Ok - so my setup is fairly standard. I have the main ATC928G3000 controller, the OpenTherm bridge (on an ATAG combi), a HCC80R operating two zones, and six HR92s in separate rooms.
I've been a little sceptical about how the system has been running for a while. Last night I had one room where the set point was at 19degrees, the HR92 was reading 17degrees and pressing the button on the HR92 showed the 19degree set point, but the rad was cold. I checked the controller and it claimed it was making a 20% call for heat (the only room). The set point change was at least 90 minutes earlier, so this wasn't due to a delayed update. I removed the HR92, manually opened up the valve, reseated the HR92 and it happily ran through a valve cycle.
Just now I had another similar situation, though this time it was quite close to set point change times. Three bedrooms where the HR92 was reading 0.5 or 1 degrees above set point, but I could hear the water running through the valves and the rads were quite warm to hot, and one room that was 1 degree below set point and the rad is stone cold. Checked the controller, and it claims only one room making a 10% call for heat - the one with the cold rad.
I'm also a little paranoid when I hear my boiler pump running after my set points have all reduced an hour or so earlier, and no one has been running hot water.
Mostly, if I set an override from the controller or from my phone it's updating within a couple of minutes. So, I'm not thinking this is a communications issue between the controller and the HR92s. The OpenTherm controller is flashing green as expected, and I have no errors or warnings logged.
I know the system is supposed to apply analytical heating strategies, but this seems just wrong.
Has anyone got any ideas?
Thanks,
Ben.
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Another update.
Another bedroom that was reading 19.5degrees with a set point of 20degrees. The controller claims the room was making a 35% call for heat, but the rad was completely cold. I waited 5 minutes. Nothing changed, so I adjusted the set point up to 20.5degrees manually on the HR92 dial and the valve immediately opened up and the rad started heating.
This is getting really frustrating.
Fortunately I have two towel rads without a TRV, otherwise Evohome would be instructing the boiler to heat with no valves open to the return on the boiler. When I talked to tech support prior to installing the system they recommended that all my rads should have a HR92 in order for the system to work correctly, and that no additional pressure relief is necessary because any time there is a call for heat at least one valve should already be sufficiently open. Well - that seems to be completely inaccurate from what I'm seeing with my system!
This can't be right. Does anyone have any advice?
Odd behaviour from HR92s
Odd behaviour from HR92s
Last edited by Eniodi on Wed Apr 29, 2020 8:08 pm, edited 1 time in total.
Re: Odd behaviour from HR92s
I experience the same, but with the HR91s:
The boiler will be firing, the two towel radiators are blazing hot, so the boiler has been at it for a while, yet the radiator that is 0.5 degrees below setpoint is stone cold.
I’ve only had the Evohome system for a couple of weeks so idk if this is expected behaviour, but it seems like a massive waste of gas and money if this is the way it is supposed to work. I expected more for the amount of money this system costs.
Is there anything we can do?
The boiler will be firing, the two towel radiators are blazing hot, so the boiler has been at it for a while, yet the radiator that is 0.5 degrees below setpoint is stone cold.
I’ve only had the Evohome system for a couple of weeks so idk if this is expected behaviour, but it seems like a massive waste of gas and money if this is the way it is supposed to work. I expected more for the amount of money this system costs.
Is there anything we can do?
Re: Odd behaviour from HR92s
Hi, what valves are you using? I'm using the Pegler Terrier 3 bodies - all brand new a couple of weeks before installing Evohome. The Peglers are on the Evohome approved list, and are supposed to be compatible.
I'm finding that the low end throw of the valves, after the HR92 self calibrates, means that the valve head needs another 1/4 to 1/2 turn before water starts to flow when the Evohome controller is registering a demand less than 20%. This means that Evohome thinks the valve is open, but it isn't. Boost the set point, increase the demand % and the valve opens further allowing flow. If the demand is lower, it'll just fight the system until the room cools enough to increase the % demand.
I've been in a lengthy battle with Honeywell support about this. They've had me swapping valve heads all over, with no change in behaviour. The valves are not sticking - remove the HR92 head and spin the black wheel and water immediately flows.
They have suggested this is a "mechanical" issue - though I cannot see how as nothing is sticking and the valve heads are seated nice and firmly. I says it's a calibration issue with the HR92. They are now suggesting I swap out all my valves for Honeywell Valencia ones - at some considerable effort and cost. And if that doesn't fix the issue - waste of time and money!
They keep nagging me for updates on me monitoring the system, but over the summer the ambient temperate hasn't been right for testing it all again. As we move into colder weather I'll be testing this all again.
I'm finding that the low end throw of the valves, after the HR92 self calibrates, means that the valve head needs another 1/4 to 1/2 turn before water starts to flow when the Evohome controller is registering a demand less than 20%. This means that Evohome thinks the valve is open, but it isn't. Boost the set point, increase the demand % and the valve opens further allowing flow. If the demand is lower, it'll just fight the system until the room cools enough to increase the % demand.
I've been in a lengthy battle with Honeywell support about this. They've had me swapping valve heads all over, with no change in behaviour. The valves are not sticking - remove the HR92 head and spin the black wheel and water immediately flows.
They have suggested this is a "mechanical" issue - though I cannot see how as nothing is sticking and the valve heads are seated nice and firmly. I says it's a calibration issue with the HR92. They are now suggesting I swap out all my valves for Honeywell Valencia ones - at some considerable effort and cost. And if that doesn't fix the issue - waste of time and money!
They keep nagging me for updates on me monitoring the system, but over the summer the ambient temperate hasn't been right for testing it all again. As we move into colder weather I'll be testing this all again.
Re: Odd behaviour from HR92s
Incidentally, it is NOT supposed to work like this.
Low % demand is supposed so allow some heating on your rads to maintain your room temperature around the set point. I also find that the Evohome controller shows rooms are around set point but still have low demand, at around 5%.
I also find that the HR92 is showing termpatures 0.5 degrees out from the main controller at times.
Another weird thing - my hallway says it is currently 18 degrees - if I boost the set point to 20 degrees at the main controller, all of a sudden the controller reports the hallway is at 19.5 degrees within a few seconds, and the HR92 hasn't yet opened up. It's all a bit fishy I think.
Low % demand is supposed so allow some heating on your rads to maintain your room temperature around the set point. I also find that the Evohome controller shows rooms are around set point but still have low demand, at around 5%.
I also find that the HR92 is showing termpatures 0.5 degrees out from the main controller at times.
Another weird thing - my hallway says it is currently 18 degrees - if I boost the set point to 20 degrees at the main controller, all of a sudden the controller reports the hallway is at 19.5 degrees within a few seconds, and the HR92 hasn't yet opened up. It's all a bit fishy I think.
Re: Odd behaviour from HR92s
I bought the official Honeywell valves to go with the evohome system. I believe they are called Valencia, yeah. I was replacing all the radiators so I figured I’d do it all properly.
It’s exactly like you say! The radiator is stone cold, or the valve opens a smidge, letting in a tiny trickle of warm water, not near enough to warm anything. Only a small corner will be “warm” (more like: not cold...). Adjust the setpoint 1 degree higher and bam: valve opens.
I’ve also noticed that the temperature on the main controller jumps as soon as I change the set point. Almost as if a renewed communication with the HR9x sends an updated temperature.
I’m rather annoyed, I thought this system would end up saving me money, but if the boiler is heating constantly amd no valves are opening, I’ll have two sauna like bathrooms and a chilly house, even in the middle of the night.
It’s exactly like you say! The radiator is stone cold, or the valve opens a smidge, letting in a tiny trickle of warm water, not near enough to warm anything. Only a small corner will be “warm” (more like: not cold...). Adjust the setpoint 1 degree higher and bam: valve opens.
I’ve also noticed that the temperature on the main controller jumps as soon as I change the set point. Almost as if a renewed communication with the HR9x sends an updated temperature.
I’m rather annoyed, I thought this system would end up saving me money, but if the boiler is heating constantly amd no valves are opening, I’ll have two sauna like bathrooms and a chilly house, even in the middle of the night.
Re: Odd behaviour from HR92s
The valve being open slightly is supposed to be the case - so if your demand is 10%, it should be allowing a proportional amount through (not fully open). So your rad should be warm (maybe not hot) to maintain room temperature - but it should not be stone cold.
I can hear the flow in the valve if I open it manually, and using a laser thermometer shows the heat jump when some flow starts.
I also have the OpenTherm bridge, so I expected the Evohome controller to regulate the heat demand proportionally at the boiler. So, a ramped heat. I don't expect scolding hots towel rads when just one regular rad is demanding 10% heat.
The system really is not playing the way it is advertised. I've been running it for over a year, so it's had plenty of time to "figure out how my house works", as is the claim of the so-called fuzzy logic. I'm a software engineer and don't believe they know what "fuzzy logic" actually means. Seems like a lame excuse for not giving accurate reporting at the Evohome controller of exactly what is going on under the hood. The new(wish) feature showing the heat demand in the system panel doesn't seem to show accurate immediate information. You can skip back and forth in the panel a few times and the numbers will jump from 0% to 100%. My ATAG boiler is also often showing a demand for heating (with the pump running) when the Evohome controller is saying 0%.
I can hear the flow in the valve if I open it manually, and using a laser thermometer shows the heat jump when some flow starts.
I also have the OpenTherm bridge, so I expected the Evohome controller to regulate the heat demand proportionally at the boiler. So, a ramped heat. I don't expect scolding hots towel rads when just one regular rad is demanding 10% heat.
The system really is not playing the way it is advertised. I've been running it for over a year, so it's had plenty of time to "figure out how my house works", as is the claim of the so-called fuzzy logic. I'm a software engineer and don't believe they know what "fuzzy logic" actually means. Seems like a lame excuse for not giving accurate reporting at the Evohome controller of exactly what is going on under the hood. The new(wish) feature showing the heat demand in the system panel doesn't seem to show accurate immediate information. You can skip back and forth in the panel a few times and the numbers will jump from 0% to 100%. My ATAG boiler is also often showing a demand for heating (with the pump running) when the Evohome controller is saying 0%.
Re: Odd behaviour from HR92s
If, as you say, the Valencias perform no better, Honeywell can get stuffed before I replace all my valves.
Re: Odd behaviour from HR92s
I might have to test it for a bit longer to form a more solid opinion. It’s been in place for two weeks now and the weather hasn’t been that cold yet.
The temp definitely jumps up on the controller when adjusting the set point. That is certain.
I’ll need to check how much the boiler heats when a valve is open just a smidge, and how long that lasts. Maybe it’s just me being paranoid
If the boiler kicks in for a few minutes and then simply pumps that around, that would be better than it going and going and going while the valve is only ever so slightly open. I’ll simply have to look into that.
Btw where can I see what the demand is? I don’t have the opentherm devices so idk if I can actually see that info.
But as I said, I’ll keep an eye on it now that the weather turns colder. Two weeks, of which most days were warm and sunny, is not the ideal period to get to know how this system operates!
The temp definitely jumps up on the controller when adjusting the set point. That is certain.
I’ll need to check how much the boiler heats when a valve is open just a smidge, and how long that lasts. Maybe it’s just me being paranoid
If the boiler kicks in for a few minutes and then simply pumps that around, that would be better than it going and going and going while the valve is only ever so slightly open. I’ll simply have to look into that. Btw where can I see what the demand is? I don’t have the opentherm devices so idk if I can actually see that info.
But as I said, I’ll keep an eye on it now that the weather turns colder. Two weeks, of which most days were warm and sunny, is not the ideal period to get to know how this system operates!
Re: Odd behaviour from HR92s
On the controller, hold the "Settings" button for 5 seconds, hit the green tick, then go into "System Summary". There it lists every room, and the demand for heat as a %, along with the total % demand put on the boiler.
There are a few hidden pages that will show you software versions, etc.
Did you install yourself, or did an engineer do it for you?
There are a few hidden pages that will show you software versions, etc.
Did you install yourself, or did an engineer do it for you?
Re: Odd behaviour from HR92s
An engineer did it for me, one that had all the necessary Honeywell training, so I expect it to be installed properly 
I’ll keep you posted if I notice anything else weird.
And thank you, found the “secret” settings. That’ll be good to keep an eye on! The more you know!
I’ll keep you posted if I notice anything else weird.
And thank you, found the “secret” settings. That’ll be good to keep an eye on! The more you know!