3 Port Honeywell valve problem

[wull67]

From Honeywell, "the lever is not a position indicator" http://www.honeywelluk.com/documents/All/pdf/975.pdf

 

[TG2015]

Yep, fully aware that the lever on the side is not relevant to this.

I had removed the cover and was observing the internal mechanism.

I must admit to having a sneaking admiration for the design of the valve now that I understand it better.
Its a very clever but simple piece of engineering, and is a joy to watch it working.

However, it does have one fly in the ointment, and that is that if CH was the last option called before the controller switches the system off, power will remain to the motor. This causes the motor (and therefore the actuator housing) to get warm, and aside from using a small amount of electricity, it will likely help shorten the motors life.

I've 'fixed' this by now ensuring that the last program to be called is always HW, followed by a system shutdown. That way there is no power remaining to the Honeywell, and the valve remains at the HW (B) position.

Now the only risk is that the rubber ball valve will begin to indent, and eventually allow water to seep through, but that's for another time

As I noted in my previous post, the Honeywell is no longer a suspect, the problem lies somewhere else.

I just need some help trying to work out how to find it.

 

[75pete]

Yes it is a good valve. The ball will as you say indent over the years, ours lasted over 20 before it needed a replacement, hope your "shut down" works for you.

 

[D_Hailsham]

The other wire connected to the grey should come from the LP522 terminal 1, which is HW OFF.

Remove the LP522 from the backplate and check there are no stray strands touching an adjacent terminal.

When you turn HW on to get the fault, is this done by the timer in the LP522 or are you physically pressing the button so the display reads On? The difference is that the timer operates a relay, so the problem could be due to a sticky relay.

You can mimic the operation of the LP522 by temporarily linking L to T1 (HW OFF), T3 (HW ON) and T4 (CH ON).
T3 Only = HW ON
T3 and T4 = HW and CH (Mid-position)
T1 and T4 = CH only

The relevant thermostat will also need to be set appropriately.

 

[TG2015]

We first noticed the problem when the timer switched to add HW whilst the CH was running. The timer lights were correct (both HW and CH illuminated), but the HW remained cold.
During all the testing, we've been pressing the buttons to illuminate the display for HW & CH.

Thanks for the tips.
Will also look at the programmer for stray wires.

 

[TG2015]

Looked at wiring, all clean, no shorting strands.

I phoned Drayton, and spoke to a very helpful man there at the Technical department, Martin.
We did some testing over the phone and concluded that the LP522 has a faulty HW relay.

The controller works fine except in the sequence when the CH is on, and then HW is selected on the programmer.
At this point the indicater light for HW correctly illuminates, but the HW relay doesn't switch to drop the voltage from T1.
Its only when CH is switched off that the relay operates as it should.

Martin suggested that since the relay switching voltage is quite low, maybe something is is pulling the voltage even lower only when CH is active. Back EFM perhaps?

Anyway, will try a new programmer, and hopefully, the saga will end.

Will update when I've changed it, just to confirm if that was the problem.

Many thanks for your help, particularly D_Hailsham
I really appreciate it.

 

[D_Hailsham]

We did some testing over the phone and concluded that the LP522 has a faulty HW relay.

Isn't that what I suggested in my last post?

Let us know how (in this topic) you get on with the new programmer.

 

[TG2015]

Isn't that what I suggested in my last post?

Yes

When you turn HW on to get the fault, is this done by the timer in the LP522 or are you physically pressing the button so the display reads On? The difference is that the timer operates a relay, so the problem could be due to a sticky relay.

Since I could hear relays switching with both the timer and manual override, and I wasn't prepared to poke around a inside, I phoned Drayton.

Let us know how (in this topic) you get on with the new programmer.

Yes, I will. That's what I said in my last post.

And, once again, many thanks for your help.
Without it I would not have been able to hold a meaningful technical conversation with Drayton, or be able to eliminate the Honeywell valve as the culprit.

To be continued...

 

[TG2015]

New Drayton controller arrived today.
Took off old one and dropped in the new one.

And......it works like a dream !

Brilliant result.
Very happy!