Week 23, and all is not well.
It's chuffing cold outside (to readers outside of the UK, that's a local expression used in northern England that makes no sense like many of our expressions) and on far to many occasions it's been bloody cold inside too!.
We've gone from loving the system to fighting it, and fighting it every day since winter arrived towards the end of November. More specifically we're fighting the boiler, however the issues the boiler is having are caused directly by our installation of Evohome as I'll explain. If you're thinking of installing Evohome this might be a useful read that could save you some pain, some unnecessary shivering and potentially some cash too.
Just to top things off in the last couple of days we've had a new hardware fault pop up with the Evohome system, this does not feel like the experience we wanted when we spent a small fortune to "upgrade" our heating which was supposed to save us money in the long run (I'll come back to the money saving part later!) and make our lives more comfortable.
Let's get the hardware fault out of the way before we get into too much detail with the other issues.
Two days ago whilst in the airing cupboard the other half noticed one of the control boxes was displaying a red flashing light. A quick check of the controller and sure enough it's reporting a "Comms Fault".
Until we've got further information I'm assuming this is a hardware error as nothing in the surround area or indeed the house has moved / been installed that would change the comms. In the positions everything is in (the controller being in the next room to the airing cupboard) it's run without issue for the last 23 weeks, so it's hard to see that this could be anything other than a hardware issue at this point in time.
Anyone that's read the other blogs in this series will know we've always had an error message displayed on the hot water, however that has continued to work exactly as it should and has never shown a red flashing light on the control unit. That's not the case here as the heating pump has certainly had it's operation effected and I've had to manually turn it on / off a couple of times since the fault has shown up.
I've contacted our installer to see what they say, hopefully we'll get a more positive response than we ever did around the hot water fault. I'll of course update the blog once I know the root cause and solution. Right now the heating pump seems to just run all of the time (that 100W pump is not saving us money constantly running) and the boiler kicks in and out as needed. Not ideal but at least we're warm.
So hardware issues out of the way let's talk about the day to day battle to keep the house warm which we've not always won, no fun when it minus six outside and you come home from work to find the heating has been off all day.
This will be a longish post so i'll punctuate it with headings to make it easier to digest or quicker to skip through to the bits you might be more interested in. Also at this point i'll also say we're not alone with the issues I'm going to talk about as trawling the various forums on the internet other people have seen the same issue. If I'd found those posts before hand I might had taken a different route to getting the system installed.
How did we get here ?
At the end of September 2017 we had Evohome installed by a Honeywell approved installer, with an investment like this we thought it best to be done by an expert, I also know next to nothing about heating systems so this for us was the best route. You can install the system yourself but our's was not a DIY project. Our installation replaced all of the existing TRV's with the Evohome HR92 motorised radiator values as well as control systems for underfloor heating, hot water and the boiler.
Being the end of summer following installation the boiler was only really taking care of the hot water with very occasional evening tops ups of heat from the central heating. As reported in our other blog posts all was going well and we were really enjoying the new system. However just as we thought we were sailing off into the sunset for a wonderful life with our new heating system the seas began to boil, or actually quite the opposite, they went cold. This is not the dream we were sold.
Something is not quite right
Towards the end of November we started to experience something we'd never seen before with our boiler "non volatile lockout". This fault code soon became far to well known having to reset the boiler with ever increasing frequency.
We started to keep a diary of lock outs to see if we could find a pattern and trace the cause, it seems when the temperatures dropped from around five to six degrees down to about two or three we would have more issues, but it was only very rough data.
The issues range from lock out every few hours to not being able to get it to light for three or four hours at a time. Two boiler engineers have said the issue is due to heat lock out, both having varying theories as to the root cause.
One stated the system was suffering due to a lack of a by pass loop and the whole system would need to be ripped out and reinstalled including most of the pipes (it does have a bypass loop so that's nonsense), the other saying we should not be seeing this issue and perhaps a change to the bypass would help (seems to make more sense).
So Whats The Root Cause ?
It does appear the root cause is indeed a heat lock out caused by the fact the temperature of the water coming back into the boiler is far to hot having hardly reduced in temperature since leaving the boiler. We've not yet measured the out / return temps but we've "proven" this in other ways.
We found when they system was only heating water at the back end of the summer we never had any issues, this has been reported by other people with the same issues.
Whenever the boiler has been off all night it can be reset and will light first time in the mornings, presumably due to the water in the system being cold (so no heat lock out).
We find there are a lot more lock outs when only a few radiators are calling for heat. This makes sense as our boiler is not a modulating boiler so it's all or nothing in terms of the temperature of the water being sent around the system. If it's only going to one or two rooms there is very little in the way of temperature drop meaning the boiler soon gets over heated.
We've also found if we have a situation where we can't get things running this can be resolved by opening up the values on all of the radiators (setting rooms to a higher temp than they are at) and running the pump for fifteen mins. After this the boiler will normal light up as the water has cooled sufficiently to not trip it out.
So How Do We Fix This ?.
It feels like we have both a short and long term option here.
Over the last few days we seem to have found a short term option that seems to work (fingers crossed although writing about it is probably going to cause it to all go wrong). By turning down the boiler temperature and ensuring that almost all of the rooms are set to at least 18 degrees (at the same time), the boiler seems to happily chug along all day without any lock outs. As the pump control is now not working the pump stays on all day and the boiled kicks in and out as needed.
I can't help feeling that in essence what I'm actually doing here is simulating how a traditional TRV works i.e. all rooms heating at the same time. This appears to be working as it's ensuring the returning water to the boiler is much cooler than when it left. It's also proven the heat lock out theory rather than it being a boiler issue.
Longer term it's clear we need a modulating boiler that can turn the temperature of the water up and down as required depending how many radiators are calling for heat. Evohome can run opentherm so it makes sense to find a boiler than can be fully controlled by the system itself using that protocol. This will not only make more efficient use of gas but will also avoid lock outs.
Are we saving money ?
Since installing the system I've noticed the boiler seem to run a lot more than it used to in a "traditional" set up. I'm used to the heating being on in the day / evenings and then off all night until it kicks back on in the early hours to drag the temperature of the hours back up to where it needs to be.
Evohome is always monitoring the temperature so the boiler comes on at all hours to keep the rooms to the temperatures set. Typically it will come on to warm up a room, go off and then be back on twenty mins later to heat the next room calling for heat. This feels like the boiler is on a lot and whilst we have a non modulating boiler this is using quite a bit of gas. As we've only lived here six months we don't have any base line to compare the heating costs against, however it does feel like the gas use is higher than it should be. With the heating pumps also running more than normal there is an extra cost of electricity, we will probably get those changed for more energy efficient ones.
The gas use is around £100 - £125 per month which seems very high given we're on the cheapest tariff that's available. The place is by no means roasting, we've even thought about dropping the old TRV's back into the system to get some baseline comparisons.
I have often wondered if this is really saving saving money due to how much time the boiler is on for, that said it's perhaps on for less when it's on. I do feel if you fit the system to a non modulating boiler you'll probably find the savings are more limited than with a boiler than the self modulate. As with most things like this the savings will vary on individual cases so if you're installing the system you'd need to measure against your own baseline.
Conclusion
Over all we still like the system, being able to easily control the temperature of each room against a schedule that's easily controllable does feel more like living in 2018 than 1988 and that's a good thing. The Alexa integration is still rock solid and gets used a lot in the evenings when we want to nudge the temperature up a few degrees (although for the last few months that's meant a trip to the boiler to check it it's actually on and has not locked out).
The issue seems to be that because we can be calling for so little heat we're asking the boiler to cope with something it was never really designed for and it's finding it hard to cope. Our boiler is 16 years old so it's either on or off, it's unable to modulate as a modern boiler would, therefore I'd suggest if you're considering installing Evohome you check to make sure your boiler is going to be able to cope with the reduced demand that will sometimes be placed on it. Ours is happy when lot's of heat is needed, it's the lower demands that lock it out.
We made almost everyone room it's own zone which probably made the system worse, if you were doing less rooms (or creating bigger zones) then you might be OK. It's perhaps worth simulating this before you do an install by turning down a number of radiators to see how your system copes for a few days.
IF we can get the hardware issues fixed and the new boiler we are considering resolves the issues I'm sure that once again our heating system will become invisible and not be something we ever think about, which is exactly what we want from a system.
Let's see how we get on over the next few weeks, I'll report back as we make what will hopefully be swift progress.
If you have any questions or comments we'd love to hear them in the comments below.
It's chuffing cold outside (to readers outside of the UK, that's a local expression used in northern England that makes no sense like many of our expressions) and on far to many occasions it's been bloody cold inside too!.
It's chuffing cold outside, yes that is a local expression.
We've gone from loving the system to fighting it, and fighting it every day since winter arrived towards the end of November. More specifically we're fighting the boiler, however the issues the boiler is having are caused directly by our installation of Evohome as I'll explain. If you're thinking of installing Evohome this might be a useful read that could save you some pain, some unnecessary shivering and potentially some cash too.
Just to top things off in the last couple of days we've had a new hardware fault pop up with the Evohome system, this does not feel like the experience we wanted when we spent a small fortune to "upgrade" our heating which was supposed to save us money in the long run (I'll come back to the money saving part later!) and make our lives more comfortable.
Let's get the hardware fault out of the way before we get into too much detail with the other issues.
Two days ago whilst in the airing cupboard the other half noticed one of the control boxes was displaying a red flashing light. A quick check of the controller and sure enough it's reporting a "Comms Fault".
Until we've got further information I'm assuming this is a hardware error as nothing in the surround area or indeed the house has moved / been installed that would change the comms. In the positions everything is in (the controller being in the next room to the airing cupboard) it's run without issue for the last 23 weeks, so it's hard to see that this could be anything other than a hardware issue at this point in time.
Anyone that's read the other blogs in this series will know we've always had an error message displayed on the hot water, however that has continued to work exactly as it should and has never shown a red flashing light on the control unit. That's not the case here as the heating pump has certainly had it's operation effected and I've had to manually turn it on / off a couple of times since the fault has shown up.
I've contacted our installer to see what they say, hopefully we'll get a more positive response than we ever did around the hot water fault. I'll of course update the blog once I know the root cause and solution. Right now the heating pump seems to just run all of the time (that 100W pump is not saving us money constantly running) and the boiler kicks in and out as needed. Not ideal but at least we're warm.
Above: Flashing red lights are never good when it comes to home automation.
Above: Houston, we have a problem.
So hardware issues out of the way let's talk about the day to day battle to keep the house warm which we've not always won, no fun when it minus six outside and you come home from work to find the heating has been off all day.
This will be a longish post so i'll punctuate it with headings to make it easier to digest or quicker to skip through to the bits you might be more interested in. Also at this point i'll also say we're not alone with the issues I'm going to talk about as trawling the various forums on the internet other people have seen the same issue. If I'd found those posts before hand I might had taken a different route to getting the system installed.
How did we get here ?
At the end of September 2017 we had Evohome installed by a Honeywell approved installer, with an investment like this we thought it best to be done by an expert, I also know next to nothing about heating systems so this for us was the best route. You can install the system yourself but our's was not a DIY project. Our installation replaced all of the existing TRV's with the Evohome HR92 motorised radiator values as well as control systems for underfloor heating, hot water and the boiler.
Being the end of summer following installation the boiler was only really taking care of the hot water with very occasional evening tops ups of heat from the central heating. As reported in our other blog posts all was going well and we were really enjoying the new system. However just as we thought we were sailing off into the sunset for a wonderful life with our new heating system the seas began to boil, or actually quite the opposite, they went cold. This is not the dream we were sold.
Something is not quite right
Towards the end of November we started to experience something we'd never seen before with our boiler "non volatile lockout". This fault code soon became far to well known having to reset the boiler with ever increasing frequency.
Above: The reset switch that we've become very familiar with.
The issues range from lock out every few hours to not being able to get it to light for three or four hours at a time. Two boiler engineers have said the issue is due to heat lock out, both having varying theories as to the root cause.
One stated the system was suffering due to a lack of a by pass loop and the whole system would need to be ripped out and reinstalled including most of the pipes (it does have a bypass loop so that's nonsense), the other saying we should not be seeing this issue and perhaps a change to the bypass would help (seems to make more sense).
So Whats The Root Cause ?
It does appear the root cause is indeed a heat lock out caused by the fact the temperature of the water coming back into the boiler is far to hot having hardly reduced in temperature since leaving the boiler. We've not yet measured the out / return temps but we've "proven" this in other ways.
We found when they system was only heating water at the back end of the summer we never had any issues, this has been reported by other people with the same issues.
Whenever the boiler has been off all night it can be reset and will light first time in the mornings, presumably due to the water in the system being cold (so no heat lock out).
We find there are a lot more lock outs when only a few radiators are calling for heat. This makes sense as our boiler is not a modulating boiler so it's all or nothing in terms of the temperature of the water being sent around the system. If it's only going to one or two rooms there is very little in the way of temperature drop meaning the boiler soon gets over heated.
We've also found if we have a situation where we can't get things running this can be resolved by opening up the values on all of the radiators (setting rooms to a higher temp than they are at) and running the pump for fifteen mins. After this the boiler will normal light up as the water has cooled sufficiently to not trip it out.
So How Do We Fix This ?.
It feels like we have both a short and long term option here.
Over the last few days we seem to have found a short term option that seems to work (fingers crossed although writing about it is probably going to cause it to all go wrong). By turning down the boiler temperature and ensuring that almost all of the rooms are set to at least 18 degrees (at the same time), the boiler seems to happily chug along all day without any lock outs. As the pump control is now not working the pump stays on all day and the boiled kicks in and out as needed.
I can't help feeling that in essence what I'm actually doing here is simulating how a traditional TRV works i.e. all rooms heating at the same time. This appears to be working as it's ensuring the returning water to the boiler is much cooler than when it left. It's also proven the heat lock out theory rather than it being a boiler issue.
Longer term it's clear we need a modulating boiler that can turn the temperature of the water up and down as required depending how many radiators are calling for heat. Evohome can run opentherm so it makes sense to find a boiler than can be fully controlled by the system itself using that protocol. This will not only make more efficient use of gas but will also avoid lock outs.
Are we saving money ?
Since installing the system I've noticed the boiler seem to run a lot more than it used to in a "traditional" set up. I'm used to the heating being on in the day / evenings and then off all night until it kicks back on in the early hours to drag the temperature of the hours back up to where it needs to be.
Evohome is always monitoring the temperature so the boiler comes on at all hours to keep the rooms to the temperatures set. Typically it will come on to warm up a room, go off and then be back on twenty mins later to heat the next room calling for heat. This feels like the boiler is on a lot and whilst we have a non modulating boiler this is using quite a bit of gas. As we've only lived here six months we don't have any base line to compare the heating costs against, however it does feel like the gas use is higher than it should be. With the heating pumps also running more than normal there is an extra cost of electricity, we will probably get those changed for more energy efficient ones.
The gas use is around £100 - £125 per month which seems very high given we're on the cheapest tariff that's available. The place is by no means roasting, we've even thought about dropping the old TRV's back into the system to get some baseline comparisons.
I have often wondered if this is really saving saving money due to how much time the boiler is on for, that said it's perhaps on for less when it's on. I do feel if you fit the system to a non modulating boiler you'll probably find the savings are more limited than with a boiler than the self modulate. As with most things like this the savings will vary on individual cases so if you're installing the system you'd need to measure against your own baseline.
Conclusion
Over all we still like the system, being able to easily control the temperature of each room against a schedule that's easily controllable does feel more like living in 2018 than 1988 and that's a good thing. The Alexa integration is still rock solid and gets used a lot in the evenings when we want to nudge the temperature up a few degrees (although for the last few months that's meant a trip to the boiler to check it it's actually on and has not locked out).
The issue seems to be that because we can be calling for so little heat we're asking the boiler to cope with something it was never really designed for and it's finding it hard to cope. Our boiler is 16 years old so it's either on or off, it's unable to modulate as a modern boiler would, therefore I'd suggest if you're considering installing Evohome you check to make sure your boiler is going to be able to cope with the reduced demand that will sometimes be placed on it. Ours is happy when lot's of heat is needed, it's the lower demands that lock it out.
We made almost everyone room it's own zone which probably made the system worse, if you were doing less rooms (or creating bigger zones) then you might be OK. It's perhaps worth simulating this before you do an install by turning down a number of radiators to see how your system copes for a few days.
IF we can get the hardware issues fixed and the new boiler we are considering resolves the issues I'm sure that once again our heating system will become invisible and not be something we ever think about, which is exactly what we want from a system.
Let's see how we get on over the next few weeks, I'll report back as we make what will hopefully be swift progress.
If you have any questions or comments we'd love to hear them in the comments below.
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