Mystery always on towel rails

Apodemus

Jeepers_Creepers said:

I think it's in the UK, so yeah.

...but probably not cold enough that a frost guard function is always on - unless it's failed!

Jeepers_Creepers

Ah! I see!

oniongirl

The saga continues....

We are now in a situation where the heating only comes on if the hot water is on. We have two separate valves for CH and HW, so this situation blows my little mind.

So my next question is... Would accidentally wiring the valves incorrectly do this? Hot water to heating and vice versa? I have no idea what's going on any more     I don't know whether to waste my plumber friends time (I'm presuming he wired them back up backwards, but maybe he didn't), so if an electrician might be better? Or....?

I'm at a loss.

Jeepers_Creepers

Lawdie.

Ok, your 'plumber friend' had a look at your DHW valve? I presume he removed the motorised head, and checked the valve body below? He said the valve was sticky, so that probably caused the issue with the head? That all makes sense.

Almost certainly he did not unwire the head as there was no need, so he couldn't have rewired it incorrectly. Ditto with the CH valve - he didn't even touch this, I'm guessing, so couldn't have swapped the wiring over.

Originally the DHW valve's head appeared to be stuck open, so the boiler always ran, your towel rads were always hot, and presumably your hot cylinder was always piping hot. After your P-F had a looksee, the DHW valve now appeared to be always closed, or at least not calling for heat any more?!

You need to give us some info that you haven't managed to as yet. The Honeywell programmer is in the same cupboard as the cylinder and valves, yes? Cool. You need to tell us what these two valves do when called on to act. For this, you need to ensure the room stat is set 'high' so it's calling for heat, and the cylinder is also set higher than the water temp so ditto. Set the Honeywell programmer to be 'off' for both CH and DHW. All done? Cool.

You should know by now what sound the pump makes - it's a very gentle constant hummmmmmm - possibly best felt rather than heard.

You should really have heard the valves operate at some point too, surely? They go 'whhiiirrrrr' very audiblt and distinctly for around 3 or so seconds when asked to open, with the sound sort of accelerating then slowing slightly and stopping with an audible 'click' - that is the switch being triggered. When asked to close, they start to 'whhhirrrr' again, starting with that click (as the switch opens again) and returning under rapid spring power to its off or closed position. When the valve is closed (off) the manual lever should be pushed tight against the 'auto' end and very stiff to move. When 'open', this lever is loose and can be moved all the way across to the 'manual' end (but don't get it caught in the retaining barb).

Have you got that absolutely clear in your mind? Cool.

Ok, with the room stat 'high' and the cylinder stat 'high', first turn on the CH on the Honeywell. Does the CH valve whirr as described above? Does the lever go 'loose'? Does the pump start running as soon as the valve goes 'click'. Does the water to the valve become hot after a short while - 10, 20 seconds? Good. Now turn the CH off again at the Honeywell - does the valve immediately click and whirr and go back to where it was before? Does the lever stiffen up? Has the pump stopped?

Answers on a postcard, please.

Now repeat for the DHW.

oniongirl

I appreciate all the help, JC! I wailed at my plumber friend who said not to panic, was back a few days later and discovered the live wire for the heating wasn't actually connected to anything. Which would explain things. 

Everything has been running smoothly since. 

I wonder if the sellers might have removed a smart thermostat when they left and didn't wire this one back in properly because I can't imagine how they didn't notice.

Jeepers_Creepers

D'oh!

Pleased it's sorted :-)