By-pass valve

[Jaded]

Hi. In my plumbing system there is a device labelled 'bypass valve, do not adjust'. It has a scale (with a pointer) marked between 0.05 and 0.5 bar; the rest position is at 0.5. It seems to be connected between the flow and return of the primary coil of the DHW cylinder. What circumstance is this valve designed to deal with? Please. J

 

[diamondgas]

Pump pressure on the inward side of the valve!

It's serves to regulate the flow through the circuit it is attached to and give a continuous flow through your central heating boiler ... That's my initial brain strain thoughts anyhoo's

 

[Jaded]

DG - thanks. Are you able to say whether the rest position at 0.5 means the valve is open (water flowing through the valve) or closed? J

 

[diamondgas]

Depends on the pump, pump setting as far as i remember! Not an installer I admit But I think you set the valve to the corresponding setting on the heating pump that is 0.5 - 6m head? Sure there are others here more up to help you to be honest! When i was installing it was a "gate valve just cracked!" LOL

 

[AWheating]

[DLMURL]http://www.myson.co.uk/static_files/my/media/downloads/ABV_Technical_instruction.pdf[/DLMURL]

 

[diamondgas]

[DLMURL]http://www.myson.co.uk/static_files/my/media/downloads/ABV_Technical_instruction.pdf[/DLMURL]

And setting 0.1 means? That's as clear as mud IMHO seem to missing a cupl of pages ...lol .... i'e' no scale on the example diagrams! I know it's beneficial to keep a certain flow rate through the boiler for efficiency and through the heating system for reduction of noise and again efficency , but I'm blown if I know what, flow rate and pressure diff?

Enlighten me?

 

[REDSAW]

it means do not touch.

 

[Best]

I think of it as a valve that should normally stay closed, when set properly, until the system is only pumping through one rad or cylinder, ( often when TRVs or circuits close off on modern systems ) That means the pump is not losing it's pump flow ability.
But that is putting it simply, & more for sealed heating. Other factors may have to be considered, like recommended flow through boiler & if the system is at risk of pumping into expansion tank.
I wonder about these valves, once fitted & set well, - what if they fail? or get a bit of dirt in them? as they are basically a washer under a variable set pressure using a spring. Who would check them?

 

[kay-jay]

the bypass guarantees a flow through the heating circuit in the event that trv's/human error closes all rads. this protects the pump from burning out trying to pump against a closed route (static head).

the valve is practically closed in normal operation so water taking path of least resistance will circulate around the circuit. if all rads where closed the pump would generate enough force to push the spring loaded bypass valve open and create an open mini-circuit back to boiler.

best you can check operation by isolating main circuit

 

[Best]

best you can check operation by isolating main circuit

I know that! Lol! But was just pointing out, that I doubt they are checked often, except on new work.
Good description of bypass function you give.

 

[Jaded]

From what I've gathered?? This particular bypass valve has been installed to guard against the primary coil in the DHW cylinder being blocked or furred up, preventing flow through the boiler. Thanks to all. J

 

[kay-jay]

Same thing. If it is installed before the port valves it will protect the pump from burning out on either hot water or heating demands.

Sent from my GT-I9100 using Tapatalk