Bypass

[Armo74]

Hi guys,

Could someone please clarify for me is an automatic bypass required if installing a 3 port valve? I am under the impression that it does not as 1 valve is always open. Or does it depend on the requirement of the boiler manufactures instructions?

Thanks.

 

[mrgas]

bypass not needed with 3port as long as heating circuit has one radiator open.

 

[bengasman]

bypass not needed with 3port as long as heating circuit has one radiator open.

WITHOUT the possibility of closing that rad i.e. lockshield on both sides in stead of wheelhead or trv on one side.

 

[45yearsagasman]

And the correct flow rate is maintained through the boiler. I think that just about covers it.

 

[Armo74]

Thanks for the replies,

Going by the above comments would it be an idea to fit one to be on the safe side just incase the bypass radiator accidently gets turned off.

 

[bengasman]

Thanks for the replies,

Going by the above comments would it be an idea to fit one to be on the safe side just incase the bypass radiator accidently gets turned off.

Easier just to make sure the rad does not get turned off; take the plastic head off and Bob's your uncle.

 

[Armo74]

Thanks.

 

[gasafengineer]

This is the reason heat sink radiators 'should' be fitted with lockshield caps.

 

[Armo74]

thanks Gasafengineer,

By heat sink radiators do you mean bypass radiators?

 

[chilli985]

a lot of new boilers MIS insist on automatic bypass being fitted on 3 port systems

 

[mysteryman]

That's just to cover their backs against boilers being installed by numpties.

 

[numpty1]

That's just to cover their backs against boilers being installed by numpties.

not quite true mm,3 ports close the heating side and the bypass is around the coil in the cly approx 10% so the remarks about l/s valves are invalid as the port is closed by the room stat reaching temp.abv is best fitted before the mv or the bypass rad teed off before.but hey what would a numpty installer know

 

[ChrisR]

If I understand you right, numpty1, that's wrong, certainly for a Honeywell valve, others may be different.
At the end of CH call,, ie when the room stat is satisfied, the valve stays open in the CH position, it doesn't spring back.
It's held there by the "HW OFF" line inside the valve. Have a listen some time