Heating/water on without timer

[jar]

Hi

Heating and water controlled by Danfoss timer (PP715 I think). Boiler in airing cupboard.

Recently, either the heating or the water continues to heat even when the timer has switched off. Timer lights are off but the boiler continues to kick on/off as it would when timer is on.

We have a maintenance contract with gas company but, of course, it didn't do it when the guy was out.

It is VERY annoying because the only way to stop it is to switch the system off at the mains switch. The system isn't particularly noisy but can seem 10 times louder when you're trying to sleep at night !!

Anyone seen this before - I would assume it's something like a relay or switch not closing when it's supposed to but I'm only guessing.

I know we'll need to get an engineer out again but I'd still like to know what might be causing this.

Cheers

 

[seco services]

have you got any of these ?

poss one is sticking open.

 

[gaspro1981]

the make and model of the boiler would be useful

 

[jar]

Guys - thanks for the responses.

seco services - yes, there appear to be 2 devices like these under the water tank shelf. They're in an enclosed area and facing the wrong way to get part numbers etc from them.

gaspro1981 - sorry, didn't mention the boiler because I assumed it would be a timer issue. It's an Ideal Classic FF250. This is downstairs in the kitchen. Hot water tank & timer upstairs in bedroom airing cupboard. Main water tanks are in loft.

Also - I've checked the timer again and it's actually a Danfoss FP715.

Cheers

 

[seco services]

when you turn the programmer off and the system keeps running check what valve has hot pipework on both sides of the valve.

that will be the one thats stuck.

is your hw hotter than useal ?
is it your rads that are staying hot ?

 

[jar]

seco services - I'll check when they've both been off (or meant to be) for a while. I switched the heating timer off a couple of hours ago but unfortunately the water timer kicked in which I'd forgotten to switch to off. I've now switched this off as well but I'll need to try this again at a more reasonable time tomorrow.

At the moment, both ends of both of these devices (valves ?) are hot - while I'm sitting here I can hear the boiler kicking on and off. I can also hear water still circulating upstairs at the hot water tank. I don't know if this is normal but it never seems to stop now. I'm sure it used to be all quiet at the water tank unless the heating or water were switched on.

Cheers

 

[seco services]

if the poss fault is the hw valve not switch off then your hw out of your taps will be a lot hot than what the stat on the cylinder is set to.
because its not cutting the boiler off at say 60 degrees .

 

[LeadFarmer]

Is it a pre heat function?

My Ideal Isar boiler has this function. It constantly switches on every now and again throughout the day and night for about 1 minute. This way it keeps the water hot ready for when I turn a tap on.

This isnt a feature I like as it seems a waste of energy (and money) to heat water that I may not need. I assume it means I have hot water more instantly instead of standing with the hot tap on waiting for the boiler to do its thing.

Ive an Ideal engineer visiting me for a repair in the next few days so might ask if he can fit a pre-heat disabling kit that ive heard about. I'd rather wait a short while for the water to get hot than have the boiler fire up constantly on the off chance I might want hot water.

 

[D_Hailsham]

have you got any of these ?

poss one is sticking open.

These valves have four wires:brown, blue, grey and orange. Disconnect the grey wire of one valve and check if the problem stops; if it does that valve is faulty. If the problem continues, disconnect the grey of the second valve and check again. If it now stops the problem is in the second valve but if it continues the problem lies elsewhere.

 

[jar]

Thanks for the suggestion - I'll try this when I get the chance. May be a couple of days as I'm home late next few days. I'm assuming disconnecting one of the wires isn't likely to kill anything, including myself (I'll cut the power before doing anything !!) ? I know, stupid question but just to make sure.

 

[kevindgas]

Turn of power supply
take the timer off the wallplate 2 screws underneath
with a multimeter set on buzzer test between 1 & 3 and 1 & 4 (on timeclock not wallplate) if either buzz then timer is kacked (had 1 yesterday where 1 & 4 were permanently joined due to malfunction)
there may be a link wire between L & 1 (240volt)
if not then terms 1,2,3 & 4 are seperated and power through them comes from elsewhere most likely to be 240v still (can be 12 or 24 in combi's)

 

[D_Hailsham]

I'm assuming disconnecting one of the wires isn't likely to kill anything, including myself (I'll cut the power before doing anything !!) ?

Cutting the power first is a good idea - but don't forget to turn it back on to do the test.

The grey and orange wires are the two connections to a switch in the valve which closes when the valve opens. If the valves have been wired as per the "standard" method, the grey wire should be dead. But, as it does not matter which way round the grey and orange wires are connected, you may find that the grey wire is live when you turn the power on. So be careful.