On Wed, 30 Sep 2020 14:24:08 +0100, "www.GymRatZ.co.uk"
wrote:

On 30/09/2020 13:41, The Nomad wrote:
All assembled knowledgeable folk,

I fear the time has come, the ravenheat boiler has expired, no spark,
fan runs etc. etc. but not spark, not even the clicking from the
igniter ...

Do I:

a) buy a new PCB and hope or

b) Get a new boiler - this one is knackered, rusty internally (DAHIK -
IJD - OK)

if b) as I suspect it will have to happen in the next short while
anyway Worcerster-Bosh, Vallaint or ???

Your thoughts on makes is welcomed

I'll throw one out there...
Viessmann

My combi at home is a German "Micromat EC" (originally bought based on
"Dr Evil"'s recommendation!) which at the time it was installed the
plumber was impressed with its radial burner box etc, more a thing of
commercial boilers than domestic apparently. It's now around 16 years
old and admittedly I've had to replace the diverter valve a number of
times, the pump once, hot-glue the condensate siphon, replace a number
of dead o-rings on numerous occasions and so-on but on the whole it's
been superb, built in weather compensation with user customisable
temp/flow ramp, ideal for the UFH. Certainly never had to get an
engineer to do any repairs; so having looked at what's around Viessmann
appeared to be the closest thing in terms of "quality" so that would be
my next replacement rather than the go-to WB or Valliant.
Worth checking out as an alternative.

Thanks to all,

Viessmann is looking quite likely as so far they are the only lot that
have done a quote (all the other are too busy - will be 3 week just for a
visit to quote).

Not too bad a price, a little under 2k, about what I was expecting

Oh well, at least the fan heater works

Avpx

--
"The significant owl hoots in the night."
(Guards! Guards!)
12:10:01 up 1 day, 2:48, 10 users, load average: 7.16, 6.66, 6.60

In article ,
The Nomad wrote:
Viessmann is looking quite likely as so far they are the only lot that
have done a quote (all the other are too busy - will be 3 week just for a
visit to quote).

This presumably is a Viessmann approved installer, rather than Viessmann
themselves?

I did a self install, and got a much better price for my Viessmann on
Ebay, than from the local agent. Of course a pro plumber using them a lot
may have got a better discount. Ebay was £300 less than them, including
delivery, with the 32 kW system boiler costing just under £1k. About 12
years ago.

Be interesting if the latest model has more convenient self diagnosis,
etc. By plugging in a PC? Doing it via the onboard controls isn't the
easiest of things. And setting up the weather compensation.

--
*Don't use no double negatives *

Dave Plowman London SW
To e-mail, change noise into sound.

On 03/10/2020 13:03, Dave Plowman (News) wrote:
In article ,
The Nomad wrote:
Viessmann is looking quite likely as so far they are the only lot that
have done a quote (all the other are too busy - will be 3 week just for a
visit to quote).

This presumably is a Viessmann approved installer, rather than Viessmann
themselves?

I did a self install, and got a much better price for my Viessmann on
Ebay, than from the local agent. Of course a pro plumber using them a lot
may have got a better discount. Ebay was £300 less than them, including
delivery, with the 32 kW system boiler costing just under £1k. About 12
years ago.

When shopping for my Vaillant boiler and unvented cylinder and some
replacement rads, I approached our local plumbers merchant to get a
price. They were pretty close to the best online price I could find for
the boiler and cylinder anyway. So ordered it from them along with all
the other materials I would need, and let them deliver and unload it
straight into my garage. :-)

Be interesting if the latest model has more convenient self diagnosis,
etc. By plugging in a PC? Doing it via the onboard controls isn't the
easiest of things. And setting up the weather compensation.

Yeah its surprising with modern ebus style controls that more makers
don't offer that option.

--
Cheers,

John.

/================================================== ===============\
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| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 03/10/2020 10:46, John Smith wrote:
On 2020-10-02 22:20:46 +0000, said:

In most cases a 24kW boiler is not permitted to run on 15mm now,
current regs are more demanding re pressure drop. Worcester Bosch do a
pdf:
Technical Training Bulletin: Natural Gas (G20) Supply Pipe Sizing.
that explains how to calculate what's required.

We had a new Vaillant condensing system boiler installed yesterday and
the installer played it safe and put in a 18kw unit as he said the 15mm
gas pipe run was probably quite long and it is about 4 metres in a
straight line from the meter without taking into account the true path
under the hallway/kitchen.. The boiler so far is working fine and we
have hot water and heating after 10 days without and it's comfortably
driving 15 rads in about the same time as the old 24kw unit.

24kW equates to around 2.16 m^3/hour [1]

So if you work within the 1mBar pressure drop permitted, your maximum
pipe length will be somewhere 3 and 6m [2]

So if you take the 6m discharge rate, and scale it for the slightly
higher actual demand you get :

1 mBar pressure drop = ( 1 / 6 x 1.9 ) x actual length x 2.19

1/actual length = 0.192

actual length = 5.2m

So yup with 4m of straight pipe, potentially another 1m or so of
equivalent length in elbows etc, plus the rises to the boiler and the
meter, you would be pushing it at 24kW

(in reality it would probably still work since most boilers will be a
little more flexible than the pipe sizing regulations would imply)

Only hitch was a bleed hole rounded off in one old rad so that's been
taken out of the system for now.


[1] http://wiki.diyfaq.org.uk/index.php/...its#Converting

[2] http://wiki.diyfaq.org.uk/index.php/...ng#Design_Data

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
John Rumm wrote:
Be interesting if the latest model has more convenient self diagnosis,
etc. By plugging in a PC? Doing it via the onboard controls isn't the
easiest of things. And setting up the weather compensation.

Yeah its surprising with modern ebus style controls that more makers
don't offer that option.

To me, it would make sense to be able to set things via decent software.
Rather than multi-function buttons and the tiny screen menu on the built
in programmer.

Of course the cry would then go up - what about those who don't have a
computer or smart phone? I'd say good luck to a technophobe programming
one anyway.

--
*Before they invented drawing boards, what did they go back to?

Dave Plowman London SW
To e-mail, change noise into sound.

In article , John
Rumm scribeth thus
On 30/09/2020 19:36, John Smith wrote:
On 2020-09-30 15:38:13 +0000, Mike Clarke said:

On 30/09/2020 14:59, John Smith wrote:

Don't install one that is overated - our house has 16 rads/hot water
cylinder but a 24kw boiler is OK.

Unless it supplies a shower and it's a combi boiler and you want a
good flow of hot water.

I'm talking about a system boiler heating an unvented cylinder. In our
three story house the pressure is good enough for a very good shower on
the top floor.

Anyway just had the engineer in and he couldn't fix our old Vaillant. He
didn't have both PCBs on the van but the minimum cost to fix would be
about £300-£350 assuming one board would fix it and if both boards are
implicated that's about £500.

So I've asked him for quotes on a new 28kw (his suggestion) Vaillant and
Ideal, which he says he can fit on Friday or Monday.

At least i didn't have to pay him tonight as no fix no fee.

Might be worth giving Geoff at CET ltd a call to see if he has
re-manufactured PCBs for the boiler (basically he does PCB exchange -
you buy recon ones, and send him the dead ones - at a fraction of the
price from the OEM)

https://www.cetltd.com/




Yep second that....
--
Tony Sayer


Man is least himself when he talks in his own person.

Give him a keyboard, and he will reveal himself.

On 30/09/2020 16:03, alan_m wrote:
On 30/09/2020 14:11, No Name wrote:

There might be an opportunity to get some cheap insulation/energy
efficiency work done on your house as part of Rishi's Grant scheme....


There was a bit on the radio this afternoon warning people not to get
scammed by the salesman who offer to do the grant paperwork on your
behalf. The advice was also to not to buy from anyone who cold calls.

Apparently there are hundreds of companies recently registered with
Green Home or similar in their company name just waiting to take peoples
money with overpriced work.


And in the meantime they are claiming bounce back loans to buy property
with !!.

On 30/09/2020 14:24, www.GymRatZ.co.uk wrote:
I've had to replace the diverter valve a number of
times, the pump once, hot-glue the condensate siphon, replace a number
of dead o-rings on numerous occasions and so-on but on the whole it's
been superb,

Isn't that like asking 'What did the Romans do for us' ?

On 30/09/2020 21:20, charles wrote:
In article 2020093020352434361-nospam@nospamcom,
John Smith wrote:
On 2020-09-30 18:58:53 +0000, John Rumm said:

With modern modulating boilers that is less of a problem in the past. A
boiler with a wide modulation range is also desirable. The Vaillant
24kW models often go do to around 6kW.

John, thanks for your suggesting about the PCBs but at 20 years old I
think it's time to replace the whole thing and also it will be quicker.

One possible problem regarding rating and the way new boilers work -
our gas supply pipe to the current boiler is 15mm - is this likely to
be a problem for a condensing system boiler - I know it would be for a
combi boiler. Maybe there is a ceiling on rating or some makers only
specify 22mm.

Digging up the kitchen floor is not a great option...

we have a 75kW boiler with a 22mm supply. The boiler specification sheet
should tell you the size of supply pipe needed.


Gulp. How big is your house ?. Surely anything over 38kW would
put you close to the limit of a domestic meter anyway and usually
need a 28mm supply.

In article ,
Andrew wrote:
On 30/09/2020 21:20, charles wrote:
In article 2020093020352434361-nospam@nospamcom,
John Smith wrote:
On 2020-09-30 18:58:53 +0000, John Rumm said:

With modern modulating boilers that is less of a problem in the past. A
boiler with a wide modulation range is also desirable. The Vaillant
24kW models often go do to around 6kW.

John, thanks for your suggesting about the PCBs but at 20 years old I
think it's time to replace the whole thing and also it will be quicker.

One possible problem regarding rating and the way new boilers work -
our gas supply pipe to the current boiler is 15mm - is this likely to
be a problem for a condensing system boiler - I know it would be for a
combi boiler. Maybe there is a ceiling on rating or some makers only
specify 22mm.

Digging up the kitchen floor is not a great option...

we have a 75kW boiler with a 22mm supply. The boiler specification sheet
should tell you the size of supply pipe needed.


Gulp. How big is your house ?. Surely anything over 38kW would
put you close to the limit of a domestic meter anyway and usually
need a 28mm supply.

It is, of course, me muddling imperial & metric measurements. in metric
26.7kW.

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On 04/10/2020 11:46, Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
Be interesting if the latest model has more convenient self diagnosis,
etc. By plugging in a PC? Doing it via the onboard controls isn't the
easiest of things. And setting up the weather compensation.

Yeah its surprising with modern ebus style controls that more makers
don't offer that option.

To me, it would make sense to be able to set things via decent software.
Rather than multi-function buttons and the tiny screen menu on the built
in programmer.

Yup certainly. On the Vaillant VR470 there is a reasonable interface
(large backlit screen) and jog wheel to select options etc - so not as
bad as using the small LCD on the boiler, but it would still be better
sat on a computer with a PDF of the manual open on the screen beside you.

Of course the cry would then go up - what about those who don't have a
computer or smart phone? I'd say good luck to a technophobe programming
one anyway.

Well the setup is usually the domain of the professional (present
company excepted), so it seems perfectly reasonable for their business
to own a laptop as well as a flue gas analyser and any other special kit
required for the business of installing heating systems.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 04/10/2020 17:58, charles wrote:
In article ,
Andrew wrote:
On 30/09/2020 21:20, charles wrote:
In article 2020093020352434361-nospam@nospamcom,
John Smith wrote:
On 2020-09-30 18:58:53 +0000, John Rumm said:

With modern modulating boilers that is less of a problem in the past. A
boiler with a wide modulation range is also desirable. The Vaillant
24kW models often go do to around 6kW.

John, thanks for your suggesting about the PCBs but at 20 years old I
think it's time to replace the whole thing and also it will be quicker.

One possible problem regarding rating and the way new boilers work -
our gas supply pipe to the current boiler is 15mm - is this likely to
be a problem for a condensing system boiler - I know it would be for a
combi boiler. Maybe there is a ceiling on rating or some makers only
specify 22mm.

Digging up the kitchen floor is not a great option...

we have a 75kW boiler with a 22mm supply. The boiler specification sheet
should tell you the size of supply pipe needed.


Gulp. How big is your house ?. Surely anything over 38kW would
put you close to the limit of a domestic meter anyway and usually
need a 28mm supply.

It is, of course, me muddling imperial & metric measurements. in metric
26.7kW.

Ah, that seems more reasonable, and easily in the scope of what you can
get out of a "normal" U6 domestic meter.

(although that would be 91k BTU/hour rather than 75k)



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 02/10/2020 23:42:17, Fredxx wrote:
On 02/10/2020 23:20:46, wrote:
On Wednesday, 30 September 2020 20:35:29 UTC+1, John SmithÂ* wrote:
On 2020-09-30 18:58:53 +0000, John Rumm said:

With modern modulating boilers that is less of a problem in the past. A
boiler with a wide modulation range is also desirable. The Vaillant
24kW models often go do to around 6kW.

John, thanks for your suggesting about the PCBs but at 20 years old I
think it's time to replace the whole thing and also it will be quicker.

maybe you could find a similar used one & swap it, but probably you won't


One possible problem regarding rating and the way new boilers work -
our gas supply pipe to the current boiler is 15mm - is this likely to
be a problem for a condensing system boiler - I know it would be for a
combi boiler. Maybe there is a ceiling on rating or some makers only
specify 22mm.

Digging up the kitchen floor is not a great option...

In most cases a 24kW boiler is not permitted to run on 15mm now,
current regs are more demanding re pressure drop. Worcester Bosch do a
pdf:
Technical Training Bulletin: Natural Gas (G20) Supply Pipe Sizing.
that explains how to calculate what's required.

Do you have a link?

I didn't think so.

I think this is far more helpful:
http://wiki.diyfaq.org.uk/index.php/Gas_pipe_sizing

On 06/10/2020 20:53, Fredxx wrote:
On 02/10/2020 23:42:17, Fredxx wrote:
On 02/10/2020 23:20:46, wrote:
On Wednesday, 30 September 2020 20:35:29 UTC+1, John SmithÂ* wrote:
On 2020-09-30 18:58:53 +0000, John Rumm said:

With modern modulating boilers that is less of a problem in the
past. A
boiler with a wide modulation range is also desirable. The Vaillant
24kW models often go do to around 6kW.

John, thanks for your suggesting about the PCBs but at 20 years old I
think it's time to replace the whole thing and also it will be quicker.

maybe you could find a similar used one & swap it, but probably you
won't


One possible problem regarding rating and the way new boilers work -
our gas supply pipe to the current boiler is 15mm - is this likely to
be a problem for a condensing system boiler - I know it would be for a
combi boiler. Maybe there is a ceiling on rating or some makers only
specify 22mm.

Digging up the kitchen floor is not a great option...

In most cases a 24kW boiler is not permitted to run on 15mm now,
current regs are more demanding re pressure drop. Worcester Bosch do
a pdf:
Technical Training Bulletin: Natural Gas (G20) Supply Pipe Sizing.
that explains how to calculate what's required.

Do you have a link?

I didn't think so.

I did find this:

http://www.worcester-bosch.co.uk/sup...ownload/TB0053

Although their note that a 24kW boiler's max gas rate is 2.6 m^3/h is
slightly surprising... it would suggest an efficiency of only 80% if its
giving a true 24kW output, and hence drawing gas at a rate of nearly 30kW

(my previous calc was assuming that the input rate is 24kW, which is
likely an underestimate, since most boiler specs now quote output power
rather than input).

Oh, and I missed the brackets round the 6 x 1.9

If I redo my sum with their flow rate, that brings the maximum down to
~4.4m total effective length. (although they also indicate that the
pressure at the boiler inlet only need be 18mBar rather than the 20 one
designs for)



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 07/10/2020 01:10, John Rumm wrote:

snip

I did find this:

http://www.worcester-bosch.co.uk/sup...ownload/TB0053

Although their note that a 24kW boiler's max gas rate is 2.6 m^3/h is
slightly surprising... it would suggest an efficiency of only 80% if its
giving a true 24kW output, and hence drawing gas at a rate of nearly 30kW

(my previous calc was assuming that the input rate is 24kW, which is
likely an underestimate, since most boiler specs now quote output power
rather than input).


I have a vague memory that the calorific value (CV) for natural gas is
permitted to vary over quite a wide range. I have absolutely no idea
what value boiler makers [have to] use when quoting gas rates and power
but do just wonder if the 24 kW is based on a low (if not the minimum) CV.

--
Robin
reply-to address is (intended to be) valid

On 07/10/2020 01:10:11, John Rumm wrote:
On 06/10/2020 20:53, Fredxx wrote:
On 02/10/2020 23:42:17, Fredxx wrote:
On 02/10/2020 23:20:46, wrote:
On Wednesday, 30 September 2020 20:35:29 UTC+1, John SmithÂ* wrote:
On 2020-09-30 18:58:53 +0000, John Rumm said:

With modern modulating boilers that is less of a problem in the
past. A
boiler with a wide modulation range is also desirable. The Vaillant
24kW models often go do to around 6kW.

John, thanks for your suggesting about the PCBs but at 20 years old I
think it's time to replace the whole thing and also it will be
quicker.

maybe you could find a similar used one & swap it, but probably you
won't


One possible problem regarding rating and the way new boilers work -
our gas supply pipe to the current boiler is 15mm - is this likely to
be a problem for a condensing system boiler - I know it would be for a
combi boiler. Maybe there is a ceiling on rating or some makers only
specify 22mm.

Digging up the kitchen floor is not a great option...

In most cases a 24kW boiler is not permitted to run on 15mm now,
current regs are more demanding re pressure drop. Worcester Bosch do
a pdf:
Technical Training Bulletin: Natural Gas (G20) Supply Pipe Sizing.
that explains how to calculate what's required.

Do you have a link?

I didn't think so.

I did find this:

http://www.worcester-bosch.co.uk/sup...ownload/TB0053

Your google must be better than mine. I did look for a short while but
gave up.

I find it annoying when someone makes a claim and then doesn't back it
up, the request for a link was genuine.

A stove was fitted where I've worked on a branch going to a boiler. It's
a long length of pipe to both boiler and stove and I can can hear the
gas ring change note momentarily as the boiler fires up.

Although their note that a 24kW boiler's max gas rate is 2.6 m^3/h is
slightly surprising... it would suggest an efficiency of only 80% if its
giving a true 24kW output, and hence drawing gas at a rate of nearly 30kW

That's a little worrying?

(my previous calc was assuming that the input rate is 24kW, which is
likely an underestimate, since most boiler specs now quote output power
rather than input).

Oh, and I missed the brackets round the 6 x 1.9

If I redo my sum with their flow rate, that brings the maximum down to
~4.4m total effective length. (although they also indicate that the
pressure at the boiler inlet only need be 18mBar rather than the 20 one
designs for)

I think boilers are designed to cater for low pressures because of poor
regulation rather than any assumptions about pressure drop in pipes.

On 07/10/2020 13:19, Fredxx wrote:
On 07/10/2020 01:10:11, John Rumm wrote:
On 06/10/2020 20:53, Fredxx wrote:
On 02/10/2020 23:42:17, Fredxx wrote:
On 02/10/2020 23:20:46, wrote:
On Wednesday, 30 September 2020 20:35:29 UTC+1, John SmithÂ* wrote:
On 2020-09-30 18:58:53 +0000, John Rumm said:

With modern modulating boilers that is less of a problem in the
past. A
boiler with a wide modulation range is also desirable. The Vaillant
24kW models often go do to around 6kW.

John, thanks for your suggesting about the PCBs but at 20 years old I
think it's time to replace the whole thing and also it will be
quicker.

maybe you could find a similar used one & swap it, but probably you
won't


One possible problem regarding rating and the way new boilers work -
our gas supply pipe to the current boiler is 15mm - is this likely to
be a problem for a condensing system boiler - I know it would be
for a
combi boiler. Maybe there is a ceiling on rating or some makers only
specify 22mm.

Digging up the kitchen floor is not a great option...

In most cases a 24kW boiler is not permitted to run on 15mm now,
current regs are more demanding re pressure drop. Worcester Bosch
do a pdf:
Technical Training Bulletin: Natural Gas (G20) Supply Pipe Sizing.
that explains how to calculate what's required.

Do you have a link?

I didn't think so.

I did find this:

http://www.worcester-bosch.co.uk/sup...ownload/TB0053

Your google must be better than mine. I did look for a short while but
gave up.

That was somewhat tricky to find and then disentangle from the google
redirect to it, since could not find an actual landing page that links
to it. However it just dawned on me that I can now do a link search on
that one. So we get to:

https://contracts.worcester-bosch.co.../boiler?page=3

(there are a few other interesting docs there)

I find it annoying when someone makes a claim and then doesn't back it
up, the request for a link was genuine.

Well par for the course...

A stove was fitted where I've worked on a branch going to a boiler. It's
a long length of pipe to both boiler and stove and I can can hear the
gas ring change note momentarily as the boiler fires up.

If it dips and then recovers, it could just be a reflection of the main
gas governor taking a moment to adjust in response to a large step
change in demand. (which arguable a long pipe run might actually smooth
slightly, rather than make worse)

Although their note that a 24kW boiler's max gas rate is 2.6 m^3/h is
slightly surprising... it would suggest an efficiency of only 80% if
its giving a true 24kW output, and hence drawing gas at a rate of
nearly 30kW

That's a little worrying?

Well they say that's peak rate 10 mins after ignition. If the boiler
attempts to modulate on actual output power rather than gas rate[1],
then when the system is warming up, but not yet enough to modulate the
output down, condensation efficiency would likely be tailing off a bit.

[1] and that's a big if, since it seem more complicated to do.

(my previous calc was assuming that the input rate is 24kW, which is
likely an underestimate, since most boiler specs now quote output
power rather than input).

Oh, and I missed the brackets round the 6 x 1.9

If I redo my sum with their flow rate, that brings the maximum down to
~4.4m total effective length. (although they also indicate that the
pressure at the boiler inlet only need be 18mBar rather than the 20
one designs for)

I think boilers are designed to cater for low pressures because of poor
regulation rather than any assumptions about pressure drop in pipes.

Quite possibly - but it also explains why a number of installations seem
to work in practice, even when they their supply pipework is well out of
spec.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 2020-10-08 10:24:50 +0000, John Rumm said:

Quite possibly - but it also explains why a number of installations
seem to work in practice, even when they their supply pipework is well
out of spec.

So our new Vaillant has conked out tonight after working perfectly for
a week. Won't fire up, just like the old Vaillant now scrapped, which
also failed on a Friday evening.

It seems to be a gas valve issue and I hope it is and not intolerance
with the supply. The only other gas appliance we have - a 5 ring gas
hob - is working OK.

So all I can do is call out Vaillant under their warranty as the
installer can't touch it without voiding the warranty.

This is distressing for the family...

John Smith wrote:
On 2020-10-08 10:24:50 +0000, John Rumm said:

Quite possibly - but it also explains why a number of installations
seem to work in practice, even when they their supply pipework is well
out of spec.

So our new Vaillant has conked out tonight after working perfectly for
a week. Won't fire up, just like the old Vaillant now scrapped, which
also failed on a Friday evening.

I presume youve checked the system pressure (assuming its a sealed
system)?

Tim

--
Please don't feed the trolls

On 2020-10-09 20:59:04 +0000, Tim+ said:

John Smith wrote:
On 2020-10-08 10:24:50 +0000, John Rumm said:

Quite possibly - but it also explains why a number of installations
seem to work in practice, even when they their supply pipework is well
out of spec.

So our new Vaillant has conked out tonight after working perfectly for
a week. Won't fire up, just like the old Vaillant now scrapped, which
also failed on a Friday evening.

I presume youve checked the system pressure (assuming its a sealed
system)?

Pressure is about midway between upper and lower on the display.

The installer measured the appliance gas pressure at 20mbar so it
should be OK. I called him and he said it may be a faulty gas valve.
Not good for a new boiler and a brand rated as the most reliable.

On 09/10/2020 22:35, John Smith wrote:
On 2020-10-09 20:59:04 +0000, Tim+ said:

John Smith wrote:
On 2020-10-08 10:24:50 +0000, John Rumm said:

Quite possibly - but it also explains why a number of installations
seem to work in practice, even when they their supply pipework is well
out of spec.

So our new Vaillant has conked out tonight after working perfectly for
a week. Won't fire up, just like the old Vaillant now scrapped, which
also failed on a Friday evening.

I presume youve checked the system pressure (assuming its a sealed
system)?

Pressure is about midway between upper and lower on the display.

Any fault codes?

The installer measured the appliance gas pressure at 20mbar so it should
be OK.Â* I called him and he said it may be a faulty gas valve. Not good
for a new boiler and a brand rated as the most reliable.

Just because they are reliable as a group, it does not mean yours is
going to be perfect!


--
Cheers,

John.

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On 2020-10-09 22:08:30 +0000, John Rumm said:

Just because they are reliable as a group, it does not mean yours is
going to be perfect!

Indeed. Vaillant engineer fixed it on Wednesday in 15 minutes - it was
a faulty gas valve. But he let something slip - that the valves often
fail and he said he'd fitted an uprated component. This tells me that
there is stock being fitted by installers with a known issue, or at
least known internally to Vaillant.

Anyway it has a 7 year warranty so they can keep on coming to fix it
for free and I will ask for comensation for downtime.