CH needed to get HW

[Lesa]

Hi,
I really need some advice on my CH/HW System!

It used to work fine on timer and on 'constant' until I had the water cylinder replaced. It may be coincidence that I now have this problem, but thought it worth mentioning!

Now I can't get HW unless I put the CH on as well.

This was my original WORK AROUND TO GET HOT WATER:

Put HW on Constant, press CH onto Constant. The heating thermostat light comes on in the hall and the light for the hot water thermostat in the airing cupboard comes on.

You can then turn CH off either at the main switch (by boiler) OR you can turn thermostat down to 'temp reached' .
HW continues to warm up as the boiler stays on and the green light of the airing cupboard stays on

NOW to get HW we do the same but even though I turn the CH off at the main or the thermostat it STAYS ON despite all the physical signs says its off!

I thought it might be the Alternator but we only had that replaced a year ago (after getting excellent advice via this site!). Could it have broken? Is there any way of testing it? It's one of the pop off front ones and the plummer who fitted the water cylinder said he can hear the motor?

Please an anyone give me some pointers?

Thanks,
Lesa

 

[Hugh Jaleak]

Hmmmm. Alternators are found on engines to charge the battery of the vehicle....

My guess is Motorised valve on HW side. Looking through your previous posts I think you have a 3 port valve, did you ever get it fixed or replaced? (Unless that is your alternator... I would have expected it to last longer than a year though.) What make is it?

The motor in the valve may well be working, but unless it activates the microswitch (or the microswitch is faulty), it wont send power to the boiler to tell it to fire when the HW calls for heat.

 

[Lesa]

LOL! I meant actuator not alternator!!! Serves me right for posting it at the end of the day!

It's a Drayton mid-position actuator and we had it replaced. So, from what you are saying, despite being able to hear it whirring it just might not be 'engaging' because of a broken/faulty microswitch? Does that mean a whole new part? I'm guessing that there is no way of testing this?

Would this affect the heating being on, despite all the electrics telling me it's off?

In your opinion, could it be anything else? We have replaced the Potterton Control Box (EP2002) as we thoought it may be this, but that's made no impact.

I re-read my previous posts and it's the reverse of the issues we had last time. At least it's 'Summer' this time!

Thanks SO much for helping me with this. I think this site is AMAZING!

Lesa

 

[Hugh Jaleak]

I am unsure now. Teaches me to read posts too late at night, didnt take it all in properly.

I am concerned if you can turn the main switch off for the system and it is still working, then something is seriously amiss. ALL power to the system should come through the main switch, if its not isolating the entire system then there is a rogue 240v feed somewhere.

I strongly advise you get a competant electrician who understands CH wiring to check it out. Replacing parts will not achieve a result if the wiring to the system has been bodged, and at worst it could be potentially dangerous.

 

[Lesa]

Thanks for the update.

Could it be that in addition to the microswitch being faulty/damaged that the thermostat could have broken?

Is it possible that when I initiate the CH to fire up the HW that the thermostat stays stuck 'on' and can't switch itself off until the HW is turned/timed off?

We were having problems with the thermostat around this time that the HW/CH issues began. It basically wouldn't shut off even when we turned it down to 10degrees. It still thought it hadn't reached that temperature.

Another question, our water cylinder in the airing cupboard sprung a leak and we had it replaced. In the process of replacing it, is it possible that anything could have been done to cause the problems I am experiencing. The system worked absolutely fine until a few weeks after the cylinder change. Co-incidence?

There has been no re-wiring of the system since the actuator was changed last January. It's worked great, until a week or so after the cylinder was changed. Even then it was only wiring in a handful of wires on a like to like basis and this was done by my brother in law who is an A1 Electrician.

I appreciate all your help so far!

Thanks,
Lesa

 

[Lesa]

One thing I forgot to mention is that despite the water only being 'on' for 30mins in teh morning and 30 minutes in the evening, it's piping hot and lasts all day.

I am a busy mum of two so I'm forever washing up, washing my hands and using water.

I hope you have a 'Eureke!' moment with all this info!!

Lesa

 

[picasso]

I would check that the immersion heater hasnt been left on by mistake, the other problems sound like a wiring error somewhere along the way.

 

[Lesa]

Hi!

Could it be the faulty/damaged actuator and a broken thermostat that could cause this problem?

Just to be clear the CH is put on to activate the HW. The CH then stays 'on' when I turn it off at the control panel. It stays on whilst the HW is on and then when the 'timed' period comes ot an end, they both turn off together.

When the HW is activated and the CH has been manually turned off, the thermostat doesn't register as 'on' but the radiators remain 'on'.

Is this clearer?!

Lesa

 

[Hugh Jaleak]

Fantastic link here about how Y plan wiring works, might give you a better understanding of what may or may not be going on electrically! Click on central heating system info. http://octaveblue.co.uk/

Just a thought, when the cylinder was replaced was the valve removed. May be worth checking its on the right way round!

 

[mysteryman]

You mentioned 'whirring' from the valve. It should be silent except when it is motoring, although sometimes they hum a bit.

The advice to get someone in is good - he needs knowledge of wiring central heating systems. Not all sparks have this.