Do I need a bypass

Ianwzzz

My Daughter has purchased a property with an Amptec electric boiler on a Y plan fully pumped heating system (radiators). The installation instructions that have been left from the previous owner say the system must have a 22mm auto bypass of at least 2m of pipework. I seem to remember years ago I was told if you have a 3 port motorised valve (Y plan) you don't need a bypass as one ports is always open. Does anyone know if this is correct or did I just dream it up.

Thanks.

southcoastrgi

all modern systems req a bypass, what happens if the valve is on heating only & the rads all shut off where does the water pump ? around the bypass

Ianwzzz

southcoastrgi wrote: »

all modern systems req a bypass, what happens if the valve is on heating only & the rads all shut off where does the water pump ? around the bypass

Thanks for your reply. Do you mean if the radiators shut off on their TRVs or the room stat?

There is one radiator that has not got a thermostatic radiator valve, so if all the other rads shut off there is still one radiator on.

If the room stat shuts off and closes the 3 port valve, does the other port not open up to allow a bypass, which is what I thought happened in my first post.