Question regarding my UFH setup

[V1ks]

Hi Guys,

 

I am new to the forums and I have been reading a lot on here and finally decide to put my Q to you all, i hope you can help me out. I know a little bit about UFH how things operate but i am still learning by reading posts on here so please excuse me for my silly questions below. I am sorry in adv if some of this may be answered in posts, before posting i have searched around but couldn't find a straight answer hence my post. 

 

I live in a terraced house with 3 stories (loft room) I have had wet UFH since 2020 (installed as part of refurbishment) and things have been working ok but have some question regarding my setup. During the renovations the ground floor was fully concerted with 100mm insulation boards sitting on top and then UFH laid on top held by clips, then 65mm of dry screed on top of the pipes which was left for about a month to dry. In the living room self levelling screed was added to get a flat surface as possible. I Also made sure EDGE insulation was put in all around to ensure no heat loss. Pipes laid at 200mm apart across the whole floor in 4 circuits. 

 

My kitchen has Tiles and my living room has LVT flooring with around 3mm underlay. The manifold (Keyplum is he brand) sits under the stairs, it has a Wilo pump set on speed 2 and the boiler (Vaillant 637 system boiler) along with unvented Horizontal tank sits in the loft. First floor has 3 rooms each one with radiator along with the loft room. UFH is controlled by 3 Thermostats (2 in the living room and 1 for the kitchen), they are not hard wired and have wireless setup with Neo Hub. 

 

I just want to know from guys on here if the setup i have and the time it takes to heat up the floor.... and if i can make this more efficient or what i have is the best its going to get. 

 

So the manifold has 4 ports/zones which cover the ground floor, and all the Flow gauges are fully open and the Temperature on the manifold TRV is set to 55c, the flow temp on the boiler is set to 65c. if the radiators on the first floor aren't running at the same time as the UFH then it takes around 4 hours for the floor to warm up in the kitchen and slightly longer in the living room. If the radiators or hot water is on while the UFH is running then i find that the UFH takes a hit and slows down, i assume this is expected due to hot water being sent to the radiators/hot water tank?

 

I read on another thread here about the Salus Actuator and how if those are installed then one dont need to worry about the Flow/Return temperatures and the Manifold TRV can just left on max? My only concern is that with me having different floor types would the LVT be affected for e.g. if the floor got too hot or these actuators are designed to ensure subfloor doesn't get above 27c?

 

Is there anything else i can to to make my setup any better or this is working as designed or its worth installing the Salus self balancing Actuators?

 

I have set my UFH  thermostats like this: (monday to sunday).

 

4am         8am          4pm            8pm

21c           18c           21c              18c              << Target temp

 

With the above the UFH would only kick in at 4am and then stop at 8am and then start again at 4pm and stop at 8pm. Outside of these hours if the weather got really cold then it would just come on as expected.

 

Happy for any positive and negative feedback. 

 

[Temp]

I might not be the best person here to comment but..

 

I would check which has priority the rads or UFH or do they both come on together? 

 

Having two stats in one room (living room) is unusual unless there is some sort of partition. If it's a large room then one stat controlling two UFH loops is more normal.

 

My personal view is that UFH is better suited to houses which normally have one person at home most days. In that case having the UHF rooms drop to say 18C in the daytime and 20C in the evening works. If you are both working then it's tempting to have it totally off in the daytime and the the warm up and cool down  time makes it less suitable.

 

 

 

Edited November 22, 2022 by Temp

[V1ks]

Hi Temp, 

 

Thanks for the reply...

 

 If my understanding is correct then since the hot water coming from the boiler which is split into 3 (T off) and each one has its own zone valve, whichever zone is calling for hot water will open the valve whilst the other stay shut and if all 3 are calling for heat then the water is flowing into all 3? In addition i just had a quick search on google about hot water priority and it states that the system needs to be setup in a certain way when being installed and i dont think every boiler supports it? 

 

Generally my wife is at home hence keeping the UFH during the day to 18c but as i said before it very rarely comes on during the day because its on during the morning so the house doesnt seem to get that that cold where it drops below 18c. Alot of this also weather dependent because if its very cold outside then there is a chance it will come on between 8am and 5pm. I have kept at 18c so its a comfortable temp for us.

 

I hope someone can share their feedback on the other settings ive mentioned regarding the TRV on the manifold etc. I am very tempted to get the Salus Actuators but will wait for a bit to see what feedback i get... 

 

Thanks once again....

 

 

[PeterW]

14 hours ago, V1ks said:

 

I read on another thread here about the Salus Actuator and how if those are installed then one dont need to worry about the Flow/Return temperatures and the Manifold TRV can just left on max

 That’s not correct - it is the  flow valves you open fully not the TRV !! The Salus valves will control to a delta 7°C between flow and return temps

[PeterW]

Vaillant has a pump in the boiler so if the rads or cylinder is calling for heat then that will be the shortest flow or path of least resistance. Ideally you need the UFH flow setting to be higher than the boiler as the manifold is a circulation pump so when it needs more hot water from the boiler then it should be able to pull from the main circuit. I’m assuming somewhere there are zone valves ..? 

[V1ks]

23 hours ago, PeterW said:

 That’s not correct - it is the  flow valves you open fully not the TRV !! The Salus valves will control to a delta 7°C between flow and return temps

 

Thanks PeterW, good to know regarding the TRV...so i assume leaving it on 55c which is what its currently  set to is ok for the floor type i have if i do opt to get the Salus actuators. Just another Q would i need to adjust the Flow Temperature on the boiler at all which is currently set to 65c?

 

On your Q regarding the Zone Valves yes there are 3 under the boiler:>> Hot Water Tank, UFH and Radiators (heating).  Sorry but what do you mean by "Ideally you need the UFH flow setting to be higher than the boiler " are you suggesting the Flow gauges on top of the manifold to be fully open?

 

 

Edited November 24, 2022 by V1ks

[ProDave]

The only thing I question is do you have a 3 channel programmer?  (if not that is an upgrade you should do)

 

That would allow the UFH to turn on earlier as it takes longer to warm up, and the radiators to turn on a bit later.

 

It is already plumbed with 3 motorised valves so should be an easy upgrade if not already a 3 channel programmer.

[PeterW]

7 hours ago, V1ks said:

 

Thanks PeterW, good to know regarding the TRV...so i assume leaving it on 55c which is what its currently  set to is ok for the floor type i have if i do opt to get the Salus actuators. Just another Q would i need to adjust the Flow Temperature on the boiler at all which is currently set to 65c?

 

On your Q regarding the Zone Valves yes there are 3 under the boiler:>> Hot Water Tank, UFH and Radiators (heating).  Sorry but what do you mean by "Ideally you need the UFH flow setting to be higher than the boiler " are you suggesting the Flow gauges on top of the manifold to be fully open?

 

 

55°C is way too hot for UFH ..! Drop it to 45°C max - you shouldn’t need to “feel” UFH warm on your feet. 
 

The manifold pump needs setting to 3 if the boiler pump is set to 2 - otherwise the least resistance route will be the rads and the UFH will be compromised 

[V1ks]

On 24/11/2022 at 11:25, ProDave said:

The only thing I question is do you have a 3 channel programmer?  (if not that is an upgrade you should do)

 

That would allow the UFH to turn on earlier as it takes longer to warm up, and the radiators to turn on a bit later.

 

It is already plumbed with 3 motorised valves so should be an easy upgrade if not already a 3 channel programmer.

 

I dont think i have a 3 channel programmer, the only thing i have is wiring next to the boiler where all the Zone valves are connected inc my Hive system and then a cable run which goes to the Heatmiser next to the manifold. I will check out this 3 channel programmer you mention. 

 

On 24/11/2022 at 18:19, PeterW said:

55°C is way too hot for UFH ..! Drop it to 45°C max - you shouldn’t need to “feel” UFH warm on your feet. 
 

The manifold pump needs setting to 3 if the boiler pump is set to 2 - otherwise the least resistance route will be the rads and the UFH will be compromised 

 

I did have the UFH on 45c before but found that the return flow pipes would be very cold not sure if this is normal? I dont know but i always thought u should be able to feel the warmth of the UFH until you mention this to me. The pump inside the boiler >> i dont know what speed that is set to, is there a way to check this??

 

As for the Rads they only come on for a hour in the morning and hour in the evening. 

 

I can certainly switch the temp back down to 45c and change the pump speed on the manifold back 3 to see how that goes.

 

Just generally speaking if i went with the above setup, how long should one expect the UFH heating to say increase the temp from 18c to 20 in the kitchen/living room (i understand this there alot of variables to this) ? I am asking because it could be that im not allowing the UFH to run long enough on lower temp, which i assume is the efficient way rather than having the the TRV on the manifold to be 55c and the flow temp on the boiler to be 65/70c?

 

or should i just set the temp on the thermostats to say 18c or 20c without any timings so the UFH will just kick in throughout the day/night every time the temp drops below the target? or this is not efficient and the way i have right now is perfectly fine...?  i just want to understand how other on here are running their system 

 

Thanks for responses back...

 

Edited November 26, 2022 by V1ks

[V1ks]

i found this in the Boiler install manual today, this is for the pump inside the boiler. I can get a gas safe guy to confirm this but would changing the setting from default would help push the water around faster from the boiler to the manifold? since the boiler is in the loft and manifold is on the ground floor im wondering the return flow to the boiler is slow?