My underfloor heating

[lizzie]

Hello all and thanks for the suggestion of a new thread.

 

I have UFH powered by a gas boiler.  It is in an MBC slab. It was commissioned last December and left on by installer.  Over the following months all the builders working in the house messed with it, too hot, too cold etc.  None of them ever asked or told me what they had done I just had reports from others that the heating was up and down like a yo yo etc.

 

We moved in end April just as heatwave hit and so have not had UFH on until now...well not tried to have it on that is.

 

I have a Frankishe Robbens system with Heatmiser controls via wall boxes and an ap.The system is split between manifold 1 (bedroom wing) and manifold 2 (living wing). Bedroom wing terminal lights up, pipes get hot never felt a warm floor but clearly something is happening, woud be nice to get some heat into the bathroom floors.  Living wing terminal does not light up (other than power light) and pipes from boiler do not get hot..ergo no heating.

 

Have tried upping temp on ap and wall boxes, flame shows and boiler kicks in but still pipes are cold at manifold and no heat comes. There is what looks like a TRVnear the pump but I dont know what that should be set at.

 

Yesterday I gave the motorised valve and the pump a good thump in case they were stuck.  I started to get fleeting heating up of pipes but it only lasted a few minutes, the house was still cold.  

 

I have driven myself nuts with Dr Google. I have floor sensors as well as air sensors.  I think must be the floor sensors that are stopping heat from kicking in.  Does that make sense?

 

Ive upped floor sensors to 28 degrees on the thermostat and have some heat in the manifold pipes now.

 

If this is it can anyone tell me now how I control the heating to keep the house warm. MVHR running in the background.

 

Any help greatly appreciated. TIA.

 

 

Edited September 16, 2018 by lizzie

[AliG]

We just had some issues with our system when we started using it for the first time.

 

You may have to get the installer to come back and have a look at it if people have been messing around with it.

 

The thing that looks like a TRV should be a mixer valve that controls how hot the water flowing through the UFH is. I would expect 30Cish in a MBC slab.

 

The big gauge at the top is a combined temperature and pressure valve I think. It seems to be showing a flow temperature of just less than 30C.

 

I think the small gauges are showing the temperature of the water flowing from the boiler, it looks like it is coming in at about 65C.

 

So when a thermostat calls for heat (flame shows as you said), you should see the boiler light and valve light come on on the Heatmiser wiring centre. I must admit I am not sure how it works with a floor sensor, all of ours are air sensors so you simply set them relative to the temperature in the room. Assuming though that they are calling for heat -

 

You will also see the light come on corresponding to the thermostat calling for heat and this will be connected to the actuators on the bottom side of the manifold, one thermostat could be connected to more than one actuator depending on the size of the room. as it may have more than one pipe circuit You will see the top of these rise as they open the circuit and the little float in the flow meter at the top should drop showing that water is flowing in the circuit.

 

Looking at the fifth picture, I see two actuators open but the flow meters above them don't seem to have dropped. This suggests to me maybe a pump problem. Does the pump on the manifold run when the thermostat calls for heat. Another possible issue is that the pin is stuck in the mixer valve as can happen in a TRV.

 

In my system we were having the same issue and there was another pump closer to the boiler that sent hot water to the manifold. It wasn't kicking in when the manifold called for heat.

 

I am by no means an expert on these systems, this is just what I found trying to figure my system out. I did find that it is quite hard to feel the pipes for water flowing as it is not that hot, the flow meter is what you should look for.

 

As for the Living Room, if no circuit light comes on and no boiler or valve light either then the thermostat is not correctly wired to the wiring centre or there is something about how it is et that is stopping it calling for heat.

 

 

 

 

Edited September 16, 2018 by AliG

[lizzie]

Thank you @AliG at least I have a clue what some of the dials are now!

[ProDave]

Okay. The BASICS of how it should work.

 

When you turn a themostat in a any particular room up to the point it calls for heat, that should turn on the manifold that feeds is. So in your picture 3, whatever room is connected to zone 1 is calling for heat, so the manifold pump should be running (you should be able to hear that) the pipes should get warm, and you should see one or more of the flow meters (the things with glass tubes along the top of the manifold) showing that water is flowing (may take a couple of minutes for the flow to show as the thermal actuators are a bit slow)

 

So lets start with that manifold in picture 3, is the pump running, are any pipes hot and are any flow meters showing water flow?

 

The other manifold that does not have a power light, that is your first challenge to find out why there is no power. Is a switch turned off anywhere? Id there a programmer or time clock that has not been set to come on?

 

Top left on the manifold is a pressure and temperature gauge. What does the temperature say (that is the flow temperature in the heating pipes)

[Nickfromwales]

I think the system may feature floor sensors because there is a potential for super high flow temp to accidentally get to the floor in the event of a few items failing. The idea being that the system wont allow heat / flow ( manifold pump to come on ) unless the system is at a preset temp or < the setting. If its set to 28, I'd set it higher like 38oC and run it from there. 

The two smaller gauges adjacent to each other show the flow and return temps, so if one is higher eg flow then there is heat being circulated and dissipated at least slightly, as if it wasn't then the flow and return temps would be near identical. 

Turn the white TRV heads all to 35oC and make sure the probes ( on the end of the pig tailed capillary wires ) are pushed home snugly.  

[newhome]

So that room where the stat shows 25 degrees, is that what it thinks the temperature is currently or what you have set it to? There's no flame so presumably that room is not calling for heat? When you say you have a mix or air and floor sensors is that on the same stat? My floor probe is only in the bathroom, all the others work from the air temp. 

 

I bought one of these as advised on here. At least I can go round and point at the floor and see what the temperature is at various locations if I need to:

 

https://www.amazon.co.uk/Non-contact-Thermometer-58°F-1022°F-Temperature-Technology/dp/B01AT9TON0/ref=sr_1_3?ie=UTF8&amp;qid=1537117945&amp;sr=8-3&amp;keywords=ir+thermometer

 

I also have several of these strapped to various things in the service room that enables me just to double check the temperature in various locations as the thermometer doesn't work very well on pipes. 

 

https://www.amazon.co.uk/DollaTek-Thermometer-Temperature-External-Refrigerator/dp/B07DK4R9V8/ref=sr_1_12?s=electronics&amp;ie=UTF8&amp;qid=1537118085&amp;sr=1-12&amp;keywords=fridge+thermometer

 

 

 

 

 

 

[ProDave]

I know this won't help but I don't like those Heatmiser programmable thermostat things. They are complicated beasts to set up.  Give me a simple thermostat with a dial, and a separate conventional central heating time clock to set the on and off times (that's what I have in my house)

[newhome]

3 minutes ago, ProDave said:

I know this won't help but I don't like those Heatmiser programmable thermostat things. They are complicated beasts to set up.  Give me a simple thermostat with a dial, and a separate conventional central heating time clock to set the on and off times (that's what I have in my house)

 

I would have agreed with you a few months ago but I find them great now that I know how they work TBH especially with the central controller that does every room (Lizzie has her app for that but that wasn't available 8 years ago when we bought the controls). They do take a bit of getting used to for sure though. 

 

[nod]

16 hours ago, lizzie said:

Hello all and thanks for the suggestion of a new thread.

 

I have UFH powered by a gas boiler.  It is in an MBC slab. It was commissioned last December and left on by installer.  Over the following months all the builders working in the house messed with it, too hot, too cold etc.  None of them ever asked or told me what they had done I just had reports from others that the heating was up and down like a yo yo etc.

 

We moved in end April just as heatwave hit and so have not had UFH on until now...well not tried to have it on that is.

 

I have a Frankishe Robbens system with Heatmiser controls via wall boxes and an ap.The system is split between manifold 1 (bedroom wing) and manifold 2 (living wing). Bedroom wing terminal lights up, pipes get hot never felt a warm floor but clearly something is happening, woud be nice to get some heat into the bathroom floors.  Living wing terminal does not light up (other than power light) and pipes from boiler do not get hot..ergo no heating.

 

Have tried upping temp on ap and wall boxes, flame shows and boiler kicks in but still pipes are cold at manifold and no heat comes. There is what looks like a TRVnear the pump but I dont know what that should be set at.

 

Yesterday I gave the motorised valve and the pump a good thump in case they were stuck.  I started to get fleeting heating up of pipes but it only lasted a few minutes, the house was still cold.  

 

I have driven myself nuts with Dr Google. I have floor sensors as well as air sensors.  I think must be the floor sensors that are stopping heat from kicking in.  Does that make sense?

 

Ive upped floor sensors to 28 degrees on the thermostat and have some heat in the manifold pipes now.

 

If this is it can anyone tell me now how I control the heating to keep the house warm. MVHR running in the background.

 

Any help greatly appreciated. TIA.

I’ve the exact same system It was commissioned a couple of months back

simalar problems to yours 

I decided in the end to drain it all off and refill Works a treat now

[lizzie]

1 hour ago, ProDave said:

When you turn a themostat in a any particular room up to the point it calls for heat, that should turn on the manifold that feeds is. So in your picture 3, whatever room is connected to zone 1 is calling for heat, so the manifold pump should be running (you should be able to hear that) the pipes should get warm, and you should see one or more of the flow meters (the things with glass tubes along the top of the manifold) showing that water is flowing (may take a couple of minutes for the flow to show as the thermal actuators are a bit slow)

 

That works I can hear a small whir from the pumpmbut the pipes are cold.

 

So lets start with that manifold in picture 3, is the pump running, are any pipes hot and are any flow meters showing water flow?

The pump is running I think, there is a green light and a red light but the pipes are cold. The small meters show the same 25 on each (a bit over 70), the actuator (?) for the zone feels warm and the little red thing above has a small jiggle.  The TRV is set to about 30.  The wall thermostat shows a temp of 23 - this is floor only for this zone (en suite), floor temp is set at 25.  Noe of the room stats on this manifold are calling for heat and I have them all turned up to 25. with floor temp the same.  Should the floor temp and air temp be set differently?

 

 

Quote

 

The other manifold that does not have a power light, that is your first challenge to find out why there is no power. Is a switch turned off anywhere? Id there a programmer or time clock that has not been set to come on?  

It is on I dont know why it didnt come out in the pic but there is power to it.

 

Top left on the manifold is a pressure and temperature gauge. What does the temperature say (that is the flow temperature in the he

All zones are off on this manifold small dials say 65 on left and 62 on right, the big dial says 20 and the boiler is saying 62. 

For the first time ever the pipes are hot on this manifold.

Room stats and floor temps are set to 25.

 

1 hour ago, Nickfromwales said:

I think the system may feature floor sensors because there is a potential for super high flow temp to accidentally get to the floor in the event of a few items failing. The idea being that the system wont allow heat / flow ( manifold pump to come on ) unless the system is at a preset temp or < the setting. If its set to 28, I'd set it higher like 38oC and run it from there. 

The two smaller gauges adjacent to each other show the flow and return temps, so if one is higher eg flow then there is heat being circulated and dissipated at least slightly, as if it wasn't then the flow and return temps would be near identical. 

Turn the white TRV heads all to 35oC and make sure the probes ( on the end of the pig tailed capillary wires ) are pushed home snugly.  

Done all that....zones comes on when floor temp ramped up. will have to wait and see if pipes get hot.  Up to now zones on and appears to be working but pipes cold so fingers crossed. probes on end of pig tails...the red things?

 

Thank you both will spend the evening  monitoring.

Edited September 16, 2018 by lizzie

[lizzie]

1 hour ago, newhome said:

So that room where the stat shows 25 degrees, is that what it thinks the temperature is currently or what you have set it to? There's no flame so presumably that room is not calling for heat? When you say you have a mix or air and floor sensors is that on the same stat? My floor probe is only in the bathroom, all the others work from the air temp. 

Yes floor sensors on every stat and air also except en suite which is floor only.

Quote

 

I bought one of these as advised on here. At least I can go round and point at the floor and see what the temperature is at various locations if I need to:

 

https://www.amazon.co.uk/Non-contact-Thermometer-58°F-1022°F-Temperature-Technology/dp/B01AT9TON0/ref=sr_1_3?ie=UTF8&amp;qid=1537117945&amp;sr=8-3&amp;keywords=ir+thermometer

 

I also have several of these strapped to various things in the service room that enables me just to double check the temperature in various locations as the thermometer doesn't work very well on pipes. 

 

https://www.amazon.co.uk/DollaTek-Thermometer-Temperature-External-Refrigerator/dp/B07DK4R9V8/ref=sr_1_12?s=electronics&amp;ie=UTF8&amp;qid=1537118085&amp;sr=1-12&amp;keywords=fridge+thermometer

 

Great I will get some of these!  Thank you.

 

 

 

 

 

Edited September 16, 2018 by lizzie

[PeterW]

Those UH8 manifold units are a b!tch to diagnose unless you take the covers off.. It would be useful to know if they are slaved to each other and which one is controlling the boiler.

 

@lizzieDoes every room have a stat..? looks like only 2 or 3 zones are calling for heat, put your hand on the pump - it should be warm not hot.

 

My guess is the manifold actuators aren't coming on or someone has played with the flow settings - both need the installer to rectify...

 

 

[Onoff]

11 hours ago, newhome said:

I also have several of these strapped to various things in the service room that enables me just to double check the temperature in various locations as the thermometer doesn't work very well on pipes. 

 

https://www.amazon.co.uk/DollaTek-Thermometer-Temperature-External-Refrigerator/dp/B07DK4R9V8/ref=sr_1_12?

 

These aren't the ones I linked you are they? Seem more expensive than I paid. Thinking to get a few to help figure my "valve"issues. The point and shoot, cheapo, laser thermometer, I don't really rate tbh. Temp varies wildly according to how close you are to the object.

[newhome]

There are 3 in a pack with these. The ones you pointed me at were 99p each but were from China so took an age to come. There are probably UK based ones that are a bit cheaper. 

 

The thermometer isn’t bad. It’s not that far off the little stat temp as long as it’s not a pipe or something it doesn’t read well. As long as you use it as a guide it’s fine. I tend to put it fairly near to the surface I’m reading. It doesn’t work that well from miles away. 

[Triassic]

These user and equipment guides might help https://www.underfloorheating.co.uk/product-data-underfloor-heating

[lizzie]

thanks @Triassic I looked at those but oculdnt make a lot of sense of it.

[lizzie]

@PeterW yes all rooms have a stat they are in separate zones.  These are wireless stats and connect to a hub from there I can comtrol via app. I can also use up and down keys on stats themselves to change temp settings. I have now found the way to see room temp and floor temp, they are set to show room temp only.

 

I have no idea on the way this whole thing works, I have a plant room I do not understand.  Pre move in I bought a lable  machine in anticipation of a handover where I could lable  things for future ref.  That handover never happened. I was never shown anything on the heating system (or anything else) at all and have been trying to work it out via trial and error....and very much error.

 

Pipes only seem to get warm if I do as @Nickfromwales suggests and ramp the floor temp right up into the mid 30’s

 

I dont know what the floor temp should be relative to air temp and which is controlling which.

 

All I want to do is get it so that the house is at an even temp of mid 20’s say from 7am-10pm with a little cooler overnight.

 

Those little blue bits on the actuators seem to pop up randomly - when pipes are cold and there is no heating.

 

My installer is not local and I have been waiting weeks for him to come and look at mvhr which has issues,  I will add heating to the list and hope he comes before the really cold weather meantime all help to get it working in some fashion gratefully received.

[PeterW]

5 minutes ago, lizzie said:

Those little blue bits on the actuators seem to pop up randomly - when pipes are cold and there is no heating.

 

 

Thats correct - they pop up to allow hot water into the loops. 

 

Do  you have the schematic ..??? Would be useful to see what was designed. 

[lizzie]

1 minute ago, PeterW said:

 

Thats correct - they pop up to allow hot water into the loops. 

 

Do  you have the schematic ..??? Would be useful to see what was designed. 

Ah good to know that about the pop ups!

 

I do have the schematic I have to dash out now but will put it on when I get back later and thank you.

[ProDave]

14 minutes ago, lizzie said:

pipes only seem to get warm if I do as @Nickfromwales suggests and ramp the floor temp right up into the mid 30’s

 

I dont know what the floor temp should be relative to air temp and which is controlling which.

 

That's because less than 30 and they won't feel warm to the touch.

 

If you want the room to heat to mid 20's (which would have m sitting in my boxers complaining it was too hot) you are going to need a floor temprature of 30 or more anyway I suspect.

 

So start with the manifold mixer hot enough you can feel the heat to determine what is ans what is not working, then when it is all sorted and working wind the temperature down a bit.

[Nickfromwales]

14 hours ago, ProDave said:

I know this won't help but I don't like those Heatmiser programmable thermostat things. They are complicated beasts to set up.  Give me a simple thermostat with a dial, and a separate conventional central heating time clock to set the on and off times (that's what I have in my house)

Rotary mechanical room thermostats are not at all suitable for UFH and give terrible over / undershoot. The digital controls are king for UFH as otherwise you have no idea of what temp you’ve selected or what temp the room is currently at. 

The cruder the controls, the worse the performance. 

[AliG]

I agree, I have the Heatmiser system and it is fantastic for seeing what is going on and quickly programming multiple thermostats.

 

I can call my wife and have her tell the builders to close the door when they leave it open as I can see straight away the temperature dropping in a room. See below for the utility room over the last week.

 

It was the Heatmiser that helped me to see the heating wasn't working correctly as I can see the temperature ramp up on the charts that it provides when the heating comes on and that wasn't happening in some rooms.

 

Floor and air sensors are unusual in a wet UFH system. Presumably you just set the room temperature so the installer must set up the floor stats to limit the floor temp relative to this.

Edited September 17, 2018 by AliG

[Nickfromwales]

To be getting meaningful hearing input, all of the ( utilised ) zone lights need to be on on the control box and that will show ‘call for heat’ aka demand from each zone. 

A single zone ( eg one stat controlling a large area ) can be multiple actuators all operating from the one demand. Not all wiring centres are fully utilised eg you may have to buy and 8-way cry to connect 5 zones, so 6,7 & 8 will be redundant. 

Turn all the stats down to zero and wait 10 mins, then turn one up to max. See if, after 10 mins or less, a zone light lights on the ctr and heat can be felt in one or more pipes. If they can, make a note of which pipes get warm ( which actuators can be seen to be open ( blue indicator ? )) and switch everything back to zero. Leave the system cool down for an hour or so and repeat with the next room stat leaving the previously tested one off. 

Spend a day on it for your own sanity and then when lazy bollocks eventually turns up you can be better informed and not so easily fobbed off. 

PS, ring him today and tell him he has 5 working days to attend site. Inform him that if he fails to attend then you will pay another plumber to check his work and rectify and he shall have the bill. Guys proper taking the piss. Stop being so nice and give him a deadline. Beware that if other trades have adjusted anything that we can’t idebtify here he may play the ‘not my fault’ card, possibly with merit, so let’s get through as much here as we can. 

 

This could simply be the loops airlocked and that the system wasn’t commissioned properly. We’re you about when the system was filled with water and tested ? They should have connected a hose to a drain from the UFH manifold and used cold mains pressure to blast each loop through. If that wasn’t done and it was left to purge itself then that’s wrong and you’ll likely have airlocks. 

[Nickfromwales]

1 minute ago, AliG said:

Floor and air sensors are unusual in a wet UFH system. Presumably you jus set the room temperature so the installer must set up the floor stats to limit the floor temp relative to this.

Agree. Normally the high limit stat is directly on the manifold flow. If the flow temp gets over 50oC for eg then the stat contacts break. The manifold pump is fed via those contacts. 

Very strange to have floor sensors, @lizzie can you have a squint at the MIs to see if you can deselect them in the programming. ? Go on, you can’t break it lol. 

[Ferdinand]

18 minutes ago, Nickfromwales said:

Rotary mechanical room thermostats are not at all suitable for UFH and give terrible over / undershoot. The digital controls are king for UFH as otherwise you have no idea of what temp you’ve selected or what temp the room is currently at. 

The cruder the controls, the worse the performance. 

 

I have these, which are probably the devil's spawn, but I just have them all set high enough to be out of the loop.

 

We run it as essentially a single zone, and if I want a room excluded I just turn it right down.

 

 

Ferdinand

 

Edited September 17, 2018 by Ferdinand