MAJOR help required

[markshark]

Timeserved plumber of 6 years, always have a look on this site but never had the need to ask as always someone else has the problem and i just look through that thread..........

Now, i have recently went to a central heating system, 26 years old

Radiators stopped working all over the house after a radiator that had been off for over 2 years was turned on

So changed the pump as it was making noises and at 26 years old it would not do any harm

2 radiators upstairs and a towel rail now working with new pump, downstairs not, so turned upstairs off, downstairs still not heating up apart from one closest to the boiler but only the flow pipes warm

So i turned a radiator off, took off the plug at the top and connected into the mains water system and blasted some water in to see if i could shift air. FAIL

Now ive traced all pipes and its just not wanting to go round the downstairs circuit, i listened to the coil at the cylinder and i would certainly say the pump is pumping round the coil which it should not be doing as its a gravity hot water/pumped heating system.

Is there anyway of stemming the flow to the coil other than put valves on and close them off a little??!!??

Any other suggestions welcome, no matter how silly they might seem, please ask anything!!!!

 

[Rob]

You wont clear an air lock if its still circulating round the cylinder. If its fully pumped but no MV cut in a gate valve so you can isolate it.

 

[markshark]

Thats my next move, surely cant be an air lock, ive more or less opened all pipework, its all old compression fittings and the heat has moved round the radiators when ive been opening up pipes?

 

[steve32]

i would be looking for a blockage in pipework
take a magnet and see if you have a magnetic attraction on all the pipework around the area of the cold feed, vent and pump the stronger the magnetic attraction the more the pipes will be blocked
if there is an attraction then you will need to replace pipework on flow in area of cold feed/vent and system will need a good flush

hope this helps

Steve

 

[Slugbabydotcom]

i listened to the coil at the cylinder and i would certainly say the pump is pumping round the coil which it should not be doing as its a gravity hot water/pumped heating system.

That sounds like a red herring to me. What boiler is it? are there 2 or 4 pipes going to it?
I've got the feeling that the downstairs circuit is full of crud.
I do recall one system with a bad airlock where the downstairs rads wouldnt work until I flushed quite a lot of water through it from a drain off under the d/s floorboards.

 

[markshark]

Baxi back boiler. 4 pipes two coming off for the gravity hot water in inch pipes and 2 for the heating in 22mm.

When the pumps off the noise stops at the cylinder, when the pumps put back on it starts again, thats the only reason ive come to this conclusion, im maybe clutching at straws though

Also when ive opened up fittings below the floor, the water seems to be clear enough and fast flowing as well, which again might not tell me anything but a blockage doesnt seem likely as it "seems" clean enough

Thanks very much for yer input guys

 

[Razor900]

Don't get offended but.....

Are you sure the pump is the same way round as the old one. It's probably on the return but which way is it pumping????

 

[markshark]

No offence taken, yeah its on the right way

And yes its on the return

 

[Gastel]

Could be by-pass problem...no? You say the problems started when a rad was turned on, this tells me water has took the easiest circuit once this rad was opened, therefore taking the flow from the other rads.....check the pipework & the by-pass,could be it needs a cple turns in.

 

[markshark]

No by-pass, its only what the customer said happened, i cant tell you that 100% but they have no reason to lie as theres no way they have been fiddling with the pipework as i have opened up the floors and its certainly not been opened since it was put in

 

[holty]

one pipe system or two?