Central heating issue after bleeding radiators

[BeelzebubUK]

Sometime last night it looks like my central heating failed......I'm assuming after I had bled some of the radiators. There was air/gas in a couple of radiators which started to flow but the very last radiator would not flow. Tghought I'd leave it till next day to check again.

After realising it was getting a bit cold later on I checked the boiler (Glowworm 30hxi) and it had an F5 error. I reset the overheat thermostat and then reset the boiler and it fired up but was reaching maximum temperature in about 30 seconds and shutting off again.

Left it overnight to see if it would fire up OK in the morning but it still has the same overheating problem.

Have checked at the tank upstairs and the pump (Grundfos Selectric) is very hot to the touch and took the silver screw cap off but no air or water coming out (not sure if thats the right thing to check though). Also there is no pressure to the Pressure/Expansion vessel.

So at the moment I'm not sure if this is a boiler or the pump or something else entirely causing the problem. Just wanted to see what other steps I can take to check for the problem before calling out a CH engineer.

Any help appreciated.


Edit : I'd turned the immersion on 30 mins agao and now there is water dripping from some kind of overflow next to the tank upstairs (its got an open bit so you can see the water dripping down)

 

[Prof.plumb]

sounds like your heating tank has run dry. go in your loft you will see a small tank push the ball valve down this will free it off and wil fill system job done.

 

[BeelzebubUK]

Hi. Haven't got any tank in the loft. Just the boiler in the kitchen, tank and pressure/expansion vessel in the airing cupboard.

 

[Dirksdonuts]

Hi. Haven't got any tank in the loft. Just the boiler in the kitchen, tank and pressure/expansion vessel in the airing cupboard.

Sounds like the water has got too low. You need to look under the boiler and find the water inlet for the boiler.

Has the system got a pressure valve on the front which should show 0-5

If it has then let the water in slowly until the valve reads 2 or 3 then stop the water coming in and reset or turn it off then on and it should all work fine

Let us know.

 

[Dan Robinson]

If it has then let the water in slowly until the valve reads 2 or 3 then stop the water coming in and reset or turn it off then on and it should all work fine

Let us know.

Are you nuts? Take the pressure to 1.5 only.

 

[Dan Robinson]

water dripping from some kind of overflow next to the tank upstairs (its got an open bit so you can see the water dripping down)

Sounds like you have a Megaflo yes?

If so the internal air bubble probably needs recharging - there is usually a sticker on the side of the tank that tells you how to do that.

 

[BeelzebubUK]

OK wasn't confident fiddling around with any valves so called someone out. Explained to him what happened and he just opened 2 valves near the pressure/expansion vessel and hey presto it filled up to about 1.5 bar and closed them off and the central heating came on.

I had to see the funny side of it although it did cost me £100 for the callout. You live and learn I suppose

Thanks for the replies. I think Dirksdonuts was on the mark with your info.

 

[Goldspoon]

£100 for driving to you and twisting a couple of knobs. I think I'd have asked him if he wanted the shirt off my back at the same time. Do you not feel totally and utterly ripped off and taken for a ride?

 

[mogget]

he just opened 2 valves near the pressure/expansion vessel and hey presto it filled up to about 1.5 bar and closed them off and the central heating came on.

Now you know where your filling loop is, you'll be able to top it up yourself next time. An expensive lesson though!

 

[Dirksdonuts]

That was a costly job. I only found out the same way but lookily enough had a friendly plumber who was just passing by that day.

Yes and sorry the pressure should be 1.5bar and not 2-3. Keep and eye on it and if it reads higher than 2 just bleed the rad again and take a bit of the water out, or if it drops then use the valve underneath like he did to top it back up.

Regards

Dirksdonuts

 

[mogget]

That was a costly job. I only found out the same way but lookily enough had a friendly plumber who was just passing by that day.

Yes and sorry the pressure should be 1.5bar and not 2-3.

Just to clarify for the OP, this is the pressure when the boiler's off and the radiators are cold. When the system heats up it's normal for the pressure to rise, but if it goes above about 2.5 then something's wrong.