Worcester Boiler not firing after a drain and refill. Single pipe system.

[JonnyH12]

We had two rads taken out to do some insulation. The plumber drained the system, took the rads of and then capped them off.

He didn't refill the system, and I don't think he realised that the boiler also fed the HW tank.

As of this morning, the boiler won't fire and we have no HW.

Having realised the HW isn't working, the plover came back today and refilled the system (I think), and all the rads have been bled.

But now, When I turn the HW on, the boiler turns on but does not ignite.

If I go into the status code, I get error code 2965, which seems to be related to low pressure or water in the system.


The plumber is now away for a few days and we have no HW. We don't need the CH.

Any ideas how I can try and fix? Picture of the pipework included

 

[CBW]

If he didn’t realise that the boiler fed the hot water cylinder, then that’s not very good. Sounds like there could just still be air in the system. If you’re desperate for hot water, maybe use the immersion heater?

 

[JonnyH12]

If he didn’t realise that the boiler fed the hot water cylinder, then that’s not very good. Sounds like there could just still be air in the system. If you’re desperate for hot water, maybe use the immersion heater?

No it's really not good and really frustrating. I thought I had clearly explained the system to him.

Good idea on the immersion heater. I have never used it and don't know how to, but it's also not wired in so I'd have to give that a go if I was feeling brave

 

[JonnyH12]

If he didn’t realise that the boiler fed the hot water cylinder, then that’s not very good. Sounds like there could just still be air in the system. If you’re desperate for hot water, maybe use the immersion heater?

Any tips on flushing air out of the system? Should I leave everything running, including the grundfos pumps to circulate the water round or just let things settle?

 

[CBW]

I didn’t see the immersion not wired up. Could be the motorised valve not fully energising. As for air, sometimes it takes a few attempts to get the air out.

 

[kidgreen61]

You don'y say which model your boiler is, some of them (Greenstar Juniors) have a vent pipe inside the cover which has to opened to allow air to escape.

 

[JonnyH12]

You don'y say which model your boiler is, some of them (Greenstar Juniors) have a vent pipe inside the cover which has to opened to allow air to escape.

Its Greenstar 8000.i THINK its supposed to auto vent.

I've realised that the boiler is firing, and hot water is getting as far as my low loss header and then not going any further. The boiler then must shut off.

The LLH is supposed to auto vent too.

 

[oldbutnotdead]

Low loss headers aren't a particularly common feature. There will be pump(s) on the 'load' side of the LLH- are they running? Has your random plumber turned off any isolating valves on the load side?

 

[JonnyH12]

Low loss headers aren't a particularly common feature. There will be pump(s) on the 'load' side of the LLH- are they running? Has your random plumber turned off any isolating valves on the load side?

Yes it's running. It's Grundfos UPS3. The manual says to set it to speed three and let it run for a while.

My system is a Grundfos Pump on the load side of the LLH, being fed from the Worcster Greenstar Boiler. Then motorised valves feeding the single pipe CH system around the house and another for the HW cylinder. On the return for both of those is another grundfos pump, back into the LLH. These are all working as expected.

As of this morning, the hot water for CH seems to be slowly getting around the single pipe - but it's lukewarm. It's hot on the load side of the LLH though, as you'd expect.

I've gone around and bled the radiators again and a couple let our some air, but not a lot.

Still doesn't seem to be feeding the hot water cylinder.

There arent any valves, except the one that is fed from the small tank up in the loft. He had turned this off, but when I told him we didnt have hot water he came back and turned this back on. Everything else is the same.

 

[oldbutnotdead]

You've got isolating valves on the pump to the right of the llh. Have you checked them? And the iso valves on the other pump (if the 'plumber' says he didn't touch them i'd check them anyway, he's arrived to a working system and left a non-working system so not the best)

 

[JonnyH12]

You've got isolating valves on the pump to the right of the llh. Have you checked them? And the iso valves on the other pump (if the 'plumber' says he didn't touch them i'd check them anyway, he's arrived to a working system and left a non-working system so not the best)

Do you mean the red circle in the image?

I'm 99% sure he didnt touch them - the only thing he did turn was the red stopcock at the bottom, right, which is from the tank in the loft.

The water is flowing - I can feel it and as of today it's lukewarm to the left of the LLH, but it's not flowing properly and the pumps are louder than they usually are.

I'm pretty sure it's either air in the system or not enough water. Im not sure how to fix either of those. I've wired in the immersion heater, but that doesnt seem to be doing anything

 

[oldbutnotdead]

Yes that one (probably one the other side as well). Check the Magnaclean valves as well, mebbe worth pulling it out & seeing if it is full of carp. Is this pressurised or open vent?- if the latter your clown may have dragged rubbish down from the f & e tank .

 

[JonnyH12]

Yes that one (probably one the other side as well). Check the Magnaclean valves as well, mebbe worth pulling it out & seeing if it is full of carp. Is this pressurised or open vent?- if the latter your clown may have dragged rubbish down from the f & e tank .

I think it's called an open vent? There's a tank with a ballcock in the loft that's easily opened.

When I bleed the radiators black stuff comes out, that hasn't happened before. I tried turning one of the taps under the boiler, and that was black water too.

So possibly full of crap now?

How would one clear that out?

 

[oldbutnotdead]

Black water isn't good but not on its own a disaster - draining down and refilling has loosened up sludge in the radiators.
First job- go up in the loft and check the f & e tank isn't full of dust and rubbish- if it is it needs cleaning out.
Next job is to see if you still have circulation on the load side of the LLH- easiest rough check on this will be;
Switch heat sources off
If you can isolate the heat sources from the llh then do so- def isolate the gas boiler.
Close both valves on the Magnaclean
Check any other control valves
Take the lid off (or better is to take the pot off and acquire a fitting that'll let you attach a hosepipe to the valve)
Put a bucket underneath, be prepared for mess
Crack one valve open slightly, continue to open until the flow out of the pot threatens to get out of control
See how long it takes to fill the bucket.
Close that valve, empty the bucket, crack the other valve as above, again time the bucket fill.

If there is a blockage, there will be significantly less flow from one of those valves.