central heating on all the time

Hi We have oil fired boiler Camray quartet with one pump and two acl lifestyle 2 port valves, everything has been working fine last few years but now boiler and pump running constantly even with programmer set to off for both HW and CH only way I can stop running is to turn of main supply to system. Any ideas what problem could be.

Reply to
Martin Evans
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I think the controller's knackered. Probably the relay/s have welded on. I suppose it's possible that a tank stat could give the same result but without checking diagrams I wouldn't know. If you've got a meter can you get it onto the terminals in the controller with the controller on and see if the outputs are being switched. which controller is it by the way?

-- Malc

Reply to
Malc

In message , Martin Evans writes

Have the contacts in the programmer welded themselves together ?

Reply to
raden

If there are two valves it suggests an S plan system so the current drawn through the programmer contacts is negligible (valve motor only) I'd suggest the contacts in one of the motorised valve limit switches might be the culprit. In each valve cable there will be an orange wire and a grey wire from the limit switches. These will be connected together in the wiring centre terminal box (orange to orange and grey to grey) with a live feed to (usually) the grey wires and a switched supply from the orange wires to the boiler and the pump. Carefully seperate one grey at a time from the terminal (isolating while doing this or you will get the little men up your arm) and try each time to see when the short circuited one is found. You then have a choice of changing the microswitch which is a buggering about task or changing the valve head if its of a vintage with a removable head and a five wire swap, just keep a note of where the old wire colours went before pulling them apart.

Reply to
John

Stuck motorised valve.

Same here. Must replace it. Simple job. So far its responded to hammer blows..:D

Reply to
The Natural Philosopher

I my case its teh valve motor nd gear train that is the problem, not the switch. In order to actually have the rads getting hot, the valve must be stuck open, not just the switch shorted.

If teh switch shorts but teh valve closes you get pum.boiler running but short cycling and no hot rads..

Reply to
The Natural Philosopher

I read the ops post as the boiler and pump running but nothing about the rads or hot water being "on"

Reply to
John

hot water and radiators are all hot

Reply to
Martin Evans

So the valves are both open? Have you taken a look into the wiring centre and tested to see whether the motor "open" signals are present on the wiring to the valve motors (brown wires in the multicore flexibles) Just to help a little a standard s-plan valve head uses brown (or in the case of Danfoss valves brown&white) as the motor supply, blue as motor neutral, green&yellow as earth, grey and orange are connected to the limit switch which closes contact when the valve is open. A few such as Honeywell also have a white wire which is used with an alternative changeover contact limit switch for use in a c-plan system. If the brown wires are live then the problem will be outside the valve motor heads and the programmer needs more investigation always assuming that there aren't any external influences such as frost stats.

Reply to
John

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