no hot water!!

[mimmo]

hi everyone, big problems, i have a conventional system with two, two port valves. gas fired boiler which should provide central heating combined with hot water. the heating seems to work, well the boiler fires and hot water pumps through the pipes of the hwsv. when it fires the rads are warm/hot at the top and cold at the bottom. i take it they r full of sludge!! would that effect the hot water?the biggest prob is that no hot water comes from the taps!! any suggestions? the system is about 22 yrs old and only services have been made to the boiler annually. why cant i get any hot water?? the programmer seems to be fine, so does the roomstat. cylinder stat is at 65 degs. i noticed that both valves shut at the time of firing of boiler, then if i manually set them to the on position then i get some hot water, do i really need to change the two port valve? or is there air in the system? someone pls helppppppppp!!!

[Roger Mills]

It sounds as if you have an S-Plan system [See S-Plan in

for schematics etc.]

The principle of an S-Plan system is that the motorised valves are controlled by the programmer and room/cylinder stats, and that the motorised valves then control the boiler and pump by means of secondary switches in the valve actuators which close when the valves are fully open.

If the programmer and cylinder stat don't cause the boiler to fire, the most likely cause is that the HW valve isn't opening or, if it *is* opening, its secondary contacts are not working.

If the valve isn't opening, it could be that the 'wet' part of the valve has partially seized so that the actuator can't provide enough torque to open it - or it could be a failed motor in the actuator. The latter is probably the most likely answer.

Remove the actuator from the valve, and check that the spindle of the wet bit isn't unduly stiff to turn. Check whether the actuator motors to the open position when there is a demand for HW, but it is detached from the valve. It should then become apparent where the problem lies. If it's just the motor, and you don't mind doing a bit of soldering, you can replace that for a few quid without needing to replace the whole actuator.

If the wet part has seized, it will need to be replaced - involving a partial drain-down - unless you manage to free it by turning it back and forth a few times.

[mimmo]

hey roger, thank you very much for your advice, if it is the valve then, which i think it is, can u tell then it needs replacing if it gets hot when not in use?cos one of them certinally does.

thanx again for your response!!

[Roger Mills]

If you're talking about the electrical part (actuator), that will get warm when the valve is open but should *not* be warm when there is no demand because there should be no power going to the motor.

Has the system *ever* worked properly? Have any components been changed recently? Could it be wired incorrectly?

Have you done the checks which I suggested earlier - with the actuator removed from the valve? If not, do them now, and let us know what happens.

[Fentoozler]

Be carefull, a 22yo zone valve will possibly have a non-removable head.

Angus

[mike]

"Fentoozler" wrote in news: [e-mail]:

Depends on the hammer I use.

mike