Heating problem

TKK

I have a sealed gas heating system which is giving me some problems. The pressure guage on the boiler (Vokera mynute 14e) has never gotten much above 0 since we moved in last July. I didn't pay much heed to it as the heating is working fine - all radiators heat properly and there is a good supply of hot water to the taps.

However last night I hit a problem. I had the radiator and all other fixtures removed from the ensuite as part of a fix for a leak from the shower through cracked grouting. I went to reinstall the radiator - connected up the pipes, determined which was the feed by pipe temperature, opened the valve and bleed screw and nothing. What has happened is that 3-4 inches of water has gone into the radiator but no more (I opened the outlet valve and the radiator heated to that level once the circuit was open). There is no air coming out the bleed screw. It's as if there isn't enough pressure in the system to force the air out.

I immediately suspected that the feed into the heating system was turned off. The cylinder feed pipe coming down from the tank in the attic has a T-junction one side of which feeds the heating system. The inline valve was on (and is working - I checked). There is a non-return valve after this on the line so I suspected that this was blocked and took it out to clean it (I also tested it after cleaning by connecting it to the feed pipe for the wash hand basin in the ensuite and it's fine).

Can anyone shed any light on where the problem might be??? I'm at a loss here folks.

beldin

There should be a connection from the mains water to the heating system pipes. The problem is you don't have enough water in the heating system.
This filler pipe can be anyplace but usually in the hot press or else underneath the boiler.
The pressure guage in the boiler should be topped up to just under 1 bar.
This may be needed to do once or twice as the air gets released out of the system.
On my system it is under the boiler and is just a small silver valve connected to a flexible pipe which is connected to the boilers pipes.

happy hunting , if you open the correct one you should hear water entering the system. Just don't put too much water in as that can cause problems later on. Just keep the pressure under 1 bar when the system is cold.

TKK

I've found where the system is topped up - it's in the hotpress and doesn't feed from the mains but from the cylinder feed from the tank in the attic. There is a valve there to turn it on/off but that's been left in the permanently on position.

stapeler

I've seen similiar recently and there's was a bleed screw off the primary circuit in the hotpress. Opened that and let out some air. Also inflated the tank above the boiler to 1bar. Found some good info on the http://www.diynot.com/forums/ forum. Vokera also have a good website with drawings for most of their boilers if it's of any use.

TKK

Ok from what I'm reading it appears the system may be an open system as there is no expansion vessel (except in the boiler???) and also there appears to be a vent pipe though I always thought that there had to be a seperate tank for this type of system?

TKK

There is also an air release (or at least that's what I think it is) off the heating circuit. It's like a sealed cup with a valve on the top like a car tyre valve.

TKK

I've only gone and solved it

I did some more experimentation tonight to see if I could figure out why the system would not fill the radiator. I was basically wondering if it would fill at all if water was let go so I opened one of the pipes off the radiator and very quickly had a bucket of water filled! That got me thinking...

The problem??? Dirt!!!

The radiator had been off the wall and empty for about two months in total. During that time whatever dirt was in there managed to dry and form a seal around the bleed hole which blocked the air from coming out even with the bleed screw removed. I poked at it with a light nail and out came all the air.