Something I detest. I have never known anyone to experience gas CH have a good word for night storage radiators.
A gas system boiler without any pumps or water valves is as simple as you can get.
Apart from an economy 7 heat store boiler of course. But they tend to be quite big.
My Ideal Logic Combi 24 not only takes some time to deliver hot water for washing up; it also frequently goes cold during a shower (and filling the washing up bowl), before going hot again. I haven't managed to persuade anyone (independent gas engineer or Ideal engineer) that there is a problem. They just 'replace something' and leave. This is the problem with intermittent/partial (rather than complete) failure.
I fitted a 35kW Ideal ISAR at a previous house. The boilers had not been on the market that long so there was not much reliability data to go on (however it did fit the small space available, and was available with the 35kW output that I would suggest is the minimum sensible for a family home - hence why I took a punt). In use it was at the time the best combi I had used. I had one fault - a failed DHW temp sensor in the four years or so I owned it. Reports suggest that the new owners did have additional problems with it and ditched it some years later.
The build quality was actually fairly good and the design layout / serviceability fairly good (although not in the Vaillant league). The weak point at the time (so it turns out) was the quality of the electronics. ITRC Geoff at CET reporting very large numbers of PCB failures on this range. I don't know if that has changed in recent times.
Noise wise, it was not bad - better that the CH only boiler it replaced, but not as quiet as my current Vaillant system boiler. (not sure I would want even that in a bedroom though)
I have noticed that weather compensation reduces that noise quite a bit most of the time. I can guestimate the outside temp early in the morning when waking up just by listening to how much pipe expansion is going on. Its noticeable more "clanky" on very cold days when the flow temp is higher.
They're all right if you know how warm it's going to be the following day and you want to heat the place 24 hours. Maybe the modern storage heaters are better, but I found it hard to control the output of stored heat.
No pumps or valves? They must be quite complicated inside.
What's one of them? I thought you just had a cylinder with an off-peak immersion at the bottom and a peak one at the top, fed by a cold water tank.
In which case, it sounds like the installer has not set it up correctly. There is no reason it should take any longer to heat the place than any other boiler of comparable power.
Best of all if you have good insulation is an electric boiler feeding a wet rad system, and hot water tank heated with immersion on economy 7. Most of our morning CH is on during economy 7 time anyway so reduces cost. We don't have gas, but even if we did I think I would still opt for all electric heating. Very quiet, very simple, very low maintenance, very easy to fit.
T i m snipped-for-privacy@spaced.me.uk> posted
It's never on full. A few seconds after it ignites after a new call for heat, the burner output drops to minimum or near-minimum, and stays there for at least half an hour, sometimes more. The flow water temperature hangs around at 35-40 all this time, so the rads never get properly hot.
It doesn't know what the target *room* temperature is, only whether it's calling for heat or not. It never gets anywhere near the target *flow* temperture, which I have set at 65degC.
Unlikely, I think; if a combi did what ours does it would be completely unmarketable.
Only that the design makes it do so, apparently regardless of any of the d-register settings. A bit of googling shows that this is a very common complaint about Ecotec 600 series models.
A simple system boiler has a variable speed fan and a modulating gas valve. No other moving parts.
Yes it is effectively a very big cylinder with a heat exchanger and mixing valves.
40kW gas burner in the combi - unlikely to find that power in an electric shower.
That would be my guess too. Given that both "Which" and regular posters here tend to put Vaillant and Worcester Bosch at the top of the pile particularly for hardware.
I found the criteria Which use is somewhat unclear. They also don't appear to have actually tested ANY boilers. They simply quote "Brand Reliability" so how reliable a brand is overall. Of the Ideal they say...
Pros Good reliability record and customers and engineers are fond of the brand.
Cons No significant cons.
I also know when I read some of the other reviews(e.g. TVs) there are aspects of their testing which strikes of "Political Correctness". I have an LG which TV which is rated a "best buy" but it has a really annoying "feature" where when you open the program guide the TV channel stops playing instead of going to small screen like my LG... (which has other grumbles)...
Dave
That sounds unlikely[1], and more to the point does not concur with my experience, I have had no problem with my 624 bringing 21 rads up to flow temperature quickly and warming the house as required.
That I can believe - but that does not make it the boiler's fault.
However without far more information on the actual installation and the controls in use, probably not much else can be said at this point.
[1] Worth keeping in mind though that these are boilers have sophisticated control systems and a vast array of installation options - so its not uncommon to get a setup that does not behave as you would expect.
Dumb question... can you not fit the new one in the same place as the old?
How did you manage it, then? All advice gratefully received.
The installer left the boiler on factory default settings. I don't blame him. The manual is almost completely incomprehensible to me, and I've got an electronics engineering degree.
It does make it Vaillant's fault, though. My previous boiler (Potterton Kingfisher, basic analogue controls, no software) worked straight out of the box. Heated the place - six-bedroom Victorian detached house - in minutes.
I have 14 rads all on the same circuit, controlled by a single on/off room thermostat. Separate 2-way valves for CH and HW. Towel rad connected to the bypass circuit. Completely standard.
I've already tried most of the advice available on the Web re adjusting d-registers. It didn't work.
The problem with the existing boiler appears to be a blocked chimney. Its been in place for 40 years so has a metal chimney liner which I understand isn't allowed any more. Its no where near an outside wall. the way the house is built modern safety rules would probably require scaffold to get to the top of the chinmey...
Dave
Do you have an attic?
Boiler now push out so little heat from their casing there is no need to locate them in a place you want to keep warm.
To be fair it did not require anything particularly difficult, although my system configuration is quite different to yours with 2 heating zones, and 1 DHW, VR470 weather compensation with external temperature sensor acting as the main prog stat, VR85 secondary stat for second heating zone, unvented cylinder, and a VR61 control unit interfacing to the 2 port zone valves. Cylinder NTC temp sensor wired back to the boiler. All controls running on ebus.
The main adjustments I needed to make was to pick a response curve to better match the rate of heat loss of the house. (its that which informs the choice of flow temp based on external temperature and also the deviation between actual temp and demanded temp). I also specified desired DHW temp (the system runs split temperature - using higher flow temps for cylinder reheats), and a day of the week to run an anti legionella cycle on the cylinder (basically heating it to 70 rather than the normal 60). Then main day and setback temps, and finally setup what times of day I want heating and DHW.
(I also confused myself by labelling my two zones as Upstairs and Downstairs, and convinced myself I had the wrong zone valve being controlled by each stat. So swapped them over and it was still not making sense. In the end I eventually realised I had it right the first time, but had labelled the zoned back to front!)
One of the nice things about having the ebus controls is all the settings can be accessed and configured using more straightforward menus etc from the main programmer - so you never need to delve into d registers manually
IME Valliant manuals are not always that helpful - they have plenty of low level detail but it can be difficult to find high level overviews of how the bits of the system integrate, and how you chose which is the most appropriate way to do something.
Was the Potterton a modulating boiler? (i.e. could it vary its burner output power, or did it always run at max output)
How is this towel rail bypass configured?
For example, if the bypass was opening too soon / easily, then the boiler would see the return temperature ramping up quickly to approach the flow temperature. This would cause it to reduce boiler output power to try and match the actual load - which because of the high return temp would look very small.
You can also get a similar effect on a system that is well out of balance such that the bulk of the flow passes through one or two rads, and hence the boiler will again see a rapid rise in return temperature, which it will interpret as the house being up to temperature, and so back off the power.
If its something to do with the setup of the wet bits, this might not be something you can fix with a settings change. An old non modulating boiler may perform better in circumstances like those described, since it will run flat out until the stat turns it off or it cycles on the its internal upper limit stat.
Are pipes creaking a boiler problem or more of a problem of poor installation of hot water or CH pipework?
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