Solar pump not working properly

[Sharonjh]

Hi,

I have solar heating which is run on the filtration plumbing. ie have to have filter pump running while solar pump is running. When I turn the solar pump on and I hear it running but it will only start to push water to the solar absorbers if I crack open the discharge union on the pump for a second or two and allow some water to come out. Any ideas what might be happening?

 

[setsailsoon]

Sharon,

Are the absorbers elevated? Do you have a vacuum breaker installed? Was it working previously? A photo or two would be helpful.

Chris

 

[Sharonjh]

The absorbers are on the roof. I think this is the vacuum relief valve. When I unscrewed it I heard air being released so it must be faulty. Can’t find a replacement one that looks the same.

 

[Sharonjh]

I just bought this off eBay. It has the correct thread size so should work ok.