Posted by: @colin

@webcmg Good luck! Bear in mind it'll take a while heat up the screed etc. I've got the Room temp Mod set to inactive so it solely relies on outdoor temp/Weather Comp. 

@colin You know you want to get the problem sorted when you get out of bed to set this up! I also have room temp mod set to "none".

Do you have Adaptive heat curve set to "No"?

What is your desired heating temp set to on the controller ? 21 deg c?

Posted by: @webcmg

@colin You know you want to get the problem sorted when you get out of bed to set this up! I also have room temp mod set to "none".

Do you have Adaptive heat curve set to "No"?

What is your desired heating temp set to on the controller ? 21 deg c?

🤣Yep, I've been out of bed to fine tune ours regularly for a few months. The Mrs is happier at least now she's warmer.

Adaptive Heat Curve should be off when only relying on external sensor, you'll notice that's the recommended setting in the system diagrams.

I don't rely on my indoor sensor (my VRC 720 is in the garage) and don't have it assigned to any zones. I don't need to set a desired indoor temp. Hopefully you can find the VRC 700 settings to match.

Posted by: @alec-morrow

Are you using vaillant mixers for the floor? Or is there a pump for each floor zone?

raise heat curve and shut down all the floor and see how the rads respond?

No, I think there is a pump for each manifold and actuators for each zone. Will try this if Colin's approach isn't working. Thanks.

@colin You know you want to get the problem sorted when you get out of bed to set this up! I also have room temp mod set to "none".

Do you have Adaptive heat curve set to "No"?

What is your desired heating temp set to on the controller ? 21 deg c?

🤣Yep, I've been out of bed to fine tune ours regularly for a few months. The Mrs is happier at least now she's warmer.

Adaptive Heat Curve should be off when only relying on external sensor, you'll notice that's the recommended setting in the system diagrams.

I don't rely on my indoor sensor (my VRC 720 is in the garage) and don't have it assigned to any zones. I don't need to set a desired indoor temp. Hopefully you can find the VRC 700 settings to match.

By the sound of it you're in my parallel universe in Scotland! Wife unhappy and cold, controller in the garage, new build home, similar ASHP setup....

I don't have an indoor sensor either and that setting is also turned off already, but the panel has a desired temp setting which helps to modulate the water flow temp. At 21 deg the target flow temp was 33 deg so will monitor and adjust as required.

Thanks for your help, I will definitely buy you a pint if this turns out to work for us.

I’m a heating engineer and use these controls regularly

Vrc700/720 should be in occupied space so it can measure room temperature usefully.

it’s not a good idea to use anything other than vaillant controls with vaillant heat pumps. So if you have them jut programme them as a top limit stat. 

with rads and UFH then a vrc71 or 70 should control electronic mixers  to create zones. Multiple zones then appear in the screen. Each zone should be uniform emitters and floor structure/covering.

it’s a spectacular bit if kit, but vaillant not very good at promoting it and in a bid to build market suggest it will work with on off controls which it can do. But frankly I would never do that as it’s unfair to end users.

if you have multiple zones with on off controls I would expect to see a vr71 box somewhere..by the heat pump 

bein elsewhere 

@colin do you know or can you measure the flow temp to and from your radiators and ufh? Upstairs still freezing, rads cold despite 3 litres per minute flow on each circuit. Suspect you have a mixer built into the system. 

Can you see any zones and different temp flow/heat curve for the radiator zones? If not I'm baffled by how it works. 

Downstairs is toasty though! 

Posted by: @alec-morrow

I’m a heating engineer and use these controls regularly

 

Vrc700/720 should be in occupied space so it can measure room temperature usefully.

it’s not a good idea to use anything other than vaillant controls with vaillant heat pumps. So if you have them jut programme them as a top limit stat. 

with rads and UFH then a vrc71 or 70 should control electronic mixers  to create zones. Multiple zones then appear in the screen. Each zone should be uniform emitters and floor structure/covering.

it’s a spectacular bit if kit, but vaillant not very good at promoting it and in a bid to build market suggest it will work with on off controls which it can do. But frankly I would never do that as it’s unfair to end users.

if you have multiple zones with on off controls I would expect to see a vr71 box somewhere..by the heat pump 

 

 

bein elsewhere 

@alec-morrow I'm coming to the realisation that this is indeed the problem. There is a single zone and no electronic mixer. We have a VRC700 indoors in the garage next to the heat pump.

Sorry, but what does uniform emmiters and floor stucture/covering mean?

Is it likely to be expensive to resolve by adding a mixer? You can probably see the setup from pics in post 1

Ps  I assume you meant vrc700 rather than vr70 or vr71, or are these different components? 

@webcmg I have multiple Zigbee temp sensors to monitor temperature throughout the house, I stuck one on a radiator and also use an electricity smart meter and collect all the data into Home Assistant for monitoring it all. I have one sensor stuck to a radiator. I've attached a couple of diagrams so you can see the temp you can expect to see from the radiators and electricity usage.

The Heat Pump panel tells me the flow rate but that's an overall figure for both radiators and UFH depending on what's active which is both most of the time.

Do you have a motorised valve that control radiators and/or UFH ? Our engineer installed a timer for the valve supplying the radiators. If you have one, check the valve is open. Your radiators shouldn't be cold if the valves open. When I first moved in, we found things hadn't been set up correctly and had to manually override a valve and all worked after that.

Were your radiators specced for a low flow temp?

@webcmg 

A mixer will give you control over the lower desired temp circuit, ideally the UFH. Given the rooms with rads are cold you either need a bigger rad or a higher flow temp. (Higher flow temp is bad for efficiency) 

The real question is what size rads do you need to warm up the room. You can see from the calculation below that for the current flow temp the rad needs to be 4x the size then for a conventional gas boiler setup. 

Assuming the top end of average flow to rads is 36deg and an air temp of 18.5deg I.e. a delta of 17.5 the rad would put out only 26% of the quoted delta t at 50deg. (Most rad figures are quoted in this figure) 

Posted by: @webcmg

@colin do you know or can you measure the flow temp to and from your radiators and ufh? Upstairs still freezing, rads cold despite 3 litres per minute flow on each circuit. Suspect you have a mixer built into the system. 

Can you see any zones and different temp flow/heat curve for the radiator zones? If not I'm baffled by how it works. 

Downstairs is toasty though! 

Hi,

How are you measuring the flow rate and where is this being done? 3 litres per minute would seem rather low to me, I do believe the normal flow rate would be in the region of 10 to 25 litres per minute.

If downstairs is toasty, then check that any zone valves are operating correctly, or any pumps are operating when required. If you have a wireless thermostat then check to see if you are suffering dropout, which is closing any valve or shutting off any pump prematurely.

Posted by: @derek-m

Posted by: @webcmg

@colin do you know or can you measure the flow temp to and from your radiators and ufh? Upstairs still freezing, rads cold despite 3 litres per minute flow on each circuit. Suspect you have a mixer built into the system. 

Can you see any zones and different temp flow/heat curve for the radiator zones? If not I'm baffled by how it works. 

Downstairs is toasty though! 

Hi,

How are you measuring the flow rate and where is this being done? 3 litres per minute would seem rather low to me, I do believe the normal flow rate would be in the region of 10 to 25 litres per minute.

If downstairs is toasty, then check that any zone valves are operating correctly, or any pumps are operating when required. If you have a wireless thermostat then check to see if you are suffering dropout, which is closing any valve or shutting off any pump prematurely.

Hi @derek-m

There are little caps on top of the manifold, which are between 2.5/3 when the heating is active.  I assumed this was litres per minute, but could be wrong.  All valves are open but I have just noticed that the UFH water is coming off the top of the buffer and the radiators from the bottom of the buffer. The lower pipes to the radiators are certainly colder than the top pipes - is this to be expected from a buffer? I've deactivated the UFH to see if the radiators heat up.

Posted by: @mattengineer

@webcmg 

A mixer will give you control over the lower desired temp circuit, ideally the UFH. Given the rooms with rads are cold you either need a bigger rad or a higher flow temp. (Higher flow temp is bad for efficiency) 

The real question is what size rads do you need to warm up the room. You can see from the calculation below that for the current flow temp the rad needs to be 4x the size then for a conventional gas boiler setup. 

Assuming the top end of average flow to rads is 36deg and an air temp of 18.5deg I.e. a delta of 17.5 the rad would put out only 26% of the quoted delta t at 50deg. (Most rad figures are quoted in this figure) 

@mattengineer I have been told the radiators have been oversized to the requirements of the ASHP system. The radiator on the landing is a triple radiator and the others are probably slightly larger than normal, but not massively. How can I tell if they are suitable?