Central Heating cannot be turned off! Potterton EP2002 timer

[rjsdavis]

Getting to my limits of usefulness I'm afraid

It sounds to me that the valve has got stuck with the micro switches in the on position. Not sure how that works when you say both sliders on the timer are switched to the off position!!!

Not sure if there is any way to free the gears/working of the valve. What ever way of doing that you would have to be careful of live electrics etc.

Perhaps that would become apparent when/if you take it off. Freeing the valve may resolve the function of the three way valve, solving the problem!

However requesting a plumber to call with the hope of now sounding a bit more confident regarding three way valves is somewhere near to saving you a bit of money.

Thank you so much for bothering to help (unlike some).

I think my logic is just to get a new silver box for the valve and fit it (freeing up the vlave itself whilst the box is off) - I don't think they're massively expensive?

From what I can see on Ebay, a three port valve with motor etc is about £30 for a new Honeywell unit. I'd be buying the exact same make/model so that I can turn the electric off and simply pop the old silver box off, put the new one on, wire it in and hopefully problem sorted?

 

[matt1e]

Hi rj
if the valve does not return to the hotwater positon (the lever stiffens up) when the power is off (not off at the programmer I mean totally off via the heatng spur/isolator etc) then that is one problem you have as the valve is likely to have seized in the mid position this would make the central heating follow the hot water times with the roomstat having no effect

so if the hot water is turned off at the programmer,does the central heating still come on?

if its still coming on at the preprogramed times with the sliders off
then your replacement programmer is faulty

Matt

 

[45yearsagasman]

May 15th til now and you still haven't fixed it.

I might have done if you'd posted a helpful reply like everyone else. Please don't post anything else, as I can do without the sarcasm from forum trolls.

If you look to the start of the thread you'll see I was the first to try to help you. As soon as others join in with different suggestions, it gets too complicated for me and I bale out. With over 500 thanks the last thing I am is a troll.

 

[tryitandsee]

For what it's worth, it's worth replacing as you say.

Just make sure that the sliders are working, as said before, they are complete pants engineering wise.
Does both red indicator lights work (right of slider) when you advance/turn on/ etc.? They should light up when switched to those positions.

Again, has anyone other than you disturbed any wiring to the controller or threeway valve. Mine are in the airing cupboard and the kids always pull the towels out, wires and all!!!

 

[matt1e]

If you look to the start of the thread you'll see I was the first to try to help you. As soon as others join in with different suggestions, it gets too complicated for me and I bale out. With over 500 thanks the last thing I am is a troll.

I'll vouch for ya 45yearsagasman

 

[rjsdavis]

Hi Matt - thanks again for the reply... here goes:

Hi rj
if the valve does not return to the hotwater positon (the lever stiffens up) when the power is off (not off at the programmer I mean totally off via the heatng spur/isolator etc) then that is one problem you have as the valve is likely to have seized in the mid position this would make the central heating follow the hot water times with the roomstat having no effect

so if the hot water is turned off at the programmer,does the central heating still come on?

It doesn't matter which way the switches are positioned on the programmer. You can have HW on timed and CH on OFF, HW on OFF and CH on ON etc etc - the hot water and CH actually only come on at the times programmed into the EP2002!

Also, the system has only one thermostat which is downstairs in the hall. This was the first thing I turned down to ZERO to attempt to stop the CH coming on, but again, this makes no difference at all, and the CH continues to come on (HOT!) no matter what position the EP2002 is in, and no matter what temp reading is shown on the thermostat.

Therefore, I think you're right that the valve is seized?

By this, do you mean the part that projects up from the brass valve itself which is all that can be seen once the silver motor box housing has been unscrewed and removed (using the YouTube video posted earlier as my reference point) and that the silver housing effectively "sits on" and controls?

if its still coming on at the preprogramed times with the sliders off
then your replacement programmer is faulty

Can't be.... surely? The replacement EP2002 that I put on to replace it was brand spanking new! I didn't replace the backplate to be fair (still have if of course), but I couldn't see how this was the likely culprit in any case, and there were so many wires to unscrew, I wasn't able to label them and make sure that they all went into their respective correct positions with the new backplate!

 

[rjsdavis]

Just make sure that the sliders are working, as said before, they are complete pants engineering wise.
Does both red indicator lights work (right of slider) when you advance/turn on/ etc.? They should light up when switched to those
positions.
[\quote]
Yep, the sliders are VERY stiff. Stiff as being new (and notchy) just as you'd expect a brand new unit to be. The old sliders on the old were extremely loose by comparison and there's hardly any "feel" to them at all as you move them along. And yes, on the new programmer, the red lights do indeed light as they should do when the programmer is live on a timed part of the day. Except where the override switch is OFF, and then the red light is also OFF. E.g. the CH is always OFF at the moment, and the red light on the programmer never comes on. However the fecking CH stills comes on and boils the house to death!

Again, has anyone other than you disturbed any wiring to the controller or threeway valve. Mine are in the airing cupboard and the kids always pull the towels out, wires and all!!!

Nope - am very confident that this is all secure. The valve is tucked away beside the hot water cylinder in the airing cupboard and is actually a bitch to reach! I haven't actually yet disturbed any wiring at all yet, as I wanted to clear what I need to do before I do it. Only thing disturbed thus far was to fit and program the new EP2002 which was done with the whole house power off.

There is some sort of intermediary box between the EP2002 and the valve. Have uploaded some pics here....

Close up view of EP2002 (brand new)

New Potterton EP2002

• rjsdavis
• 28 Jun 2012
• 1

Backside view of motor valve and wiring box

Backside of 3 port valve, and seperate wiring box

• rjsdavis
• 28 Jun 2012
• 1

Longshot view of everything in the airing cupboard

Long view of airing cupboard contents

• rjsdavis
• 28 Jun 2012
• 1

Close up view of text on the motor valve

Close up view of 3 port valve motor unit.

• rjsdavis
• 28 Jun 2012
• 1

 

[tryitandsee]

I would change the valve head.

You need to work out which replacement head you require as there are two

www.honeywelluk.com/products/Valves/Motorised-Valves/


Diverter or midway diverter, I assume yours is V4073A mid way?

 

[rjsdavis]

Diverter or midway diverter, I assume yours is V4073A mid way?

I know less than you do! I'm assuming from the last photo of the text on the motorised bit of the valve, that it is in the "A" version - midway diverter....

 

[tryitandsee]

......eyes not as good as they used to be!!

 

[rjsdavis]

New Honeywell V4073A 3 port valve en route!

They were more than 80 notes in the local plumbing suppliers! £33 on Ebay. Bargain!

 

[craig51]

Lets hope there isnt a reason its so cheap!

Does it come with the body aswell??? CHances are its stuck solid, hence your issues.

 

[rjsdavis]

Yep - had four of them, and simply unwanted.

They can be bought from traders for about £40 if you shop around a bit.

I do hope it's not stuck solid - I was really hoping not to have to do any plumbing / piping work! I was hoping that replacing the silver head unit would be enough!

Am ready to tap with the hammer, and twist with some pliers once the old head unit is off, which will hopefully free up anything that is stuck. If not, looks like a plumbers going to have to come in and drain the system down to replace the brass valve element.... Gggrrrrrrr.....

 

[craig51]

If it is solid, and you can free it up, i would put money on it going solid again after a few weeks and lots of hot/cold cycles. Just some friendly heads up advice for you. I've been there before only to have to go back and change it.

Its not too hard to change. You can bung it , but if your a novice the simplest way is

1/ Isolate either the feed into the header tank, OR the mains into the house.

2/ Open drain point outside. This will start to drain the system top - bottom. If the 3 port valve is in the upstairs cupboard, you only really need to drain the header tank and the pipes leading down to it. To prove the water is down to that level, once drain is open, wait 2mins, then open a bleed point on a radiator. If no water comes out, close the drain, and slowly but surely undo the 3 couplings.

3. Once replaced, while not forgetting to fit in the right direction, turn on water and bled rads etc.

4. turn power on and hope for the best.

 

[rjsdavis]

1/ Isolate either the feed into the header tank.

That's the bit I'm likely to arse up.... Don't especially want to drain the whole system by isolating the mains in - so am moving into plumber territory there!!