CH Flow pipe empty of water on Powemax 155x open vent system

[Aktar Miah]

Hi folks, my little boy tore out one of downstairs rads by trying to free his little scooter that got stuck under and caused a huge flood. The hot water tank got completely emptied out as a result.
I have since repaired the rad and the tank seems to have refilled itself as expected because I get plenty of hot water in the taps.
But the radiators have all stopped working and I have tried a number of different things:

• Closed all rads in the house (9 in total) except for 1 downstairs, which I'm trying to revive.
• Bled the air from the rads.
  
• Checked the FE tank in the loft and its full of water and the feed pipe is below the water.
• Drained the system again to check that the FE tank is indeed refilling the the cylinder and it seems to be doing it.
• Replaced the circulation pump on the false assumption that the pump has packed up (original needed replacing anyway)
• Tried reversing the flow of the water by swapping the live/neutral wires for the pump but it just spins the same way.

All of the above didn't work so I remove the pump with an Alan key and opened up the valve above the pump, expecting the water to gush out but its completely empty.

Just now I pumped water back up the CH flow pipe (above the pump) to try to top up the water as there is no built in top up valve. The water does indeed go into the tank because I can hear it overflow into the FE tank in the loft. When I was satisfied I closed the valve, refitted the pump, opened up the valve and restarted the system.

Unfortunately that didn't work so now I'm at a loss.

The system has no air relief valve that I can see, and I have removed all panels and followed all pipework as well as combed through the system handbook.

I'm planning to upgrade in a years time as part of a build but I need it to last for this winter. Any pointers would be appreciated.

 

[Newboy]

Some of your post doesn't make much sense - pulling a radiator off the wall won't empty the hot water cylinder.

How many tanks/cisterns do you have in the loft?

 

[Aktar Miah]

Hi, thanks for your response; theres only 1 tank in the loft.
My understanding of the system is that cylinder directly feeds the rads while the DHW is indirect.

 

[terryplumb]

will need a lot more info before any meaningful advice can be given.as newboy says above some info you have given does not make sense. when flood happened ,i assume you went around closing off valves. which ones did you close ? pics of hot water cylinder and pipework all around it will be a good start.and answer new boys questions

 

[Aktar Miah]

Hi Terry here are some pics. When the flood happened I turned off the main cold water feed pipe into the house. There were no other obvious shut off for the rads. That made no difference so I attached a hose to the draincock and let all the water out of the system from the other end of the rad while blocking the broken pipe.

And theres only 1 tank in the loft. From literature its an FE tank.

Thanks.

 

[terryplumb]

ok ,some terminology that you are using is confusing .your boiler is a combi boiler ,with built in heat store.and delivers domestic hot water to taps ,on demand, by taking in mains cold water and heating it as it passes thru the boiler. this is not known as an indirect system. the tank in loft ( f & e ) feeds the boiler and radiators as you said. Hope you have corrected the polarity at the pump ,back to the way it was . so , do all the radiators now have full water content ? if so ,bleed air out of pump using the big silver screw ,directly under the " katsu" word. don't take the screw out. sounds like you may have an airlock. when you then turn central heating / boiler on what is the boiler doing ?

 

[Hot&Cold]

If your lucky you will just have an air lock.
But Check the ch pump is pumping down away from boiler and pump valves are actually physically open,the gate could have seized shut.
As you drained down the system from the radiator this would have left a lot of water in the thermal store so when refilling at full blast via the loft tank the 22mm combined feed/vent could have struggled to clear air but got enough water into the store to operate hw.
The ch take off from the store is higher so there could be air there.Maybe drain the store from the drain point at the bottom of the cylinder store,it looks like something a hose pipe can be pushed on to.
When its all drained out undo the flow ch nut on the store make sure there is no physical blockage do same for the ch return connection then refill very slowly so air will vent out.expect it to fill in an hour.
When full turn on all radiators valves,vent them and the pumps.Run the boiler and when the hw store is satisifed power is supplied to the ch pump,it could work and its free.

 

[DaveHerns]

What did you repair the radiator with? Has this caused a blockage? Or did you replace it?

 

[andytw]

Can you post a picture of the top of the boiler with the top case off please. May be able to help you.

 

[andytw]

https://www.diynot.com/diy/threads/problems-bleeding-a-powermax-140-open-vented-system.351198/