M
Mickyplumb
Got bullied into fitting a combi in place of an old servowarm boiler (the one with the swing out rad) today. Kept on at the landlord to at least change the rads and valves as it was all in pretty rough shape. Also, the rads were thin steel.
The existing system was fed via a tiny bucket, the system works at a virtually non existing pressure.
Well, whilst filling up the system, every so often we were hearing a banging type noise, similar to the noise a boiler makes when it overheats when a pump has packed up. Vented the system of air as you do but experience told me something was weird as the needle was really bouncing excessively when I was switching the filling loop on and off.
FACT - when us heating engineers get a feeling that something is wrong, it usually is.
Anyway, set her up at around 1.25 BAR and fired the boiler. All ran well for 10 mins, bit of air, nothing much . Then all of a sudden, there was an almighty bang. Again, everything was fine but the gauge now read .8 bar. Ran round like a nutter but all was fine, the property was above a shop so ran down there expecting that 5 litres had emptied down there. Absolutely nothing.
Then another 2 loud bangs and at the same time I saw the living room rad shudder like crazy but thought it was just some crazy build up of air and the boiler had momentarily boiled up. Checked the gauge, ZERO pressure.
Again, ran round and no leaks, ran into the shop, nothing.
Bloody foxed by this time.
Switched on the filling loop up to .25, held for a min and then dropped to .1 Made no sense.
Did it again, thinking that maybe the boiler was venting air out of the AAV like crazy but in reality knew this wasn't going on.
The he fact that the pressure was holding, even though very low told me that there can't be a pipe in half so I filled up again to 1 BAR and it held.
Fired the boiler again and all ran fine for 10 mins......all of a sudden BANG and it was coming from the front room.
Ran around again, pressure to half a BAR. Then the tenant screamed and the rear panel of the double sided rad had split and started spraying out the back luckily against the wall like a bloody fire hydrant !
Running over with bowls and saucepans to the rad after jamming open the PRV on the boiler I could not believe what I saw. Looking down on top of the double panel rad, the rear panel had blown up like a balloon with the back of it pushing and the wall and the front of it pushing on the rear of the front panel, had pulled out the raw plugs of the brackets.
Basically, all the bangs were the sections in the rads separating one by one. Then, the expansion of the rad was absorbing the pressure in the system whenever I was topping it up.
And, the bouncing on the needle must have been the rad acting as a bouncing bladder.
Being honest, this really shook me up as there were 2 young children playing in the room all the time this was going on as it could easily had been the front panel and sprayed 70-80 degree water over the littluns.
Okay, if it was the front panel, I probably would have noticed it bowing but it took me a while to calm down.
I shouldn't have let the landlord push me into doing this job, I think I got away lightly.
A lesson for all I think.
Mick
The existing system was fed via a tiny bucket, the system works at a virtually non existing pressure.
Well, whilst filling up the system, every so often we were hearing a banging type noise, similar to the noise a boiler makes when it overheats when a pump has packed up. Vented the system of air as you do but experience told me something was weird as the needle was really bouncing excessively when I was switching the filling loop on and off.
FACT - when us heating engineers get a feeling that something is wrong, it usually is.
Anyway, set her up at around 1.25 BAR and fired the boiler. All ran well for 10 mins, bit of air, nothing much . Then all of a sudden, there was an almighty bang. Again, everything was fine but the gauge now read .8 bar. Ran round like a nutter but all was fine, the property was above a shop so ran down there expecting that 5 litres had emptied down there. Absolutely nothing.
Then another 2 loud bangs and at the same time I saw the living room rad shudder like crazy but thought it was just some crazy build up of air and the boiler had momentarily boiled up. Checked the gauge, ZERO pressure.
Again, ran round and no leaks, ran into the shop, nothing.
Bloody foxed by this time.
Switched on the filling loop up to .25, held for a min and then dropped to .1 Made no sense.
Did it again, thinking that maybe the boiler was venting air out of the AAV like crazy but in reality knew this wasn't going on.
The he fact that the pressure was holding, even though very low told me that there can't be a pipe in half so I filled up again to 1 BAR and it held.
Fired the boiler again and all ran fine for 10 mins......all of a sudden BANG and it was coming from the front room.
Ran around again, pressure to half a BAR. Then the tenant screamed and the rear panel of the double sided rad had split and started spraying out the back luckily against the wall like a bloody fire hydrant !
Running over with bowls and saucepans to the rad after jamming open the PRV on the boiler I could not believe what I saw. Looking down on top of the double panel rad, the rear panel had blown up like a balloon with the back of it pushing and the wall and the front of it pushing on the rear of the front panel, had pulled out the raw plugs of the brackets.
Basically, all the bangs were the sections in the rads separating one by one. Then, the expansion of the rad was absorbing the pressure in the system whenever I was topping it up.
And, the bouncing on the needle must have been the rad acting as a bouncing bladder.
Being honest, this really shook me up as there were 2 young children playing in the room all the time this was going on as it could easily had been the front panel and sprayed 70-80 degree water over the littluns.
Okay, if it was the front panel, I probably would have noticed it bowing but it took me a while to calm down.
I shouldn't have let the landlord push me into doing this job, I think I got away lightly.
A lesson for all I think.
Mick
