Samsung Air Source Heat Pump

[athlonoc]

My ASHP has been set to 55 degrees C for the legionella in the control panel but I thought it had to be set to 60.
Engineer seemed to think this is ok.

I note that in 6 weeks I have had error E919 which is telling me the unit couldn't perform the correct heat for legionella thus the error code.
However it's set lower than I though and I have checked the thermostat probe that goes into the Joule tank to make sure it's seated right into it and checked the immersion heater is set to maximum.

It doesn't seem right that the error if frequent and always after the Tuesday night legionella process even though it's not being asked to get to 60 like I thought.

Q - Is 55 degrees C acceptable or MUST this be 60 degrees C for it to kill off Legionella bacteria.

Q - If the above is ok and knowing I've checked the probe into the tank and checked the dial on the emersion heater is correct what would cause the constant error for not getting to temp in the allotted time? Is it possible that the thermostat is faulty?

Thanks

 

[Chuck]

There's no simple formula when it comes to legionella. All the regulations I'm aware of are risk-based. If the 55 °C system is being tested periodically it'll likely be okay. 60 °C lowers the risk enough that in a domestic system regular testing is not usually considered necessary. Further details here:

HSE - Legionnaires' disease - Risk systems - Hot and cold water systems

The maintenance of a water system in a clean state is an important part of managing the risk from legionella.

www.hse.gov.uk

 

[oz-plumber]

Check the specs of the unit.
The unit may throw a fault code if the temperature isn't 60C or above.

Basic specs on Legionella kill times:

65C - 2 minutes
60C - 32 minutes
55C - 6 hours

Don't know of any manufacturers that would recommend 55C for Legionella kill.
Most I've dealt with state 65C

 

[athlonoc]

Check the specs of the unit.
The unit may throw a fault code if the temperature isn't 60C or above.

Basic specs on Legionella kill times:

65C - 2 minutes
60C - 32 minutes
55C - 6 hours

Don't know of any manufacturers that would recommend 55C for Legionella kill.
Most I've dealt with state 65C

The plumber has been back to see the unit.

It's a Samsung Rev. G6 R32 12kW with Joule 250L tank.
See attached pictures.

Plumber states it doesn't allow in the control panel to set temp higher than 55C for legionella

Is the error coming because the system doesn't hit the correct temp in a specified amount of time?
Is there a way to increase that time and or raise the temperature?

The daily temp is set at 53C and from what I've been told once it drops 5C below that target temp of 53C it will heat up the tank.

Any thoughts on whether something is being missed here with my set up?

 

[snowhead]

The cause of the error will be not reaching Temp for the whole of the required time.
So either actual Temp not high enough at all,
Or temp not high enough for the whole of the time required.

Has the immersion heater been checked to see if it's actually producing heat (drawing current)?

Is something else happening in the house to reduce the water temp on Tuesday, like everyone going to the Gym and coming back and showering?
Is the Hot water noticeably hotter the morning after the Legionella Control period?

Have you tried changing the day / time of the control period?

 

[athlonoc]

The cause of the error will be not reaching Temp for the whole of the required time.
So either actual Temp not high enough at all,
Or temp not high enough for the whole of the time required.

Has the immersion heater been checked to see if it's actually producing heat (drawing current)?

Is something else happening in the house to reduce the water temp on Tuesday, like everyone going to the Gym and coming back and showering?
Is the Hot water noticeably hotter the morning after the Legionella Control period?

Have you tried changing the day / time of the control period?

Thank you for the above.

Immersion not been checked apart from setting on the immersion which is as far over on the + symbol as it can go and the probe is fitted as far in as it can go. I accept that doesn't mean its working correctly though.

There are just two of us. One showers for less than a minute in the morning and the other for 3 or 4 minutes in the early evening. Rarely have a bath to draw copious amounts of water at any given time.

I think the water seems hotter after the Tuesday late night immersion period.

I can see the usage on Tuesday averages 20kW compared to the rest of the week where they collectively amount to 15kW on average.

Not tried changing the day / time. I guess I could give that a go myself.

Thank you again for helping to understand the issue.

 

[athlonoc]

I've just looked at the disinfection settings and they are set as follows
Start Time 0 hour ( I assume that is midnight ) of the day it's set to which is Tuesday?
Target Temp 55C ( it does go to 70C ) Not sure why plumber said it couldn't go higher )
Duration - 60 min
Maximum Time - 8 Hours ( Not sure what that implies )

 

[Chuck]

Maximum Time - 8 Hours ( Not sure what that implies )

You'll need to read the manufacturer's instructions to be sure but it is most likely the maximum time the unit will spend trying to achieve the target temperature for disinfection before giving up and registering an error code.

I suspect that your plumber discovered that the system could only just get to 55°C and that setting the target higher resulted in lots of fault codes. Setting the target to 55°C meant that it usually managed but, as you have noticed, not always.

In your position I'd be suspecting a faulty unit and would be asking the manufacturer for a service call.

 

[Nacnud]

ed to see if it's actually producing heat (draw

I've just looked at the disinfection settings and they are set as follows
Start Time 0 hour ( I assume that is midnight ) of the day it's set to which is Tuesday?
Target Temp 55C ( it does go to 70C ) Not sure why plumber said it couldn't go higher )
Duration - 60 min
Maximum Time - 8 Hours ( Not sure what that implies )

did you get anywhere with this? I have exactly the same issue

 

[George Payne]

I have a related issue, from which I have found that the maximum tank temp for normal heating is 55 degrees. This is the limit on the Samsung control unit (field setting 3021), the pump is supposed to be capable of 70 degrees, but there is no way of setting this. I am currently playing with the legionella settings to see if I can use this as a normal daily heating function. I’m equally puzzled by the settings noted by Athlonoc. Start time setting is hours, we’ll see if setting it to 3 hours starts it a 3a.m. The control unit interface is really clunky and old fashioned, with all the Samsung technology resting on this they should be doing much better.

 

[oz-plumber]

Contact the Manufacturer and or Supplier of Heat Pump - and hound the **** out of them for a solution.

We've actually stopped installing them - too many problems, no product / manufacturer support.
Don't perform as per specs and so on.
Even done systems as per 'recommended suppliers specs' and still have issues.

Will they replace unit - no - prefer to leave customer with inadequate hot water or heating and hope the problem goes away.

 

[Ant87]

I have a related issue, from which I have found that the maximum tank temp for normal heating is 55 degrees. This is the limit on the Samsung control unit (field setting 3021), the pump is supposed to be capable of 70 degrees, but there is no way of setting this. I am currently playing with the legionella settings to see if I can use this as a normal daily heating function. I’m equally puzzled by the settings noted by Athlonoc. Start time setting is hours, we’ll see if setting it to 3 hours starts it a 3a.m. The control unit interface is really clunky and old fashioned, with all the Samsung technology resting on this they should be doing much better.

Hi George,

The normal temperature of the cylinder would be 55degC maximum, which will likely require some immersion heater input.
A cylinder set to 70degC would be all from the immersion heater and would cost an obscene amount of money to maintain. (Unless it is the new HT unit which I believe is slightly more capable at higher temperatures).
It would be far more economical to set the cylinder at 50degC for every day use and disinfection once a week at 60-65degC for the appropriate time.

Disinfection start time is in hours so "3" would be 3am and so on.

Thanks