Weird pump set-up ??? Advice please..

[Ponx]

hi there. My unvented heating system has a single pump which is located in the upstairs airing cupboard. The pump outlet feeds a motorised valve for the heating and a motorised valve for the hot water. However, there is also a direct feed from the pump to the return side of the hot water cylinder . Does this make sense to anyone please ??

 

[Mastermixlee]

Likely a Bypass pipe from your description.

 

[Ponx]

What role would this have...??

 

[Mastermixlee]

So when the motorised valves shut of at the end of a deman the water has a path to dissipate the heat from the boiler (utilising a pump overrun) or if the heating is on but all the rads are turned off then It provides a path for the water flow.

 

[Ponx]

Would it not be normal to have a bypass valve fitted ?? there is no valve on this system so I would have thought the pump flow would have followed the path of least resistance....

 

[Aire]

Would it not be normal to have a bypass valve fitted ?? there is no valve on this system so I would have thought the pump flow would have followed the path of least resistance..

Should be a bypass valve, take a pic of the set up so we can confirm if it's wrong or not.

 

[Ponx]

As you can see in the photo... on the outlet of the pump there is a red valve (my mistake as I thought it was a safety valve) Assuming this is the bypass valve, then you can see it joins a pipe direct from the pump to the hot water return.. so effectively bypassing the bypass valve...the device in the foreground is the auto air vent which sits just before the motorised valve for the hot water flow(not in picture).

 

[Gasmk1]

whats the big silver thing to the left where the pipe enters

 

[Ponx]

It’s an automatic air bleed.. it’s not that big, it just looks it in the picture.. after the air bleed it goes to the motorised valve for hot water input..

 

[steadyon]

The item with the red cap looks like an automatic bypass valve. Essentially its a spring loaded valve set to open when the pressure on the inlet side reaches a preset value. Thus if all your radiators are shut off, and the hot water motorised valve is closed, the pressure on the valve increases, and any excess hot water is shunted directly from flow to return to provide a cooling path for the water.

 

[Ponx]

Hi there. You will also see though that there is a bypass pipe that runs straight from the pump to the return of the cylinder without going through the by pass valve. In other words there is an “always open” bypass.. which doesn’t seem to make sense to me...

 

[Aire]

It does look to be piped incorrectly. Can we get a pic from further away to show more of the set up.

 

[Ponx]

Here is pic from further away...

 

[Gasmk1]

looks more like a de-aerator the auto by-pass is just above the pump

 

[Gasmk1]

Intatec - 1 1/4" FBSP - Automatic Air Separator for use in Heating System - AAS019212560

 

[Aire]

Here is pic from further away...

View attachment 39682

It does look piped wrong, nothing wrong with the bypass. But the tee piece circled in red doesn't need to be there

 

[Ponx]

Thanks, that’s what I suspected...

 

[John.g]

Are the CH & HW systems heating up OK with all this re circulation taking place?.

 

[Ponx]

Yes... so would you recommend I leave it as is ??

 

[John.g]

If it ain't broke then?, it must be some pump to give sufficient head to still satisfy both systems when there could be something like 30 LPM recirculating through that by pass piping assuming no orifice/restrictor fitted.