Newbie help - water UFH Anti cycle with Valiant ecotech 831

[kash]

Hi I'm Kash and im new here - looking for some advice/help.

I'm sorry that my first post is one seeking help and not a general hello!

I'm not too clued up so thought i'd post on here to get some feedback. I've used the search function and tried a few things but it hasn't seem to have done the trick.

I've just had a wet underfloor heating system installed by my builder who refurbished our extension and kitchen. I have questions around the boiler entering anti cycle mode every 5-10 minutes as I'm not sure if this is normal function or not (didn't do this before UFH was installed)

I have the following equipment/setup

Valiant Ecotec 831 boiler
Hive thermostat for central heating
Digital thermostat for UFH
Emetti UFH Manifold & actuators
Reliance zone valve
8 radiators of various sizes
kitchen UFH with a tile finish



The UFH and central work independently of each other.

When the UFH is on, it boiler runs for several minutes before it enters anti cycle mode for several minutes and the process repeats.

I've done a factor reset, tried setting the heating flow temp to various temps and tried adjusting other settings but still not sure as the issue persists.

Partial load is set to Auto (d0)
overrun time is set to 15 mins (d1)
Anti cycle time is set to 20 mins (default - d3)
Heating flow/return - set to flow (d17)
Pump operating mode - ECO (d18)
Heating flow temp - 55 degrees (d71)
DHW temp - 65 degrees
Comfort mode - OFF

The thermostat on the UFH manifold/pump is set to 65 degrees and the other knob on the pump is set to 5.

What further info can I provide to get some help?

Can anyone explain from what I've said as to why this may be happening and what settings can/should I change, and to what values should they be set?

Its a medium size 3bed house.

The zone valve is connect to the central heating flow pipe (if thats any useful info)

 

[Chalked]

Drop anti cycling to 5 min . I would run the heating temp higher too.

 

[kash]

Drop anti cycling to 5 min . I would run the heating temp higher too.

I'm sure i tried this and it didn't make too much difference

 

[kash]

tested again and no joy

 

[Sparkgap]

When you say he CH and UFH work independently of each other, I take it you can just run the boiler to do the UFH? Does it happen when running the CH as well? I think the boiler trying to cope with the small UFH load might be the problem.

 

[kash]

When you say he CH and UFH work independently of each other, I take it you can just run the boiler to do the UFH? Does it happen when running the CH as well? I think the boiler trying to cope with the small UFH load might be the problem.

correct. i can run just the UFH without the rads gettting hot.

I havent actually tried to be honest as its at my parents house -- ill check.

What if it only happens with only UFH? any ideas or solutions?
What if its with both UFH and central heating?

 

[kash]

Update: only happens when UFH is on. or when both UHF and central heating is on. Does not happen when just central heating is on.

This means the UHF is causing it.

Suggestions?

 

[kash]

I went round to my parents today and set the anti cycle time to 5 mins, and set output to max + heating flow temp to 76 degrees.

I also set the thermostat on the UFH mixer to max (70degrees).

It takes about 5/6 minutes for the boiler to go into anti cycle mode.

Is there anyone that's willing to come out and help, or can anyone be recmommneded? Based in southall- Ub1

 

[chris watkins]

I went round to my parents today and set the anti cycle time to 5 mins, and set output to max + heating flow temp to 76 degrees.

I also set the thermostat on the UFH mixer to max (70degrees).

Do not leave it set this high, the max for that type of floor is around 50deg C

1. you could burn your bare feet (or cook a baby if it was left on the floor)

2. you can damage the floor / furniture

 

[kash]

Do not leave it set this high, the max for that type of floor is around 50deg C

1. you could burn your bare feet (or cook a baby if it was left on the floor)

2. you can damage the floor / furniture

But the digital thermostat is set to 25 degrees so would turn off before it got to that temp?

But ok will turn it down until I can get someone to look at it

 

[wattsie1987]

Do not leave it set this high, the max for that type of floor is around 50deg C

1. you could burn your bare feet (or cook a baby if it was left on the floor)

2. you can damage the floor / furniture

Thermo blending valve will prevent this tho....

That boiler can only modulate down to a minimum of 5kW as above it sounds as if your UFH is less than this so causing cycling.

 

[kash]

Thermo blending valve will prevent this tho....

That boiler can only modulate down to a minimum of 5kW as above it sounds as if your UFH is less than this so causing cycling.

How is it fixed then?

 

[wattsie1987]

How is it fixed then?

I don't think it can be. Decreasing the heating partial load will increase heat up time and take longer to get to the cycling stage but will then have an adverse effect on the radiator circuit. Its like trying to get a car to do 5mph in top gear.

 

[chris watkins]

11.1.4 Setting the return flow temperature control
If the boiler is connected to an underfloor heating system, the temperature control can be changed from flow temperature regulation (factory setting) to return flow temperature control under diagnosis code "D.017".

Have you checked the temp control setting has been changed from flow to return? as per MIs

 

[chris watkins]

I went round to my parents today and set the anti cycle time to 5 mins, and set output to max + heating flow temp to 76 degrees.

I also set the thermostat on the UFH mixer to max (70degrees).

It takes about 5/6 minutes for the boiler to go into anti cycle mode.

Is there anyone that's willing to come out and help, or can anyone be recmommneded? Based in southall- Ub1

Thermo blending valve will prevent this tho....

That boiler can only modulate down to a minimum of 5kW as above it sounds as if your UFH is less than this so causing cycling.

He has set it to 70 max so it be blending much.

Kash that sets the water temp circulating in the UFH pipes & will give a very high floor surface temperature, the room stat is only picking up the room air temp.

 

[kash]

He has set it to 70 max so it be blending much.

Kash that sets the water temp circulating in the UFH pipes & will give a very high floor surface temperature, the room stat is only picking up the room air temp.

Mixer stat is now back at 50.
I should have said that the other digital room stat is set to floor temp only. It has the option to be air temp, and and floor temp or floor temp only.

 

[kash]

I spoke to valiant this morning who said it will more then lilkey be a balance/circulation issue.

Now I just need someone to come and look at it for me....

 

[kash]

I had a company come out who told me that i needed to power flush my whole system (only installed 2 months ago) and that I should probably fit a bypass valve as this was probably causing the problem.

I will get a bypass valve fitted by not by them - they wanted £140 an hour and he said I'd be looking at half a days work just for the valve, which I'm not so sure about. They also charged me £96 to come out and have a look. he spent 45 minutes just talking to me and shining a torch at the system, then said well i cant do it today anyway so need to come back!? not sure why he bothered coming out in the first place.

Ive had a quote for £150 to fit the valve and check the system over and get it up and running properly so will give this independent installer a try.

It seems that not having the bypass valve is causing the boiler to enter anticyle mode. watch this space, will let you know how i get on.

Here are some pictures of my setup that for some reason, i couldn't add before!

 

[rpm]

Most likely because you`ve now posted 12 times Kash and are considered safe not to post any "unsavoury" photos if you get my drift. lol

 

[kash]

I have a plumber in at the moment! Finally! somoneone who turned up when they said they would!

fitting a drain valve to make the system easier to drain in future and installing a bypass valve as we speak.

Watch this space - fingers cross that this will be the solution to my problems!

 

[kash]

ok - same issue.

totally confused....

boiler gets to the temp set on the manifold thermostat then enters cycle mode. temp drops quicker now then fires up again.....

 

[kash]

Blending valve set to max
Bypass valve is almost fully open

I'll upload pics of the new pipe work shortly. Any suggestions?

 

[kash]

Here's todays pipework

 

[chris watkins]

Thermo blending valve will prevent this tho....

That boiler can only modulate down to a minimum of 5kW as above it sounds as if your UFH is less than this so causing cycling.

As above, you have a 2 pipe coil plastic UFH system, the chances are it can't loose the heat to the building structure as quick as the boiler on its minimum burn rate can produce it therefore it will have to stop for a while until the water temperature drops.

You can't square the circle you have a big boiler so that you can produce domestic hot water instantaneously (combi) it can't in the next produce heat at such a slow rate that you can just have the UFH on its own with no other load.

 

[kash]

ok cool -

so in its current working order, just want to make sure this isnt going to ruin the boiler?

 

[kash]

The plumber I used agrees too but said he would speak to vailant anyway just to get a better understanding. not that im hoping for anything more now - as long as its safe and wont break anything

 

[Worcester]

Buffer tank, simples.

Buffers started to be used before modulating boilers to stop short cycling, it can do the same here, probably only need a small 100 litre one and it'll work nicely, the ufh will still work just fine and the boiler won't short cycle as much

Buffer Buy online

You'll need an extra circulation pump for the central heating and or dhw, or you could just put it on the ufh circuit. then you might get away with a 50 litre buffer and no extra pumps - install it as a 4 port buffer.

They key thing here is that your builder is at fault under the Consumer Rights Act 2015 and he should be paying to correct it not you.

 

[kash]

Been quoted around £500 to supply and fit!?

Yikes...

 

[Worcester]

That's a reasonable price, however as above, it is your Builder's legal responsibility to fix this.

He is supposed to be an experienced person, so a mistake / error of this type is his problem to solve not yours

They key thing here is that your builder is at fault under the Consumer Rights Act 2015 and he should be paying to correct it not you.

 

[chris watkins]

That's a reasonable price, however as above, it is your Builder's legal responsibility to fix this.
He is supposed to be an experienced person, so a mistake / error of this type is his problem to solve not yours

Just playing devils advocate here Worcester but couldn't the builder simple claim that the UFH was never designed to work independently from the other parts of the heating heating ? and when the two were running together if the boiler then entered anti-cycling mode that this was acceptable for a medium 3 bed house.

I have installed single zone UFH to new kitchen / diners but never offered it as an independent zone.

I believe the OP had the UF system added to an existing system so I suppose it comes down to when you could ague that the UFH design should dictate the total design including the boiler.

 

[Worcester]

It depends whether the builder hooked it up to the heating system or not

If the builder specified the ufh system to work with the existing system and installed it, including the controls for a single zone, then it would be reasonable (as a consumer) to assume that he knows what we is doing, so it would be the builders responsibility,

If the builder just installed it to the manifold with no additional controls, so it ran as the radiators do (controlled by the hive) and the customer then added a room/zome control for the ufh, either personally, or by employing someone directly to hook it all up, then it will fall on the consumer.

The key things is that the consumer should expect a working system from an 'expert' (builder / plumber / heating engineer), if the client starts adding or specifying elements, then they are taking on the role of the expert. (Which we make clear to our clients the moment they start specifying something we have concerns over )

So if the builder either specified , included or offered the extra room control, and didn't mention / make clear the possible consequences, then the builder is responsible.

 

[kash]

It depends whether the builder hooked it up to the heating system or not

If the builder specified the ufh system to work with the existing system and installed it, including the controls for a single zone, then it would be reasonable (as a consumer) to assume that he knows what we is doing, so it would be the builders responsibility,

If the builder just installed it to the manifold with no additional controls, so it ran as the radiators do (controlled by the hive) and the customer then added a room/zome control for the ufh, either personally, or by employing someone directly to hook it all up, then it will fall on the consumer.

The key things is that the consumer should expect a working system from an 'expert' (builder / plumber / heating engineer), if the client starts adding or specifying elements, then they are taking on the role of the expert. (Which we make clear to our clients the moment they start specifying something we have concerns over )

So if the builder either specified , included or offered the extra room control, and didn't mention / make clear the possible consequences, then the builder is responsible.

It was originally installed on the same circuit as the heating but did not want it configured like that as when the UFH was on, the radiators got hot and the house was way too hot. It was then separated out using a zone valve and the actuators.

I sourced and supplied the UFH kit and he just installed it. There was probably a miscommunication as i never specified that i wanted it on a separate circuit - i just assumed this was how it was to work.

Maybe she should have explained the consequences in detail, however there was a million things going on with the extension refit at the time and i think we both just assumed that we both knew how the sytem was going to work.

in terms of fitting the other tank, there really isnt space or anywhere that it could go without a lot of working pipes and deconstruction / reconstruction of the new kitchen I dont think its worth it at this stage, especially if the boiler isnt being damaged or working in an unsafe way.

Yes the floor does get warm and reach temperature but the boiler just cycles (but not as much as it used to).

 

[Worcester]

@Kash thanks for the honesty too often we only get half the story.

I would suggest that some very careful balancing of the system so that the house doesn't get hot, just warm when you need it will help reduce the cycling.

Most people don't realise that it is usually more efficient to run a heating systems by altering temperatures during the day, NOT switching it on and off.

Typically we will configure each zone with a least 4 times / temps, getting up, day time, evening, nightime, never actually switching it off, and choosing appropriate temperatures. As they are used at different times during the day we also usually separate upstairs and downstairs doing the same in each.
Where possible we install room by room controls and set multiple times/temps for each and every room, - honeywell evohome will retrofit pn existing trv's.

It will take a while to get it configured just right, though will be worth it in the end.

Once configured, don't play with it!! - Don't let the misses switch it on and off (it takes a while to educate our customers ! )

Our chosen controls: Honeywell evohome and Heatmiser Neo as both offer internet control so can be tweaked remotely (Heatmiser Neo even has a web remotely controlled plug/socket )

By doing that
a) you will reduce your overall heating costs
b) have a much more comfortable living environment
c) you will reduce the cycling.


The floor temp really shouldn't be higher that 40°-45° flow (set on the TMV) lowering the boiler temp - so long as the rads also manage to heat the house will also reduce cycling. - Even better if the boiler accepts weather compensation it will reduce the boiler flow temperature automatically.

 

[kash]

telling half the story never helps anyone....

part of me think I should have been better informed by the supplier (maybe?) as i explained the current and desired outcomes.

I'll set the TMW to under 50. The boiler is set to 75 for its flow temp - what would be the ideal setting where it wont effect the central heating much?

 

[kash]

Been a while since i've been on.

Whilst the boiler still cycles, its much less (seems to have settled itself) and it operates ok.

In hindsight, I wouldnt have had a combi boiler installed as the house has two bathrooms with 2 showers and UFH and think it probably would have been a better solution in the house.