Fault on Kingspan Air Source Heat Pump

[philiom]

We have a customer with 2 - 15kw Air Source Heat Pumps Model KHP0042, getting 9 flashes on pcb indicating flow switch issues, the only way it will restart is to turn of all power then it starts up for 5 - hrs and goes back to 9 flashes

We had a similar fault about 30 months ago and we replaced the flow switches and it worked fine, tried new flow switches this time and it still has the same fault, when we had the fault the last time I could ring Kingspan technical for help, unfortunately they stopped supplying them and the tech help stopped, would appreciate any help or guidance.

[ProDave]

The obvious question is are you sure the flow rate is high enough? if it's only just enough to trip the flow switch it could be unreliable.  Faster pump speed?

[Jeremy Harris]

Welcome to Buildhub.

 

As you've probably found out by now, Kingspan didn't ever manufacture these heat pumps and, like Glowworm, who also re-badged the same Carrier range of heat pumps, their technical support wasn't great (but better than Glowworm, I think - they didn't seem to have a clue about "their" product - I bought one of the last old stock ones they had very cheaply).  The good news is that the heat pumps are made by Carrier, one of the world's largest heat pump manufacturers, so all the technical guidance from Carrier will apply equally to to these re-badged "Kingspan" models.

 

The LED diagnostic thing is pretty crude, and you can get a lot more information by using the Command Unit display.  Unfortunately, Kingspan chose not to use the Carrier Command Unit, but instead just used an extension of the diagnostic LED that's on the main PCB, and frankly that isn't a great deal of help in tracking down the real problem.

 

As a general rule, flow related errors are usually down to a restriction in the system somewhere.  With the Command Unit the display will indicate this, and show the unit trying to restart, encountering a flow error, shutting down, then trying another restart a minute or so later.  I had this fault on my system initially, because with the buffer tank/hot water tank valve closed and the thermal actuators on the UFH being slow to open (they take around 5 minutes or so to open) the flow resistance would be too great and the unit would stop with a flow error.  In my case the fix was to use a normal boiler-type adjustable pressure bypass valve directly across the ASHP flow and return and then adjust this so it would just open when all the house-side valves were closed, so reducing the flow resistance and avoiding the flow error.  As soon as the UFH valve or tank valve opened the bypass valve closes, as the flow pressure drops.  This works a treat.

 

You might want to have a read of this thread, as there are some documents and info there that may be of help:

 

 

[philiom]

26 minutes ago, ProDave said:

The obvious question is are you sure the flow rate is high enough? if it's only just enough to trip the flow switch it could be unreliable.  Faster pump speed?

Hi Dave, thanks for the prompt response, the pump speeds are on maximum, When it happened 30 months ago we did change the auto by-pass before we changed the flow switches but it turned out to be the flow switches , that is something I could look at, not sure if the pumps them selves are slowing down, I have measure the resistance and am going to get onto Grundfoss, the air source units were fitted in 2012, I have a controller we can set up and see what is happening.

[philiom]

41 minutes ago, JSHarris said:

Welcome to Buildhub.

 

As you've probably found out by now, Kingspan didn't ever manufacture these heat pumps and, like Glowworm, who also re-badged the same Carrier range of heat pumps, their technical support wasn't great (but better than Glowworm, I think - they didn't seem to have a clue about "their" product - I bought one of the last old stock ones they had very cheaply).  The good news is that the heat pumps are made by Carrier, one of the world's largest heat pump manufacturers, so all the technical guidance from Carrier will apply equally to to these re-badged "Kingspan" models.

 

The LED diagnostic thing is pretty crude, and you can get a lot more information by using the Command Unit display.  Unfortunately, Kingspan chose not to use the Carrier Command Unit, but instead just used an extension of the diagnostic LED that's on the main PCB, and frankly that isn't a great deal of help in tracking down the real problem.

 

As a general rule, flow related errors are usually down to a restriction in the system somewhere.  With the Command Unit the display will indicate this, and show the unit trying to restart, encountering a flow error, shutting down, then trying another restart a minute or so later.  I had this fault on my system initially, because with the buffer tank/hot water tank valve closed and the thermal actuators on the UFH being slow to open (they take around 5 minutes or so to open) the flow resistance would be too great and the unit would stop with a flow error.  In my case the fix was to use a normal boiler-type adjustable pressure bypass valve directly across the ASHP flow and return and then adjust this so it would just open when all the house-side valves were closed, so reducing the flow resistance and avoiding the flow error.  As soon as the UFH valve or tank valve opened the bypass valve closes, as the flow pressure drops.  This works a treat.

 

You might want to have a read of this thread, as there are some documents and info there that may be of help:

 

 

 

41 minutes ago, JSHarris said:

Welcome to Buildhub.

 

As you've probably found out by now, Kingspan didn't ever manufacture these heat pumps and, like Glowworm, who also re-badged the same Carrier range of heat pumps, their technical support wasn't great (but better than Glowworm, I think - they didn't seem to have a clue about "their" product - I bought one of the last old stock ones they had very cheaply).  The good news is that the heat pumps are made by Carrier, one of the world's largest heat pump manufacturers, so all the technical guidance from Carrier will apply equally to to these re-badged "Kingspan" models.

 

The LED diagnostic thing is pretty crude, and you can get a lot more information by using the Command Unit display.  Unfortunately, Kingspan chose not to use the Carrier Command Unit, but instead just used an extension of the diagnostic LED that's on the main PCB, and frankly that isn't a great deal of help in tracking down the real problem.

 

As a general rule, flow related errors are usually down to a restriction in the system somewhere.  With the Command Unit the display will indicate this, and show the unit trying to restart, encountering a flow error, shutting down, then trying another restart a minute or so later.  I had this fault on my system initially, because with the buffer tank/hot water tank valve closed and the thermal actuators on the UFH being slow to open (they take around 5 minutes or so to open) the flow resistance would be too great and the unit would stop with a flow error.  In my case the fix was to use a normal boiler-type adjustable pressure bypass valve directly across the ASHP flow and return and then adjust this so it would just open when all the house-side valves were closed, so reducing the flow resistance and avoiding the flow error.  As soon as the UFH valve or tank valve opened the bypass valve closes, as the flow pressure drops.  This works a treat.

 

You might want to have a read of this thread, as there are some documents and info there that may be of help:

 

 

To GS Harris, thanks for the prompt reply, As I said to Dave we are going to try a few things on the system, you mention the controller, I have attached a pic of the controller and will try it on the 2 units.

[Jeremy Harris]

That Carrier Command Unit is very useful, damned pity that Kingspan didn't supply it as standard with their version, as Glowworm did with their re-badged version of the same unit.  I was lucky, and had the Command Unit supplied with my heat pump, and it's proved invaluable in getting the settings adjusted to better suit the UK climate, amongst other things.

 

Is there a filter or strainer on the return to the ASHP as there should be?  Just wondering if that may be partially clogged and reducing the flow enough to trigger the fault condition.  Carrier recommend a Y strainer on the return, not sure what Kingspan recommended, but Glowworm just followed the Carrier recommendation in their MIs.

[philiom]

15 minutes ago, JSHarris said:

That Carrier Command Unit is very useful, damned pity that Kingspan didn't supply it as standard with their version, as Glowworm did with their re-badged version of the same unit.  I was lucky, and had the Command Unit supplied with my heat pump, and it's proved invaluable in getting the settings adjusted to better suit the UK climate, amongst other things.

 

Is there a filter or strainer on the return to the ASHP as there should be?  Just wondering if that may be partially clogged and reducing the flow enough to trigger the fault condition.  Carrier recommend a Y strainer on the return, not sure what Kingspan recommended, but Glowworm just followed the Carrier recommendation in their MIs.

The filters have been checked and clean ( they are on the return),  its was a complete brand new system, one thing that had happened was the safety valves were passing and this was traced to the filling loop left switched on accidentally by the owner, it has lost all of its anti-freeze (Fernox HE15c) but dont think this is related to the problem with the flow, we have to reinstall fresh anti freeze, unless you think otherwise?

All the radiators were sized for the temp of the air source and the cylinder came from Kingspan. The pumps are Grundfos UPS 32-870 180 and a new Honeywell By-pass was replaced when we had the issue with the flow switches about 30 months ago.

[Jeremy Harris]

It definitely needs antifreeze if the units are ever switched off in cold weather, as there isn't a lot of insulation internally around the primary circuit to water PHE (at least there isn't in mine, it's just wrapped with maybe 25mm of neoprene inside the case).

 

I can't see how losing the antifreeze/inhibitor would cause this problem, either, the filter(s) would tend to show if there was any potential corrosion product problem.  If the pressure bypass is working, and was replaced anyway, it's unlikely to be that, either.

 

There's a pressure switch on the flow side, inside the unit, that triggers the over-pressure warning on the Command Unit (lower left caution caption, then flip through the diagnostic sequences on the Command Unit to find the code). 

 

Alternatively, have you tried looking at the diagnostic LEDs on the main board inside the unit itself?  There are a couple of DIP switches and a series of surface mounts LEDs, and there are two levels of diagnostic info available from the LED sequences.  This photo nicked from the other thread shows the LEDs and DIP switches:

 

 

and page 23 of the installation manual gives the codes:

 

 

My guess is that you may have been through this process already - apologies if it sounds like I'm teaching grandmother to suck eggs, just trying to cover all the bases that I'm aware of (and bear in mind my knowledge was gained from installing and then reverse engineering how the unit works, as I use mine for cooling as well as heating, something that neither Kingspan or Glowworm refer to, but Carrier confirmed that the units are fully bidirectional).

 

The photo shows the "case thermostat operation" which is a bit confusing by it indicates that the flow temperature, as measured internally, has reached the set point.  Unfortunately this isn't a useful indication, as it will show that initial code when the unit has tripped because of a low flow condition - in essence the internal side is up to the set temperature even though that may be because the flow is restricted.

 

 

[philiom]

50 minutes ago, JSHarris said:

That Carrier Command Unit is very useful, damned pity that Kingspan didn't supply it as standard with their version, as Glowworm did with their re-badged version of the same unit.  I was lucky, and had the Command Unit supplied with my heat pump, and it's proved invaluable in getting the settings adjusted to better suit the UK climate, amongst other things.

 

Is there a filter or strainer on the return to the ASHP as there should be?  Just wondering if that may be partially clogged and reducing the flow enough to trigger the fault condition.  Carrier recommend a Y strainer on the return, not sure what Kingspan recommended, but Glowworm just followed the Carrier recommendation in their MIs.

 

7 minutes ago, JSHarris said:

It definitely needs antifreeze if the units are ever switched off in cold weather, as there isn't a lot of insulation internally around the primary circuit to water PHE (at least there isn't in mine, it's just wrapped with maybe 25mm of neoprene inside the case).

 

I can't see how losing the antifreeze/inhibitor would cause this problem, either, the filter(s) would tend to show if there was any potential corrosion product problem.  If the pressure bypass is working, and was replaced anyway, it's unlikely to be that, either.

 

There's a pressure switch on the flow side, inside the unit, that triggers the over-pressure warning on the Command Unit (lower left caution caption, then flip through the diagnostic sequences on the Command Unit to find the code). 

 

Alternatively, have you tried looking at the diagnostic LEDs on the main board inside the unit itself?  There are a couple of DIP switches and a series of surface mounts LEDs, and there are two levels of diagnostic info available from the LED sequences.  This photo nicked from the other thread shows the LEDs and DIP switches:

 

 

and page 23 of the installation manual gives the codes:

 

 

My guess is that you may have been through this process already - apologies if it sounds like I'm teaching grandmother to suck eggs, just trying to cover all the bases that I'm aware of (and bear in mind my knowledge was gained from installing and then reverse engineering how the unit works, as I use mine for cooling as well as heating, something that neither Kingspan or Glowworm refer to, but Carrier confirmed that the units are fully bidirectional).

 

 

Thanks for the info, really appreciate yours and Daves input. I have only been reading the flashes (9) on the red led on the board, I am a heating engineer so don't get too involved with the units themselves I usually get someone who knows how the internals work, I think its an external problem as the same fault is occurring on both units and I can't see two identical parts failing on two separate units at the same time.

[Onoff]

Numpty know nothing here....

 

If you've lost the anti freeze in the system as in liquid volume, could that in effect give rise to a LOW pressure fault, something the system doesn't detect as such?

[Jeremy Harris]

33 minutes ago, philiom said:

 

Thanks for the info, really appreciate yours and Daves input. I have only been reading the flashes (9) on the red led on the board, I am a heating engineer so don't get too involved with the units themselves I usually get someone who knows how the internals work, I think its an external problem as the same fault is occurring on both units and I can't see two identical parts failing on two separate units at the same time.

 

 

A word of caution if you want to gain access to the main boards - there are live mains terminals that can be very easily touched, even by the outer cover as it's being removed (ask me how I found this out!) so always best to isolate the power, then take the covers off, then power the units back up.  The area around the diagnostic LEDs and DIP switches is pretty safe, as it's mainly low voltage DC stuff in that area, it's just the poor protection around the mains power connections that's  a potential gotcha (pun intended....).  Quite why Carrier didn't just fit insulating shields over the exposed terminals is beyond me, as they really are very easy to accidentally touch, and the unit has to be powered up with the cover off to access the diagnostic LEDs.

[philiom]

26 minutes ago, Onoff said:

Numpty know nothing here....

 

If you've lost the anti freeze in the system as in liquid volume, could that in effect give rise to a LOW pressure fault, something the system doesn't detect as such?

Hi, The system is not empty, its just got water in at the moment and its at 1.3 bar

[philiom]

21 minutes ago, JSHarris said:

 

 

A word of caution if you want to gain access to the main boards - there are live mains terminals that can be very easily touched, even by the outer cover as it's being removed (ask me how I found this out!) so always best to isolate the power, then take the covers off, then power the units back up.  The area around the diagnostic LEDs and DIP switches is pretty safe, as it's mainly low voltage DC stuff in that area, it's just the poor protection around the mains power connections that's  a potential gotcha (pun intended....).  Quite why Carrier didn't just fit insulating shields over the exposed terminals is beyond me, as they really are very easy to accidentally touch, and the unit has to be powered up with the cover off to access the diagnostic LEDs.

I know I had the cover off a few times and know what you mean about the terminals!!

[SteamyTea]

Re the Command Unit, I know that @joe90 got one 'from near Southampton.

Carrier have an office in Leatherhead, so it may have been there.

http://www.carrieraircon.co.uk/contact-us/

 

Just spent 5 minutes being shunted around a phone system.

The man to talk to is down my way, almost.

Michael Opie, Plymouth.  01752 753200

 

There seems to be some confusion as Carrier and now Carrier-Toshiba and the phone system is just dreadful.

 

Good luck with it all.

 

Edited April 9, 2018 by SteamyTea

[philiom]

22 hours ago, SteamyTea said:

Re the Command Unit, I know that @joe90 got one 'from near Southampton.

Carrier have an office in Leatherhead, so it may have been there.

http://www.carrieraircon.co.uk/contact-us/

 

Just spent 5 minutes being shunted around a phone system.

The man to talk to is down my way, almost.

Michael Opie, Plymouth.  01752 753200

 

There seems to be some confusion as Carrier and now Carrier-Toshiba and the phone system is just dreadful.

 

Good luck with it all.

 

Thanks!

[philiom]

On 4/9/2018 at 12:02, JSHarris said:

 

 

A word of caution if you want to gain access to the main boards - there are live mains terminals that can be very easily touched, even by the outer cover as it's being removed (ask me how I found this out!) so always best to isolate the power, then take the covers off, then power the units back up.  The area around the diagnostic LEDs and DIP switches is pretty safe, as it's mainly low voltage DC stuff in that area, it's just the poor protection around the mains power connections that's  a potential gotcha (pun intended....).  Quite why Carrier didn't just fit insulating shields over the exposed terminals is beyond me, as they really are very easy to accidentally touch, and the unit has to be powered up with the cover off to access the diagnostic LEDs.

I have just had a thought about the issue of the possible flow problems, each pump has a 1 1/4" non return valve, it is a flap type unit as I have never seen the plastic internal one lasting very long. As there has been fresh water running through it, it may have caused the valves to stop moving fully, they are made of Gun Metal. Its something I will have to check, also it maybe the Honeywell auto by-pass needing a bit of adjustment, as you can imagine with having 2 - 15kw units it was not practical to use  the three port valves, there are 4 zones ( 3 for heating and 1 for hot water) so its a big S plan (Honeywell Zone valves) and the microswitches in the valves are using the low voltage to switch the ASHP, it has all worked fine until now and its puzzling!!  

[Jeremy Harris]

FWIW, I found that adjusting the bypass on our system was a bit fiddly.  Setting it a fraction to high causes a flow error and shutdown, setting it a fraction too low and it bypasses when it should be allowing the  flow and return to go via their selected circuits.  I think I spent a good hour, adjusting the bypass, monitoring the start up behaviour on the Command Unit, checking that the bypass wasn't letting by once the UFH valves had opened, then repeating the exercise until the setting was spot on.  I can't remember the make of bypass valve I fitted, but one useful thing about it was that it made a distinct "click" as it closed, which helped a lot when trying to get the pressure set.

[philiom]

13 hours ago, JSHarris said:

FWIW, I found that adjusting the bypass on our system was a bit fiddly.  Setting it a fraction to high causes a flow error and shutdown, setting it a fraction too low and it bypasses when it should be allowing the  flow and return to go via their selected circuits.  I think I spent a good hour, adjusting the bypass, monitoring the start up behaviour on the Command Unit, checking that the bypass wasn't letting by once the UFH valves had opened, then repeating the exercise until the setting was spot on.  I can't remember the make of bypass valve I fitted, but one useful thing about it was that it made a distinct "click" as it closed, which helped a lot when trying to get the pressure set.

I know what you mean, its a fiddly job, been trying to think of a system that would open a zone valve to act as a bypass but the crossover time may be too short. 

[Jeremy Harris]

39 minutes ago, philiom said:

I know what you mean, its a fiddly job, been trying to think of a system that would open a zone valve to act as a bypass but the crossover time may be too short. 

 

One option (although not  great one in my view) is to fit a low loss header in place of the bypass.  The snag is that they work very well when there is a relatively high temperature differential between flow and return, as with a boiler system, but there will be an increased tendency for flow and return to mix in the LLH as the temperature differential drops.  Having said that, some types of LLH have, I believe, been optimised to work reasonably well at the sort of temperature differential you might get with an ASHP, and a LLH does have the advantages of needing no adjustments and being maintenance free, so from an installer's perspective they look attractive.  The small loss of heat pump efficiency as the system/house comes up towards target temperature and the flow and return start to mix in the LLH may be a price worth paying if it fixes the flow problem.

[philiom]

5 hours ago, JSHarris said:

 

One option (although not  great one in my view) is to fit a low loss header in place of the bypass.  The snag is that they work very well when there is a relatively high temperature differential between flow and return, as with a boiler system, but there will be an increased tendency for flow and return to mix in the LLH as the temperature differential drops.  Having said that, some types of LLH have, I believe, been optimised to work reasonably well at the sort of temperature differential you might get with an ASHP, and a LLH does have the advantages of needing no adjustments and being maintenance free, so from an installer's perspective they look attractive.  The small loss of heat pump efficiency as the system/house comes up towards target temperature and the flow and return start to mix in the LLH may be a price worth paying if it fixes the flow problem.

I cant see the customer wanting to pay up for that, its worked fine for 5 years and now its a problem, there going to say its down to me if we suggested that, space is not great either.

[Jeremy Harris]

It's certainly hard to think of something that could happen after five years to cause this.  I reckon that going through the diagnostics using the Command Unit connected might be the best way to track down the sequence that's causing the flow error shutdown.  One problem is that the final errors shown on the diagnostic LEDs may not be the actual cause, as one fault can lead to other error messages due to the knock on effects it creates.

 

The big problem is that if it takes 5 hours of running before the thing throws an error and shutdown, you could be there for ages trying to track it down.  The fact that it's affecting two units at the same time seems really odd, too, and makes me wonder whether it's something other than the heat pumps that's causing the fault.  Equally odd is that when the error occurred 30 months ago you had to replace two flow switches to fix it, it seems a heck of a coincidence for two to fail together.

 

Any chance of a system diagram to try and have a look at what might possibly be the root cause of this?

[SteamyTea]

Has anyone managed to track down a supply of Command Units yet?  Be a useful resource for the Kingspans.