Condesning (NOT combi) Boiler recomendations

[The Nomad]

Morning all,

I fear that the time is approaching when a new boiler is needed (vented pumped system).

The condensate from the current boiler has (for a while now it seems) been not running down the proper pipe but is dribbling out of the combustion chamber itself.

Thus there are issues with the 'pilot' flame not igniting some times when heat is called for. The system goes through the fan on, igniter 'sparking' (or not) but no 'pilot' flame and hence no main burner and hence it goes into lock-out. This is usually at o'dark:30 in the morning so I awake to a cold-er house & only warm water (which is supposed to run at about 3am for an hour to top up the tank).

So what is currently considered to be a good make/model (the house is a

1970's bungalow with average insulation 4 beds 1 bathroom and fairly big kitchen) in sub-urban Norfolk.

I don't need past history (I've been reading this group for mumble years so have heard all the stories) I do NOT want a combi boiler, nor mains pressure hot water (as it is low here), nor solar stuf etc.

Many thanks for any thoughts, mostly reliability. The current boiler is

7 years old and appears to be knackered.

(The previous boiler was only changed because the Gas Co. refused to replace my meter (they wanted to do it not me) as it was not a room sealed one and they considered it in a bathroom! It was a room with a shower and a bog but hey! The gas man did say "Oh shame you were out when I called, we'll be back in touch to re-arrange the meter change" which was very nice of him. In other words not unsafe but not to the required standard for a new fit so not allowed!).

Avpx

[newshound]

As you know, the consensus here tends to be for Vaillant or Worcester Bosch. FWIW I have an ecotec 637 and I am very pleased with it. Unless you want the "fancy" control stuff with outside temperature monitoring, I would stick with the simple mechanical programmer. I bought the add-on electronic programmer expecting it to have more flexibility than it has, and it added some complications, for example I had to reverse the diverter valve because the controller gives "volts means hot water" whereas the UK convention is the other way around. Or perhaps both of these are the other way around.

[John Rumm]

Do you want to stay with a vented primary, or are you happy going sealed? (far more choice if you do)

(you can use a sealed primary with a vented hot water cylinder so long as you have an "indirect" cylinder)

Do you have a separate pump, or are you after a system boiler?

Having made the choice about a year ago, I went with a Vaillant Ecotec

624 - but that was partly influenced by needing a boiler that could do split temperature operation and weather compensation. Too early to tell how it will age...

[The Nomad]

Many thanks,

The programmer/controller/thermostat/TRV stuff is all in place and should 'just work' (tm).

I'll keep putting elastoplasts on it and hope it makes it to the warmer weather (and to gather some funds - fat chance :-) ) before I bite the bullet.

Hoping for minimal pipe shifting as well :-)

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[The Nomad]

Not sure of the pros/cons - will do a bit of a search

The primary water is in a coil in the tank and is contiguous with the heating circulation (but valved etc.)

Currently separate pump ... easier to replace if it borks

That, it has to be said, is the question that we can't answer in advance :-(

Many thanks

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[Allan]

[snip]

FWIW:

Which magazine: Boilers: brand satisfaction Oct 2013:

Allan (no connection with Which other than as a subscriber)

[John Rumm]

So that is an indirect cylinder. So you can use either sealed or vented primary.

Indeed. Still compared to what it replaced, it only needs last about three years to pay for itself in our case. Hopefully it will do longer!

[newshound]

I'm generally quite impressed with the build quality of the Ecotecs, as seen from the installation viewpoint.

[John Rumm]

Agreed, although that is not always the whole story. The Ideal I fitted at my last place was also very nicely put together mechanically - but then they developed a reputation for PCB problems (it was a new model when I fitted it)

[Dave Plowman (News)]

That's roughly when I installed (myself) my current Viessmann Vitodens

200WB2B system boiler. It looks like it will do a few times that easily.

Only change I had to make to my old system was to change it from open to pressurized, which is simple if you have mains water nearby the boiler. The hot water is still storage fed from a header tank.

Wish I could say it had been problem free. But it suffered from tripping randomly. Viessmann sent out an engineer under warranty who changed all the electronics. At a big expense (to them) with absolutely no benefit. When giving it its first service (clean), I stupidly broke the ionization electrode. The new one (about 40 quid) was of a totally different design, and it's not tripped out since. I'd hope newer models have better self diagnostics.

The instructions for setting it (it's got weather compensation) seem to have been written by someone from a different planet. ;-)

[harryagain]

The first thing is to make sure all efficiencies are attended to. (Eg insulation D/glazing etc.) You may get away with a smaller boiler. Make sure a proper heat loss calculation is done and you don't get an oversized (guess-the size) boiler.

[gremlin_95]

We've got a Vaillant Ecotec 937, just over 5 years old now and we've had no issues at all. Very well put together. FWIW, the earlier (2005) Ecotecs had a few issues but these have all been rectified in newer models.

You might read about having problems with leaks if converting an older vented system to a sealed system, however we didn't have any issues using mostly old pipework (roughly 30 years old) when we got the new boiler.

If you do decide to keep the system vented and go for one of the Vaillant Ecotec 400 series boilers, be sure to install a pump that is the correct size as they have quite a high pressure loss over the heat exchanger.

[YAPH]

Baxi Barcelona?

Worcester-Bosch. I think they're currently offering 5-year warranty on some models in the unlikely event you'd need it, and IME don't quibble if you do (unlike other manufacturers !)

If you want a sealed system then you can use one of their "i System" models, or if you have a feed and expansion tank for the CH then it's an Ri. You (or your installer) should do the whole-house boiler sizing calculation (see wiki) to determine what size boiler to get. If you get an iSystem (sealed system) boiler you can buy an optional built-in diverter valve kit which includes a sensor for the hot water cylinder, which allows the boiler's front-panel control to regulate the temperature of your hot water independently of the temperature of the radiators.

[The Nomad]

No it's a Ravenheat :-)

Thank you John, that is very useful (and every body else who replied as well) Ta!

Will have abash at the calcs, but feel/hope they were done last time (or may be not).

Was planning to just replace like for like - as near as poss. to reduce moving plumbing/flue etc.

Many thanks again (all)

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[YAPH]

The whole house calcs are simple and easy to do, worth checking. Apart from the online calculators I think my spreadsheed is still available from the wibble.

I missed that you had an open vented system - my bad. Ri then, with external motorised valve(s), and you'll have to keep the boiler temperature control up reasonably high to get your hot water to 60C (for avoiding Legionella) even though you could run cooler for the radiators most of the year and gain a little extra efficiency.

[The Nomad]

Will set ixquick to work :-)

Due to the 'odd', 'historic' & hard to change (more than I have) design of the pipe runs here I need the boiler up fairly anyway and the tank is set for (I think) 65C with it's separate 'stat & only re-heats very early morning.

Thanks again

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[The Nomad]

& the answer (from both your SS & the EST form) is

TaDa!

23-ish KW

Thanks, that is what I have (almost I think it is actually 24)

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[John Stumbles]

OK. Do check that your gas pipework is up to spec: for a 24kW boiler it'll need to be 22mm all the way from the meter[1]. Even though the old boiler was the same rating one sometimes finds the pipework undersized for higher-output boilers, leading to excessive pressure drop from the meter and lower than specified inlet pressure at the boiler and, and whilst it's legal to leave an existing boiler running on undersized pipework providing it's burning OK it's not legal to commission a new boiler running out of spec like that.

[1] for a 24kW boiler you've got a bit over 20 metres equivalent of pipe (where every 90 degree elbow, including branches through Tees, counts as half a metre) before you have excessive pressure drop.

[The Nomad]

John,

Yes it is!

So that's not a problem.

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[Mathew Newton]

The OP might want to also consider the Viessmann Vitodens 100-W WB1B Compac t (26KW version).

I've been considering one myself (to eventually replace my Ideal ICOS HE15 which seems to be living without issue way beyond what it ought to!) as I'v e heard good things about them, they feature a stainless steel heat exchang er and as they don't require pump overrun they can be used with an S-plan s ystem without any bypass.

For me however, I am still considering the WB Ri as my heating requirements are only 10KW and the heat input range for the 12KW WB Ri is 4-12KW compar ed to a much narrower 7.2-12KW for the Viessmann so I'm assuming the Ri wou ld result in much less cycling.

Mathew