Which central heating system

[Malc]

Hi,

This is a completely new install so a clean slate. Selections so far are

mains gas
vented hot water tank

My reason for vented is I have the head room in the loft to get >1m below the cold water tank so vented allows DIY and I have a defined flow rate independent of what the mains water pressure/flow might be (I've no idea if it is good or bad). The house has a few bathrooms.

Next choice is CH, is this regular (F&E tank) or system. I read that F&E is, according to one web site, still better - no regular fills, etc., less to go wrong. The boiler then doesn't come with a pump but maybe that is a good thing. I did look at system to start with but seems they are pretty much equal. F&E needs loft tank but then system needs water bottle and additional expansion vessel too as well as the one in the boiler. So is F&E best?

And which make? I've seen worcester-bosch and valiant suggested. I've been looking at the 30CDi and 30Ri. I would have thought there would be a hot water heating setting triggered off the HW cylinder thermostat but I can't seem to find one. Does that mean if the front dial is set to 1 the HW tank will be 35C? Kinda makes 1-4 useless settings for boilers heating hot water as well as CH. Or am I missing something on 30CDi?

For 30Ri then seems to be a wiring centre that includes a tank sensor. But the you also seem to need the clip in timer if you want to specify hw times as well as overriding the temperature. Around £200 for those two! Well OTT.

 

[muggles]

If you've got that much space in the loft I'd be thinking about future possibilities for a loft conversion, but that's up to you...


If you've got a few bathrooms you'll need a big cylinder to cope with potential max demand. A standard 1050mm high one just isn't going to cut it. Personally I'd be looking to put an unvented cylinder in wherever possible.

Go for a sealed heating system, open vented (with an F&E) tank are old hat. You won't need to refill your system boiler at all if there are no leaks on the system. If you're topping up regularly, you've got a problem. Sealed systems are also far less prone to corrosion.

As for boiler make, of the two manufacturers you've mentioned Vaillant is the best but I wouldn't have either out of choice, regardless of cost. Worcester are very good at marketing but the product leaves much to be desired IMHO. Buy an Intergas and get it installed by someone who knows what they're doing - it's quite simple on these to have a high flow temperature for your hot water (for fast HW heat-up) and a low flow temperature for your heating (for efficiency). You don't even need to buy any fancy kit to do it.

 

[Malc]

Thanks for info.

The project is a 1st floor on a bungalow so loft conversion would be a very big house. I was planning on a large cylinder, 1500mm high, in a large (2 door) airing cupboard.

So far I despair of getting sensible info from either worcester-bosch ("fit a system boiler as then you don't need to balance the radiators") or vaillant ("run boiler at 70C output as it makes no difference to efficiency").

What I'm looking for is a boiler that ups the output temperature when heating the HW but lowers it for CH so that I can run CH lower in spring/autumn for maximum efficiency and maximum condensing.

Just started looking at Intergas and I see what you mean. I'm looking at the Compact HRE SB (the air/corrosion has moved me towards system). Nice features are just add a HWC sensor and external temperature sensor to get control. And it has a OpenTherm input so I'm not tied to boiler makers kit.