Hi
I installed a few weeks ago our new Evohome installation. The CH is working as hoped but the hot water regularly (every few days) appears to overshoot the hot water temp by a considerable margin (set at 55, gets to 67). I've hooked our install up to Home Assistant so I can clearly see the hot water temps being reported overtime.
System overview:
I've read the forum, so I'm aware of others having/or have had similar issues. I've tried adjusting the battery contacts, moving the sensor, bringing the controller closer etc.. etc.. but yet still the problem persists. The only thing to be aware of is the hot water insertion sensor currently has no thermal paste applied, but it's sitting snuggly within its well.
A few observations for the hot water:
Any help, or guidance would be really appreciated.
Given the temps are being reported, I've not bothered with the thermal paste so far.
The obvious issue is the temp not being reported for an hour whilst re-heating, the moment it's reported the system shuts off etc... perfectly.
This morning, following a couple of showers we've had two consecutive 67c overshoots, yet for the previous 2-3 days things appeared to be working as planned.
This graph shows the overshoots, the green dots show when temp readings are being received. Notice the lack of readings when the temp is climbing above the set point.
Water Graph.jpg
Thanks
Dan
I installed a few weeks ago our new Evohome installation. The CH is working as hoped but the hot water regularly (every few days) appears to overshoot the hot water temp by a considerable margin (set at 55, gets to 67). I've hooked our install up to Home Assistant so I can clearly see the hot water temps being reported overtime.
System overview:
- Wifi controller
- 14 HR91s
- 2 BDR91s (one for HW, one for CH)
- Hot Water Kit, unvented cylinder, wired in series with existing high-limit stat.
- Water temp 55c, differential 5c (also tried 10c).
- Boiler via Opentherm, temp limited to 70c and being followed
I've read the forum, so I'm aware of others having/or have had similar issues. I've tried adjusting the battery contacts, moving the sensor, bringing the controller closer etc.. etc.. but yet still the problem persists. The only thing to be aware of is the hot water insertion sensor currently has no thermal paste applied, but it's sitting snuggly within its well.
A few observations for the hot water:
- Sensor signal strength is reported as excellent (5 flashes)
- Removing and replacing sensor batteries results in an immediate temp update being reported.
- Temps appear to be reported in consistently largely every hour, but sometimes every couple of hours if no water is being used.
- Temps appear to be reported more frequently when temp is changing significantly - as expected, every 5-10 mins
- However, the overshoots ONLY appear to happen when the water temp doesn't reach the set temp within 5-10 mins of the water heating, our cylinder reheats quickly. So for example, the first temp report after having a shower, occurs within 5-10 mins of starting the shower and the temp reads 54.9, no further temp is reported for 1 HOUR! By which point the water temp reaches the 66-67c, which I guess is the limit possible with the boiler set to 70c.
- If the water is reheat is reached within 5-10 mins, say 55.1, the system works perfectly, within another temp reading reported within 5 mins, the temp creeps to say 57 but otherwise is perfect.
Any help, or guidance would be really appreciated.
Given the temps are being reported, I've not bothered with the thermal paste so far.
The obvious issue is the temp not being reported for an hour whilst re-heating, the moment it's reported the system shuts off etc... perfectly.
This morning, following a couple of showers we've had two consecutive 67c overshoots, yet for the previous 2-3 days things appeared to be working as planned.
This graph shows the overshoots, the green dots show when temp readings are being received. Notice the lack of readings when the temp is climbing above the set point.
Water Graph.jpg
Thanks
Dan
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