I have had an overflowing CH expansion tank ever since I moved the central heating pump from the return side to the flow side.
I have a Danesmoor 15/19 CF utility oil boiler.
It is an open vent gravity fed hot water system with a pumped CH circuit.
I have four pipes (excluding the oil supply pipe) entering the boiler.
The two on the leftside are for the gravity feed side, the two on the right are for the CH circuit with the upper one being flow. This is where I fitted the pump, straight after the exit from the boiler (and yes the arrow points the right way). This pumps directly up into the loft and is distributed around the house to all the radiators only to return to the bottom right.
There is no bypass valves,etc fitted and all but one of the radiators have TRV valves installed, which are dual flow type.
My problem is that the CH header tank overflows when the heating first comes on and drips constantly for around an hour or so. The problem does not occur when the heating is off.
I have turned off the supply to the CH expansion tank to eliminate any possibility of the ball cock being faulty, this has been off for over a month now and still the overflow drips. Prior to this i tried bending the ballcock so the float was lower, this only resulted in the float being fully submerged in water and the water still reaching the overflow pipe. Also if i empty the tank out then it takes around about three days before it drips again.
I also constantly have to bleed one or two of the radiators and the air can be heard building up over a few days, although the rest of the house heating works fine.
I have also noticed that the heating vent which is overhanging the CH expansion tank sucks air in when the boiler starts. This I demonstrated by forcing the pipe into the water and switching the boiler on and the water could be seen being sucked into the vent pipe. Not quite sure on my system how the vent and feed pipe should be configured but I have always suffered with air problems since moving in. Most of my radiators are fairly new as I have replaced them and all others are clean as i took them outside and flushed them.
I also use inhibitor but as the system is continually overflowing of late I have been reluctant to put it in until the dripping problem stops.
My first thought was that the heating cylinder coil has a fracture in it, but because it does not fill up in the day and overflow, can this still be a possibility. Alot of money wasted if this is not the cause. Oh yes my CH expansion tank is slightly lower than the bigger HW tank, so syphoning is a possibility.
Also at the same time as moving the pump I removed a radiator in the bathroom (not fitted with a TRV valve) that was incorrectly piped into the boiler bottom left and also into the boiler bottom right (CH return). This I replaced with a towel rail that I piped into the pumped CH circuit.
Getting a plumber out is not a possibility as I like to do all my own repairs and often find this is money wasted! (No offence given)
The heating was piped up by the previous owners and is a right abortion however I am slowly sorting it out. I have a feeling the F&E pipes could be wrong but in my system not sure where they should go.
Hope someone can advice me.
I have a Danesmoor 15/19 CF utility oil boiler.
It is an open vent gravity fed hot water system with a pumped CH circuit.
I have four pipes (excluding the oil supply pipe) entering the boiler.
The two on the leftside are for the gravity feed side, the two on the right are for the CH circuit with the upper one being flow. This is where I fitted the pump, straight after the exit from the boiler (and yes the arrow points the right way). This pumps directly up into the loft and is distributed around the house to all the radiators only to return to the bottom right.
There is no bypass valves,etc fitted and all but one of the radiators have TRV valves installed, which are dual flow type.
My problem is that the CH header tank overflows when the heating first comes on and drips constantly for around an hour or so. The problem does not occur when the heating is off.
I have turned off the supply to the CH expansion tank to eliminate any possibility of the ball cock being faulty, this has been off for over a month now and still the overflow drips. Prior to this i tried bending the ballcock so the float was lower, this only resulted in the float being fully submerged in water and the water still reaching the overflow pipe. Also if i empty the tank out then it takes around about three days before it drips again.
I also constantly have to bleed one or two of the radiators and the air can be heard building up over a few days, although the rest of the house heating works fine.
I have also noticed that the heating vent which is overhanging the CH expansion tank sucks air in when the boiler starts. This I demonstrated by forcing the pipe into the water and switching the boiler on and the water could be seen being sucked into the vent pipe. Not quite sure on my system how the vent and feed pipe should be configured but I have always suffered with air problems since moving in. Most of my radiators are fairly new as I have replaced them and all others are clean as i took them outside and flushed them.
I also use inhibitor but as the system is continually overflowing of late I have been reluctant to put it in until the dripping problem stops.
My first thought was that the heating cylinder coil has a fracture in it, but because it does not fill up in the day and overflow, can this still be a possibility. Alot of money wasted if this is not the cause. Oh yes my CH expansion tank is slightly lower than the bigger HW tank, so syphoning is a possibility.
Also at the same time as moving the pump I removed a radiator in the bathroom (not fitted with a TRV valve) that was incorrectly piped into the boiler bottom left and also into the boiler bottom right (CH return). This I replaced with a towel rail that I piped into the pumped CH circuit.
Getting a plumber out is not a possibility as I like to do all my own repairs and often find this is money wasted! (No offence given)
The heating was piped up by the previous owners and is a right abortion however I am slowly sorting it out. I have a feeling the F&E pipes could be wrong but in my system not sure where they should go.
Hope someone can advice me.
