any central heating fitters on here?

Ive got a question regarding my central heating/hot water system Im hoping someone can help with.

The system in my house has a small gas boiler in the kitchen, an airing cupboard upstairs, with hot water tank, and the small gravity feed tank in the loft above that.

At the moment we only have the system making hot water, the rads and thermostat are set to off.

every evening a couple of hours after the timer has gone off, about now 8pm, I get a flow of water come out the overflow from the gravity tank, probably a couple of cup fulls.

the float in the tank is fine, and that tap isnt putting in unwanted water, but the other day i watched the pipe into the top of the tank flow water into the tank (this isnt the one with the float)

Whats the likely cause for the system to be putting too much water into the gravity tank and is this coming from the heating system, im guessing its some kind of return?

Thanks, Lee

[maviczap]

Ask Bluefishman or DirtyDog they're both plumbers I think

Ta Dah, possibly the system getting gunged up causing the water to go up the vent pipe, adding a cleaner to the system may help, also try turning the pump speed down, they usually have 1, 2, and 3, tis a little black lever on the black portion of the pump. If it still happens after that you may require some alteration to the pipework, but best would be to turn it into a sealed system, as long as your cylinder accepts that type of system, and thirdly or fourthly if it is getting on a bit it could be worth upgrading to a modern boiler, and ripping out the cylinder, but try pump speed first, hth

thankyou bluefishman, I just popped upto the airing cupboard and had a look, its one of those redy/salmon coloured grundfos ones, but the dial doesnt have any numbers to see what speed its at. theres a small cut portion below the dial, im assuming this is a 0 or 1 point, and its a couple of clicks round.

I have the system heating the water twice a day for 2 hours each, although thats prob more than i need, so i turned it off tonight, and it hasnt overflowed.

Would it help if I turned off the heating part of the programme as all Ive done is turn the rad thermostats to off and the room stat to its zero setting?

thanks

some of them have lines on them ie, 1 11 111, failing that turn your roomstat up to turn the heating on, then go to the pump and turn the lever and you will be able to tell the differance between the differant speeds, just turn it to a lower speed, if it still happens even when it is on the lowest speed, then yeah you got it, your fecked lol, nah just means it will need more work doing to the system, it's not a mega problem, but every time it pumps water into the tank it's adding more air into the system wich helps cause corrosion and puts air in the rads requiring them to need bleeding more often. Edit, on the cut out portion you refer to there may be the no's written on the lighter part, usually grey coloured, they will be quite small, but as i said you can tell by the noise and feel of the pump wheather it's on it's fastest or slowest setting. once you have finished messing with it it don't make a differance wheather you just turn down the r/stat or turn it off at the programmer, but if you are not going to be using it every day, then i would turn the heating off at the programmer and leave your r/stat at 20 or wherever you usually have it, hth, andy.

[dirtydog]

Originally Posted by maviczap

Ask Bluefishman or DirtyDog they're both plumbers I think

Someone call?

Yeah go with what the bluefish one says