Check Valve basics

[watford 99]

I would be grateful for additional basic information please. I have a valve on the outgoing side of my solar pump. I have seen it referred to as a check valve though directional valve might be a more descriptive name. Anyway, before I started to empty and refill the system I noted that the operating stem of this valve, which is turned with a 14mm spanner, was at an angle of 45 degrees. I gather that this means the valve is open in both directions of flow. My questions are 1) Is this the correct position for normal operation 2) If this is the normal position what would have been the purpose of installing a check valve when a simpler service valve would perhaps have sufficed?

[greentangerine]

My pump station has two valves (with built in temperature gauges) on the flow and return. 

In the open position, the flow can only be in the direction intend i.e. the non-return valve inside them is operational. 

45 degrees disables the non-return valve and is used only for filling and draining the system. 

Closed is well, closed ...

[KLD]

Do you have a picture of the valve? Alternatively, could you go to www.bes.co.uk and search for "check valve" and report back an order number of a part resembling yours?

Klaus

[watford 99]

Though I don't have a photo PAGE 9 of the following website shows what the valve looks like and how it operates. The pump station which it is part of was made by Paw and installed in 2006.   http://www.caleffi.us/en_US/caleffi/Details/News/files/SolarPump-Instr.pdf    (Can't seem to make a link you can click on but hope you can copy and paste it into google or whatever.

[KLD]

Looks like Greentangerine gave the answer to your questions already, and the manual you linked to says the same.

[watford 99]

What surprises me is that the system was installed in 2006 by a firm called Solarbank,who have gone out of business I understand. I moved in to the bungalow in 2007 and I think it most unlikely that the previous owners interfered with the system after it was installed. Yet I found the check valve in the 'open both directions' position i.e as you confirm, for filling and draining.
I also found the expansion vessel pressure was 1.9 bar which, from the information I have read and received from this forum, is nearly twice what I would have expected. I hope these were just oversights (the only ones) by the installer. unless he/she knows something I don't.

Thanks for your help. 

[2807]

Hello watford99

I moved in to the bungalow in 2007 and I think it most unlikely that the previous owners interfered with the system after it was installed.

I disagree, I think it highly likely that the previous owners interfered with the system on a frequent basis.  I am constantly modifying my system.  I installed an additional 3 additional radiators in the house yesterday, after overheating caused a burst pipe when I was away in March this year.  Another 20X47mm tubes to be added vertically to a south facing wall this afternoon to boost the output in the depths of winter.

I don't think I will ever stop interfering with it.

2807