Water cut off, now downstairs radiators don't work

[aptsys]

it could be when they turned mains on, a rush of water into cylinder disturbed the coil, and a piece of scale or debri sludge loosened off, and traveled round , either getting caught in pump impeller, or diverter valve. reducing the flow . maybe.

The coil and the mains water supply are independent.

 

[breadnbutter]

The coil and the mains water supply are independent.

the coil is in the cylinder, unvented indirect cylinder by the look of photo, so after not having mains water for a few hours, has possibly drained his taps, and lowered the pressure,once the mains is turned back on , your going to get a a rush of mains water entering into bottom cylinder cold inlet, were the indirect cylinder coil is. it was just a hunch that that could of disturbed the coil enough to break of debri, and work into the pump impeller.

 

[HateMyHeating]

So I've tried again, upstairs rads off and downstairs fully open for 7 hours. All radiators except 2 are warm to touch, a couple are hot. 2 that arent warm never got that hot. What is interesting I think is the inlet pipe to the rads is boiling hot, the outlet is cold to touch - almost like the water isn't making it all the way through any of the rads? This is for all of them except a small one in the WC.

Is it the pump not strong enough to get it round, or have i got an issue with all the radiators!?

Thank you all!

 

[terryplumb]

When you say ALL rads are getting hot / warm does that include the upstairs ones ? You now advise that two rads NEVER got very hot ,that would indicate a problem with their valves / pipework to them. If EVERY rad on your system was not getting to the same temperature ( within a similiar
time scale )to begin with ,you may have a balancing issue. To find out whats going on with the two rads that never used to get very hot ,turn every rad off except those two. If they then get to desired hot temp ,its a balancing issue. If they dont its valve / pipe problem.

 

[HateMyHeating]

Thanks Terry. When I say the rads are getting hot I just mean downstairs, all the others are off. The two that aren't getting hot are upright tower type ones - I think they were put in by a previous owner as part of an extension and they didn't consider the power of the boiler / pump. They usually get warm, but never hot, but that's not been a problem previously for the rest of the system. You've given me an idea to turn off all rads and turn them on one by one and see what happens

Really appreciate the help, thank you!

 

[terryplumb]

The plot thickens with every post mate. Vertical radiators must be hung a certain way up and the flow has to go into a specific port as they have a baffle ( or diverter) inside. As well as balancing correctly ,or they will never work as they should. So turning off all other rads might not make much difference ,but do try.

 

[breadnbutter]

by the looks of the pic, that pump has been replace not long ago, looks like the head was changed and the body is from old one, so cannot see that your pump is faulty ,other than it might have debri in the impellers. or pump valves are gummed up.
you would have to take pump head off to check the impellers tho.

 

[dilalio]

There's a whole host of possible causes.
When's the last time you had an engineer appraise the system for servicing etc?

Might try draining down and refilling and seeing the state of the system water that comes out.

 

[HERTS P&D]

Might try draining down and refilling and seeing the state of the system water that comes out.

I bet it will be the colour of used engine oil.

Andy

 

[dilalio]

I bet it will be the colour of used engine oil.

Andy

Exactly. First thing for a diyer to check for themselves as they can fart about, trying to treat it at their leisure with only a few quid on chemicals... Before spending out on part swaps and perhaps a powerflush

 

[HateMyHeating]

So turning off all other rads might not make much difference ,but do try.

Terry - it's thickening further! Turning off all rads except these got them to temp so I assume it's a lack of power in the system to cope with all the rads?

you would have to take pump head off to check the impellers tho.

I took the bleed screw off and checked the impeller is rotating fine.

There's a whole host of possible causes.
When's the last time you had an engineer appraise the system for servicing etc?

Might try draining down and refilling and seeing the state of the system water that comes out.

January this year - they cleaned the system

I bet it will be the colour of used engine oil.

Andy

I've attached a pic of the water that came out one of the radiator drainage valves, unfortunately (fortunately!?) it's pretty clear.

I'm really confused by this:
1) the boiler is firing up
2) the pump is working
3) the zone value to the rads is open
4) it doesn't seem to be sludge (or should I be checking somewhere else?)

But... Still hot water doesn't seem to be going around the system properly. I turned off all rads except one and that somehow seemed to make it worse - that one radiator didn't get hot and now after turning rads back on, none of them do! The pipe coming into the pump is pretty cool, the pipe coming out of the pump is warm but not hot (it used to be hot). Should there be a temperature difference between the two? It seems odd to me...

I think though it might be pump related because the pump is not to the touch despite nothing else being... Is that a sign of a dying pump?

Thanks all for helping this absolute novice

 

[ianmcd]

just because the pump is rotating when you remove the screw doesnt meat that the actual impellor hasnt sheared or is blocked, isolate the pump and remove the pump head, 4 allen bolts and check the impellor and the pump body

 

[terryplumb]

You clearly have a circulation issue ,if you now do not have ANY radiators heating up . When no demand for domestic hot water ,just central heating, do the pipes going into and out of the hot water cylinder ( flow and return ) get hot ?

 

[dilalio]

Have you a manual or automatic bypass valve? If manual check that it ain't open too much!

 

[HateMyHeating]

Ok it's starting to make sense. The pipes to the hot water tank weren't hot when the heating was on with no call for water. So I'm trying to take off the 4 Allen bolts on the pump but they are very stuck at the moment