Would it be accurate to say, in general, that weather compensation on
condensing boilers lowers flow temperature as outside temperatures rise?

I ask partly because my boiler's weather compensation has a number of 'slope'
settings, presumably to compensate for levels of insulation etc. Would a a
better insulated home, requiring a lower flow temperature, result in a more
efficiently operating boiler?

--
Cheers, Rob, Sheffield UK

On 13/12/2022 10:10, RJH wrote:
> Would it be accurate to say, in general, that weather compensation on
> condensing boilers lowers flow temperature as outside temperatures rise?
>
> I ask partly because my boiler's weather compensation has a number of 'slope'
> settings, presumably to compensate for levels of insulation etc. Would a a
> better insulated home, requiring a lower flow temperature, result in a more
> efficiently operating boiler?

One thing I do recall about them under these conditions is that the
condensate drain has a nasty habit of blocking as the water freezes on
the walls of the pipe until it blocks. Then the boiler interlocks out.

--
Regards,
Martin Brown

On 13/12/2022 10:10, RJH wrote:
> Would it be accurate to say, in general, that weather compensation on
> condensing boilers lowers flow temperature as outside temperatures rise?

Yes! The heating system will be able to much more closely match it's
output, to the demand of your home. Which means that rather than your
boiler starting and running flat out, until the demand ends, knowing
what what the actual demand is, it can precisely match it, with no under
or overshoot.

Rather than the creaking of pipes, as the boiler fires, then switches
off, the flow of heat is much better controlled, by the boiler being
precisely modulated.

>
> I ask partly because my boiler's weather compensation has a number of 'slope'
> settings, presumably to compensate for levels of insulation etc. Would a a
> better insulated home, requiring a lower flow temperature, result in a more
> efficiently operating boiler?

Yes! For my system, you set an initial slope, but the system itself
'learns' and adjusts it's slope itself, to fine tune itself.

On 13/12/2022 10:10, RJH wrote:

> Would it be accurate to say, in general, that weather compensation on
> condensing boilers lowers flow temperature as outside temperatures rise?

Yup generally. It will use the lowest flow temperature it can to get the
required result. So that in turn may lower return temperature and so
flue gas temperature as well.

> I ask partly because my boiler's weather compensation has a number of 'slope'
> settings, presumably to compensate for levels of insulation etc. Would a a
> better insulated home, requiring a lower flow temperature, result in a more
> efficiently operating boiler?
Generally yes.

--
Cheers,

John.

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

On 13/12/2022 10:13, Martin Brown wrote:
> On 13/12/2022 10:10, RJH wrote:
>> Would it be accurate to say, in general, that weather compensation on
>> condensing boilers lowers flow temperature as outside temperatures rise?
>>
>> I ask partly because my boiler's weather compensation has a number of
>> 'slope'
>> settings, presumably to compensate for levels of insulation etc. Would
>> a a
>> better insulated home, requiring a lower flow temperature, result in a
>> more
>> efficiently operating boiler?
>
> One thing I do recall about them under these conditions is that the
> condensate drain has a nasty habit of blocking as the water freezes on
> the walls of the pipe until it blocks. Then the boiler interlocks out.

Not sure what this has to do with weather compensation as such. Better
efficiency will tend to produce more condensate rather than less, making
freezing of the condensate pipe less likely.

However frozen condensate pipes in general are not good. These are
usually a result of a failure by the installer to do an adequate job
making sure that it does not happen. Following the installers
instruction manual would be a good start in many cases!

So transition to a much larger pipe before you exit the building. If
running through a cold space like a loft, then insulate it, and if need
be provide trace heating. Don't do daft stuff like discharge condensate
onto a roof, or drop it out of a pipe exiting an external wall as if it
ware and over pressure vent pipe.

--
Cheers,

John.

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

On Tuesday, 13 December 2022 at 12:52:04 UTC, John Rumm wrote:
> On 13/12/2022 10:13, Martin Brown wrote:
> > On 13/12/2022 10:10, RJH wrote:
> >> Would it be accurate to say, in general, that weather compensation on
> >> condensing boilers lowers flow temperature as outside temperatures rise?
> >>
> >> I ask partly because my boiler's weather compensation has a number of
> >> 'slope'
> >> settings, presumably to compensate for levels of insulation etc. Would
> >> a a
> >> better insulated home, requiring a lower flow temperature, result in a
> >> more
> >> efficiently operating boiler?
> >
> > One thing I do recall about them under these conditions is that the
> > condensate drain has a nasty habit of blocking as the water freezes on
> > the walls of the pipe until it blocks. Then the boiler interlocks out.
> Not sure what this has to do with weather compensation as such. Better
> efficiency will tend to produce more condensate rather than less, making
> freezing of the condensate pipe less likely.
>
> However frozen condensate pipes in general are not good. These are
> usually a result of a failure by the installer to do an adequate job
> making sure that it does not happen. Following the installers
> instruction manual would be a good start in many cases!
>
> So transition to a much larger pipe before you exit the building. If
> running through a cold space like a loft, then insulate it, and if need
> be provide trace heating. Don't do daft stuff like discharge condensate
> onto a roof, or drop it out of a pipe exiting an external wall as if it
> ware and over pressure vent pipe.
> --
> Cheers,
>
> John.
>
> /=================================================================\
> | Internode Ltd - http://www.internode.co.uk |
> |-----------------------------------------------------------------|
> | John Rumm - john(at)internode(dot)co(dot)uk |
> \=================================================================/
I've routed the condensate via a washing machine hockey stick trap into a conveniently located internal soil pipe on occasion. Almost zero chance of freezing unless the house becomes derelict.

On 13/12/2022 17:07, John J wrote:
> On Tuesday, 13 December 2022 at 12:52:04 UTC, John Rumm wrote:
>> On 13/12/2022 10:13, Martin Brown wrote:
>>> On 13/12/2022 10:10, RJH wrote:
>>>> Would it be accurate to say, in general, that weather
>>>> compensation on condensing boilers lowers flow temperature as
>>>> outside temperatures rise?
>>>>
>>>> I ask partly because my boiler's weather compensation has a
>>>> number of 'slope' settings, presumably to compensate for levels
>>>> of insulation etc. Would a a better insulated home, requiring a
>>>> lower flow temperature, result in a more efficiently operating
>>>> boiler?
>>>
>>> One thing I do recall about them under these conditions is that
>>> the condensate drain has a nasty habit of blocking as the water
>>> freezes on the walls of the pipe until it blocks. Then the boiler
>>> interlocks out.
>> Not sure what this has to do with weather compensation as such.
>> Better efficiency will tend to produce more condensate rather than
>> less, making freezing of the condensate pipe less likely.
>>
>> However frozen condensate pipes in general are not good. These are
>> usually a result of a failure by the installer to do an adequate
>> job making sure that it does not happen. Following the installers
>> instruction manual would be a good start in many cases!
>>
>> So transition to a much larger pipe before you exit the building.
>> If running through a cold space like a loft, then insulate it, and
>> if need be provide trace heating. Don't do daft stuff like
>> discharge condensate onto a roof, or drop it out of a pipe exiting
>> an external wall as if it ware and over pressure vent pipe.

> I've routed the condensate via a washing machine hockey stick trap
> into a conveniently located internal soil pipe on occasion. Almost
> zero chance of freezing unless the house becomes derelict.

Yup, I did similar - it runs into the 50mm waste pipe that collects the
outlets from DW, and WM etc.

--
Cheers,

John.

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

In article <tn9shg$2gonm$2@dont-email.me>,
John Rumm <see.my.signature@nowhere.null> wrote:
> However frozen condensate pipes in general are not good. These are
> usually a result of a failure by the installer to do an adequate job
> making sure that it does not happen. Following the installers
> instruction manual would be a good start in many cases!

True. It's odd how everyone will tell you you must use a pro to install a
boiler - yet the instructions on how to do this without problems very
often ignored. If the wealth of posts about frozen ones are anything to go
by.

--
*The average person falls asleep in seven minutes *

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

In article <tnabss$2icea$1@dont-email.me>,
John Rumm <see.my.signature@nowhere.null> wrote:
> > I've routed the condensate via a washing machine hockey stick trap
> > into a conveniently located internal soil pipe on occasion. Almost
> > zero chance of freezing unless the house becomes derelict.

> Yup, I did similar - it runs into the 50mm waste pipe that collects the
> outlets from DW, and WM etc.

Had a once workmate who is a bit anal about some things tell me it
shouldn't go into a drain without treating it first. Pollutes the sewers
or something. And described some device he's bought at vast cost to make
it safe.
But my boiler instructions give details of using a foul water drain, rain
water one and a soakaway. And a German boiler, so often more 'green' about
such things.

--
*It's not hard to meet expenses... they're everywhere.

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

On 22/12/2022 15:31, Dave Plowman (News) wrote:
> True. It's odd how everyone will tell you you must use a pro to install a
> boiler - yet the instructions on how to do this without problems very
> often ignored. If the wealth of posts about frozen ones are anything to go
> by.

+1

On 22/12/2022 15:36, Dave Plowman (News) wrote:
> In article <tnabss$2icea$1@dont-email.me>,
> John Rumm <see.my.signature@nowhere.null> wrote:
>>> I've routed the condensate via a washing machine hockey stick trap
>>> into a conveniently located internal soil pipe on occasion. Almost
>>> zero chance of freezing unless the house becomes derelict.
>
>> Yup, I did similar - it runs into the 50mm waste pipe that collects the
>> outlets from DW, and WM etc.
>
> Had a once workmate who is a bit anal about some things tell me it
> shouldn't go into a drain without treating it first. Pollutes the sewers
> or something. And described some device he's bought at vast cost to make
> it safe.
> But my boiler instructions give details of using a foul water drain, rain
> water one and a soakaway. And a German boiler, so often more 'green' about
> such things.

It is mildly acidic - about as much as lemon juice. So there is usually
a recommendation that it be mixed with other waste water if being sent
to a metal pipe.

However I can't see a problem with it diluted at sewer volume!

--
Cheers,

John.

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

On 13 Dec 2022 at 17:14:04 GMT, John Rumm wrote:

>
>
>> I've routed the condensate via a washing machine hockey stick trap
>> into a conveniently located internal soil pipe on occasion. Almost
>> zero chance of freezing unless the house becomes derelict.
>
> Yup, I did similar - it runs into the 50mm waste pipe that collects the
> outlets from DW, and WM etc.

I've done that.

Sometimes the pressure of say the washing machine draining does seem to push
up to the boiler and creates a bubbling sound in (what I assume to be) the
condensate reservoir. I've been meaning to look at a way of preventing that
happening - any suggestions?

--
Cheers, Rob, Sheffield UK

On 23/12/2022 08:22, RJH wrote:
> On 13 Dec 2022 at 17:14:04 GMT, John Rumm wrote:
>
>>
>>
>>> I've routed the condensate via a washing machine hockey stick trap
>>> into a conveniently located internal soil pipe on occasion. Almost
>>> zero chance of freezing unless the house becomes derelict.
>>
>> Yup, I did similar - it runs into the 50mm waste pipe that collects the
>> outlets from DW, and WM etc.
>
> I've done that.
>
> Sometimes the pressure of say the washing machine draining does seem to push
> up to the boiler and creates a bubbling sound in (what I assume to be) the
> condensate reservoir. I've been meaning to look at a way of preventing that
> happening - any suggestions?

I trimmed down the height of the stand pipe waste for the WM, and put a
swept tee on the top. Hooked the WM waste hose into the top of the tee,
and then fed the 21mm condensate drain into the side of the tee using a
boss to convert the sizes.

So the top of the pipe is still open to the air, and the trap on the
standpipe is still a significant drop below. The condensate is being
added to the pipe above the outlet of the WM waste hose that pokes down
the pipe a bit. So there is no air seal, and the WM waste does not
directly go near the outlet from the condensate drain.

It has always worked nicely.

--
Cheers,

John.

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

On Friday, 23 December 2022 at 08:22:39 UTC, RJH wrote:
> On 13 Dec 2022 at 17:14:04 GMT, John Rumm wrote:
>
> >
> >
> >> I've routed the condensate via a washing machine hockey stick trap
> >> into a conveniently located internal soil pipe on occasion. Almost
> >> zero chance of freezing unless the house becomes derelict.
> >
> > Yup, I did similar - it runs into the 50mm waste pipe that collects the
> > outlets from DW, and WM etc.
> I've done that.
>
> Sometimes the pressure of say the washing machine draining does seem to push
> up to the boiler and creates a bubbling sound in (what I assume to be) the
> condensate reservoir. I've been meaning to look at a way of preventing that
> happening - any suggestions?
> --
> Cheers, Rob, Sheffield UK
Use a dedicated washing machine trap. Take the condensate pipe into the top of the upright and don't seal it. Start by putting a cupfull of water into the trap to provide a water stink seal to prevent sewer gases escaping.

In message <0fc366ab-cb1f-4c22-be43-1220a8c1ead8n@googlegroups.com>,
John J <johnjessop46@gmail.com> writes
>On Friday, 23 December 2022 at 08:22:39 UTC, RJH wrote:
>> On 13 Dec 2022 at 17:14:04 GMT, John Rumm wrote:
>>
>> >
>> >
>> >> I've routed the condensate via a washing machine hockey stick trap
>> >> into a conveniently located internal soil pipe on occasion. Almost
>> >> zero chance of freezing unless the house becomes derelict.
>> >
>> > Yup, I did similar - it runs into the 50mm waste pipe that collects the
>> > outlets from DW, and WM etc.
>> I've done that.
>>
>> Sometimes the pressure of say the washing machine draining does seem to push
>> up to the boiler and creates a bubbling sound in (what I assume to be) the
>> condensate reservoir. I've been meaning to look at a way of preventing that
>> happening - any suggestions?
>> --
>> Cheers, Rob, Sheffield UK
>Use a dedicated washing machine trap. Take the condensate pipe into the
>top of the upright and don't seal it. Start by putting a cupfull of
>water into the trap to provide a water stink seal to prevent sewer
>gases escaping.

Umm. Not to be over picky but, shouldn't these devices include a
tundish?

--
Tim Lamb

On 23/12/2022 11:39, Tim Lamb wrote:
> In message <0fc366ab-cb1f-4c22-be43-1220a8c1ead8n@googlegroups.com>,
> John J <johnjessop46@gmail.com> writes
>> On Friday, 23 December 2022 at 08:22:39 UTC, RJH wrote:
>>> On 13 Dec 2022 at 17:14:04 GMT, John Rumm wrote:
>>>
>>> >
>>> >
>>> >> I've routed the condensate via a washing machine hockey stick trap
>>> >> into a conveniently located internal soil pipe on occasion. Almost
>>> >> zero chance of freezing unless the house becomes derelict.
>>> >
>>> > Yup, I did similar - it runs into the 50mm waste pipe that collects
>>> the
>>> > outlets from DW, and WM etc.
>>> I've done that.
>>>
>>> Sometimes the pressure of say the washing machine draining does seem
>>> to push
>>> up to the boiler and creates a bubbling sound in (what I assume to
>>> be) the
>>> condensate reservoir. I've been meaning to look at a way of
>>> preventing that
>>> happening - any suggestions?
>>> --
>>> Cheers, Rob, Sheffield UK
>> Use a dedicated washing machine trap. Take the condensate pipe into
>> the top of the upright and don't seal it. Start by putting a cupfull
>> of water into the trap to provide a water stink seal to prevent sewer
>> gases escaping.
>
> Umm. Not to be over picky but, shouldn't these devices include a tundish?
>

There has to be a visible air break and a 75mm seal but ISTM that's met
with a pipe into the top of an open w/m hockey stick. AFAIK nothing says
you need to be able to *see* if there's condensate coming out ;)
--
Robin
reply-to address is (intended to be) valid

On 23/12/2022 11:01, John J wrote:
> Use a dedicated washing machine trap. Take the condensate pipe into the top of the upright and don't seal it. Start by putting a cupfull of water into the trap to provide a water stink seal to prevent sewer gases escaping.

On my Vailant boiler it says

Condensate discharge systems

It is not necessary to provide extra traps in the discharge
pipe as there is already a trap inside the boiler. Fitting an
extra trap may cause the boiler siphon to work incorrectly.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 23/12/2022 11:59, alan_m wrote:
> On 23/12/2022 11:01, John J wrote:
>> Use a dedicated washing machine trap. Take the condensate pipe into
>> the top of the upright and don't seal it. Start by putting a cupfull
>> of water into the trap to provide a water stink seal to prevent sewer
>> gases escaping.
>
> On my Vailant boiler it says
>
> Condensate discharge systems
>
> It is not necessary to provide extra traps in the discharge
> pipe as there is already a trap inside the boiler. Fitting an
> extra trap may cause the boiler siphon to work incorrectly.
>

The permitted diagrams for the condensate discharge show one method of
connecting to a sink waste BUT ONLY USES ONE trap for both and the
condensate is connected before the trap, presumably so the pipe is open
to the air via the sink plug and sink overflow holes.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

In message <0ad68f00-e14d-2e4d-19df-bd01eac78a58@outlook.com>, Robin
<rbw@outlook.com> writes
>On 23/12/2022 11:39, Tim Lamb wrote:
>> In message <0fc366ab-cb1f-4c22-be43-1220a8c1ead8n@googlegroups.com>,
>>John J <johnjessop46@gmail.com> writes
>>> On Friday, 23 December 2022 at 08:22:39 UTC, RJH wrote:
>>>> On 13 Dec 2022 at 17:14:04 GMT, John Rumm wrote:
>>>>
>>>> >
>>>> >
>>>> >> I've routed the condensate via a washing machine hockey stick trap
>>>> >> into a conveniently located internal soil pipe on occasion. Almost
>>>> >> zero chance of freezing unless the house becomes derelict.
>>>> >
>>>> > Yup, I did similar - it runs into the 50mm waste pipe that
>>>> >collects
>>>> the
>>>> > outlets from DW, and WM etc.
>>>> I've done that.
>>>>
>>>> Sometimes the pressure of say the washing machine draining does
>>>>seem to push
>>>> up to the boiler and creates a bubbling sound in (what I assume to
>>>>be) the
>>>> condensate reservoir. I've been meaning to look at a way of
>>>>preventing that
>>>> happening - any suggestions?
>>>> -- Cheers, Rob, Sheffield UK
>>> Use a dedicated washing machine trap. Take the condensate pipe into
>>>the top of the upright and don't seal it. Start by putting a cupfull
>>>of water into the trap to provide a water stink seal to prevent sewer
>>>gases escaping.
>> Umm. Not to be over picky but, shouldn't these devices include a
>>tundish?
>>
>
>There has to be a visible air break and a 75mm seal but ISTM that's met
>with a pipe into the top of an open w/m hockey stick. AFAIK nothing
>says you need to be able to *see* if there's condensate coming out ;)

Ah. I was thinking more about the situation where the installer has
linked the boiler pressure relief valve piping to the condensate run
off.

--
Tim Lamb

On 23/12/2022 11:39, Tim Lamb wrote:
> In message <0fc366ab-cb1f-4c22-be43-1220a8c1ead8n@googlegroups.com>,
> John J <johnjessop46@gmail.com> writes
>> On Friday, 23 December 2022 at 08:22:39 UTC, RJH wrote:
>>> On 13 Dec 2022 at 17:14:04 GMT, John Rumm wrote:
>>>
>>> >
>>> >
>>> >> I've routed the condensate via a washing machine hockey stick trap
>>> >> into a conveniently located internal soil pipe on occasion. Almost
>>> >> zero chance of freezing unless the house becomes derelict.
>>> >
>>> > Yup, I did similar - it runs into the 50mm waste pipe that collects
>>> the
>>> > outlets from DW, and WM etc.
>>> I've done that.
>>>
>>> Sometimes the pressure of say the washing machine draining does seem
>>> to push
>>> up to the boiler and creates a bubbling sound in (what I assume to
>>> be) the
>>> condensate reservoir. I've been meaning to look at a way of
>>> preventing that
>>> happening - any suggestions?
>>> --
>>> Cheers, Rob, Sheffield UK
>> Use a dedicated washing machine trap. Take the condensate pipe into
>> the top of the upright and don't seal it. Start by putting a cupfull
>> of water into the trap to provide a water stink seal to prevent sewer
>> gases escaping.
>
> Umm. Not to be over picky but, shouldn't these devices include a tundish?

No requirement. The need for a tundish occurs when you have the
potential to back contaminate the mains water supply. Typically on an
unvented cylinder fed direct from the main, the over temp and over
pressure relief valves would discharge via a tundish. That provides and
air gap and also a visible indication that water is being passed.

Condensate is just a by product of combustion - no derived from the
mains water.

--
Cheers,

John.

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

On 23/12/2022 12:24, Tim Lamb wrote:
> In message <0ad68f00-e14d-2e4d-19df-bd01eac78a58@outlook.com>, Robin
> <rbw@outlook.com> writes
>> On 23/12/2022 11:39, Tim Lamb wrote:
>>> In message <0fc366ab-cb1f-4c22-be43-1220a8c1ead8n@googlegroups.com>,
>>> John J <johnjessop46@gmail.com> writes
>>>> On Friday, 23 December 2022 at 08:22:39 UTC, RJH wrote:
>>>>> On 13 Dec 2022 at 17:14:04 GMT, John Rumm wrote:
>>>>>
>>>>> >
>>>>> >
>>>>> >> I've routed the condensate via a washing machine hockey stick trap
>>>>> >> into a conveniently located internal soil pipe on occasion. Almost
>>>>> >> zero chance of freezing unless the house becomes derelict.
>>>>> >
>>>>> > Yup, I did similar - it runs into the 50mm waste pipe that >collects
>>>>> the
>>>>> > outlets from DW, and WM etc.
>>>>> I've done that.
>>>>>
>>>>> Sometimes the pressure of say the washing machine draining does
>>>>> seem  to push
>>>>> up to the boiler and creates a bubbling sound in (what I assume to
>>>>> be) the
>>>>> condensate reservoir. I've been meaning to look at a way of
>>>>> preventing that
>>>>> happening - any suggestions?
>>>>> --  Cheers, Rob, Sheffield UK
>>>> Use a dedicated washing machine trap. Take the condensate pipe into
>>>> the top of the upright and don't seal it. Start by putting a cupfull
>>>> of water into the trap to provide a water stink seal to prevent
>>>> sewer gases escaping.
>>>  Umm. Not to be over picky but, shouldn't these devices include a
>>> tundish?
>>>
>>
>> There has to be a visible air break and a 75mm seal but ISTM that's
>> met with a pipe into the top of an open w/m hockey stick. AFAIK
>> nothing says you need to be able to *see* if there's condensate coming
>> out ;)
>
> Ah. I was thinking more about the situation where the installer has
> linked the boiler pressure relief valve piping to the condensate run off.

Even then the boiler pressure relief is normally in the primary side of
the heating circuit - very much not potable water from the mains supply.

There *is* a requirement for a double check valve on the filling loop
however since that is a place where the mains is in close proximity to
contaminated water in the CH system.

--
Cheers,

John.

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

On 23/12/2022 12:07, alan_m wrote:
> On 23/12/2022 11:59, alan_m wrote:
>> On 23/12/2022 11:01, John J wrote:
>>> Use a dedicated washing machine trap. Take the condensate pipe into
>>> the top of the upright and don't seal it. Start by putting a cupfull
>>> of water into the trap to provide a water stink seal to prevent sewer
>>> gases escaping.
>>
>> On my Vailant boiler it says
>>
>> Condensate discharge systems
>>
>> It is not necessary to provide extra traps in the discharge
>> pipe as there is already a trap inside the boiler. Fitting an
>> extra trap may cause the boiler siphon to work incorrectly.
>>
>
> The permitted diagrams for the condensate discharge show one method of
> connecting to a sink waste BUT ONLY USES ONE trap for both and the
> condensate is connected before the trap, presumably so the pipe is open
> to the air via the sink plug and sink overflow holes.

The trap in the boiler also functions like a siphonic flush mechanism -
discharging condensate in a batch rather than as a constant dribble.
That makes freezing less likely in the first place.

Subsequent traps don't matter so long as the pipe connection to them is
not airtight (since then the overflow of water from a larger downstream
trap could suck water from the condensate trap). That would potentially
allow a path for the escape of combustion by products into the
condensate pipework.

--
Cheers,

John.

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

In article <to50ie$1qgec$2@dont-email.me>,
John Rumm <see.my.signature@nowhere.null> wrote:
> There *is* a requirement for a double check valve on the filling loop
> however since that is a place where the mains is in close proximity to
> contaminated water in the CH system.

The instructions for my Viessmann said the pipe between the two check
valves should be removable - which generally means a flexible. And should
be removed when not in use. Wonder how many do?

--
*Procrastination is the art of keeping up with yesterday.

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

On 01/01/2023 15:27, Dave Plowman (News) wrote:
> In article <to50ie$1qgec$2@dont-email.me>,
> John Rumm <see.my.signature@nowhere.null> wrote:
>> There *is* a requirement for a double check valve on the filling loop
>> however since that is a place where the mains is in close proximity to
>> contaminated water in the CH system.
>
> The instructions for my Viessmann said the pipe between the two check
> valves should be removable - which generally means a flexible. And should
> be removed when not in use. Wonder how many do?

Depends on how "visible" it is I expect. Some boilers have built in
filling loops that can't be removed anyway.

--
Cheers,

John.

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