Hot water on when not required!

londonboy123 · 6 May 2008

Hello again, my second question! ...

I have a problem with my hot water, in that it always comes on when I turn my heating on. It has only recently started to happen! I have a book I bought and it is very useful and detailed but I donot understand fully all of it, as I am not a plumber/hesting engineer! It has a section on: HOT WATER ON WHEN NOT REQUIRED (Programmer Indicates Off). And has step by step fault finding.

It says: First ensure prog is set for fully pumped
Then: Attempt to simulate fault, try PROG, HW on, CH on, then HW off with room at cyl stats calling for Heat.
Then it says: M/Valve(s) correctly orientated: 3 PORT, A: CH (which it is)
Next it says: 3 port: Is grey lead live when fault occurs (how do I find this out)?? This is where I got stuck!!! Anyone know how I can find this out/how to do this?

Thank you for helping ..

D_Hailsham · 6 May 2008

londonboy123 said:
Next it says: 3 port: Is grey lead live when fault occurs

The lead which comes out of the 3 port valve has several wires: white, blue, orange and grey.

This lead should go into a box together with leads from the pump, thermostats and boiler.

Take the lid of the box and use a volt meter to check the voltage on the grey wire. Careful, its 230V AC in the box!

This explains How a Mid position Valve Works

londonboy123 · 6 May 2008

ok, so is a voltmeter different from a multimeter? do i just move it over the wire or have to disconnect it?! thanks for your help.

D_Hailsham · 7 May 2008

londonboy123 said:
ok, so is a voltmeter different from a multimeter? do i just move it over the wire or have to disconnect it?! thanks for your help.

A Volt meter just measures voltage. A multimeter can measure voltage, current, resistance etc.

If you have a multimeter, switch it to the 250. or higher, AC voltage setting.

One probe should be touch a terminal with Neutral (blue) wires, the other probe should be touch the terminal with the grey wire. If there is voltage on the grey wire, the meter will read about 230-240V AC; if no voltage, the meter will read zero. These are AC voltages, so make sure you hold the probes by their insulation.

It does not matter which probe touches which terminal!

londonboy123 · 7 May 2008

ok thanks for your advice. I will go to Wickes later on today and buy a voltmeter/multimeter. See if I can get a good deal!! I take it I only have to touch a part of the insulated wire and not the actual part which goes into the junction box!!? Just checking! I will read the instructions that come with it anyway to be on the safe side!

Are there any other ways you can test to see if a motorised valve is faulty?

D_Hailsham · 8 May 2008

londonboy123 said:
I take it I only have to touch a part of the insulated wire and not the actual part which goes into the junction box!!? Just checking! I will read the instructions that come with it anyway to be on the safe side!

There is not much point in touching the insulation

You have to touch the actual terminal, which means taking the lid off the junction box.

Are there any other ways you can test to see if a motorised valve is faulty?[/quote]
Yes!!

Turn off CH and HW at the programmer and turn CH and HW stats down low
Turn HW on at programmer and turn the HW stat up to max. The boiler should light and the pump work.
If it works go to next step. If it does not work, either the programmer or the HW stat is faulty.
Turn the CH on at programmer, leaving CH stat low. The boiler should continue to run for HW
Turn CH stat up. The motorized valve motor should run and the valve move top mid position, so CH and HW are both on.
Turn HW stat down. The motor should run to open CH only and the boiler continue running for CH only.
Turn HW off at programmer. The CH should still run
Turn CH stat down. The boiler/pump should stop

Please report the findings of your tests; then you will get more help

Here is a typical wiring diagram for the Y-Plan, which uses a mid-position valve.

ollski · 8 May 2008

just change the valve.

londonboy123 · 9 May 2008

ok, let me try and get this straight!!!!

I have to touch the unsheathed part of the grey wire (as mentioned before) from the motorised valve, and any neutral blue wire (unsheated part also) in the junction box with another probe from the multimeter? I know all neutrals wire up in the same part of the junction box from looking earlier and from the y plan standard wiring diagram!! BUT I read that the MCB to the circuit should be isolated first before removing the junction box cover)!, but if i isolate it then NO voltage will be getting through anyway!!!! Sorry if I sound really ignorant here btw!

Agile · 9 May 2008

I would not be advising you to be using a multimeter because I am not at all sure you could do it safely.

But if you must then you will get much better value and considerable choice if you go to a Maplins.

Tony

londonboy123 · 9 May 2008

Hi - I agree I am not 100percent sure hot to use a multi meter and i'll have to read the instruction slowly and carfeully before attempting to use it! I have a book I bought a little while ago, called Central Heating Fault Finding & Repair. It is very good, very detailed. That's why I enquired about it- wasn't sure what they meant by testing to see if the grey wire from the motorised valve was live! is this hard to do in all seriousness ??

D_Hailsham · 9 May 2008

londonboy123 said:
Hi - I agree I am not 100percent sure hot to use a multi meter and i'll have to read the instruction slowly and carfeully before attempting to use it! I have a book I bought a little while ago, called Central Heating Fault Finding & Repair. It is very good, very detailed. That's why I enquired about it- wasn't sure what they meant by testing to see if the grey wire from the motorised valve was live! is this hard to do in all seriousness ??

You have been given very explicit instructions, yet you come back and ask the same thing.

I am beginning to think this is a wind-up.

londonboy123 · 9 May 2008

I am sorry! I am not winding you up intentionally! Really sorry. Just as mentioned I want to be 100percent sure before working on it as electrics can kill... My apologies once again.

D_Hailsham · 9 May 2008

londonboy123 said:
I am sorry! I am not winding you up intentionally! Really sorry. Just as mentioned I want to be 100percent sure before working on it as electrics can kill... My apologies once again.

OK Apology accepted

Let's see if we can sort you out!

Forget the meter for the moment, as you are obviously not comfortable using one, and concentrate on simple tests.

I gave you instructions a few posts back how to test the motorized valve. Why not try each test, in turn and post the results?

gavinda · 10 May 2008

having read the length of this thread, my advice would be listen to agile, get somene who knows what they are doing. the best bit of diy knowledge is knowing when to just get the proffesionals in to begin with. especially where life and limb is concerned

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Hot water on when not required!

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