Pump staying on, boiler going on and off....

[GrahamPearce]

Hi

Long story

Glowworm Micron 50ff system, and yes I have already changed out the motherboard.... a genuine new replacement, procured at great expense, and it made no difference.

Everything is working, timers, thermostats, rads hot when supposed to be, water hot when supposed to be.

Great then, no problem!?!

Well, not exactly, the pump appears to be running constantly, and the boiler comes on and off when it is not required by the timer or thermostat (it is just heating up the closed off circuit and then cooling down again, note there is a bypass valve).

I am aware that the boiler and pump are switched on by the valve(s) (orange wire), assuming there is demand from timer/thermostat(s).

However, one of the two are on with no demand, thus the pump keeps running.

I suspect two issues.....

1. The valves whilst they are working, could the switched power to the pump and boiler be stuck in the on position?

2. The wiring is a total mess (well, it's a jumble of choc blocks), but after a period of following of wires and staring into wiring diagrams (and trying out the new multimeter), appears to be ok. It may not be though IANAE.

I have also ordered and just received the Honeywell wiring centre, as I am intent on wiring the system up to a proper clearly marked 'container'.

Anyone have any better ideas?

Help/confirmation/ideas on diagnosis, would be gratefully received.

Regards

Graham

 

[picasso]

Your thoughts are correct a stuck 2 port valve will make the pump run and the boiler cycle, all you have to do now is determine which one is sticking.

 

[ianmcd]

Well Graham

You seem to to have all the answers to your own questions ? try asking a question instead of telling us what we need to tell you

 

[45yearsagasman]

Easily done at the wiring centre. Work safe and disconnect one orange at a time and check the results.

 

[GrahamPearce]

Easily done at the wiring centre. Work safe and disconnect one orange at a time and check the results.

That's the job of the day today......

Check for continuity across the grey/orange when the valve(s) is closed. For info the valves do appear to open and close appropriately.

I am currently assuming that a microswitch may be stuck?

If I get continuity, I will (on Monday) remove the actuator and take a good look inside, and if not I'll get down to rewiring the lot in the new Honeywell wiring box.

Regards the valves, one of the actuators is a generic replacement, no brand that I could find, but model number BGMVSP2, the other is a Honeywell VC4613.

Any known issues with the above and the microswitches?

Thanks to all, and yes I have done some research, I was just wondering whether I was on the right track.....

 

[GrahamPearce]

Well Graham

You seem to to have all the answers to your own questions ? try asking a question instead of telling us what we need to tell you

Hi, sorry, I was looking for some confirmation that I was on the right track, either that or suggestions of what else might be causing the Pump always on scenario.

Regards

Graham

 

[picasso]

The first valve is a drayton and the wiring is standard for a two port valve, the honeywell is a more complicated piece of kit, do a google search on how its wired as it works completly differently to a standard 2 port and is expensive !

 

[GrahamPearce]

The first valve is a drayton and the wiring is standard for a two port valve, the honeywell is a more complicated piece of kit, do a google search on how its wired as it works completly differently to a standard 2 port and is expensive !

Hi

Thanks...

Is it significant that the Drayton is on the Central Heating circuit and the Honeywell on the Hot Water circuit?

Yes......I had noticed how expensive the Honeywell is to replace, but I did read on another thread how a guy replaced the microswitch in one, for just a few quid.

I'll report back on progress.......

 

[Tipper]

If/when you discover which valve is at fault, it's better to change the whole valve motor head as it will provide a more reliable result.

Frankly fiddling with motors and switches is only for the truly tight-assed or those who want to charge many hours for a simple external component change!

 

[GrahamPearce]

Reporting back......

Well problem is with Drayton Valve Actuator, continuity through the orange and grey regardless of whether the valve is opened or closed.

Sorted....

After removing and dismantling actuator; well I had to try......didn't I; the microswitch on the actuator was stuck, and no amount of jiggery or pokery would get it to disconnect.

Well, apart from a quick spray and clean up with the old WD40, and now it works a treat.

Actuator re-installed, tested and working.

Priceless.......