Heat pumps are not boilers but heat sources.
But the better new inverter controlled heat pumps are variable output so they do modulate.
Heat pumps are not boilers but heat sources.
But the better new inverter controlled heat pumps are variable output so they do modulate.
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My point was that, if you have a systrm with an ON/OFF heat pump, you may need a thermal store to avoid frequent starts under part-load conditions.
Boilers are heat sources.
you cant give good advice if your knowledge is restricted to one product.
Quite, you don't want heats pumps frequently starting and stopping or the COP falls through the floor.
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Thats why the inverter controlled modulating heat pumps are so superior ( albeit at a higher price ).
I also expect they will be less prone to freezing up.
Tony
B
BertCoombes
Below the lowest kW rating a boiler will cycle on directly connected UFH. Most are 6kW minimum. Geminox make a boiler that modulates from 0.9 Kw to 10 kW. Ideal for direct UFH connecting most homes. For DHW use a large Intergas combi as a multi-point as it is reliable having few controls.
Have simple, cheap. zone vales for the UFH zones and stat-programmers on each zone. No weather compensation needed. Have a pipe stat set to 50C to protect the plastic UFH pipes. Set Geminox to approx 40-45C.
Do the costings. They all add up. Large thermal stores are not cheap. It is also simple and easy to connect up, and takes up far less space.
Have simple, cheap. zone vales for the UFH zones and stat-programmers on each zone. No weather compensation needed. Have a pipe stat set to 50C to protect the plastic UFH pipes. Set Geminox to approx 40-45C.
Do the costings. They all add up. Large thermal stores are not cheap. It is also simple and easy to connect up, and takes up far less space.
B
BertCoombes
A
ALEC1
well improve it....
vocabulary is important, so we may be spltting hairs...
vocabulary is important, so we may be spltting hairs...
Dr. Drivel (aka Water Systems, etc., ) I presume?
You could reduce the cycling on part load with a thermal store. Your proposal involves the use of 2 boilers, a Geminox for UFH and the Intergas for DHW. You could achieve the same with a secondary mixing valve.
The pipe stat is used to protect the floor finishes, not the plastic pipes. I think they'll take anything a domestic boiler could put out.
Virtually every proprietary UFH system includes a mixer valve, a manually-adjusted TMV on cheaper systems, to regulate the flow temperature to the UFH. The manufacturers will agree that a WC mixing valve ( automatic adjustment) is preferable.
B
BertCoombes
I do not write drivel on water systems.
I have done what I proposed. It is highly cost effective and quick to install. There is no expensive cylinder used. Adequate mains pressure and flow is a pre-requisite for the DHW, as you are using a defacto high-flow multi-point. The cost of the two boilers is way less than a quality thermal store and boiler and all the ancillary parts. It is very simple to design and install.
This system requires no mixing valve of any description. You set the UFH flow temperature by setting the boiler temperature. The pipe stat is to protect the UFH plastic pipe and floor. Have it wired to cut out the boiler and zone valves. The boiler rarely cycles as it can modulate so low. It gives just the right amount of heat the UFH zones require. Rarely does it call for less that 0.9 kW. By the time the system needs less that 0.9kW of heat delivered, all zones have shut down on the stat-programmers.
No need for expensive TMVs, multiple pumps or manifold. Just a make your own manifold using off-the-shelf zone valves, using the end switch to switch off and on the boiler.
There are some very good high DHW output combis that can be used as multi-points. The problem using them for UFH is that they cannot modulate low enough, so a dedicated UFH boiler comes in making the CH section of the combi redundant.
It there is a large DHW demand then a thermal store makes sense. But even then a DHW only thermal store may be all that is needed. A small cheap boiler can heat the DHW thermal store with the Geminox boiler heating only the UFH. It will still be quite a cheap system to a full UFH/DHW thermal store/boiler setup. High output Combi boilers can supply most demand for most homes. The great advantage is that they do not run out of DHW and no waiting.
B
BertCoombes
Disclaimer:
I do not work for Geminox. They happen to make the lowest modulating boiler available.
I do not work for Geminox. They happen to make the lowest modulating boiler available.
B
BertCoombes
To state that thermal stores heated via condensing boilers do not condense is grossly wrong. UFH zones return very cool water to the bottom of thermal stores. Likewise with the return of DHW plate heat exchangers. This very cool water gets pumped into the return of the condensing boiler which then runs very efficiently. Stratification also ensures cooler water is at the bottom the thermal store cylinder while very hot water is at the top where it is needed, giving a massive difference in temperature from top to bottom. Do not take my word for it, put some temperature gauges on key pipes on a thermal store and you will see what I am stating.
I have radiators upstairs drivel what happens to the theory/drivel now.
D
DeltaT2
Oh you'll need a third boiler for that DIA, perhaps you can find a corner somewhere for it??? Perhaps it'll be wise to fit an electric shower also, you never know when a boiler will go down!!!
Ah it's going to be a fun Summer on here with Dr Drivel!!!...........
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