central heating help please (wood burner overheating?)

[jonboy1982]

Hi, I have a central heating system that uses a back boiler from a wood burner. Today i went to fire it up after we had fitted 2 new radiators that were missing from when we moved in. Started it up and only 1 radiator become hot and then i realised i hadn't bled the system. Did that and got rid of a lot of air.

Started the heating again (lit fire etc) and 3 radiators 9all upstairs) got hot. Then 2 stopped being hot. After a while a rather worrying hissing water spurting noise came from the roof area which on investigation was the expansion pipe spewing water out into the tank.

So stopped heating, mopped up water, cooled the tank manually. Then tried turning pump down but same result.

So have gone from last year having some working rads and no loft issues to having 1 working rad (which seems to work without pump on???) and serious issues.

Please help me... do i have an air lock or could it be the pump?

Thanks

Jo

 

[seco services]

more like crud in the system.

 

[jonboy1982]

and how do i get rid ofcrud in the system?

 

[kevplumb]

bleed the pump first View media item 667

 

[jonboy1982]

Just tried that -- no air came out

 

[JohnD]

if you bleed the highest radiator in the house, does water squirt out forcefully?

if not you probably have a blockage in the feed pipe from the small loft tank. This is very common but it usually becomes apparent after you have done some plumbing work, especially fitting a rad after it has been removed for redecorating. But you could start by verifying that the feed and expansion tank has water in it and the float valve works when you push the float down.

 

[jonboy1982]

the expansion tank has water in it and the float works. Have checked 2 of the upsatirs rads -- one (which wasn't getting hot seems to spurt water out at a decent pressure. the other, which got red hot and then stopped just before the loft turned into a sauna, seems to just sort of dribbble out -- water is clear though

 

[JohnD]

check again

if you have no blockage, both upstairs rads should squirt and keep squirting, even if you let pints of water out.

are these rads higher than the pump?

when you took the screw out of the pump, you will see a spindle behind it. this has a slot that a screwdriver fits. it should turn easily with a screwdriver (when turned off) and should spin when turned on.

if, when turned on, the pump gets hotter than the pipes, water is not flowing through it. it might be jammed, blocked, or dry.

clear water does not mean you have no blockage (the sediment is heavy).

It would be useful to know how old the system is, and when you think it last had cleaner or inhibitor added, and if the pipework design and build looks sensible and professional, or clumsily done.

I am not a pro.

 

[jonboy1982]

check again

if you have no blockage, both upstairs rads should squirt and keep squirting, even if you let pints of water out.

are these rads higher than the pump? -- YES JUST

when you took the screw out of the pump, you will see a spindle behind it. this has a slot that a screwdriver fits. it should turn easily with a screwdriver (when turned off) and should spin when turned on. -- WHEN YOU TAKE THE SCREW IOUT THERE IS A HOLE FULL OF CLEAR WATER

if, when turned on, the pump gets hotter than the pipes, water is not flowing through it. it might be jammed, blocked, or dry. -- PUMP WAS A LOT HOTTER THAN THE PIPES

clear water does not mean you have no blockage (the sediment is heavy). --OK

It would be useful to know how old the system is, and when you think it last had cleaner or inhibitor added. -- NO IDEA, MOVED IN LAST YEAR AND JUDING BY THE LAST LOT WHO OWNED IT I WOULD BE SURPRISED IF IT HAD HAD ANYTHING IN THE LAST 5 YEARS IF NOT MORE. THEY HAD RENMOVED SOME RADS WITH OTHERS NEEDS VALVES REPLACING SO AFRIAD DON'T KNOW.

I am not a pro. -- YOU KNOW MORE THAN ME

 

[JohnD]

see if the pump spindle will turn

(a) with your screwdriver

(b) when turned on

bleed the rads again and see if water keeps squirting out

 

[jonboy1982]

wierd -- just tried to turn thing but, there isn't anything to turn. however when i removed screw and to be technical here -- pocked about a bit, the pump aslowly at first and then rapiodly started to bleed air. Turn on after and one by one radiators came back after bleeding. -- does this mean it was air not crud? or would a clen out still be advisable?

 

[Nige F]

poking about probably freed the pump spindle

 

[JohnD]

if it is pumping round now, I would strongly suggest adding a litre of Sentinel X400. This will loosen the old sediment. You will know it is working when the circulating water goes inky black with the sediment it has started to wash away. After 4 weeks or so drain it all out and rinse, and refill using X100 inhibitor.

The chemicals will cost about £15 each

If you can do simple plumbing and can afford another £100 add a Magnaclean as well, I guarantee you will be amazed and delighted to see how much black sludge it traps out of the water.