Choosing a boiler - again.

[Dave Plowman (News)]

I'm going to replace my ultra reliable Potterton Kingfisher this summer. It's an 80,000 BTU, floor standing, basic electrics room sealed type. So what would be the best replacement? Having been used to such reliability that is important - as is availability of any spares if needed. Efficiency should also be near top of the class - obviously.

The boiler is sited in a cupboard, so could be either floor or wall mounted. I intend doing the installation myself and having it finally commissioned by a suitably qualified person.

A 'system' type boiler would not be very practical in this case - the pump and three port valve etc are situated at the other side of the room along with the storage cylinder and I'd prefer not to have to lift the floor to alter pipework.

[Doctor Drivel]

Viessman 333 floor mounted stored water (thermal store) combi - can be DIYed. Top quality. Highly reliable. Simple to install. Then with high pressure DHW you can get rid of the pump pumping one tap in the kitchen.

[Dave Plowman (News)]

Thank you for answering the question you think I should have asked.

[Doctor Drivel]

This is what you need to buy and do. This is for your own good.

[Tournifreak]

Can I ask why you want to change it? If it's so reliable it seems a bit odd to get shot of it.

Jon.

[Bob Eager]

Discount the idea of the Viessman combi then...it cannot be a solution.

[Dave Plowman (News)]

It's some 25 years old and can't go on for ever? And has an efficiency of about 80%. My gas bills are over 1000 quid a year so a 20% or so saving should be cost effective. I'm also intending re-decorating the room it's in so now would seem the ideal time.

[Andy Hall]

Notwithstanding the choice of model, and the presumably inappropriate technology, Viessmann do make good quality products.

[Doctor Drivel]

People like you should not presume. If he has a main good enough in flow/pressure, then the Viessmann 333 is the ideal choice for him. It will create space too and do away with his pumps all over the place.

[Doctor Drivel]

You are clearly a plantpot.

[Dave Plowman (News)]

But do they make a boiler of the type I want? I'll do some searching.

[Dave Plowman (News)]

Dribble, many have been telling you for your own good you need to seek treatment. But you ignore them. So why do you expect others to take advice from you?

Watch my lips. No combi made will suit my requirements. Which *you* can't possibly understand. Nor would I want one which did even if it existed.

[Doctor Drivel]

Yes it is the 333.

[Andy Hall]

The question is whether you specifically want a floor standing boiler or one that will fit into the space vacated by one. If you can do the latter, then there is very much more choice. Don't forget the various models which can use 50mm muPVC pipe for flue and air supply.

As to the system aspect...... I can appreciate not wanting to have to rip out pipes and home run the DHW and CH back to the boiler. However, some system boilers have a pump but not a diverter valve. In that scenario, all you would have to do is to take out the existing pump and bridge the pipe work and use the pump in the boiler. That should be minimally invasive.

[Andy Hall]

Said the pot as he called the kettle black.

How do you know?

There's a difference between space and worthwhile usable space.

[Ed Sirett]

The integral pump in a system boiler should not be a problem, just replace the existing pump with a piece of pipe. I strongly advise going to a sealed system.

Depending on whether the existing boiler is on an outside wall (Pott Kingfisher 80 RS) or uses a chimney (Pott Kingfisher 80 CF) then the approach will need to be different. If the flue is difficult then a Keston Celsius 25 is a good choice, mine's been really reliable over 4 years, but others have not had such good experience.

Otherwise a suitable Vaillant or Worcester would be fine.

Before taking out the old unit try to measure the gas inlet pressure if it makes 18 mbar then you should be OK with a modern boiler. Sometimes older boilers were installed with (grossly) inadequate pipework.

[Ed Sirett]

But I'm, fairly sure they do a system version. Even if they don't but you like Viessman on quality and price, you could still install the combi with the HW outlet capped off.

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[Ed Sirett]

You should get about 15% saving if all the rest of the system is up to current standards. If you need to add TRVs and/or a wall themrostat and/or a cylinder thermostat you should get more.

[RedOnRed]

80% efficiency for a 25 year old boiler sounds unusually high. The boiler we had replaced a couple years ago wasn't much older then that and was about 55% efficient.

[timegoesby]

The 333 is a thermal store and boiler all in one box. A 1-box fit. That will suit you OK that is certain, and most others. It will fit in the same place as the old boiler as well. If your mains flow and pressure is good enough, if I was you I would go for the 333, or a one similar. It has a high hot water flow rate being a thermal store using a plate heat exchnager. Viessmann make superb boilers. Can't go wrong.