We had a Hansgrohe thermostatic shower though not quite the same design. Far cheaper than anything else we looked at and worked perfectly with our Combi and reacted quickly enough when the toilet was flushed.
Maybe not the only or optimum solution but we never had any issues with it.
AJ
Here is a cut & paste from Plumbworld on a stand alone pressure equalising valve:
"- Automatically equalises hot and cold water pressure by dynamically adjusting the higher water pressure to balance with the lower
- Can turn a manual shower into a shower that doesn't suffer temperature fluctuations
- Provides - stable water temperature
- Pressure range 3psi to 150psi
- Eliminates risk of scalding
- Cost effective and easy to install
- Cast brass body, Premium nickel finish
- 15mm compression connections
- Can be used on low and "mains" pressure hot water systems
- Ideal for - Rest Homes, Hostels, Hotels, Private Homes, Sports Clubs, Hospitals
- Can turn a manual shower into a shower that doesn't suffer temperature fluctuations "
A poor performing thermostatic valve or a standard mixer can really perform after fitting one of these on the supply. The Mira 415 has one built-in. It may be cost effective to buy a standard non-thermostatic mixer and one of these @ £35 plus VAT, if space is available. Then it is a matter of only replacing the valve if it goes wrong rather than a whole expensive mixer.
You clearly live in a doll's house. When I turn on a tap, I get 30 l/min. This would lead to a drop in temperature. Furthermore, the combi is likely to be set to 60C output to allow dishwashing. Therefore, even on quite moderate hot water flow rates, you'll be in the temperature unstable range.
Whilst the Mira is undoubtedly a high quality product, it suffers from a vital flaw is that it doesn't have separate flow and temperature controls. My mother uses the cheap thermostatic one downstairs as the Mira is too difficult to set the temperature of and can't have the flow turned down.
I agree with the first part (but don't mind the high flow) and like to leave the temperature setting alone and use the flow control as an on/off, not experimenting to get the right temperature every time.
Christian.
temperature
You clearly know nothing of this subject. We shall continue....
You have a heat bank with a thermostatic blending valve controlling DHW temperature, not a combi.
What are you on about? Oh, don't bother.
The 415 only has manual flow control and auto pressure balancing. No auto temp control to maintain a setpoint temperature, only manual by mixing hot and cold water to user requirements.
The Excel mixer controls the flow through the mixer and a fast acting temperature control, one reason why Simon Stroud experiences virtually no fluctuations.
You can regulate the flow on an Mira shower. What are you on about?
Yes, but you are proposing that turning on a hot tap would produce only 6 lpm at the tap. You'd got hot water faster by warming cold water between your buttocks.
I'm saying that with the combi set for 60C, the 15 lpm spec of the boiler (at 40C) equates to around 9.5 litres per minute. Draw any more than this and the temperature will drop, requiring adjustment at the mixer.
I don't dispute that pressure balancing is an essential feature. I would not buy a shower mixer without that feature. However, it is quite possible (indeed, is normal) to buy a shower mixer both pressure balanced (for speed of correction) and thermostatically controlled (for temperature pre-selection and adjusting to varying water supply temperatures).
Christian.
We might be talking about different models. She has a single control. Anti-clockwise is off. Then rotating clockwise slightly turns it on. Turning it further adjusts the temperature. It said Mira 415 on the box, but there might be multiple versions of this mixer.
Christian.
OK. Reading the official Mira 415 instructions:
"Initial anticlockwise movement turns the water on at full flow of cold water, further anticlockwise movement increases the temperature. The flow rate is determined by the supply pressures at the shower control inlets, or by the effective output power of the heater appliance. Flow rates for gas heater appliances can vary typically between 8 l/min (winter) and 15 l/min (summer)."
OTOH, I can't see how the flow rate would be determined by the heater output without some manually adjusted throttling, although the instructions do say something about having an automatic device in the combi to throttle when the flow reduces. Of course, most combis don't have this feature. They just run cold.
Christian.
Where did you get that from?
If you draw large amounts of water at other taps the temp will down. Turn all your hot taps on your heat bank suffer the same.
It is not normal to buy a mixer with both functions at all. Most buy only thermostatic mixers only.
The 415 has limited flow control. The idea is to get a minimum flow so that pressure valves can fully open. ON many combi's this is not the case and just a trickle of water will be enough to fire the burner.
The older models certainly did have a good range. The newer versions are obviously limited.
If the pressure/flow is pretyty equal on cold and hot then the appliance can ramp it up and down.
The up market versions do. If this is a problem then flow controls valves can be inserted in to the combi inlet and cold to the shower. Set to 15 l/min, the combi maximum flowrate, then you will never run cold.
One point not covered that I have noticed is to consider if anyone has any problems with particular controls. In this household one person has arthritic hands and cannot cope with slippery knobs on taps or shower controls. Some showers have levers available, possibly as an option, for flow and temperature controls or a combined lever for both. I never thought about such matters when I was young but it matters now to some of us.
It has no flow control beyond on/off. Once turned on, it will pass as much water as will fit through the pipework, valve and shower head.
Christian.
Whatever you say.
I have bought 2 cheap thermostatic mixer showers in the last 3 years. Both had pressure balancing operation as well as thermostatic. Each was under 100 quid. In each case, they were the cheapest thermostatic mixer valves sold by the shop.
Christian.
OK, then. How did you set the flow rate and temperature? Where was this mythical flow rate setting knob?
Christian.
You turned the knob.
On your side?
.andy
To email, substitute .nospam with .gl
I thought turning the knob on your side was for opening the door in your pyjamas.
I haven't got a knob on my side......
.andy
To email, substitute .nospam with .gl
IME the stat will prevent the boiler exceeding the maximum selected temperature. However, there is nothing it can do once the maximum heat output of the boiler is already demanded. For DHW at 60 degrees this will be at quite modest flow rates even on high output combis. The result is the DHW temp will fall (and by a large margin). ISTM that a thermostatic mixer will be able to take account of a large swing in output temperature from say 60 down to 45 by varing the cold input from "some" to "practically none" - I can't see how just balancing the pressure alone can achieve the same result.
but that does not take account of the fall in the DHW temperature that accompanies the pressure fall - if you are balancing only on pressure you must assume a constant (ish) temperature supply of HW.
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