boiler keeps getting air locks, why?
Discussion
I've just moved into a house with a Baxi Boston floor standing open flue boiler. Ive only been in the house a month and have lost all hot water twice due to air locks in the cylinder. Any advice as to how and why this keeps happening? A family relative who is a plumber has suggested pressurising the cylinder to do away with the cold water feed tank.
I've always had combi's so this thing is alien to me. Maybe time to invest in a combi system?
I've always had combi's so this thing is alien to me. Maybe time to invest in a combi system?
If I understand correctly you are running out of hot water. The common problem is a blocked float valve on the cold water cistern. The problem probably occurs when you run two baths in quick succession, the cold cistern cannot fill fast enough to keep pace with demand and air is drawn into the cylinder cold feed,poorly installed pipework traps the air.
The water gets cooler each time it is demanded not always from running baths. The central heating gets red hot even though there is no hot water We get by with as we have an electric shower but is still less than ideal.
I have tried everything and I mean everything!!! Bled all the rads with the system shut down starting from bottom to top. Then putting the cold water feed from the washing machine onto the hot to push the air out..still nothing. Have tried twice to crack each union around the cylinder resulting in me getting soaked each time. I will try to get a few pics of the shoddy home built system tomorrow.
About mid way up the cylinder is the overflow with a bleed point, tried that too but yep you guessed it still nothing.
As an Engineer it pains me not to know how to fix something so simple. Got the wife's uncle whos a plumber coming round, so fingers crossed. Do you think pressurising the cylinder is a good idea?
I have tried everything and I mean everything!!! Bled all the rads with the system shut down starting from bottom to top. Then putting the cold water feed from the washing machine onto the hot to push the air out..still nothing. Have tried twice to crack each union around the cylinder resulting in me getting soaked each time. I will try to get a few pics of the shoddy home built system tomorrow.
About mid way up the cylinder is the overflow with a bleed point, tried that too but yep you guessed it still nothing.
As an Engineer it pains me not to know how to fix something so simple. Got the wife's uncle whos a plumber coming round, so fingers crossed. Do you think pressurising the cylinder is a good idea?
I still get cold water from the hot tap when the darn thing plays up.
The idea of the hot and cold washing machine feeds is that the cold water is a higher pressure than the hot and "should" push the air lock up and out into the cylinder cold water tank. Lots of people swear it works, not convinced myself.
The idea of the hot and cold washing machine feeds is that the cold water is a higher pressure than the hot and "should" push the air lock up and out into the cylinder cold water tank. Lots of people swear it works, not convinced myself.
What happens if you turn off the CH (by turning down the 'stat) and have the HW on? Test to see if the return pipe from the cylinder to the boiler warms up. If the boiler is firing but shutting down without the hot going to the cylinder, it's sludged up.
What size are the feed/return runs to the cylinder?
What size are the feed/return runs to the cylinder?
Well had the plumber out who's the wifes uncle and he put it down to a number of factors.
First was the fact that the cold water feed to the tank was not high enough above the cylinder. Second was the shocking DIY installation by who ever fitted the system way back, with some of the pipe fittings only hand tight. The pipes feeding the coil in the cylinder had limsescale deposits at the joint with the cylinder indicating a leak at some point.
He got us up and running again by "boiling off" the cylinder? didn't ask too many questions as I'm going to replace it with a combi now. The cost to pressurise and replace the cylinder isn't far off what the cost of a new boiler will cost, bearing in mind we'll get it at a "family price"
First was the fact that the cold water feed to the tank was not high enough above the cylinder. Second was the shocking DIY installation by who ever fitted the system way back, with some of the pipe fittings only hand tight. The pipes feeding the coil in the cylinder had limsescale deposits at the joint with the cylinder indicating a leak at some point.
He got us up and running again by "boiling off" the cylinder? didn't ask too many questions as I'm going to replace it with a combi now. The cost to pressurise and replace the cylinder isn't far off what the cost of a new boiler will cost, bearing in mind we'll get it at a "family price"
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