issue with refilling heating system

[baggielad]

I have just converted a gravity fed system to a fully pumped. when I first filled it up there appeared to be no flow when the pump was turned on. However, eventually with adjusting pump speed and turning it on and off both the hot water and central heating warmed up. However, the cylinder had developed a leak and had to be replaced and therefore had to drain it all down again.

However, when I then refilled there again is no flow. The boiler fires up and the pump turns on, but the hot water from the boiler is not flowing through the pipe work. The vent from the the boiler becomes hot and of course the boiler stat soon turns it off. There is water in the ground floor radiators but when I try and bleed the upstairs nothing comes out (air or water!)

I would be grateful for any suggestions.

 

[McCombi]

Sounds like your cold feed may be blocked. Search this site and you'll find how to rectify it.

 

[Andygasman2010]

Did you not alter the cold feed and vent when you did the conversion? Usually you'd need to.

 

[baggielad]

Did you not alter the cold feed and vent when you did the conversion? Usually you'd need to.

Thanks for that. When I converted I did use old pipe work.

 

[baggielad]

Did you not alter the cold feed and vent when you did the conversion? Usually you'd need to.

Yes, the system was a primatic and therefore had to install a new f&e tank. I installed a new vent pipe from the boiler which involved a new run of 22mm pipe to the attic connected to the old cylinder flow pipe down to the boiler. I also used the old 28mm return pipe as the new cold feed with a run of 15mm up to the tank in the attic (cylinder is on the first floor).

 

[baggielad]

Sounds like your cold feed may be blocked. Search this site and you'll find how to rectify it.

I've just partially drained down the system and water is flowing through the f&e tank so I assume that the cold feed is not blocked? Could it be an air-lock?

 

[stardanny]

A photos of pipework in airing cupboard would help.

Did you fit a 2 port or 3 port valve?

Sound like airlock.

Dan.

 

[HERTS P&D]

As Above.

Sounds like an air lock, are there any bleed valves next to the cylinder?

Andy

 

[Andygasman2010]

Doesn't sound like a blockage then, going by what you've done. So it'll either be air locked (as said) or piped up wrong. Could you maybe draw a diagram or take pictures of what you've done and post it?

Where are the vent and feed connected to the system in relation to the pump and boiler? If this isn't right then bleeding it can be a nightmare.

Daft question but did you replace the pump? Could it be something a simple as seized pump?

 

[baggielad]

Thanks for the replies. After I did the partial drain down to check the cold feed wasnt blocked I turned it on again hot water began to flow. It took a couple of attempts of turning the system on and off a few times to get it working well. However, there is still a fair bit of gurgling when the system is turned off but I assume this is the system trying to purge itself of air?

In response to the question about whether it was a 2 or 3 port valve, I used a 3 port valve.