what is the effects of a sysytem bypass

[LONGCOMMON]

hi just wondering whats the system bypass for on a boiler

 

[gas4you]

To give the pump a circuit to keep pumping the hot system water around if all the trv's shut, unlikely, or a zone valve jams shut etc. Most new boilers have pump overruns built in so it keeps circulating after the burner has gone out to dissipate the heat out of the heat exchanger.

 

[LONGCOMMON]

ow right cause mine has one in, does it have anything to do with the speed that radiaters get hot ,like if i close it a bit (screw inwards )it would make the rads get hotter quicker

 

[gas4you]

Yes. If as you describe it is a manual one such as a gate valve the general setting is to close it fully and then open about 1/2 a turn.

 

[LONGCOMMON]

its on a valliant ecotec boiler i have had fitted, its just i was reading through the manual and saw it and wondered if i closed it the front roon radiater would heat up quicker

 

[gas4you]

I've never had to adust an ecotec bypass from what manufacturers have left set. I would try balancing your other rads down as much as you can first.

 

[mikej2005]

If a boiler has an in-built system bypass, does it remove the need for a pressure relief valve, as drawn in the 'Micro Bore Pipework' diagram in the pic here : http://diydata.com/planning/central_heating/pipework.php ?

 

[gas4you]

This is like reading something out of the ark An auto bypass valve is not a prv.

A prv is usually descibing a pressure reducing valve or more commonly a pressure relief valve on a system boiler or combi boiler.

Single pipe is not fitted today and probably has not been for years, microbore twin entry valves have not been made or available for years and microbore today is usually 10mm. Originally it was 6, 8, 10 or 12mm the pipe size was used to help self balance the radiators.

If you are using this site to do any diy I would respectfully suggest you ignore it

 

[Agile]

Single pipe is not fitted today and probably has not been for years,

DIA will jump on you ! He probably fitted some last month just before he retired after 46 years in the industry.

Single pipe is still the usual commercial heating circuit !

A good place to see it is in the lovely hotel that Viessmann has booked for some of us ARGI members in a couple of weeks time to see their Vitodens 300 and solar offerings.

Tony

 

[mikej2005]

If you are using this site to do any diy I would respectfully suggest you ignore it

Thanks Dave - I had spotted that it wasn't entirely up-to-date but I just thought I'd check on that valve, as I'm not too familiar with micro-bore systems and how they work.

Do you have any better links with diagrams showing a typical microbore/combi heating system ?

 

[gas4you]

I personally don't but I'm sure others on here like Chris R will. He seems to be the king of diagrams