We are converting the garage into an annex with one bedroom, bathroom, living room and a kitchen. I am thinking of installing a combi boiler to do away with water cylinder and tanks. I was just about to order one and then I remembered from the very distant past, as you turn the water on and the combi starts to work, you cannot seem to get the water temperature right and it's very hard to adjust it, as you are taking a shower. This was decades ago and they are probably better now, but have you got them and what is your experience?
Garage conversion - combi boiler suggestions
- Thread starter akist
- Start date
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still the case, if you have space for a hot water cylinder then that is a far better option.
its is easy to control temp using a decent thermostatic shower valve ,carry on
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Combi boilers were originall designed ( created ) specifically for small houses and flats where a hot water cylinder was not an option due to lack of space for th cylinder.
quoting from http://www.thnet.co.uk/thnet/BF/BFPages/overhist.htm
Generally Accepted Sites for Combination Boilers
- Properties with a single bathroom.
- Flats.
- Bedsits.
- Starter homes.
- Offices with limited hot water outlets.
- Large detached properties.
- Properties with multiple hot water outlets.
- Bedsits that use one combination boiler to supply several bedsits.
yes a combi boiler would be perfect for your needs , just fit a thermostatic shower as already advised
I take it therefore that combi boilers are as unpredictable in keeping stable water temps as I remember them.
Having said that, there is a huge price difference, a combi boiler would be something like £620 (Baxi 224 24kW Combination Boiler) whereas a same make system boiler (Baxi Megaflo 15 System Boiler)
is £950 plus £500 for the unvented cylinder - a huge difference in spending...
Having said that, there is a huge price difference, a combi boiler would be something like £620 (Baxi 224 24kW Combination Boiler) whereas a same make system boiler (Baxi Megaflo 15 System Boiler)
is £950 plus £500 for the unvented cylinder - a huge difference in spending...
That would seem to be an ideal choice for what the OP is planning to do:
They are not, and even if they were, any shower would have a thermostatic valve anyway so variations in the temperature from the boiler are irrelevant.
At what flow rate of hot water does this "perfect " temperature control by a combi cease to happen. ? . The heat the boiler can produce has a maximum limit. If the boiler is operating at that maximum and the flow rate increases then the temperature of the water will drop. The "solution" is to install a boiler with a very high heat capacity to get adequate hot water. As much as 48 kW . Then whenthe house is warm and only central heating top up is required the boiler has to modulate down to perhaps as low as 3 kW or cycle ON and OFF. The boiler has to be very well designed and complicated if it is to operate efficiently at both 48 kW and 3kW
I do know that the basic laws of physics cannot be beaten no matter how super the boiler is.
Impressive graphs by the way, Well they look impresive.
That is true until the temperature of the hot water from the boiler drops below the temperature that the thermostatic shower valve is set.
There is also the drop in water pressure when the flow rate through the boiler increases, the cold water pressure doesn't drop by the same amount
True it doesn't have the performance of a "respectable" combi ( define "respectable" ) but it does have all the performance that is necessary for a comfortable life in the cottage. The heat source being a simple heat only boiler.
And what if the flow rate to your vunder coil were to suddenly increase, and a person with a fragile heart, 6 kids an aging mother to care for, were using it..
Oh the humanity. Could you live with yourself Bernie??
By "respectable" I mean middle of the range output say 12l/min@ΔT35. Brand non-specific.
Oh the humanity. Could you live with yourself Bernie??
By "respectable" I mean middle of the range output say 12l/min@ΔT35. Brand non-specific.
As you have been told and should well know a combi is an airing cupboard and boiler in a box . There is no magic involved. They're no more complicated than a standard system. They just have a defined set of operational parameters that are easily catered for and encourage water use to be efficient.
As it only feeds the shower the "control" of the flow is in the hands of the person(s) in the shower. Turning the bath tap on draws water from the cylinder and does not affect the flow rate through the
I cannot see any indication of flow rate in those charts, only where the tap is closed. Did the flow rate change at all during those recordings ?.
( you should have removed the address information before posting them on a public forum )
So do you have an airing cupboard and boiler in a box ?. If so how much room is ther for clothes in that box ?
Shows how hard you looked.
Kitchen and outside taps fed from the cisterns are they? Dynamic pressure and flow remains the same when the cisterns are filling does it?
I have my boiler and cylinder in my garage. Cylinder is sized specifically to fill a single bath then reheat under priority to the heating Ironically it is a combi boiler installed but with the domestic side unused..
Possibly ... The plots would tell you, if you know what you are looking for
.
You have no idea who lives there and where they are, nor when the grabs were taken. I cover a massive area and a career of 20 years. You know what you can do with that sanctimonious claptrap.
P. S. I bet myself a second G&T you'd bring something like this up. Pathetic when you think about it..
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