Hot water not working - conventional boiler system

[firapara]

Hi guys,

Can you please help me with my boiler problem? I have a Worcester boiler with hot water tank.

- Two weeks ago I turned hot water off (on the control panel set it to OFF) as I did not need the hot water.

- A few days later a plumber came to my house to install a towel rail and move some cold/hot water pipes in the shower area. He put some rubber plugs in my cold water tank on the roof, so there was no need to drain the system. He’s has done the same for the heating expansion tank, when he was doing the towel rail.

- Now (10 days later) I need hot water, but it does not work. When I turn hot water on, the boiler works for 1 minute and then it turns off. If I leave the hot water ON (on the boiler control panel) I can hear some water flow inside the pipes between the boiler and hot water tank, but the boiler is still not working, i.e. no gas is burning inside. And the water does not get warm. I have also noticed that if I leave hot water ON (on the panel) in about 15 Multihead Grundfos pump gets hot.

Any advice please?

Thanks,

 

[ScottishGasMan]

Possibly air in the system, Have you tryed turning the Heating on to see if radiators still work?

 

[firapara]

Possibly air in the system, Have you tryed turning the Heating on to see if radiators still work?

Thanks for your response.

Heating does the same, works a minute and then the boiler turns off.

 

[ScottishGasMan]

Definetly sounds like a lack of circulation. The boiler comes on, starts to heat internally but with no flow to remove the hot water from it, it then shuts off.

Given your initial description it sound like an air lock. Or possibly the pump has seized. Id be more inclined to think airlock as you say initially you hear water movement. The pump getting hot it normal if its airlocked or seized as the waters not passing through it to keep it cool.

If you want while its running, you can try loosen the big flat screw that will probably be on the end of the pump head to release air from it, but do be carefull as they can spray hot water from them.

might also be worth checking that your plumber has removed the rubber bungs from the F+E tank and its vent pipe (sometimes people do forget)

Failing that I'd be inclined to call your plumber back out to have a look.

 

[ScottishGasMan]

Also see if there is any sort of bleed valve near your cylinder pipework and vent it if neccisarry.

 

[stardanny]

Get the plumber back. He clearly didn't ensure heating and hot water is working before leaving.

Daniel.

 

[firapara]

If you want while its running, you can try loosen the big flat screw that will probably be on the end of the pump head to release air from it, but do be careful as they can spray hot water from them.

Bled the pump, there was a tiny amount of air. The boiler is working now, although I can hear a lot of water movement in the pipes, I hope the sound will disappear with the time as the system will fill in with water?

Will leave the boiler on for a couple of hours to see if the water will get hot.

I called the plumber, he said "All I did is use the bungs", he says it is not his fault.

 

[ScottishGasMan]

Good stuff, if it does it again, turn the heating back on to help shift the air into the radiators (where they can be easily bled)

Simply using bungs does not mean that you dont introduce air into the system, however without seeing how much testing the plumber did after his work (ie a full HW+CH heat test) then We cant really comment on whether he would be to blame or not.

Open systems (especially older ones are prone to this sort of issue when work has been done on them)

If the problem persists and no amount of bleeding pump/venting rads helps then you may well have a choked cold feed pipe (very common in open vented systems) which affects its ability to refill properly. But fingers crossed its just been some air in the pump.

 

[firapara]

Good stuff, if it does it again, turn the heating back on to help shift the air into the radiators (where they can be easily bled)

Thanks,

The hot water seem top be working now. Tried the heating, it is still not working. Does the same, turns ON for a minutes and then turns off. Is there anything I can do to fix the heating?

 

[ScottishGasMan]

turn HW off. Turn Heating on. Go to pump and bleed again while its running. See how that goes.

 

[firapara]

turn HW off. Turn Heating on. Go to pump and bleed again while its running. See how that goes.

Thank you,

I have turned HW and Heating at the same time. Waited 5 minutes and turned HW off, Heating seems to be working now. If it will stop working, will try bleeding the pump again as you recommended.

Thanks for your time and help!