The new Vaillant eco TEK boiler I am fitting during the xmas holiday has
pump over-run control from the boiler. The system has three zone control
valves and a few rad's with TRV's directly connected to the F & R.

There will be occasions when the pump will be activated by the boiler and
there is no path for the water so the first job is fitting a Comap 22mm
differential bypass directly between F & R.

The unit is adjustable between 0.1 and 0.5 bar. My problem is that it is not
obvious what setting to use. There is no external indication when the thing
operates.

Does anyone have advice on how to determine the correct setting? My guess is
to keep increasing the pressure until it shuts under normal conditions.
Hopefully it will be possible to detect a flow through the valve by
temperature change.

Finally, it seems obvious to me that a better solution would be to have the
boiler open one of the zone control valves when pump over-run is required. I
can see how to do this with relays but is there a more elegant solution?

Merry xmas

Brian

On Sun, 24 Dec 2006 20:03:33 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:

The new Vaillant eco TEK boiler I am fitting during the xmas holiday has
pump over-run control from the boiler. The system has three zone control
valves and a few rad's with TRV's directly connected to the F & R.

There will be occasions when the pump will be activated by the boiler and
there is no path for the water so the first job is fitting a Comap 22mm
differential bypass directly between F & R.

Dont these boilers have built in auto bypass valves ?
Robert

wrote in message
...
On Sun, 24 Dec 2006 20:03:33 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:

The new Vaillant eco TEK boiler I am fitting during the xmas holiday has
pump over-run control from the boiler. The system has three zone control
valves and a few rad's with TRV's directly connected to the F & R.

There will be occasions when the pump will be activated by the boiler and
there is no path for the water so the first job is fitting a Comap 22mm
differential bypass directly between F & R.

Dont these boilers have built in auto bypass valves ?
Robert

You would think so but they don't.

There is are clear instructions in the manual to fit one but no details of
how etc.

Brian

In an earlier contribution to this discussion,
Brian Drury briandotdruryatdsldotpipexdotcom wrote:


Finally, it seems obvious to me that a better solution would be to
have the boiler open one of the zone control valves when pump
over-run is required. I can see how to do this with relays but is
there a more elegant solution?
That doesn't sound like a very good idea to me! Pump over-run only normally
needs to operate for a few seconds to carry away the residual heat from the
boiler when it has been shut down because all demands are satisfied. A zone
valve will take a finite time to open - by which time it is probably too
late, and the boiler will have over-heated and tripped out.

Worse still though - assuming you have an S-Plan (or S-Plan+) system - it is
the volt-free contacts in the zone valves (which close when the valve opens)
which control the boiler. So if you open a zone valve artificially when it
should otherwise be closed, it will turn the boiler back on - and that zone
will run continuously and defeat any controlling thermostats.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

In article ,
"Brian Drury" briandotdruryatdsldotpipexdotcom writes:
The new Vaillant eco TEK boiler I am fitting during the xmas holiday has
pump over-run control from the boiler. The system has three zone control
valves and a few rad's with TRV's directly connected to the F & R.

There will be occasions when the pump will be activated by the boiler and
there is no path for the water so the first job is fitting a Comap 22mm
differential bypass directly between F & R.

The unit is adjustable between 0.1 and 0.5 bar. My problem is that it is not
obvious what setting to use. There is no external indication when the thing
operates.

Does anyone have advice on how to determine the correct setting? My guess is
to keep increasing the pressure until it shuts under normal conditions.
Hopefully it will be possible to detect a flow through the valve by
temperature change.

Finally, it seems obvious to me that a better solution would be to have the
boiler open one of the zone control valves when pump over-run is required. I
can see how to do this with relays but is there a more elegant solution?

I used a mid position valve to control my 2 heating zones rather
than two zone valves. The main reason for this is there's always
a water path.

--
Andrew Gabriel

On Sun, 24 Dec 2006 20:31:47 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:


wrote in message
.. .
On Sun, 24 Dec 2006 20:03:33 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:

The new Vaillant eco TEK boiler I am fitting during the xmas holiday has
pump over-run control from the boiler. The system has three zone control
valves and a few rad's with TRV's directly connected to the F & R.

There will be occasions when the pump will be activated by the boiler and
there is no path for the water so the first job is fitting a Comap 22mm
differential bypass directly between F & R.

Dont these boilers have built in auto bypass valves ?
Robert

You would think so but they don't.

There is are clear instructions in the manual to fit one but no details of
how etc.

Brian

Sorry, all the sealed system and combi boilers have built in bypass -
it seems only the open vent version dont !
I've just fitted the ecotec plus combi and knew it had a built in
bypass.
Robert

wrote in message
...
On Sun, 24 Dec 2006 20:31:47 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:


wrote in message
. ..
On Sun, 24 Dec 2006 20:03:33 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:

The new Vaillant eco TEK boiler I am fitting during the xmas holiday has
pump over-run control from the boiler. The system has three zone control
valves and a few rad's with TRV's directly connected to the F & R.

There will be occasions when the pump will be activated by the boiler
and
there is no path for the water so the first job is fitting a Comap 22mm
differential bypass directly between F & R.

Dont these boilers have built in auto bypass valves ?
Robert

You would think so but they don't.

There is are clear instructions in the manual to fit one but no details of
how etc.

Brian

Sorry, all the sealed system and combi boilers have built in bypass -
it seems only the open vent version dont !
I've just fitted the ecotec plus combi and knew it had a built in
bypass.
Robert

Excellent, so you must know how to set it up!

I would appreciate knowing what you did.

Thanks

Brian

On Mon, 25 Dec 2006 20:05:26 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:


wrote in message
.. .
On Sun, 24 Dec 2006 20:31:47 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:


wrote in message
...
On Sun, 24 Dec 2006 20:03:33 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:

The new Vaillant eco TEK boiler I am fitting during the xmas holiday has
pump over-run control from the boiler. The system has three zone control
valves and a few rad's with TRV's directly connected to the F & R.

There will be occasions when the pump will be activated by the boiler
and
there is no path for the water so the first job is fitting a Comap 22mm
differential bypass directly between F & R.

Dont these boilers have built in auto bypass valves ?
Robert

You would think so but they don't.

There is are clear instructions in the manual to fit one but no details of
how etc.

Brian

Sorry, all the sealed system and combi boilers have built in bypass -
it seems only the open vent version dont !
I've just fitted the ecotec plus combi and knew it had a built in
bypass.
Robert

Excellent, so you must know how to set it up!

I would appreciate knowing what you did.

Thanks

Brian

My Ecotec plus 837 combi didnt really need any setting up ! Just
remember to fill condensate trap with water before firing up for first
time !

Robert

wrote in message
news
On Mon, 25 Dec 2006 20:05:26 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:


wrote in message
. ..
On Sun, 24 Dec 2006 20:31:47 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:


wrote in message
m...
On Sun, 24 Dec 2006 20:03:33 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:

The new Vaillant eco TEK boiler I am fitting during the xmas holiday
has
pump over-run control from the boiler. The system has three zone
control
valves and a few rad's with TRV's directly connected to the F & R.

There will be occasions when the pump will be activated by the boiler
and
there is no path for the water so the first job is fitting a Comap
22mm
differential bypass directly between F & R.

Dont these boilers have built in auto bypass valves ?
Robert

You would think so but they don't.

There is are clear instructions in the manual to fit one but no details
of
how etc.

Brian

Sorry, all the sealed system and combi boilers have built in bypass -
it seems only the open vent version dont !
I've just fitted the ecotec plus combi and knew it had a built in
bypass.
Robert

Excellent, so you must know how to set it up!

I would appreciate knowing what you did.

Thanks

Brian

My Ecotec plus 837 combi didnt really need any setting up ! Just
remember to fill condensate trap with water before firing up for first
time !

Robert

Thanks for the condensate tip Robert. I should have remembered but I might
not have. The instructions do mention it but it could be missed although the
checklist reminds you to check you read the instructions!

Presumably you don't have a control on your bypass valve. It is interesing
that Vaillant tell me to put my bypass in at least 1.5 metres from the
boiler. Dunno how they do that when they fit the bypass inside the combi
boiler.

The eco TEC plus 418 is on the wall but not plumbed in. The bypass is now
plumbed in and I tried adjusting it with the existing boiler running. It
seems that any setting above 0.15 bar the bypass remains shut. This is with
an average looking three speed Grundfos pump set to the lowest speed. I
think the bypass sometimes 'leaks' a little at 0.1 bar but better that than
not opening. I have left it at roughly 0.12 bar.

Google shows up several installation instructions for different makes of
bypass but none of them suggest how to determine the optimum setting. There
are vague suggestions like adjust bypass according to the system
requirements.

You would think that several people on here would know the correct way to
set it up. Maybe they have not recovered from yesterday yet.

Curiously the boiler instructions insist that all systems must have at least
one radiator not fitted with a TRV! So why the bypass valve?

Anyhow, tomorrow's job is to plumb in the eco TEK. (Must go fill up the
condensate trap before I forget)

Brian

On Tue, 26 Dec 2006 14:21:37 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:


wrote in message
news
On Mon, 25 Dec 2006 20:05:26 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:


wrote in message
...
On Sun, 24 Dec 2006 20:31:47 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:


wrote in message
om...
On Sun, 24 Dec 2006 20:03:33 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:

The new Vaillant eco TEK boiler I am fitting during the xmas holiday
has
pump over-run control from the boiler. The system has three zone
control
valves and a few rad's with TRV's directly connected to the F & R.

There will be occasions when the pump will be activated by the boiler
and
there is no path for the water so the first job is fitting a Comap
22mm
differential bypass directly between F & R.

Dont these boilers have built in auto bypass valves ?
Robert

You would think so but they don't.

There is are clear instructions in the manual to fit one but no details
of
how etc.

Brian

Sorry, all the sealed system and combi boilers have built in bypass -
it seems only the open vent version dont !
I've just fitted the ecotec plus combi and knew it had a built in
bypass.
Robert

Excellent, so you must know how to set it up!

I would appreciate knowing what you did.

Thanks

Brian

My Ecotec plus 837 combi didnt really need any setting up ! Just
remember to fill condensate trap with water before firing up for first
time !

Robert

Thanks for the condensate tip Robert. I should have remembered but I might
not have. The instructions do mention it but it could be missed although the
checklist reminds you to check you read the instructions!

Presumably you don't have a control on your bypass valve. It is interesing
that Vaillant tell me to put my bypass in at least 1.5 metres from the
boiler. Dunno how they do that when they fit the bypass inside the combi
boiler.

The eco TEC plus 418 is on the wall but not plumbed in. The bypass is now
plumbed in and I tried adjusting it with the existing boiler running. It
seems that any setting above 0.15 bar the bypass remains shut. This is with
an average looking three speed Grundfos pump set to the lowest speed. I
think the bypass sometimes 'leaks' a little at 0.1 bar but better that than
not opening. I have left it at roughly 0.12 bar.

Google shows up several installation instructions for different makes of
bypass but none of them suggest how to determine the optimum setting. There
are vague suggestions like adjust bypass according to the system
requirements.

You would think that several people on here would know the correct way to
set it up. Maybe they have not recovered from yesterday yet.

Curiously the boiler instructions insist that all systems must have at least
one radiator not fitted with a TRV! So why the bypass valve?

Anyhow, tomorrow's job is to plumb in the eco TEK. (Must go fill up the
condensate trap before I forget)

Brian



The one rad without TRV is heating the area where your thermostat is
sited.

On my Ecotec the bypass is not adjustable and the 2 speed pump sorts
itself out - (at least on any default settings).

Failure to fill the condensate trap results in combustion fumes coming
into the house !
Robert

On Tue, 26 Dec 2006 14:21:37 +0000, Brian Drury wrote:

wrote in message
news
On Mon, 25 Dec 2006 20:05:26 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:


wrote in message
...
On Sun, 24 Dec 2006 20:31:47 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:


wrote in message
om...
On Sun, 24 Dec 2006 20:03:33 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:

The new Vaillant eco TEK boiler I am fitting during the xmas holiday
has
pump over-run control from the boiler. The system has three zone
control
valves and a few rad's with TRV's directly connected to the F & R.

There will be occasions when the pump will be activated by the boiler
and
there is no path for the water so the first job is fitting a Comap
22mm
differential bypass directly between F & R.

Dont these boilers have built in auto bypass valves ?
Robert

You would think so but they don't.

There is are clear instructions in the manual to fit one but no details
of
how etc.

Brian

Sorry, all the sealed system and combi boilers have built in bypass -
it seems only the open vent version dont !
I've just fitted the ecotec plus combi and knew it had a built in
bypass.
Robert

Excellent, so you must know how to set it up!

I would appreciate knowing what you did.

Thanks

Brian

My Ecotec plus 837 combi didnt really need any setting up ! Just
remember to fill condensate trap with water before firing up for first
time !

Robert

Thanks for the condensate tip Robert. I should have remembered but I might
not have. The instructions do mention it but it could be missed although the
checklist reminds you to check you read the instructions!

Presumably you don't have a control on your bypass valve. It is interesing
that Vaillant tell me to put my bypass in at least 1.5 metres from the
boiler. Dunno how they do that when they fit the bypass inside the combi
boiler.

The eco TEC plus 418 is on the wall but not plumbed in. The bypass is now
plumbed in and I tried adjusting it with the existing boiler running. It
seems that any setting above 0.15 bar the bypass remains shut. This is with
an average looking three speed Grundfos pump set to the lowest speed. I
think the bypass sometimes 'leaks' a little at 0.1 bar but better that than
not opening. I have left it at roughly 0.12 bar.

Google shows up several installation instructions for different makes of
bypass but none of them suggest how to determine the optimum setting. There
are vague suggestions like adjust bypass according to the system
requirements.

You would think that several people on here would know the correct way to
set it up. Maybe they have not recovered from yesterday yet.

Curiously the boiler instructions insist that all systems must have at least
one radiator not fitted with a TRV! So why the bypass valve?

Anyhow, tomorrow's job is to plumb in the eco TEK. (Must go fill up the
condensate trap before I forget)

Brian

The worst that would happen if you didn't fill the trap is that flue gases
would go into the condensate drain and then perhaps somewhere else for
about 20 minutes. This is not desirable nor competent practice but frankly
not _likely_ a serious problem.

The book on the combis say to set the differential bypass to 0.35 bar.
However there is no practical way of measuring this.

I would set the by pass about 1/2 up the scale and then see if it opens
during pump overrun.




--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards

"Ed Sirett" wrote in message
...
On Tue, 26 Dec 2006 14:21:37 +0000, Brian Drury wrote:

wrote in message
news
On Mon, 25 Dec 2006 20:05:26 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:


wrote in message
m...
On Sun, 24 Dec 2006 20:31:47 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:


wrote in message
news:uboto29kjao2bqo1pflt0j4nvvkngakl2r@4ax. com...
On Sun, 24 Dec 2006 20:03:33 -0000, "Brian Drury"
briandotdruryatdsldotpipexdotcom wrote:

The new Vaillant eco TEK boiler I am fitting during the xmas holiday
has
pump over-run control from the boiler. The system has three zone
control
valves and a few rad's with TRV's directly connected to the F & R.

There will be occasions when the pump will be activated by the
boiler
and
there is no path for the water so the first job is fitting a Comap
22mm
differential bypass directly between F & R.

Dont these boilers have built in auto bypass valves ?
Robert

You would think so but they don't.

There is are clear instructions in the manual to fit one but no
details
of
how etc.

Brian

Sorry, all the sealed system and combi boilers have built in bypass -
it seems only the open vent version dont !
I've just fitted the ecotec plus combi and knew it had a built in
bypass.
Robert

Excellent, so you must know how to set it up!

I would appreciate knowing what you did.

Thanks

Brian

My Ecotec plus 837 combi didnt really need any setting up ! Just
remember to fill condensate trap with water before firing up for first
time !

Robert

Thanks for the condensate tip Robert. I should have remembered but I
might
not have. The instructions do mention it but it could be missed although
the
checklist reminds you to check you read the instructions!

Presumably you don't have a control on your bypass valve. It is
interesing
that Vaillant tell me to put my bypass in at least 1.5 metres from the
boiler. Dunno how they do that when they fit the bypass inside the combi
boiler.

The eco TEC plus 418 is on the wall but not plumbed in. The bypass is now
plumbed in and I tried adjusting it with the existing boiler running. It
seems that any setting above 0.15 bar the bypass remains shut. This is
with
an average looking three speed Grundfos pump set to the lowest speed. I
think the bypass sometimes 'leaks' a little at 0.1 bar but better that
than
not opening. I have left it at roughly 0.12 bar.

Google shows up several installation instructions for different makes of
bypass but none of them suggest how to determine the optimum setting.
There
are vague suggestions like adjust bypass according to the system
requirements.

You would think that several people on here would know the correct way to
set it up. Maybe they have not recovered from yesterday yet.

Curiously the boiler instructions insist that all systems must have at
least
one radiator not fitted with a TRV! So why the bypass valve?

Anyhow, tomorrow's job is to plumb in the eco TEK. (Must go fill up the
condensate trap before I forget)

Brian

The worst that would happen if you didn't fill the trap is that flue gases
would go into the condensate drain and then perhaps somewhere else for
about 20 minutes. This is not desirable nor competent practice but frankly
not _likely_ a serious problem.

The book on the combis say to set the differential bypass to 0.35 bar.
However there is no practical way of measuring this.

I would set the by pass about 1/2 up the scale and then see if it opens
during pump overrun.


Thanks Ed.

You right there is no way fumes will leak if the trap is not filled with
water but it says to do it so I did it.

Maybe Robert is collecting the condensate indoors

Now the boiler is running it looks as if we have just chosen a new pope. The
steam cloud coming from the chimney is quite impresive.

I have found the bypass works best at the lowest setting.

Maybe Robert is collecting the condensate indoors


Just for initial testing purposes
But as the the condensate pipe doesnt have to be a
sealed connection all the way to the drain, there is still the
potential for fumes to void into house if condensate trap isnt filled
..
Robert