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Newbie help - water UFH Anti cycle with Valiant ecotech 831

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K

kash

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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)
 
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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.
 
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Sparkgap said:
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.
Click to expand...

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?
 
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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
 
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kash said:
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).
Click to expand...

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
 
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chris watkins said:
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
Click to expand...

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
 
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chris watkins said:
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
Click to expand...

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.
 
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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
 
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kash said:
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
Click to expand...

wattsie1987 said:
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.
Click to expand...

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.
 
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chris watkins said:
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.
Click to expand...

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.
 
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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!




 
Last edited:
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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!
 
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wattsie1987 said:
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.
Click to expand...

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.
 
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