vent pipe run

[corgiman]

Just remembered...one last one for tonight ...do I need a bypass valve even though i already have a bathroom rad serving as one (straight off the return and flow from the boiler) if so, where should be situated on the system?

thats a mouthfull there

what boiler do you

oh nuts i am too tired tonight

 

[Tinkler]

mmm someone cheated

Possibly...but i remember someone mentioning that it was done where head height was an issue....as it is in a single storey it may be because of that

As a side issue...I'm putting my pump next to the boiler... its going to have plenty of elbows on the run as its going to come down off the top (boiler connections)and then back up and into loft...are there any issues with that?

not on the flow I hope

If you mean the pump, yes...Manufacturer actually specifies pump to be on the flow and before the vent.

 

[doitall]

mmm someone cheated

Possibly...but i remember someone mentioning that it was done where head height was an issue....as it is in a single storey it may be because of that

As a side issue...I'm putting my pump next to the boiler... its going to have plenty of elbows on the run as its going to come down off the top (boiler connections)and then back up and into loft...are there any issues with that?

not on the flow I hope

If you mean the pump, yes...Manufacturer actually specifies pump to be on the flow and before the vent.

Complete rubbish, you cannot block the vent which must be open to atmosphere.

 

[doitall]

Reading this and your other post you would be advised to get someone who knows what they're doing before you blow the place up

 

[corgiman]

mmm someone cheated

Possibly...but i remember someone mentioning that it was done where head height was an issue....as it is in a single storey it may be because of that

As a side issue...I'm putting my pump next to the boiler... its going to have plenty of elbows on the run as its going to come down off the top (boiler connections)and then back up and into loft...are there any issues with that?

not on the flow I hope

If you mean the pump, yes...Manufacturer actually specifies pump to be on the flow and before the vent.

Complete rubbish, you cannot block the vent which must be open to atmosphere.

no you put the pump on the flow (although as long as there is no air ingress as a result you can put your pump where u like) but the feed and expansion must go to the negative side of the pump.

dont quite get what you mean DIA??

Oops just read his bit again NOT BEFORE THE VENT in any circumstances DIA is utterly right

maybe an idea to pay someone competent mate before you make any more mistakes

 

[Tinkler]

Just remembered...one last one for tonight ...do I need a bypass valve even though i already have a bathroom rad serving as one (straight off the return and flow from the boiler) if so, where should be situated on the system?

thats a mouthfull there

what boiler do you

oh nuts i am too tired tonight

Sorry, I hope I'm not to blame but, rest assured...









....I'll be back! ...G-night!

 

[Tinkler]

mmm someone cheated

Possibly...but i remember someone mentioning that it was done where head height was an issue....as it is in a single storey it may be because of that

As a side issue...I'm putting my pump next to the boiler... its going to have plenty of elbows on the run as its going to come down off the top (boiler connections)and then back up and into loft...are there any issues with that?

not on the flow I hope

If you mean the pump, yes...Manufacturer actually specifies pump to be on the flow and before the vent.

Complete rubbish, you cannot block the vent which must be open to atmosphere.

no you put the pump on the flow (although as long as there is no air ingress as a result you can put your pump where u like) but the feed and expansion must go to the negative side of the pump.

dont quite get what you mean DIA??

Oops just read his bit again NOT BEFORE THE VENT in any circumstances DIA is utterly right

maybe an idea to pay someone competent mate before you make any more mistakes

Can you do me a favour and check the schematic of M Is for installation and tell me what I'm not seeing please....I'm getting very confused. Vitodens 100 Compact[/url]

 

[doitall]

As I said complete rubbish.

I suggest you take the issue up with the manufacturer, because they have it wrong.

 

[corgiman]

looking at the diagram i dont see why this should not work as both the feed and expansion (take note that it aint combined ) are both under positive pressure therefore air ingress is unlikely, ergo it will conform to BS (sorry cannot think of the number off the top of my head)

and as for mi's being wrong, well as they are the first port of call for the safe and satisfactory installation of an appliance then you must follow them and if they turn out to be wrong then it will be the manufacturers problem

 

[chrishutt]

I'm surprised that Viessmann should suggest putting the pump before the vent, but they may have their reasons. It would be very interesting to know what they were!

The obvious objection to their arrangement is that the escape route for steam and boiling water (in the unlikely event of boiler thermostatic/overheat control failure) is slightly obstructed by the convoluted route through the pump. Even worse if a pump valve was shut, but I don't know if the boiler would even light without any pump generated flow so that scenario may be virtually impossible.

Corgiman, when you have an open system the feed tank connection is always the neutral point. Everything before it will be under positive pump pressure and everything after it under negative pump pressure (suction). So whether the pump is before or after the vent and feed connections, the vent itself will be under positive pressure.

 

[doitall]

looking at the diagram i dont see why this should not work as both the feed and expansion (take note that it aint combined ) are both under positive pressure therefore air ingress is unlikely, ergo it will conform to BS (sorry cannot think of the number off the top of my head)

and as for mi's being wrong, well as they are the first port of call for the safe and satisfactory installation of an appliance then you must follow them and if they turn out to be wrong then it will be the manufacturers problem

Manufacturers make mistakes, installing an appliance that contraviens the regs, is irresponsible apart from dam stupid.

 

[ChrisR]

when you have an open system the feed tank connection is always the neutral point. Everything before it will be under positive pump pressure and everything after it under negative pump pressure (suction). So whether the pump is before or after the vent and feed connections, the vent itself will be under positive pressure.

As Harry Enfield might say:
Now I don't believe you meant to say that!

 

[corgiman]

looking at the diagram i dont see why this should not work as both the feed and expansion (take note that it aint combined ) are both under positive pressure therefore air ingress is unlikely, ergo it will conform to BS (sorry cannot think of the number off the top of my head)

and as for mi's being wrong, well as they are the first port of call for the safe and satisfactory installation of an appliance then you must follow them and if they turn out to be wrong then it will be the manufacturers problem

Manufacturers make mistakes, installing an appliance that contraviens the regs, is irresponsible apart from dam stupid.

where in gas safety installation regs does it sipulate the correct positioning of feed and expansion pipes DIA?

And MI take precendance over GSIR 98

 

[corgiman]

I'm surprised that Viessmann should suggest putting the pump before the vent, but they may have their reasons. It would be very interesting to know what they were!

The obvious objection to their arrangement is that the escape route for steam and boiling water (in the unlikely event of boiler thermostatic/overheat control failure) is slightly obstructed by the convoluted route through the pump. Even worse if a pump valve was shut, but I don't know if the boiler would even light without any pump generated flow so that scenario may be virtually impossible.

Corgiman, when you have an open system the feed tank connection is always the neutral point. Everything before it will be under positive pump pressure and everything after it under negative pump pressure (suction). So whether the pump is before or after the vent and feed connections, the vent itself will be under positive pressure.

er thanks for that chris, but knew that one already,

I have edited this cos i read it again, no your are wrong, if the vents is on the positive side of the boiler its under positive pressure, if on the negative side its under negative pressure.

but only if the feed is on the opposite side, if its is within 150mm it will get negative pressure

 

[chrishutt]

when you have an open system the feed tank connection is always the neutral point. Everything before it will be under positive pump pressure and everything after it under negative pump pressure (suction). So whether the pump is before or after the vent and feed connections, the vent itself will be under positive pressure.

As Harry Enfield might say:
Now I don't believe you meant to say that!

So what's wrong with that?

We're talking specifically about circuits with vent and feed pipes closely connected on the flow, with the pump either before or after this feed/vent connection.