Help... intermittent hot water issue

[Larches]

My heating has developed a new and unwelcome quirk just recently, which is that it's sporadically failing to provide hot water. This is something that happened a few weeks back, but it seemed to go back to normal, but in the past couple of days it has happened again each day. We have a conventional setup with the following components:

Boiler: Vaillant Ecotec Plus 815
Programmer: Potterton EP2002 (pre-dates boiler)
Room stat: Danfoss Randall TP7001 (programmable)
Cylinder stat: Honeywell L641A
Diverter: Drayton Mid-Position Actuator MA1

The programmer has CH set to 'On' so that the room stat can take care of timings. The HW is set to 'Timed' and is on for something like 40 or 50 minutes in the morning and again in the afternoon, which is normally enough for our needs.

We've now had a couple of mornings where no hot water was available, and this evening there was none left after washing up, which is not usual. The programmer has an 'Ext'(end) function which I set to +1 hour just to get some hot water available again, but nothing happened. Well, the HW light illuminated on the programmer, but there was no 'click' and the boiler didn't kick in. I tried unseating the cylinder stat and turning it right up, but that made no difference. The diverter was positioned at H because the heating had been on earlier. I wondered if it might be stuck, but if I cut the power, it goes back to W. On the programmer, I moved the HW slider between On, Once, Timed and Off, and this made no difference. However, when I moved the CH slider to Off and then back to On, the boiler kicked in to heat the water (no demand from room stat and diverter moved to W).

One other thing I noticed yesterday was that if I tried to get the CH and HW on simultaneously by turning up the room and cylinder stats, it seemed to satisfy or the other demand, but not both. E.g. if it was heating the water and I turned up the room stat, the latter showed a flame (heating demand) on the screen but nothing seemed to happen, and then it eventually seemed to give up (flame disappeared). I'm fairly sure the converse also applied - i.e. when CH was active, trying to get HW didn't work. I have yet to see the diverter at position M.

Does anyone have a feel for what the problem is here? The diverter valve seems able to switch position, but could it still be at fault, or is it more likely to be the programmer (which is a bit ancient after all, and the switches have felt a bit iffy for a while)?

Any help much appreciated, as waking up to no hot water in deepest February is not a fun game.

 

[centralheatking]

My heating has developed a new and unwelcome quirk just recently, which is that it's sporadically failing to provide hot water. This is something that happened a few weeks back, but it seemed to go back to normal, but in the past couple of days it has happened again each day. We have a conventional setup with the following components:

Boiler: Vaillant Ecotec Plus 815
Programmer: Potterton EP2002 (pre-dates boiler)
Room stat: Danfoss Randall TP7001 (programmable)
Cylinder stat: Honeywell L641A
Diverter: Drayton Mid-Position Actuator MA1

The programmer has CH set to 'On' so that the room stat can take care of timings. The HW is set to 'Timed' and is on for something like 40 or 50 minutes in the morning and again in the afternoon, which is normally enough for our needs.

We've now had a couple of mornings where no hot water was available, and this evening there was none left after washing up, which is not usual. The programmer has an 'Ext'(end) function which I set to +1 hour just to get some hot water available again, but nothing happened. Well, the HW light illuminated on the programmer, but there was no 'click' and the boiler didn't kick in. I tried unseating the cylinder stat and turning it right up, but that made no difference. The diverter was positioned at H because the heating had been on earlier. I wondered if it might be stuck, but if I cut the power, it goes back to W. On the programmer, I moved the HW slider between On, Once, Timed and Off, and this made no difference. However, when I moved the CH slider to Off and then back to On, the boiler kicked in to heat the water (no demand from room stat and diverter moved to W).

One other thing I noticed yesterday was that if I tried to get the CH and HW on simultaneously by turning up the room and cylinder stats, it seemed to satisfy or the other demand, but not both. E.g. if it was heating the water and I turned up the room stat, the latter showed a flame (heating demand) on the screen but nothing seemed to happen, and then it eventually seemed to give up (flame disappeared). I'm fairly sure the converse also applied - i.e. when CH was active, trying to get HW didn't work. I have yet to see the diverter at position M.

Does anyone have a feel for what the problem is here? The diverter valve seems able to switch position, but could it still be at fault, or is it more likely to be the programmer (which is a bit ancient after all, and the switches have felt a bit iffy for a while)?

Any help much appreciated, as waking up to no hot water in deepest February is not a fun game.

The drayton might have a manual over ride lever have a play at least you might learn more Centralheatking

 

[SJB060685]

This requires a multimetre and someone who knows how to use one. I'd be starting at the programmer when calling for HW and go from there.

 

[Larches]

Thanks both. Sounds like it might be time to call in the pros... just wanted to be sure I wasn't missing anything obvious that I might be able to check or fix myself.

 

[Larches]

Hmm, haven't been able to get someone in yet, but noticed things are a bit different today. Seems the HW failed to come on again this morning as we have only lukewarm water (presumably from yesterday), but today when I pressed the 'Ext' button to get an extra hour's HW heating, it clicked in fine even though the CH was also 'On' (but inactive) at the time. I wondered if this would prevent the CH demanding heat but as soon as I upped the room thermostat, the heating kicked in and the diverter moved to M. So the plot thickens... symptoms seem inconsistent/sporadic (worst kind of problem in a way!).

 

[Larches]

In case anyone's interested, I'm reasonably sure now that this is a programmer issue, and it seems quite consistent now:

• HW is set to 'Timed' and comes on at 4pm
• CH is set to 'On' as our programmable thermostat takes care of the schedule
• At 4pm, the HW light on the programmer comes on, but nothing else happens
• If I then go and move the CH slider (not HW!) from 'On' to 'Off', there is a click from the programmer, and the HW immediately kicks in at that point (even though the light was on already)
• I can then slide the CH back to 'On', and the CH and HW work as required until the HW turns off at the set time
• Basically everything then works fine until the next time the HW is due to come on, when the above cycle begins again.

So whilst I'm no expert by any means, this would seem to point to some kind of malfunction within the programmer which is preventing the HW from clicking in until the CH is 'reset' - I'm kind of intrigued as to what sort of fault (worn relay or something?) could have that effect.

Anyway, for now I'm handling this manually as I happen to be around most of the time to do it, but will want it fixing soon. I had been considering getting Hive installed anyway, so perhaps that would kill 2 birds. Otherwise I'd probably end up paying for someone to come and do some diagnosis and tell me my programmer is knackered, and then paying again for the darned thing to be replaced. Just wish I'd gone for the Hive on Black Friday when they were about £60 cheaper than they are now (but decided against the expense at the time... aah hindsight)!

 

[SJB060685]

A multimetre will tell you all you need to know

 

[Larches]

Well anyway, then this pandemic happened and we all got locked down and here I still am with my dodgy boiler programmer, doing my manual on/off routine for the time being (not so bad when you're stuck at home anyway...).

Only now we have a new and unhelpful development. A couple of days ago, before the temperature became nice again, the house got cold enough for the stat to call for heat, but its call went unanswered. No boiler firing up, no whooshing or whirring, just the lonely, sorrowful click of the thermostat turning off again (which it seems programmed to do after a few minutes if the heating doesn't come on for whatever reason). So, leaving aside the controversial fact that yes, it's June and we still (potentially) have the heating on (I normally just leave the thermostat to take care of things throughout the year), I've been trying to figure out what has gone wrong now. I'm struggling to see how it's related to the existing problem with the programmer, as apart from when we manually turn the CH off and on again (to allow the HW to come on, as explained before), the CH switch just stays 'on' all the time.

I've had a look at the (mid-position) motorised valve, and it just sat stubbornly at 'W', even when the HW was off and the thermostat was calling for heat. I then found the manual override lever, and having moved it to 'H', lo and behold the heating kicked in. So it's good to know we can get it (albeit with manual invervention) if we need it, and the valve moves back to 'W' when the HW comes on. There seems no way of getting both simultaneously though (using the manual lever to move the indicator to 'M' doesn't work).

Now I'm beginning to wonder if we have a dodgy programmer and a dodgy motorised valve. Probably no option now but to get a heating engineer in as I've no experience in tinkering with this stuff (or indeed using a multimeter), but if anyone has theories or hints 'n' tips on things to check then I'd be glad to see them.

 

[Aquarius]

Sounds a bit like a sticking microswitch(es) in the Drayton, with the possibility of a failed/failing synchron motor.

 

[Murdoch]

The cheapest thing you could try is replace the programmer like for like.

all you need to do is put the new one on the existing back plate

 

[Larches]

Thanks both. I didn't want to shell out 80-90 quid for a new Potterton EP2 when ultimately we'd like to fit a smart thermostat anyway, but I have been looking out for a used EP2 or EP2002/3002 on Ebay and it turns out there's a fair bit of demand for them so my bids so far haven't been successful. If I were more clued up then I might be tempted to grab whatever cheap used programmer came along to tide us over, but seeing as this programmer includes some kind of wiring centre (and has unfortunately been tiled around, just to make matters worse), I've not attempted that.

 

[Murdoch]

Why don’t you buy the ep controller and if it doesn’t work then sell it on eBay

a GSR won’t be cheap, neither will a clued up decent spark

 

[Larches]

Fair point - after all, I know the market is there for them!

 

[Larches]

Right then, I got my hands on an EP2 programmer to replace the EP2002, and (thank you Potterton) it was nice and easy to do a straight swap. And the result is... as I expected, it has resolved the original problem with the HW not coming on (the timed HW profile now works fine), but it has not resolved the more recent CH problem.

As before, I've got the CH on the programmer set to 'on', to allow the (programmable) room thermostat to handle the heating. I cranked up the required temp. on the stat just to see what would happen, and heard it click as it started calling for heat, but once again at the point where I would expect to hear the boiler fire up (and the pump), absolutely nothing happened. So again, my suspicion falls on the motorised valve which was still sat at 'W'.

Therefore I'm guessing I may need to replace the motorised valve / actuator, and it seems the Drayton MA1 is common as muck so I shouldn't have trouble getting a replacement, but if anyone has a suspicion that the fault may lie elsewhere then I'd be grateful for any info before I go down that route. I'm not sure if this is something I should attempt myself anyway (unless it's easier to replace than it looks) but it would be nice if I could avoid having to call out a plumber just to confirm my diagnosis and then order the part and have them back a 2nd time to fit it.

 

[SJB060685]

When the roomstat calls for heat and with hot water off the valve should motor over to CH and supply a 230 volts live to burner switch live (orange cable). If the valve is stuck or the switch inside actuator head has failed then you won't get 230 volts to boiler and pump.
I apologise for not reading all previous comments.

 

[Larches]

Thanks, I think if I've understood that correctly then it does suggest the MA1 is at fault, as the roomstat clearly shows it's calling for heat and yet the valve remains on 'W' until I use the manual override lever to shift it to 'H'. So presumably either the valve keeps on sticking, or perhaps more likely it's the actuator switch having failed - either way I certainly get the impression it's the motorised valve that needs repairing or replacing.

 

[Larches]

The saga continues... I took off the actuator head and took some pliers to the spindle on the valve to see if it would turn. It's just a little stiff, but definitely not stuck. I then did a quick test with the head still off to see if it managed to rotate when it had no resistance (i.e. without being attached to the valve), and it did nothing when the room stat called for heat - just remained stubbornly at 'W'. I thought to myself that maybe the motor had packed in. So I goes and gets a replacement motor and guess what... exactly the same thing happens. So that's ruddy annoying. What I did notice though is that there's a slight buzz from the motor whilst the room stat is calling for heat - I could hear it and also felt the vibration, so it seemed like it was trying to do something, but even with the motor freed from the assembly it still doesn't turn.

So again, it seemed like the motor is dodgy, but what are the odds of an unused replacement motor (genuine Drayton, sealed packet) being faulty in the same way? Made me wonder if there could be something wrong with the circuit board, although it looks simple enough, and there must be some power getting to the motor (the buzz/vibration stops as soon as the room stat turns off again).

Seeing as I still don't have a multimeter (for now, although I'm beginning to wonder if it might be worth getting one - and learning how to use it ) I've no idea what to do next really, short of stumping up for a whole new head unit and hoping for the best. If anyone has either a theory as to what's going on or experience of this issue then, as ever, I'd be grateful for any further tips (as you can tell, I'm reluctant to give in and call a heating engineer as it feels like something I should be able to sort out myself, but it may yet come to that...).

 

[Aquarius]

Do you have the battery version of Danfoss or mains voltage?

 

[SJB060685]

Before you spend any more money on the valve I would get a multimeter to check what is where, it doesn't have to be an expensive one. I've had a quick read through from old comments, so forgive me if I've forgot something (a lot comes through this forum each day). Is your problem no hot water or no heating? I'm getting mixed messages from recent comments.

 

[Larches]

Do you have the battery version of Danfoss or mains voltage?

It's the battery one.
[automerge]1598346185[/automerge]

Before you spend any more money on the valve I would get a multimeter to check what is where, it doesn't have to be an expensive one. I've had a quick read through from old comments, so forgive me if I've forgot something (a lot comes through this forum each day). Is your problem no hot water or no heating? I'm getting mixed messages from recent comments.

Sorry, yes, it has been a bit convoluted as the initial problem was the HW not coming on, which I've now resolved (with a new programmer), but in the meantime the heating stopped coming on. I thought at first that the two things may be related, but I'm now reasonably sure they aren't (maybe I should have moved this bit to a new thread!). We now have the hot water coming on automatically as per its schedule, but the heating fails to do so when tested (obviously we're not actually using the CH at the moment, but just keen to get it working before the weather gets colder).

 

[SJB060685]

I would pop down to your local screwfix or toolstation and get a cheap multimeter, as i said it doesn't need to be expensive, you'd probably get one for around £15-£20.
From there I would be looking for 230 volts between a neutral and the white wire on the actuator head. What that tells you will allow you to go from there.

 

[Aquarius]

Does it need batteries in the thermostat? Have you checked the batteries, and are they alkaline?

 

[Larches]

Does it need batteries in the thermostat? Have you checked the batteries, and are they alkaline?

Yes, they're Energizer alkalines, replaced not that long ago. I think the thermostat is working fine - I can hear it click on (and the flame symbol appears) when I notch up the set temperature, and as mentioned, the actuator motor responds with this slight buzzing, and then stops when the thermostat clicks off again. As per @SJB060685, sounds like some electrical diagnosis required on the actuator head.