Automatic By-pass Valve

[snowhead]

*croppie reaches for his gimp slapping stick*

Can you pass me one as well

 

[lame plumber]

Can you pass me one as well

are we getting free samples to try, does it include a mask?

 

[R1CKY]

People are mentioning lockshields. It doesn't matter if the lock shields are wide open or nearly closed, if a TRV is shut, water can not flow through that rad. ABV are also there to keep up flow rates. If you can imagine a microbore system with 7 trvs and 1 without, all TRVS start closing and the pump is forcing water through a single pipe the size of a drinking straw, it will decrease the life of the pump and a modern boilers heat exchanger won't thank you too much either.

 

[lbp plg & htg]

Problem here is the way i posted the question,

I wanted to confirm i knew what an ABV was. The problem I was referring to was a job i'd been to had one even thought there were no TRV's on.

Whether it be a lockshield, wheelhead or TRV, once its shut its shut therefore nothing will pass through until its open again. Like I say in this instance there was a ABV on even though I didnt think it warranted one.

Croppie, complete with gimp stick and mask sorted me out ;-)

 

[snowhead]

It was probably fitted by someone who thought all systems must have one.

 

[Dannypipe]

Don't get hung up on the trv's alone. What if you have zone valves and pump overrun?

I was going to mention this at the beggining of the thread, but knew it would open a can of worms!!

 

[Mike Jackson]

It was probably fitted by someone who thought all systems must have one.

As stated earlier, it sounds like a warmfront job and we had to fit an auto bypass on every job whether it needed one or not.

 

[AWheating]

they are to ensure boiler min flow rate is available at all times and keep the boiler in condensing mode longer to some degree.

Most warm front, HA, Council type fitted systems will have them as standard with or without a need for them. Most council jobs i see now even have scale reduser and magnetic filter as standard also. Probably because they have now cotton'd on the system/boilers are done in a day and are never cleaned correctly.