Pumping water with strange noise and boiler cut outs

[helpme1986]

Hi Guys,

Would you mind taking a listen to the below

System: Condesing boiler which heats water for a hot water tank and also a open central heating system.

the first part of the video it how i think it should sound all the time, towards the end you can hear something happening with the water like there is a large section of air in the pipes.

Had this for years but recently started to cause the boiler to stop heating the water, no flashing lights or cut outs, the green light indicating it is currently heating the water goes off, this normally happens when the water in the boiler at the time is already hot enough. Its like the pump isnt pumping the water around quick enough.

Last year our pump packed up so British Gas come out and fit a new one, I was hoping this would solve the problem but it didnt

I am also finding myself bleeding the highest radiator daily when the central heating is on.

I think we have a very strange system and I struggle to understand how it works. from the pump there is 1 pipe in and 2 out, in my mind that means 1 in is from the boiler and from the 2 out, 1 is for the central heating and the other is for hot water but they are both hot when just 1 is on (and not just hot because they are close) There is also a pipe to the hot water tank which connects to the tank for the central heating, the pipe is usually hot but when the noise starts it goes freezing cold then hot again.

Hope this makes sense!

 

[45yearsagasman]

Classic symptoms of a partial blockage around area where cold feed and vent is connected to your pipework. This may help to ID where it is and the only real solution if it is that is to cut out and remove blockages manually.
Is there any sign of pumping over of hot water into the header (small) tank in your loft?
There are other causes, but check this out first. Fitting a new pump will never cure that problem. The rust stains on the front of the pump are a worry. View media item 39013

 

[helpme1986]

Thanks, will take a look when I get home and try the magnet trick.

Am I right in understanding that actually the 2 pipes coming out of the pump at 1 end are from the boiler and the other the vent (where does the vent go?) with the single pipe being to the hot water tank and central heating?

We dont have a header tank in the loft but believe what you talking about is actually above the hot water tank (which is in my bathroom but guessing location doesnt really matter as long as its high up), there is a pipe leading to that which goes hot and cold with the noise i was talking about.

as for the rust on the front, my fault! I had loosened the screw to let trapped air out but never dried it after, it is tight and not leaking.

 

[helpme1986]

oh and a blockage does sound about right, when ever we take all the water out of the central heating 1 rad always struggles to get hot water to it, there is water in there but we almost have to draw water to it by bleeding water out of it before the flow starts. Also the water is first very dark (almost black) but after a while runs a very light orange

 

[45yearsagasman]

Light orange water is not good news for your system. It indicates rapid corrosion and needs to be addressed pronto.
The diagram explains the pipe work and its location. The vent goes to the header tank and usually terminates just above it. and the cold feed is connected to the bottom of the same tank. Check it all out.

 

[helpme1986]

Untitled

• helpme1986
• 31 Aug 2012
• 1

Well here is my dodgy drawing!!!

The colours mean nothing other than to see where the pipes are going at cross overs.

Where the stop cock is is where it goes hot and cold alot.

Have tried with a magnet but dont seem to get a pull (from the places I can reach anyway)

There is alot of green stuff on the pipes with some joints looking like they used to leak but have since sealed themself