Wunda pressure test - no pressure

[Hilldes]

I filled and pressure tested the ground floor manifold at the weekend. It is a Wunda premium manifold with premium pump set.

 

I originally planned to fill and pressure test the manifold and pipes before fitting the pump set - using the pressure test kit. Then I saw this video from Wunda that appeared to connect the pump set first and then fill and pressure test. Basically, the pump set is assembled as normal and attached to the manifold, but the return temperature gauge housing is replaced by a pressure gauge.

 

The filling and purging went well, however the pressure guage did not move from zero except from a short time when it moved to 1 bar filling one of the last loops, then went back to zero. Can anyone think of a reason why the pressure gauge would not be reading? I've swapped out the pressure gauge and both show same readings.

[Hilldes]

…yet this morning the pressure gauge is reading nearly 2 bar - but has been disconnected from mains water pressure overnight ?

 

 

[Thorfun]

don't know the answer but that sure looks like some nice neat plumbing on that manifold. ?

[Fly100]

31 minutes ago, Thorfun said:

don't know the answer but that sure looks like some nice neat plumbing on that manifold. ?

 

I was just going to say the same.

[Hilldes]

1 hour ago, Thorfun said:

don't know the answer but that sure looks like some nice neat plumbing on that manifold. ?

There is something beautiful about manifolds and regimented pipes ?

 

I think the answer will have something to do with the mains pressure being applied to the top flow rail and that trying to push water in the wrong direction through the pump. But I would have thought the pressure gauge would get a reading due to pressure in the lower return rail when the valves for a given circuit are open.

[Nickfromwales]

5 hours ago, Hilldes said:

I think the answer will have something to do with the mains pressure being applied to the top flow rail and that trying to push water in the wrong direction through the pump.

The water will pressurise both sides equally as they are made common by the pipe joining both manifolds   

Are the white caps all fully open? Same for flow gauges? 
Where did you pressurise? On the drain point at the end of the lower rail, using the top as the vent?

[Hilldes]

2 hours ago, Nickfromwales said:

The water will pressurise both sides equally as they are made common by the pipe joining both manifolds   

Are the white caps all fully open? Same for flow gauges? 
Where did you pressurise? On the drain point at the end of the lower rail, using the top as the vent?

Thanks @Nickfromwales, I too would have expected each circuit as it was opened to apply pressure to the return pipe and both sides of the pump.

 

I followed the procedure in the Wunda video, so closed the white decorators caps after each loop was filled - so now they are all closed. All the flow gages were left open as per the video. The mains hose pipe was attached to the top rail and the drain hose to the bottom rail (as per Wunda video).

 

Ironically the pressure gauge is now reading 4 Bar up from 2 bar this morning ? and it has not been touched in the last 24 hours (no mains pipe connected in this time). 

 

 

 

[Hilldes]

Oops, just watched the video again. Was supposed to close the flow gauges as each circuit was filled, but didn't.  And I was supposed to re-open all flow gauges and return valves at the end and see the pressure gauge rise.

 

Will open all valves now.

Edited September 6, 2021 by Hilldes

[Temp]

+1  Leave all loop valves open for the pressure test so a leak in any floor loop will show up on the pressure gauge. 

 

You might see some variation in pressure due to temperature changes over next few days/nights.