HR92 doesn't consistently turn off the heating demand

[rachelism]

Hello everyone,

So glad I found this forum as I have been struggling with our HR92 setup. Mostly, I'm happy with it, but we have had cases when it's behaved "irrationally". I'm a self-confessed techie, so I've been trying to adjust it, and having found this forum done some tweaks to solve some of our gripes.

Recently, we've noticed that the HR92 in our baby's room is keeping the heat on. By this, I mean the target temperature is 16degrees, but displays shows actual temperature of 22.5 and the valve hasnt been closed. It is inconsistent as if I then take off the head, and re-screw, I can hear the valve then closing off. It doesn't appear to consistently do this on its own at the rough set time. The only pattern I have is that this tends to happen shortly after we've changed batteries. I've read on this forum that when you change batteries, you should open the valve fully so it recalibrates when you screw on, which seems to make it better, but eventually, it overheats the room again.

I have tested the RF Check just now, in-situ, and it says Excellent mostly, and two Goods, and have also manually done the valve for a few days, no head and this works consistently.

Any other diagnostic ideas for me please?2021-03-11 14.48.42.jpg

[DBMandrake]

Lots of points buried in there so I have a few questions:

I assume you have the HR92 set to display measured temperature rather than the set point?

How are you determining the valve hasn't closed ? By the radiator getting hot, or by the valve position reported on the HR92?

The first thing to determine is whether you have a physical problem with closing the valve or whether the HR92 is doing the wrong thing by not closing when it should.

So when the radiator seems to be on when the room is well past the set point first go into Option 10 on the HR92 menu (long press then change option 10 to 1) and see what percentage it says.

Option 10 shows valve position in a percentage - 0% means the pin is pushed down as hard as it can (fully closed) while 100% is fully up or fully flowing. Most radiator valves stop flowing below about 30% indicated pin position - at least this is the way the system is designed to operate.

The reported pin position at the point where the radiator is still heating when it shouldn't be will decide what kind of problem you have.

If the position reported is <20% and the radiator is still heating you probably have a physical problem with the valve body (seizing up/stiff) or it is not fully compatible with the HR92 in terms of valve pin travel and force required. Not all M30 x1.5 valves that an HR92 can fit will work well with it! (I say this from first hand experience of problems that lead me to changing my valve bodies)

Some valve bodies might require the Stroke setting to be set to 1 to fully close - this causes it to push down harder and move the pin further between fully closed and fully open. I use this mode on my system. (The drawback is slightly reduced battery life)

With a set point of 16 degrees and a measured temperature > 17.5C the valve pin position should be 0%. You could also check the heat demand reported for the zone in the control panel - long press on settings to get into the installer menu then go to system status, which will show the heat demand from the zone. If the HR92 valve pin position is <30% the heat demand should be 0%.

If the valve pin position is >30% then the HR92 is actually trying to open the valve so that suggests other issues causing the set point to be higher than it should be. For example if the HR92 spontaneously reboots due to a poor battery connection (poor battery connection is a common issue) that will revert the zone's set point to the default 20C until the next scheduled change. In that case tensioning of the battery contacts at the bottom should help.

[Billywizzo]

Are you checking to ensure the HR92 is properly locked into place on the radiator.
I didn’t fully lock the one in my kids room in place and it did not shut off the radiator, so the radiator was always hot when the heating was on.
Also try turning it to the off position, when you hear the valve close, turn on the heating for another room and see if the problem radiator gets hot.
It could be the HR92 not fully closing the valve for some reason.
Also try swapping it to another room and see if it still does the same, an easy way to see if the HR92 is faulty or it is something with the radiator valve causing the issue.
The part in your picture, ensure it is screwed on fully and like you said you should wind the black part out every time you take the HR92 off as it calibrates itself when you refit it.

[rachelism]

Lots of points buried in there so I have a few questions:

I assume you have the HR92 set to display measured temperature rather than the set point?

How are you determining the valve hasn't closed ? By the radiator getting hot, or by the valve position reported on the HR92?

The first thing to determine is whether you have a physical problem with closing the valve or whether the HR92 is doing the wrong thing by not closing when it should.

So when the radiator seems to be on when the room is well past the set point first go into Option 10 on the HR92 menu (long press then change option 10 to 1) and see what percentage it says.

Option 10 shows valve position in a percentage - 0% means the pin is pushed down as hard as it can (fully closed) while 100% is fully up or fully flowing. Most radiator valves stop flowing below about 30% indicated pin position - at least this is the way the system is designed to operate.

The reported pin position at the point where the radiator is still heating when it shouldn't be will decide what kind of problem you have.

If the position reported is <20% and the radiator is still heating you probably have a physical problem with the valve body (seizing up/stiff) or it is not fully compatible with the HR92 in terms of valve pin travel and force required. Not all M30 x1.5 valves that an HR92 can fit will work well with it! (I say this from first hand experience of problems that lead me to changing my valve bodies)

Some valve bodies might require the Stroke setting to be set to 1 to fully close - this causes it to push down harder and move the pin further between fully closed and fully open. I use this mode on my system. (The drawback is slightly reduced battery life)

With a set point of 16 degrees and a measured temperature > 17.5C the valve pin position should be 0%. You could also check the heat demand reported for the zone in the control panel - long press on settings to get into the installer menu then go to system status, which will show the heat demand from the zone. If the HR92 valve pin position is <30% the heat demand should be 0%.

If the valve pin position is >30% then the HR92 is actually trying to open the valve so that suggests other issues causing the set point to be higher than it should be. For example if the HR92 spontaneously reboots due to a poor battery connection (poor battery connection is a common issue) that will revert the zone's set point to the default 20C until the next scheduled change. In that case tensioning of the battery contacts at the bottom should help.

I had a look this morning when it was hot - on Option 10, it was 66%, so by my understanding of your explanation, that's open. My adaptor is the one honeywell sell for my honeywell valve. All/most of my rads are the same, and therefore have got the same valve/setup/adaptors. But it still be an issue there.

I also did the set the stroke to 1 (I believe I did this before), but then I turned the temperature down, and that seems to have doen the trick. No idea though if the stoke did it this time

I did check valve position when it was fully off, and it did say 0.

Interesting - with regards to the baterry positions. Many/All of my HR92 regularly switch off when I unscrew them and then reboot. So I'm going to try to pay attention to that.

[rachelism]

Thank you for taking the time to reply. Yes all of the above diagnosis steps, I've done and haven't managed to get a consistent behaviour. I will however do a more methodical diagnosis this time, as I'd like to get to the bottom of this.

[rachelism]

Are you checking to ensure the HR92 is properly locked into place on the radiator.
I didn’t fully lock the one in my kids room in place and it did not shut off the radiator, so the radiator was always hot when the heating was on.
Also try turning it to the off position, when you hear the valve close, turn on the heating for another room and see if the problem radiator gets hot.
It could be the HR92 not fully closing the valve for some reason.
Also try swapping it to another room and see if it still does the same, an easy way to see if the HR92 is faulty or it is something with the radiator valve causing the issue.
The part in your picture, ensure it is screwed on fully and like you said you should wind the black part out every time you take the HR92 off as it calibrates itself when you refit it.

Thank you for taking the time to reply. Yes all of the above diagnosis steps, I've done and haven't managed to get a consistent behaviour. I will however do a more methodical diagnosis this time, as I'd like to get to the bottom of this.

[DBMandrake]

I had a look this morning when it was hot - on Option 10, it was 66%, so by my understanding of your explanation, that's open. My adaptor is the one honeywell sell for my honeywell valve. All/most of my rads are the same, and therefore have got the same valve/setup/adaptors. But it still be an issue there.

66% is definitely the HR92 trying to call for heat.

Interesting - with regards to the baterry positions. Many/All of my HR92 regularly switch off when I unscrew them and then reboot. So I'm going to try to pay attention to that.

Unfortunately the battery contacts are a weak point in the HR92 design - I've had to tighten the contacts on all of mine at some point, some more than once over the 5 years I've had my system.

To test if there is an issue I take the HR92 in one hand holding it upright then bring it down with a moderate thump into the palm of my other hand - if the contacts are misbehaving the screen will go blank and it will reboot.

It's usually the bottom contacts that are to blame - remove the batteries and if you look up into the HR92 from the bottom you'll see the bottom battery contacts - use a small flat blade screw driver to push on the middle rung of the two contacts from beneath so that it bends up a couple of millimetres, then reinsert the batteries and try the palm test again and it shouldn't reboot now.

Occasionally I have had to bend the flat bar at the top slightly which closes down on the batteries as well. If you still have the tamper screws for the battery lid I would suggest fitting them as they will hold the bar down much more firmly than just the little clip in the middle and should help as well.

If the battery contacts are poor it can occasionally cause the device to reboot when the motor is trying to turn the valve - this would cause the set point in the zone to act as if you had made a manual override to 20C so could potentially be part of the problem you've seen.

[rachelism]

Hello, my valve position says 0 although the radiator is on,. Any ideas what I can check next please?

[rachelism]

Hello, I had the valve position at 0, stroke 0 (this also happened at stroke 1 though), and the valve position at 0, but radiator still on. This is after the radiator working for a few days. I'm a bit lost as to what that means. Any ideas? Also battery contacts don't seem loose as thumping it around don't make it reset/turn off

[roydonaldson]

When it is at valve 0, try taking the HR92 head off and then seeing if the radiator is still open. If it is, try turning the dial on the top and seeing if it will dial down any further.