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Thanks ill give this a try in the winter now and see how things go... I haven't really timed the burn time before it goes into anticycle mode but if from memory the chain of events are: 1. Kitchen alone calls for heat and boiler would fire up, it would then get to say 65c and then hit the anticycle mode for the time set and then it would sit on this for about 5-7min and then start up again... I did range rate it down to 12kw at one point but i dont think it run it for long enough to test, so i may try that again once i have figured what is the lowest kw i can go to. Sorry what do i mean by the below, as my manifold has the manual valve to set the temp for the flow water and electronic actuators>> isn't this normal. "Mixing valve on the manifold is a no no and old tech. Underfloor heating should be controlled by an electronic mixing valve like an esbe with an actuator."

Thanks for replying back, yes i have thought about just having 1 thermostat for Kitchen and living room to stop the cycling so i can explore this option for sure. The only thing id have to fig out is the new location for the single thermostat as my living room and kitchen is separated by internal folding doors (wood/glass). In the winter the kitchen does get more colder compare to living room, so if i had 1 stat controlling both would it not be an issue as my living room would just keep getting warm until the kitchen reached the target temp (assuming i keep the single thermostat in the kitchen). And if i kept it in the living room it could be that kitchen stays cooler as living room is likely to warm up faster. Its for this reason ive kept 2 stats one for each area. Regarding the S or Y plan - I believe (correct me if im wrong) i have a S plan as i can see that we have 3 Motorized zone valves >> one for heating, one for cylinder and the other for UFH. It

Hey Guys... I have the below setup currently and need your advise if installing weather comp will provide me better way to get the most efficiency out of my oversized boiler. its a long story reg why this big boiler was installed as at the time of install i had no idea about sizes etc and it was all done by the stupid plumber who did he whole thing. Now im just trying to get the most out of the setup i have. Vaillant 637 system boiler with Horizontal unvented tank 210L. - both are in the loft eves. I have Hive system for controlling the Rads and using Heatmiser Neo for the UFH. I have ground floor (kitchen 30 sqm and living room 24sqm) which is running on UFH. 1st floor (3 rooms) + Loft room has Rads installed along with towel rails in the 2 bathrooms. UFH heating works fine no issues on that part apart from the fact that i need to run it at slightly higher temp than i want to (50c at manifold TRV). Boiler flow is set to 65C at present. My issue: 1 - if i run the kitchen UFH alone (its a single zone) - then the boiler hits the desired temp and then goes into the egg timer screen (Anti cycle i believe). and keeps doing this - i assume this is because my boiler is too big 2 - If the kitchen and living room UFH is on together then i dont face the anticycle issue and boiler would be sitting at the target flow temp just going up and down 1c (if i rem correctly). 3 - I have hive TRV's on the 4 rads (in each room) and generally only need to warm up 3 rooms - when running just the rads i get the anticycle mode. From my above issues I know my boiler is too big for my house and for the setup i have, i know i can change the settings to reduce the kw it runs at but im not sure if that's a good way? Would installing Weather Comp would help me in my current situation. Im just trying to get the best out of what i have, or if i can install anything else to make this better. I had the boiler serviced recently and during that visit i asked the engineer if he thought my system was not setup correctly and i asked if the boiler was too big >> his response was "everything is running as it should and its good to have a bigger boiler" >>so i didnt even bother asking about weather comp to him. Hence i've come here as there are a lot of you guys who seems to know hell a lot more than some of the pros. Happy to provide more info, if i have missed anything.

I have a system boiler with 4 port manifold and I have two zones, kitchen is Tiles and living room is LVT and i find that when the UFH is On in the kitchen the boiler cant get rid off the heat quickly and would go into the anticycle mode often, so it would reach the target temp of 60c and then id get the egg timer while the pump is running. However i noticed that when both zones are on the boiler is happy to be at around 60c constant while the UFH is on and return temp at about 54c (i believe the ideal condensing temp). Also if one zone + Some rads are running the boiler doesn't go into anticycle mode.

Like you i had a similar setup with the Manifold Temp set to 55C and the boiler set to 70c (15c difference) and pump speed to 2, this setup worked well with my kitchen and living room heating up in good time. However as i have LVT in my living room i think at 55c on the manifold the floor was getting too hot so recently i have reduced the temp down to 45c and the flow on the boiler 65, changed the pump speed from 2 to 3 so i get better flow in the loops. I have been using this for the past week and seems to be stable. I think once the temp drop to 0c or lower the time it takes to heat may take longer if you are running the UFH all day.... i would say keep 10/15c difference between the temp on the manifold and boiler... or as someone pointed out above the Salus actuators could be a option too...im thinking to get them so the flow and return temp are controlled automatically.

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?

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. 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...

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?

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....

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.