I'm hoping someone can help me with my issues here...
In my flat I have a fairly old open vented gravity system that provides h/w and c/h. The system has a couple of 2-port zone valve for h/w and c/h. There is a pump on the return pipe from the h/w and c/h and the only drain cock on the system I can see is on the inlet pipe of the first radiator. On the return leg from the h/w cylinder there is also a gate valve before where the centre heating joins and the pump.
Above the floor standing boiler there are 2 tanks, one is a cold water tank and the other a feed and expansion tank. The feed and expansion tank has the over hanging vent pipe coming off from the h/w feed pipe.
I believe there is an airlock in the h/w cylinder coil after the system was partially drained by a plumber to fix an issue/replace the h/w zone valve. He didn't drain the system from the drain cock, but opted to shut off the water mains and then uncouple the return pipe where the gate valve is installed to remove the water from the top half of the system, just enough to carry out his work. He then filled the system back up after replacing the zone valve by closing the return pipe and opening the water mains so the system filled from the top tanks thereby trapping air in the system as a consequence.
I tried to get this rectified by arranging another appointment, but instead the plumber that turned up didn't even attempt to clear the airlock, but instead rewired the timer/programmer, thermostat for c/h and replaced the junction box for some reason. As a consequence the boiler kept tripping all the electrics in the flat each time it was plugged in. He initially tried to blame the electrics in the flat, but I was able to demonstrate that it was down to wiring he had done, not to mention I had the electrics checked and consumer box changed a year ago. He eventually rewired the system again, but this time the electrics didn't trip. However, he didn't fix the airlock and to be honest I'm not sure I had faith that he would do a good job.
Currently when I now turn on the h/w the boiler fires up for about a minute or so and in that time the h/w feed pipe from the boiler to the cylinder gets extremely hot. The h/w zone valve opens and the rest of the remaining h/w feed pipe heats up all the way to the connection to the h/w cylinder. The cylinder and the return pipe gets slightly lukewarm, but no where near hot. When I switch on the c/h the boiler fires up and remains on once the zone valve opens and the radiators get hot.
There is water in both tanks when I checked so am I right in thinking it is likely an airlock in the h/w cylinder? My question is how do I resolve this myself. Can I just turn off the main supply, manually open the c/h zone valve and drain the water from the system using the drain cock located at the bottom inlet of the first radiator. Once it is completely drained, do I refill it from the drain cock by attaching a hose pipe to a mains fed cold water tap rather how the plumb filled the system before? Would there be an issues affecting the central heating if I'm draining/refilling the system effectively from the c/h side? For example do I need to open the first radiator bleed valve until the water reaches the top of the radiator? Any assistance would be great and appreciated!
I've attached a diagram of my h/w & c/h system. Thanks.
In my flat I have a fairly old open vented gravity system that provides h/w and c/h. The system has a couple of 2-port zone valve for h/w and c/h. There is a pump on the return pipe from the h/w and c/h and the only drain cock on the system I can see is on the inlet pipe of the first radiator. On the return leg from the h/w cylinder there is also a gate valve before where the centre heating joins and the pump.
Above the floor standing boiler there are 2 tanks, one is a cold water tank and the other a feed and expansion tank. The feed and expansion tank has the over hanging vent pipe coming off from the h/w feed pipe.
I believe there is an airlock in the h/w cylinder coil after the system was partially drained by a plumber to fix an issue/replace the h/w zone valve. He didn't drain the system from the drain cock, but opted to shut off the water mains and then uncouple the return pipe where the gate valve is installed to remove the water from the top half of the system, just enough to carry out his work. He then filled the system back up after replacing the zone valve by closing the return pipe and opening the water mains so the system filled from the top tanks thereby trapping air in the system as a consequence.
I tried to get this rectified by arranging another appointment, but instead the plumber that turned up didn't even attempt to clear the airlock, but instead rewired the timer/programmer, thermostat for c/h and replaced the junction box for some reason. As a consequence the boiler kept tripping all the electrics in the flat each time it was plugged in. He initially tried to blame the electrics in the flat, but I was able to demonstrate that it was down to wiring he had done, not to mention I had the electrics checked and consumer box changed a year ago. He eventually rewired the system again, but this time the electrics didn't trip. However, he didn't fix the airlock and to be honest I'm not sure I had faith that he would do a good job.
Currently when I now turn on the h/w the boiler fires up for about a minute or so and in that time the h/w feed pipe from the boiler to the cylinder gets extremely hot. The h/w zone valve opens and the rest of the remaining h/w feed pipe heats up all the way to the connection to the h/w cylinder. The cylinder and the return pipe gets slightly lukewarm, but no where near hot. When I switch on the c/h the boiler fires up and remains on once the zone valve opens and the radiators get hot.
There is water in both tanks when I checked so am I right in thinking it is likely an airlock in the h/w cylinder? My question is how do I resolve this myself. Can I just turn off the main supply, manually open the c/h zone valve and drain the water from the system using the drain cock located at the bottom inlet of the first radiator. Once it is completely drained, do I refill it from the drain cock by attaching a hose pipe to a mains fed cold water tap rather how the plumb filled the system before? Would there be an issues affecting the central heating if I'm draining/refilling the system effectively from the c/h side? For example do I need to open the first radiator bleed valve until the water reaches the top of the radiator? Any assistance would be great and appreciated!
I've attached a diagram of my h/w & c/h system. Thanks.