Boiler Loop Bypass Pipe

[scolland]

Hi All,

I have a system boiler with a Megaflow hot water tank and approx. 16 radiators. My boiler seems to be pretty conventionally plumbed in except for one small bit of pipe.

I've made a diagram (below):


I really don't understand what purpose the red dotted line servers as surely it allows loads of water to take the simplest path back to the boiler without ever being circulated to the radiators or hot water cylinder.

The red circle is an isolation valve which is open, but I would think is misplaced?

I've also attached a photograph if this helps, and the same photo annotated as it's really difficult to make out from one photo.

Thanks

 

[SilentMike]

What would happen if you didn't have the bypass and both the moterised valve shut don't forget you will have pump overrun. The valve is to throttle it down

 

[scolland]

Hi SilentMike,

Thanks for your reply, that's a really good point! I'd have expected for the valve to be before the hot water return though as surely the flow through the hot water will be affected?

Shouldn't I just have an automatic bypass valve on that part of the circuit?

 

[Stigster]

I would have expected to see the bypass with the valve on that, to be adjusted and act as a manual bypass. Anyone else think that gate valve is in the wrong place?

 

[kris]

Best with an automatic bypass set to the correct pressure setting which doesn't allow the heated water back down that route unless it senses the appropriate pressure which would only happen if zone valves we're to close or if heating is switched on and all rads were closed.
Also lo looks like the tee from the return is wrong side of bypass gate valve.

 

[scolland]

kris,

Thanks for your reply. Auto bypass valve it is then. I'm guessing that with the auto bypass valve I can just leave the bypass gate valve open?

Thanks

 

[SilentMike]

Yea or since your draining down you could just get rid