help with my waterworks?

sounds like you are pulling off hot water faster than the cold water header tank can supply it to the copper cylinder, therefore drawing in air instead.. hence the cough & splutter.
Either slow down the rate at which hot water is drawn off, or increase the rate at which cold water can enter the hot water tank.. Perhaps one of the supply pipes is blocked from the header tank to the cylinder? All sorts can get in here.. how old is the plastic header tank? Is it full of the inevitable gunky stuff at the bottom? I have removed blankets, towels, pillow dead birds, mice... all in the last twenty years, & I aint even a plumber.. but like you, wont pay their kinda bills unless I have to.
Is the supply valve knackered (ball cock) Is it allowing sufficient flow rate into the header tank? (NEVER have the ball cock flow faster than the overflow can empty the tank.. disaster WILL follow if you do, in the way of a ceiling on the floor..)

Hi there,

If your hot tank and its header (feed) tank is also in the loft, then the head pressure cannot be very much. The pressure at the tap is governrd by the height difference between the tap and the tank: let's assume that is 8 foot, then you will have 8ft. of water pressure athe tank. If the cold water feed tank is, let's say, 2 foot above the hot water tank, then the hot water tank only has 2ft. of water pressure. When you run off the hot water, you are drawing it off faster than the hot tank is being recharged, therefore drawing in air.

One other possibility is that you are overheating the hot wtaer/central heating system through perhaps a too high a setting or a faulty cut-off thermostat in the boiler: this will cause steam to circulate in the system and then draw in air when things cool down. Try turning down the thermostat on the back boiler (if possible) to see if this helps.

I can talk you through things if it helps. I am a builder of 35 years experience, BTW.

Hope this helps.

thanks for the tips guys. the header tank is about level with the top of the cylinder tank. hot water pressure is pretty good but that could be the air pressure behind it. temperature is also good but it takes ages for hot water to start flowing after tap turned on. sometimes about 1 minute. i will try and run the hot tap and check out the ball cock in the header tank and have a look for crap in the bottom. there is a small bleed valve in the pipe connecting the cold feed from the header to the cylinder and the shower cold feed is also taken off this pipe. however, if there was air in this line, i would expect to see air coming out of the shower on cold selection wouldnt i?

Hi Jason,

Following from Steve's thoughts, you may need a hi-flow valve to fill the header tank for the hot water. I had to have one of these fitted when I had a water softener installed a while ago. Beats me as to why it was necessary but the softener guy was adamant and it took him some time and he didn't charge me for it so I concluded he either knew his stuff or wanted to nose around my attic.

If the system was once fine but has now turned nasty, its probably gunk as Steve suggests. As you have to change the pump anyway, why not grab a hi-flow valve while you're at it..?

Good luck!

Rich.

DO NOT put a high flow valve in, [what a bloody stupid suggestion] these are only fitted if your water pressure is very low. Different venturies high, medium and low are available very cheaply for the ball valve. If you put one in under mains pressure the water will blast out and if your ballcocks at all worn it won't be able to switch off under such pressure . It will therefore leak and as the waters gushing out your overflow probably won't cope so your tank will overflow.
If you know nowt about plumbing I suggest you stay well clear and instead pay for a decent plumber to look at the work - the last thing you want is a flood with the cold weather coming.

I take it you're not a fan of the Torbek valve?

j8hn,

If you know more about plumbing than me then I bow to your superior knowledge (and of course our desire for Jason not to get flooded).

However, I have pretty good pressure at my house, made do with a normal valve previously and have had no problems with the tank overflowing since having a hi-flow valve. The decision to fit the hi-flow at mine was made by a professional (who didn't feel the need to check water pressure).

In my case the high flow valve is a complete unit that replaces the previously fitted ballcock - that's why I called it a valve, not a venturi. This is what I was suggesting as a possibility, not a hi-flow venturi for a ball cock.

I hope this improves your rating of my previous suggestion (maybe from 'bloody stupid' to 'mildly deranged'?? )

Cheers!

Rich.