Kingspan heating (or lack of) issue

[Lynford]

Jeremy, I was just looking through the manual to try and learn how to manage to interpret the LED faults. It says about having Display 1 & Display 2 >> I read my fault as being something to do with the compressor or in that section anyway ? Then I’d need to press Sw800 to drill down further ?

 

Off

Off

On

Off

On

On

 

Or am I miles off the mark ? Sorry for all the questions !

 

 

Edited February 18, 2018 by Lynford
Spelling error

[Jeremy Harris]

If it were a compressor problem then the diagnostic LED inside would be flashing a code, as would the red LED on the board.  The manuals are confusing, probably because the heat pump is made by Carrier and the manual has been produced by Kingspan, and if Kingspan are like Glowworm, who use the same Carrier heat pumps with their name on, then back when this was installed there wasn't much technical expertise around.  Things may be better now, but I found it hard to get firm data.  This is a snapshot from the manual I have for the Kingspan Aeromax series:

 

That gives the error as being the one where the flow pressure is too high, and that fits with having radiators with TRVs perfectly, and it matches my experience of having this same error many times originally on our unit, until I fitted the pressure bypass.

 

[Lynford]

Gotcha, thanks Jeremy. The thing that confused me was that the error I got was before pressing SW800 (and I didn’t realise I needed to press the button to get another message) Your experience plus the lack of a flashing LED on the board / diagnostic box makes perfect sense. 

 

I think I’ll go up there again today to see what happens with the TRVs open, and if it faults out I can press SW800 for possibly more info. 

 

Thanks for for bearing with me,

Cheers. 

[Jeremy Harris]

I'm not entirely sure all the manual information available is 100% accurate, to be honest.  At best some of it is confusing, at worst some of it is just wrong.  I ended up drawing my own diagram for the control and relay connections, and this almost certainly is the same as your unit:

 

 

I never managed to find out what terminal 16 did, but note that it is used in your system.  I have a stack of different wiring configurations for this control board, but they are all intended for use with specific control system products, so aren't of much use except that they confirm some of the connections above, like this drawing:

 

 

[Lynford]

Thanks Jeremy. I can’t help but think life would be a lot easier with a command unit. Unfortunately they seem to be like rocking horse **** !

[Jeremy Harris]

10 minutes ago, Lynford said:

Thanks Jeremy. I can’t help but think life would be a lot easier with a command unit. Unfortunately they seem to be like rocking horse **** !

 

The Command Unit is worth having, without a doubt, as it not only allows access to a lot of settings but it also replaces the programmer/timer and room thermostat, if located in the right place.  The diagnostics and different operating parameters are displayed on it too, so you can see exactly what the heat pump is doing at a glance.  This is a photo of ours (ignore the Glow worm label, it's a Carrier unit and the Kingspan one is identical but with their name on instead):

 

 

When the heat pump is on (it's off in that photo) then there are lots of other symbols that appear, letting you know what it's doing, like this:

 

 

If the alarm indicator in the lower left comes on, you can press buttons on the Command Unit to get a code for the cause of the alarm, very easily.

[joe90]

Lynford, I managed to get a command unit from carrier, I called them in Connecticut USA and they gave me a number in Southampton, I think!. I Just googled them and their number in this country is 0870 392 9514, they have depots in  Bromsgrove and a few other places, give them a call they were very helpful and said those command units were available off the shelf ?

[Lynford]

Yep, I reckon I need one after today !

 

@joe90, thanks for the number. I think I might be using it !

[Lynford]

Afternoon gents,

 

Been back up there today, and I’m getting more confused !

 

On the pressure / TRV side of things - I was really disappointed to find that all the TRVs were almost wide open. Opened them right up and started the system, started getting some heat in the rads but never much really and then the ASHP stopped. There was no fault on the diagnostic unit, but the same leds as yesterday on the pcb withing the pump. 

 

Then its pointed out to me that a lockshield valves on one of the rads is broken (by a plumber when trying to fix a leak). The machined down part on the top has been sheared off, and I don’t know if it’s fully open or fully closed - If there was a leak I’d suggest fully closed.........could this be the flow restriction and therefore the cause of high pressure ? Fact is that this will need changing before I go further, just to eliminate it. 

 

On a different route, when the pump stopped I had the same leds on the pcb board as before. This time I knew to press SW800 to drill down further. This gave me D805 on, but that’s always on, and D802 flashing. According to the manual my FIL has (which as discussed earlier may or may not be accurate), this then points to ‘Case thermostat operation’

 

Anyone have any idea what this is, maybe it’s a red herring ?

 

I think we need the lockshield valve changed before I move on.

 

As ever, thanks for any help.

 

Cheers. 

[Jeremy Harris]

The case thermostat operating tallies with the flow being restricted.  The case thermostat shuts the heat pump down when the flow temperature reaches the set point that is internally programmed into the unit (and can only be changed using the Command Unit).  The sequence of events for a flow restriction would be that the heat pump flow temperature would increase (because the flow is being restricted), the case thermostat would call for the heat pump to shut down (which it does slowly, it takes around 30 seconds for it to ramp down under the inverter control) and then the flow pressure sensor would be triggered by the over-pressure in the flow line from the restriction.  It seems to me that this is a pretty logical fault sequence, and that the underlying cause may be a flow restriction.  The fact that the radiators only heat up slowly is another indication that there may be a flow restriction, I think.

[PeterW]

errr... dawning thought !!!
 

The Kingspan/Carrier unit needs a pretty high water flow - those grundfos pumps either work in constant flow or constant pressure mode. If they aren't set correctly then the flow through the heat pump won't be enough.

 

The other thing I can't fathom... why two pumps..??? Can you see what terminals they are wired in to..?

[Lynford]

Thanks gents.

 

@JSHarris - Jeremy, do you think the shut down (maybe) lockshield valve could be to blame ? I’m glad that these issues seem to link (the flow maybe being restricted and the ‘case thermostat’ error).

 

@PeterW - I’m home now so can’t see, I’ll certainly have a look next time. I have no idea about these systems, as you can tell, but I couldn’t understand why there are two pumps. One is on the flow, nearest the wall and one is on the return. They had these changed recently, so that person / firm may have thought there was an issue before. There were however two originally. I’ll deffo check to see where they are wired to though. Do you know how they should be set, and are they set actually on the pumps themselves ?

 

ta,

Lyndon

 

 

[PeterW]

If there is a flow and return pump then they need to point opposite directions - they currently point the same direction ie upwards which potentially means they are going against each other. 

 

May also be worth checking if those valves are fully open on each pump. 

[Lynford]

So obvious now you’ve pointed it out Peter !

 

The two drops with the pumps on had an F and an R written on the wall behind them in pencil, so I’m assuming they are Flow & Return. Next time up I’ll go in the loft and trace the pipes from the ASHP into that cupboard. If they are what I think, then yeah the pumps look like they are backing against each other. I just don’t see how we ever got any heat at all.

 

Cheers. 

 

 

[Jeremy Harris]

Good spot!  There's a Grundfos adjustable pump inside the heat pump, that comes on whenever the heat pump comes on, so that would have been trying to push the flow around.  I'm not convinced that it needs two other pumps, TBH.

[PeterW]

57 minutes ago, Lynford said:

So obvious now you’ve pointed it out Peter !

 

The two drops with the pumps on had an F and an R written on the wall behind them in pencil, so I’m assuming they are Flow & Return. Next time up I’ll go in the loft and trace the pipes from the ASHP into that cupboard. If they are what I think, then yeah the pumps look like they are backing against each other. I just don’t see how we ever got any heat at all.

 

Cheers. 

 

 

 

Ok so the simple check is to disconnect the live to one of them in the wiring box and see what happens .... 

 

As @JSHarris said, there is one in the box itself however the wiring diagram they provide shows a second pump. My guess is both are the wrong way round ...

 

HP Pump pushes >>>>

Pump A (F) pushes >>>>

Pump B (R) pushes <<<<

 

net total is low flow and potentially increased pressure on the output side of the pump where the pressure switch is which then shows as a fault ...

 

 

[Lynford]

Thanks chaps. 

 

Disconnect the the one in the return leg I’d imagine ?

 

If that works, whip it out and put it in the other way around ?

[Lynford]

Like this (please excuse the technical (??!!) drawing.....)

 

 

 

 

 

 

[PeterW]

If the return points away from the return port on the hot water cylinder then leave it connected - likewise, check the flow one isn’t pointing the wrong way as you need to leave one connected. 

[Lynford]

Evening gents,

 

I nipped up there on the way home from somewhere this afternoon.

 

Gutted to find that the pumps were pointing in the correct directions - It looks like the head of the one on the return leg had been switched around for aesthetic / wiring purposes, leaving the body in the correct orientation.

The live of both pumps was into #13 of the attached picture.

 

Should I be waiting for the Lockshield on the rad to be replaced before going any further, or would this just block the one rad off while allowing the rest of the system to function normally ?

 

Does anyone know if Carrier do domestic callouts, and if they would deal with Kingspan units as they actually made them ? Travelling up there to implement the brilliant info from here isn't the easiest way of doing things !

 

Cheers,

Lyndon

[Jeremy Harris]

I doubt that one stuck lock shield (LS) valve would cause a restriction, but with thermostatic radiator valves the LS valves often don't do much, and it's worth checking to see if all the LS valves are wide open (undo the screw, take the cover off and turn the shaft fully anticlockwise).  Also worth making sure that there isn't any air in the radiators,by cracking open each of the radiator bleed valves, just in case there's an airlock.

 

It looks as if both the circulating pumps are being switched by the auxiliary relay in the heat pump, and that should normally shut those pumps off when the heat pump is turned off by the thermostat, or when the system goes into hot water mode and the motorised valve switches across to heat the tank.  The puzzle here is that there seems to be loads of pump capacity (more than I would have thought was needed for a heat pump with just a 12 kW maximum output) in that in heating mode there are three pumps all working together to push water around the heating circuit. 

 

I can't help but wonder why the original installer fitted a second pump.  Often the integral pump in the heat pump is powerful enough on it's own, although for a large system there is the option to add an auxiliary pump, but why two of them?   There must have been a reason, and it suggests that the installer suspected that the system would need two auxiliary pumps in order to overcome the flow resistance in the system.  The problem is that it's hard to understand where that flow resistance might come from.  My best guess is that the design took into account the operating condition when all the thermostatic radiators valves were partially closed, although the normal fix for that is to fit a pressure bypass valve across the heat pump flow and return (it's what I had to do, to over come the same over-pressure shut down problem on our system).

 

Another thing worth checking is that all of the thermostatic radiator valves are actually open.  It's quite common for the operating pins to get stuck, usually closed, or partially closed.  To check, remove the thermostatic valve head (unscrew the threaded ring) and check that the pin is fully up.  It's worth putting something hard on top of each pin and making sure it pushes down and comes back up freely, under fairly strong spring  pressure.  If any are jammed, then a squirt of silicone or PTFE spray, followed by repeatedly pushing them right down and letting them spring up a little more each time will often free them.  Be cautious of trying to grab the pin to pull it up, as the lower part of the pin goes through a seal.  Down is closed and up is open on these valves.

 

I'll have another think about what the problem might be, and post again if I can think of anything.

 

 

 

 

[Guest Alphonsox]

1 hour ago, JSHarris said:

I can't help but wonder why the original installer fitted a second pump.  Often the integral pump in the heat pump is powerful enough on it's own, although for a large system there is the option to add an auxiliary pump, but why two of them?  

 

The Kingspan units do not include an integral pump - At least mine doesn't and none of the documentation indicates that the larger units have one either. This seems to be one of the differences between the different Carrier variants. According to Kingspan this is too allow the pump to be correctly sized for the particular installation.

 

https://www.plumbcenter.co.uk/wcsstore7.00.922.258/ExtendedSitesCatalogAssetStore/images/products/AssetPush/DTP_AssetPushHighRes/std.lang.all/ti/on/Kingspan_Aeromax plus_Installation.pdf

[Jeremy Harris]

Thanks for that, I'd assumed that the Kingspan was near-identical to the Glowworm-badged Carrier that we have, and that has a variable speed Grundfos pump inside the case, so can have the flow rate adjusted to suit the size of the system.  I'm not sure why there are two pumps though, as I'd have thought one would be enough.

 

 

[joe90]

Yup, I have no pump in mine. I am yet to instal it but it’s on my ( very long) to do list?

[Jeremy Harris]

There may be space to fit it inside the case, as the case etc is the same as the other Carrier units.  The pump in mine is at the bottom right hand corner of the case, you may find there is a space there in yours where the pump could be fitted.

 

The internal command board is the same for the Kingspan units as it is on mine, and that has a connection to drive an internal pump.  It's marked as 1PS on this diagram and looks to be easy enough to wire up to the board: