Help required wiring my ASHP/UFH

[Jeremy Harris]

I currently have our system set up with the thermostatic valve on the flow side of the manifold, set to around 28 deg C, and the Salus actuated valve on the return side of the manifold, with the temperature sensors clipped to the flow and return of one of the UFH loops (all our loops are set to flow at the same rate).  This is accidental on my part, as I just turned the thermostatic valve up a bit, to make sure it was open, at the time I fitted the Salus actuator.  By luck it happens to be set to under 30 deg C, which is why the Salus actuator works as well as it does.

 

Perhaps I should have read the full technical info before I fitted it!

[jack]

Out of curiosity, what was your thinking in putting the Salus valve on the return side rather than using it in place of the thermostatic valve on the flow side?

 

In my system I can't see that it makes much difference which side the Salus valve is installed, as long as you leave the thermostatic valve open enough to allow the Salus valve to work properly. 

[Jeremy Harris]

7 hours ago, jack said:

A version of this valve with an adjustable temperature differential would be excellent. 

 

I'm tempted to buy one just to see if there's a way to change the temperature differential, or, perhaps, make a new controller for the stepper motor that would allow the differential to be changed.  They are under £20, so not a great loss if I end up breaking it.

[jack]

8 hours ago, jack said:

Out of curiosity, what was your thinking in putting the Salus valve on the return side rather than using it in place of the thermostatic valve on the flow side?

 

Just bumping this one @JSHarris

 

thanks

[Jeremy Harris]

40 minutes ago, jack said:

 

Just bumping this one @JSHarris

 

thanks

 

Sorry, missed that earlier.  Two reasons, firstly the manifold came with actuator controlled valves at either end, and I'd already got the thermostatic head on the flow side.  Secondly, Salus specifying that this actuator has to go in the return side, not sure why, but it may have something to do with the banging that can happen as valves close, as @Nickfromwales mentioned.  It seems to work very well on the return, but I could fairly quickly swap it to the flow side to see if it works as well there.

[jack]

Interesting, thanks Jeremy.

 

It's actually easier for me to do as you've done, as I think I have exactly the same manifold as as you, but I was just wondering about whether I was overlooking some major factor about the choice of location.

 

I ordered one earlier today, as I can see us turning the heating on occasionally in the next couple of weeks (I'm fine but my wife is starting to get cold as of this evening!)

[joe90]

Got the underfloor heating working from a backup immersion In the buffer tank, TRV on the manifold on frost and water temp into the manifold 24’ ??? Which is ok, er indoors happy with warm feet. Wired up the ASHP and      Nothing,   Flashing LED indicates all ok, Need to go through all the wiring and check all is ok. Can’t find a commissioning doc on the way to start it fir the first time, is there anything I should be looking for (going shopping for food as my brain hurts).

[Jeremy Harris]

56 minutes ago, joe90 said:

Got the underfloor heating working from a backup immersion In the buffer tank, TRV on the manifold on frost and water temp into the manifold 24’ ??? Which is ok, er indoors happy with warm feet. Wired up the ASHP and      Nothing,   Flashing LED indicates all ok, Need to go through all the wiring and check all is ok. Can’t find a commissioning doc on the way to start it fir the first time, is there anything I should be looking for (going shopping for food as my brain hurts).

 

The ASHP will need both dry contact terminals 6 and 7 to be connected to terminal 3 in order to turn on and run in heating mode.  Terminal 3 is the 12 V supply 0 V terminal, so you can check with a meter between terminal 3 and terminals 6 and 7 to see if they are switched to 0 V OK.  If they aren't, they will float at around 12 V, and the heat pump won't turn on.

 

Watch out when doing these checks, as there are live mains terminals exposed very close to them.

[joe90]

Ah, I have not got the programmable stat that closes 3 to 6 as I was going to use the command unit as the stat, if I do this I think I need to change the parameter 100 from standard no1 to 4? (System type a2w. Nui as stat). I do have a Wunda room stat that I was going to use and have wired ready for it in the Hallway, so not sure which is best (command unit is in the cloakroom next to the plant cupboard.) when it stops raining I will get the cover off and check voltages.

[Jeremy Harris]

19 minutes ago, joe90 said:

Ah, I have not got the programmable stat that closes 3 to 6 as I was going to use the command unit as the stat, if I do this I think I need to change the parameter 100 from standard no1 to 4? (System type a2w. Nui as stat). I do have a Wunda room stat that I was going to use and have wired ready for it in the Hallway, so not sure which is best (command unit is in the cloakroom next to the plant cupboard.) when it stops raining I will get the cover off and check voltages.

 

 

Just wire link 6 and 7 to 3 for now, as that will turn the ASHP on in heating mode.  If getting out to it is a problem, then over-riding the dry contact control from the programmer may be an option, although this isn't something I've tried, so can't say for sure that it will work as expected.  What you suggest should work OK, I think, from my interpretation of the manual.

[joe90]

It’s no wonder I get confused, just started to wire the Wunda room stat and thought they had sent the wrong one, should be dry contacts but appears to show electric underfloor heating element (my electric ensuite UFH is like this). Called Wunda technical support and they tell me the manufacturer got it wrong and they assure me it’s dry contacts inside ?

[ProDave]

check VERY carefully with a meter BEFORE you connect it.

 

i.e connect a bit of flex and a plug to provide power to L and N in. Then turn the thermostat up so it calls for heat and measure with a multimeter what comes out of L1 and N1

 

You don't want to be connecting a switched L to something expecting a dry volt free contact.

[joe90]

22 minutes ago, ProDave said:

check VERY carefully with a meter BEFORE you connect it.

 

i.e connect a bit of flex and a plug to provide power to L and N in. Then turn the thermostat up so it calls for heat and measure with a multimeter what comes out of L1 and N1

 

You don't want to be connecting a switched L to something expecting a dry volt free contact.

 

Yup, tests ok. Thanks Dave, good idea ?

[joe90]

Right (big Intake of breath) wired in the Wunda room stat, timer for heating and switched it on, pump ran for a short while then tripped out an adjoining cct ?, tried again, same thing (scratching head). Turns out my builder who is putting up my new conservatory has a faulty chop saw and it’s that tripping out the same cct as the power to the room stat and timer. Perhaps I will provide an additional cct for these later.

 

Anyhow, lent them my chop saw and the pump is still running for about 10 seconds then switching off, it tries again in about 30 seconds. I think I have seen this described on the forum somewhere but can’t find it.

 

My worry is having bought my ASHP from Ebay like @ProDave I end up with the same problem as he did ?

 

“SIT REP” after about 10 attempts the ASHP is running, just hope it produces heat???

 

watch this space..............

 

 

AAARRRRGGGGGGGHHHHH. cct still tripping ( ringmain feeding timer and room stat) trips after about 6 seconds, found it’s the Wunda room stat, large spark from inside on tripping. Will be calling them first thing. Need to contact builder and apologies for blaming his chop saw?

Edited October 2, 2018 by joe90

[Triassic]

Fingers crossed.

 

Do you have a diagramme of your equipment set up?

 

 

Edited October 2, 2018 by Triassic

[joe90]

1 minute ago, Triassic said:

Do you have a diagramme of your equipment set up?

 

 

 

Yes in pencil, will do it properly and post.

 

see above post has been added to.  GGGGRRRRRR

[PeterW]

@joe90 which stat is it ..?

[joe90]

58 minutes ago, PeterW said:

@joe90 which stat is it ..?

 

Its the Wunda room stat. Just tested it all and no apparent wiring problems. Connected it again and as soon as the stat calls for heat the consumer MCBO for that ring that the room stat and timer are on trips . Fast losing the will to live ?

[ProDave]

To test the ASHP, forget the room stat, just link it out so the room calls for heat all the time, and establish that the heat pump works first.  THEN you can look at the thermostat issue.

 

What is tripping? MCB or RCD?

[Jeremy Harris]

1 hour ago, joe90 said:

Anyhow, lent them my chop saw and the pump is still running for about 10 seconds then switching off, it tries again in about 30 seconds. I think I have seen this described on the forum somewhere but can’t find it.

 

My worry is having bought my ASHP from Ebay like @ProDave I end up with the same problem as he did ?

 

“SIT REP” after about 10 attempts the ASHP is running, just hope it produces heat???

 

watch this space..............

 

 

The heat pump is tripping out because there is a flow restriction, I expect.  Mine did the same until I fitted a bypass to allow the flow and return to be "short circuited" in the event of a valve not opening in time.

 

Look at the error code on the command unit - I bet your seeing fault code 9, which is triggered when there isn't enough flow through the unit.  The cause of this for my installation (where the heat pump has an internal circulation pump) was because the valves allowing flow to the UFH and buffer were too slow to open.  As a result the ASHP sensed insufficient flow and shut down, then tried to restart around 30 seconds later.  If left long enough it would fire up OK, after the UFH thermally actuated valve had opened (takes a few minutes).

 

Fitting an adjustable pressure bypass valve fixed it, as that now opens if there is a closed valve and allows water to circulate around the flow and return, keeping the heat pump happy. 

 

 

[PeterW]

22 minutes ago, JSHarris said:

 

The heat pump is tripping out because there is a flow restriction, I expect.  Mine did the same until I fitted a bypass to allow the flow and return to be "short circuited" in the event of a valve not opening in time.

 

Look at the error code on the command unit - I bet your seeing fault code 9, which is triggered when there isn't enough flow through the unit.  The cause of this for my installation (where the heat pump has an internal circulation pump) was because the valves allowing flow to the UFH and buffer were too slow to open.  As a result the ASHP sensed insufficient flow and shut down, then tried to restart around 30 seconds later.  If left long enough it would fire up OK, after the UFH thermally actuated valve had opened (takes a few minutes).

 

Fitting an adjustable pressure bypass valve fixed it, as that now opens if there is a closed valve and allows water to circulate around the flow and return, keeping the heat pump happy. 

 

 

 

I’ve done both but the flow is to two open circuits (DHW tank or Buffer) so it means that the bypass should only be ever needed when the diverter valve is at mid position. For £8 it was a no-brainer. 

[joe90]

I will have a look in the morning.     But, when it trips it is the MCBO in the fuse board for the spur that feeds both the room stat and DHW timer. On removing the stat from the wall there is a flash and spark from inside the room stat!!! I am guessing the room stat may be faulty, if I take the switch wires off the stat and short them together there is not a problem (apart from it not doing what it is supposed to. If it was the flow that was a problem I am guessing the ASHP would just shut itself down. Glass of wine ? and TV 

for me.

 

to be continued.........

[ProDave]

9 minutes ago, joe90 said:

I will have a look in the morning.     But, when it trips it is the MCBO in the fuse board for the spur that feeds both the room stat and DHW timer. On removing the stat from the wall there is a flash and spark from inside the room stat!!! I am guessing the room stat may be faulty, if I take the switch wires off the stat and short them together there is not a problem (apart from it not doing what it is supposed to. If it was the flow that was a problem I am guessing the ASHP would just shut itself down. Glass of wine ? and TV 

for me.

 

to be continued.........

Like I say, remove that room stat and just link it our so it is calling for heat all the time and try again.

 

Does the heat pump start up or even try to start up?

 

 

[joe90]

Will try in the morning Dave. As an aside, the house is now at 23’ (UFH working on buffer tank heated by immersion) the TRV on the manifold is set to frost but the water temp going into the floor is 24’. Er indoors says it is “just right” whereas I am sweltering. I need to get this working properly otherwise i will melt.

[joe90]

I don’t think it is a flow problem because (if I understand it correctly) I have an external pump and the three way valve is normally parked at “heating” so there is no valve waiting to open when the ASHP starts up. Again I say it’s the MCBO in the fuse board that’s tripping showing a fault in the wiring which occurs when the Wunda room stat calls for heat. I will look at this after a good night kip (I hope ?).