The time has finally come to upgrade the house heating etc

[www.GymRats.uk]

The home combi. finally died last week. After successfully patching up a pin-holed back panel with 2-part plumbers "putty" the boiler lasted the winter but now pinholes have appeared in lots more places and the boiler dumped its contents over night and no-longer can I caress it back to life.

So, I've decided to sacrifice a cupboard unit in the boiler room and fit a thermal store with something like a "Vitodens 100-W Heat Only" 32KW boiler, a "SFUTS 300" 300 litre multi-fuel thermal store from Advanced Appliances, and a wood-burner/boiler upstairs in the kitchen/diner as it should give simple(ish) pipework run through a patch of floor without any UFH pipes amd also add a heat dump radiator through the wall to give an extra boost to the lounge in the depths of winter. Also gives scope to add some form of solar thermal (commercial or DIY) once up and running.

Still a bit nippy in the evenings and having to shower at the shop but it's driving a forced update and I'm soooooo over combi-boilers and worrying about whether it's condensing to save thruppence-ha'penny a year. I reckon even if not condensing it'll be far more efficient by not firing up every time someone turns on a hot tap to wash their hands etc.

Oh, just looking for "un-vented" wood-burner boilers now which I've just learnt are an actual thing as they have a "quench coil" in the boiler in case of pump/power failure to prevent water boiling.

Any other advice on perhaps "heat only" boiler makes etc let me know.

Cheers - Pete

[John Rumm]

Looks like a fairly serious bit of kit :-)

The only bit that strikes me as less than optimal is that the DHW coil in only rated at 35kw - At first sight not much better than a decent combi.

Ignoring the coil, and using an external plate heat exchanger with its input side fed from a pump connected to tappings on the cylinder would allow much higher peak transfers since you could use a 100kW PHE.

The boiler should run in condensing mode for most of the reheat anyway...

Heat only or system?

[www.GymRats.uk]

Seems to cover all bases and at 600mm wide I can hopefully get rid of the sink unit to the left and still have space for a washing machine which was originally plumbed to fit in place of the cupboard I'm now giving up for the thermal store. Never had a washing machine at home though as we do all our laundry in the shop.

Before I gutted the downstairs (main) bathroom when the dead combi was first fitted it was able to run 2 showers at the same time. We're near the top of a hill so water pressure is around 3 bar max. which limits flow rate anyway. In my first house I fitted a "Stuart Turner" (I think) shower boost pump. Gave a mega shower but emptied the hot tank in minutes... an OK shower will keep 'er happy, she'd moan about "wasting water" if it came out too fast.

I only found out the difference the other day. I'd prefer to keep as many failable(?) components as possible independent of being brand specific, and outside the boiler box. The pressure vessel is going to have to be much bigger than the would be in a system boiler (of which I already have a 25 litre one on the wall) and the heat store already has a boiler circulation pump wired in anyway then heat only seems like the perfect solution. Don't need timers etc as that's already covered by UFH room 'stats. And as much as I loved the "weather compensation" on my old combi. it wouldn't work with a heat store so the simpler the better.

Also have ion-exchange water softner in the cupboard under the existing boiler so in my mind it should be a pretty straight forward job in the main part, at least to get the cold water cut and re-connected the same day so we're no worse off than we are now.

Thankfully we still have the shower working at the shop so I have a bit of pondering and tinkering time. Think I'll rip out some cupboards this weekend and plan the attack.

Cheers - Pete