Replacement oil boiler

[Igorian]

My Potterton Statesman Flowsure boiler is just about at the end of it's life and I am looking for a suitable replacement.

I'm not sure whether to replace it with another combi system or to go for separate systems for heating and hot water.

I would be grateful for your comments/suggestions for a replacement system, includng recommendations of models and also those to avoid.

Our current system runs 9 radiators of varying size, hot water to a sink and bath upstairs and the kitchen downstairs.

 

[bogstandard]

Personally its against my religion to use anything but a combi - you will of course now have to fit a condensing boiler due to the "NEW Rules" Get a combi with a good output. I prefer Valliant. I have Valliants that are over 20 years old with only new rubbers fitted - they just wont wear out!

 

[Nixt]

Vaillant only make gas fired combi's. As for oil avoid a combi. Unfortunately you now have to go condensing but you might get away with it by saying it was already a quoted job till July maybe.

 

[gas4you]

I would suggest you look at one of the Grant UK range. From reports I've had back from my mates who install them they seem pretty good

 

[Nixt]

Installed may Grants including combi's (where no suitable alternative), Grants original combi is simple with no separate thermal store. The single primary jacket acts for CH and the DHW through a diverter and plate he.

The problem with oil combi's in general is that the latent heat gets very hot and can affect components eg AAV, PRV, Ex vessel, blending valves which are designed mainly for gas boilers with modulated heat. Even the giannoni diveter on the Grant contains a special diaphragm.

 

[Igorian]

Thanks for the replies. I've spent loads of cash maintaining the Potterton, but the same parts seem to die (2 Diverters in 4 years and it looks like the expansion vessel has died again, although it was swapped out 18 months ago. It's currently not producing much hot water, but will overheat within a matter of minutes.

How would it compare cost-wise to having separate DHW/CH systems and how difficult is it to convert from a combi system. I'm not looking for prices, but more a cost comparison, both initially and long term. If oil was your only choice, what system would you guys opt for in your homes?

If it had Intel inside, i'd be ok.

 

[Gasguru]

I converted a Flowsure+ (even more unreliable with the thermal store)back to a heat only boiler a few months ago. I ripped out all the combi parts and installed an unvented cylinder.

The basic Stateman boiler (with a Riello burner) is reliable; its just the combi side thats a mess.

I replaced the existing rubbish ball pump valves and installed proper gate pump valves, installed a new pressure gauge, expansion vessel and filling loop external to the boiler. Rewiring the control panel is easy. The unvented cylinder also gives the backup of an immersion heater and a flowrate only governed by your incomming main.

Much happier customer now

 

[oilman]

Combies earn me money!!! Does this tell you something? You can put an unvented cylinder in, and connect the outlet to the existing hot water pipe, and you will probably get similar performance. Never mind you can't get what the cylinder is capable of as far as max output goes.

You do not have to waste money on a condensing boiler for replacements yet. You will pay a lot for marginal improvement. Don't let anyone tell you otherwise. They are little better than silly things like solar panels and wind turbines. If you want to save the planet, the only way is to jump off, and take a few thousand million others with you.

You should put something like a combimate water treatment unit in if you are going to fit a combi, AND fit an additional expansion vessel.

The unvented and a boiler will cost about half as much again as a combi. If you can put in a vented tank, and re-plumb the hot pipes in 22mm where needed, it will be a lot cheaper, and a lot less hassle in the long term.

Or as gasguru says, just modify the boiler to remove the combi bits.

... flowrate only governed by your incomming main.

And the size of the hot pipes.

 

[Igorian]

Ok, i'm convinced that the combi is a bad idea.

I don't think I have the skills to do this myself, but assuming the Potty can be saved, can you give me (in laymans terms) some detail of what's involved to convert it to heat only, based on the vented system. Most of the DHW pipework appears to be 22mm, with 15mm used as it approaches the taps. I want to get a heating engineer in to take a look, but it would be good to have some knowledge of what's involved beforehand.

Thanks again for your time.

 

[oilman]

You need to disconnect the hot water pipe from the boiler and block it off at the heat exchanger inlet and outlet. This leaves the supply to the boiler for topping up the system. Remove the diverter valve, and connect its inlet to the heating circuit. Remove the heat exchanger and block off its outlet pipe. Disconnect the pump electrical connection so it can be powered from a new circuit, and do the same for the burner.

You need a cold tank in the loft, and a conventional cylinder somewhere to supply the hot water. This is then a normal hot water system, and you just need to get the cylinder output connected to the supply to the taps.

Most people will try and sell you an unvented cylinder as it's easier not having to put a tank in the loft, oh, and it's loadsamunny.

 

[simond]

I haven't found anything wrong with Grant combis. They are well made and supported by a decent warranty - and we extend ours for a further year.

You will find that there are people on this site with bugbears about certain things - I can never find a good word to say about Kestons, for example. Just cause oilman doesn't like combis doesn't necessarily mean that is representative. I have three oil men running around and none of them has a thing going about combis being unreliable.

But I must wholeheartedly agree with his comments on solar and saving the planet. Spot on. I see so many customers going on about wanting to be 'environmentally friendly' talking about solar, GSP etc and I look in the kitchen and there's an oil AGA sitting there, guzzling 49 litres per week.

 

[Gasguru]

I look in the kitchen and there's an oil AGA sitting there, guzzling 49 litres per week.

And not forgetting the big 4x4 in the driveway and electric underfloor heating in the conservatory


The conversion back to a heat only boiler should take no more than 1/2 day and about £50 in parts.

Rip out all the combi parts and chuck in the bin where they belong.

Remove leaky pump ball valves and replace with gate valves (£5.00)

Replace the auto air vent (£5.00)

Replace safety valve if necessary (£5.00)

Plumb in a new pressure gauge (£5.00) - the IMIT one is hopeless the needle can flicker just by moving the capillary

Replace the expansion vessel (£25.00 - £35.00) - relocate outside the boiler case

Fit a quality drainoff valve (£1.00) on the heat exchanger where the old expansion vessel connects

Replace the filling loop (£5.00) - quality loop eg RWC with caps

Plug the old flow connection on top of the heat exchanger (£0.50)

Re-wire the control panel as per a system boiler.

 

[Igorian]

Thanks very much for your input guys.