I've googled this and it's definitely a flow issue. 

I received this message from a heat pump expert relating to your issue and they say:

• If it's happened after an extended period of no problems then it might be that their strainer is full of debris.
• Seeing as it's happened on a day with milder weather it could be do do with TRVs shutting down maybe if it's a direct system rather than one with a buffer or header.

Flow issues can be very problematic for heat pumps as we've personally discovered. You may have an additional filter/strainer in addition to your magnetic one. We had two, and it was the strainer that was causing dramas. I think the second point is also interesting relating to flow issues caused by TRVs.

Hi Northumberland,

I think that you will find that the E911 fault is being generated by a flow sensor located in the pipework, which is in fact adjustable. Obviously, don't go adjusting the flow sensor to clear the alarm, unless it is incorrectly set.

Do you know if your Samsung unit has variable water pump speed control?

Do you have TRV's installed on your radiators? Do you have a buffer tank or low loss header installed? Do you have a bypass valve installed?

If your system is actually blocking due to the lack of a suitable filter then have a word with MCS, since your system is not fit for purpose.

@editor

Thanks for the reply –

In answer to your questions - I don’t know whether or not it’s a direct system – I do know that it has a smaller tank in the space above the hot water cylinder.

I don’t think it has additional strainers as I’m sure the engineer would have said if it had extra filters. 

The central heating ran brilliantly for first year between 2017 – 2018 .  It runs 24/7 with room temps set usually to 20 – because the cottage faces due south it gets lot of solar gain   

Since then about twice a year it stopped providing the central heating. 

October 2020 I called the installer and my plumber asked to attend as the E911 fault had returned. The following is  the conclusion report from the installer engineer 

Found the heat exchanger blocked at the entrance and had to be flushed. After adding extra pump we had 8lpm flow and after cleaning heat ex we got 32 instantly. Removed extra pump and turned the solo pump down to speed one which now provides 20lmp alone. Would suggest a particle filter is fitted by a plumber to avoid further problems.

The chief engineer (in an office in Oxford – has never been onsite) does not agree that it requires a filter even though his own engineer suggested one be fitted.  If there is no filter fitted then I am required to pay probably twice a year for someone to flush the system as well as having to pay for the annual service.  When it went wrong this last time 1^st November 2021 – I took the cottage off the market as I can’t hire a self catering cottage without heat.  I have managed several times to set it working again – turning the whole system off and then back on again.

What I have noticed is that on the Samsung controller after pressing the reset button it will show the icon for the pump then try to call for the compressor icon  – sometimes it does come on and stays on as does the heating sometimes for a few days and even about two weeks – but at other times it tries to call for the compressor which blinks on once or twice but won’t stay on.  After about three minutes I’m back to the red flashing fault again.  I have not been able to restart it since the beginning of January.

Local electrician has wired up the immersion heater so there is always hot water.   Also checked the magnetic filter which was very clean and had no debris.

@derek-m 

Thanks for coming back to me:

I’m sure it has a flow sensor – after having watched a Samsung video about water flow. 

Sorry – don’t know if it has a variable water pump speed control although I know the water pump has three settings and it’s on the highest setting.

There are no radiators only under floor heating pipes – single story building with room thermostats (4) lounge – bedroom – bathroom – entrance hall.

Hi,

You may wish to share a copy of the attached document with the engineer, if this covers your unit.

He may find the recommendation about cleaning the strainer/filter after the system has been filled and flushed, of interest.

We had a blocked filter which was easy to clear once we knew. Why don't you just get a plumber to fit one? It's a quick job and can be done fairly easily. What's the worst that can happen?

@derek-m Thanks Derek - the engineer is booked (again) for next Thursday 10th Feb 

I appreciate your advice.   

@batalto You're probably right - I have booked the installer engineer plus my own plumber to come on Thursday 10th Feb . 

I do feel as though the public are being misled into thinking heat pumps are the answer to the energy crisis.  Admittedly I ought to have been much more responsible in trying to find out about how they worked instead of assuming (never assume anything) it would solve my problem for heating the cottage - no mains gas - oil being the alternative - very rural situation - used as self catering easy for guests - just needing to use the room thermostats.  How wrong (stupid) can you be.

Obviously it's new technology (or is it ?) what I didn't realise was how difficult it would be to find someone who would come out to a fault. 

Thanks for taking the time to reply

Posted by: @batalto

We had a blocked filter which was easy to clear once we knew. Why don't you just get a plumber to fit one? It's a quick job and can be done fairly easily. What's the worst that can happen?

Hi Batalto,

The point I was making is that the Samsung installation manual refers to cleaning the strainer/filter during the commissioning procedure, which is only possible if one has actually been installed in the first place. Although Samsung appear to consider that a strainer/filter is an important piece of equipment, the installer it would appear thinks otherwise. Strange. 🙄 

Posted by: @northumberland

@batalto You're probably right - I have booked the installer engineer plus my own plumber to come on Thursday 10th Feb . 

I do feel as though the public are being misled into thinking heat pumps are the answer to the energy crisis.  Admittedly I ought to have been much more responsible in trying to find out about how they worked instead of assuming (never assume anything) it would solve my problem for heating the cottage - no mains gas - oil being the alternative - very rural situation - used as self catering easy for guests - just needing to use the room thermostats.  How wrong (stupid) can you be.

Obviously it's new technology (or is it ?) what I didn't realise was how difficult it would be to find someone who would come out to a fault. 

Thanks for taking the time to reply

 

Hi,

The point I am trying to make is that installers should be held to account for poorly designed and installed systems.

@derek-m, as far as I know, and I could be wrong, a strainer should be present on heat pump installations. Much like @northumberland, we had a magnetic filter - it was always clean. The little strainer always has some corrosive bits in it, and this leads to flow issues. I’d be surprised if a strainer wasn’t present on northumberland’s system. Ours was originally in a ghastly location so we had it moved inside the house in the utility room for easy access and cleaning.