it'll instead try and maintain the set temp by adjusting both the hot and cold flows through it to keep the correct balance.

So, if the cold supply drops off, the hot will be turned down to match, to try and keep the temp stable. What this means in practice is that the overall flow coming out the shower head will drop dramatically - but that's better than being scalded!

There comes a point where the thermostat cannot keep the temp steady even by dropping the matching flows right down, because too much water is being used elsewhere, so then it just effectively shuts off the supply completely as a safety feature. Again, better than being scalded.

Does your shower have a temperature scale on it? Does it show settings like '38oC' and stuff?

If you ever replace it, definitely go 'thermostatic'. The vast majority of shower mixers these days will be in any case.

DiamondLil

ThisIsWeird said:

A thermostatic version looks and operates pretty much the same, the only difference being that it has a thermostatic cartridge inside it. These maintain the set temp, regardless of what happens elsewhere. So if someone turns on a cold tap or flushes a loo during a shower, or even turns on another hot tap, instead of the shower temp soaring high or dropping to cold, it'll instead try and maintain the set temp by adjusting both the hot and cold flows through it to keep the correct balance.

So, if the cold supply drops off, the hot will be turned down to match, to try and keep the temp stable. What this means in practice is that the overall flow coming out the shower head will drop dramatically - but that's better than being scalded!

There comes a point where the thermostat cannot keep the temp steady even by dropping the matching flows right down, because too much water is being used elsewhere, so then it just effectively shuts off the supply completely as a safety feature. Again, better than being scalded.

Does your shower have a temperature scale on it? Does it show settings like '38oC' and stuff?

If you ever replace it, definitely go 'thermostatic'. The vast majority of shower mixers these days will be in any case.

Oh wow ! Thanks for the info @Thi@ThisIsWeird

I had no idea such things existed. When the time comes to replace what we have, I'll definitely go 'thermostatic'.

(Sounds like a Pointer Sisters lyric).

FreeBear

DiamondLil said: I had no idea such things existed. When the time comes to replace what we have, I'll definitely go 'thermostatic'.

Have a thermostatic (electric) shower here, and find it great. My water pressure is not great and at times drops below the recommended minimum flow for the shower (it has a warning light for such an event). Temperature remains unaffected unlike the old one which was either too hot or just cold. Thermostatic added some 60% to the cost of the shower, so may not appeal to the wallet if you are price conscious.

silvercar

Sometimes, stopping the flow of water to the shower can have its advantages. When my kids were teenagers and would spend ages in the shower, the ability to drop the water flow would be an encouragement for them to finish their shower.

ThisIsWeird

It can still be unpleasant in the shower even with a thermo mixer, so the warning option should remain

You'll find there's a momentary fluctuation in temp - hot or cold - whilst the thermo adjusts itself to the change of supply due to another tap being used, but not enough to risk harm. The worst that then tends to happen is that the flow rate just drops off to 'pitiful' as the thermo reduces the hot flow to match that of the lost cold, or vice versa. You can certainly still annoy folk in the shower, or send a message.

Eldi_Dos

DiamondLil said:

ThisIsWeird said:

A thermostatic version looks and operates pretty much the same, the only difference being that it has a thermostatic cartridge inside it. These maintain the set temp, regardless of what happens elsewhere. So if someone turns on a cold tap or flushes a loo during a shower, or even turns on another hot tap, instead of the shower temp soaring high or dropping to cold, it'll instead try and maintain the set temp by adjusting both the hot and cold flows through it to keep the correct balance.

So, if the cold supply drops off, the hot will be turned down to match, to try and keep the temp stable. What this means in practice is that the overall flow coming out the shower head will drop dramatically - but that's better than being scalded!

There comes a point where the thermostat cannot keep the temp steady even by dropping the matching flows right down, because too much water is being used elsewhere, so then it just effectively shuts off the supply completely as a safety feature. Again, better than being scalded.

Does your shower have a temperature scale on it? Does it show settings like '38oC' and stuff?

If you ever replace it, definitely go 'thermostatic'. The vast majority of shower mixers these days will be in any case.

Oh wow ! Thanks for the info @Thi@ThisIsWeird

I had no idea such things existed. When the time comes to replace what we have, I'll definitely go 'thermostatic'.

(Sounds like a Pointer Sisters lyric).

When you do replace it you will be moving on up.