Underfloor heating problem

PaulKK · 24-03-2012 10:51PM #1

Hi all,

Just bought a new house and trying to figure out the underfloor heating.

Had it on today for a few hours and it didnt seem to be heating up the floors at all, however I had hot water after approx 40 mins.

I checked the flow pipes on the manifold and they were warm but the returns were cold. The flow temp was reading 42 deg after the pump but the return only got just off the bottom, about 21 degrees. I had all the room stats up at about 24 degrees.

Here is the manifold:

The pump seemed to be working and was hot after approx 30 mins. It was set at speed 2 also, it seems to be a 3 speed.

Is it possible that the manifold is closed on the return? Or where is the best place to start? All valves on all pipes are open.

I have attached pics of boiler and the hot waterpump and pressure cylinder, apologies but I forgot to take a pic of the heating system pump, it is a grundfos I think.

Appreciate any advice.

freddyuk · 25-03-2012 12:00AM

New house you should have a commissioning certificate to show the system has been turned on and confirmed working correctly. If it has not been commissioned it could be full of air causing nil flow.
You can try turning the pump up to 3 but I suggest the installer /developer should be asked to confirm and resolve the problem.
There is an auto bleed valve there so try undoing the black cap to see if any air is released. Looking at the quality of the installation I would have concerns about the whole system.:eek:

PaulKK · 25-03-2012 12:11AM

House is approx 6 years old.

Yea it looks a bit amateur but can't do much about that now.

I had an engineer in approx 2 months ago and he checked everything over and said it was working. It was since switched off when when we had frost in case of damage.

How does one go about bleeding these? You mention black cap, it that the one on the return manifold on the left? Any other possible cause for this? There does not seem to be a distinction between heating water only or floors either (apart from using the immersion).

sullzz · 25-03-2012 09:04AM

Have you checked that all room stats are turned up , have you only gother 3 zones , i only see 3 actuators

heinbloed · 25-03-2012 11:34AM

Freddyuk and Sullz gave correct advise, but re-pressurise the system before further trials.

An air-vent is missing at the hot flow manifold. Hot water has a higher rate of dispensing any dissolved air than cold water, therefore an (automatic) air valve belongs at the hot/flow side.

If the boiler is equipped with it's original pump the pump's setting should be at III, at full power.

The pictures are not detailed enough to show the type of UFH piping, is that "brown Qualpex"? Or a different make,quality? Check the printing on the pipes.

PaulKK · 25-03-2012 07:22PM

Thanks everyone for the replies so far.

sullzz wrote: »

Have you checked that all room stats are turned up , have you only gother 3 zones , i only see 3 actuators

Yep all stats are turned up. I am curious myself as to why there are stats in all rooms when there are only three actuators.

heinbloed wrote: »

Freddyuk and Sullz gave correct advise, but re-pressurise the system before further trials.

Thanks, the pressure is over 1 bar when the system is running, is this high enough? If not, what is the procedure to re-pressurise?

heinbloed wrote: »

An air-vent is missing at the hot flow manifold. Hot water has a higher rate of dispensing any dissolved air than cold water, therefore an (automatic) air valve belongs at the hot/flow side.

Thanks, I will try to replace that asap.

heinbloed wrote: »

If the boiler is equipped with it's original pump the pump's setting should be at III, at full power.

I believe the pump is original, please see pic below.

heinbloed wrote: »

The pictures are not detailed enough to show the type of UFH piping, is that "brown Qualpex"? Or a different make,quality? Check the printing on the pipes.

It is a heavy duty see through plastic, my apologies but I do not know the make, I didn't think to check when I was in earlier.

More pics:

EDIT:

Just wondering is it possible to open those return valves manually? It seems just to be operated by a screw, but some of them are open to 2, some 4 etc. I presume this is to balance the system?

heinbloed · 25-03-2012 07:38PM

In your first posting the picture of the barometer at the boiler shows near-zero pressure.
This can't be correct. Read the manual of the boiler.

The expansion barrel might need topping-up, the membrane might be defect.

I never saw a pump like this (your last posting), it seems to be a mixer pump.

I never saw clear plastic used for oxigen tight UFH piping.

Is the yellow painted pipe the gas pipe and is the cable attached to it used as an earth wire? This installation should be thoroughly checked by a professional.

Get a heating engineer in, this CH system looks very unusual.

PaulKK · 25-03-2012 08:08PM

heinbloed wrote: »

In your first posting the picture of the barometer at the boiler shows near-zero pressure.
This can't be correct. Read the manual of the boiler.

The system was off when I took the pic, when it is operating the gauge reads over 1 bar.

heinbloed wrote: »

The expansion barrel might need topping-up, the membrane might be defect.

heinbloed wrote: »

I never saw a pump like this (your last posting), it seems to be a mixer pump.

I never saw clear plastic used for oxigen tight UFH piping.

Is that good or bad?

On the mixer thing, I presume that is what the "handle" is for, can you explain its purpose please?

Also, what is the round object on top of the pump with the screw on the side of it for? Is this for bleeding the system?

heinbloed wrote: »

Is the yellow painted pipe the gas pipe and is the cable attached to it used as an earth wire? This installation should be thoroughly checked by a professional.

Yep yellow is the gas and that is an earth wire.

heinbloed wrote: »

Get a heating engineer in, this CH system looks very unusual.

Its starting to look like that may be the solution

Again, thanks for your advice.

shane0007 · 26-03-2012 07:44PM

Guys, guys, there is some misadvice here. The system you have is a Heatlink system. The pipework is not qulapex. The gauges on the manifolds are flow and return temperatures. They are for information only. Flow temperatures should be 40 - 45C, with a return of 11C less. So you are not getting the correct flow rate. The big beast with the pump is your pump manifold for the ufh.

Can you hear air in the system and if so, unscrew the cap on the aav and open the other bleed screw with a radiator key to release air.

Check system pressure at the pressure gauge usully located close to the boiler or in the hot press.

It sounds more like a flow rate issue which is set on the blue actuator. This setting will depend on the length of the pipe run within that circuit. You should have a data sheet for the installation, otherwise it will have to be re-calculated.

The pump speed will be relative to the flow and return temperatures but it may be better upgrading it to a modulating pump to allow for open/closed circuits.

JohnnieK · 26-03-2012 09:53PM

You might also consider getting a modern up to date manifold set. When you said the pump gets hot is it scorching hot or just as hot as the pipe's?

Strange the boiler pressure gauge says zero. Are you sure there is one bar in it? One bar when cold!!

PaulKK · 27-03-2012 08:13AM

shane0007 wrote: »

Guys, guys, there is some misadvice here. The system you have is a Heatlink system. The pipework is not qulapex. The gauges on the manifolds are flow and return temperatures. They are for information only. Flow temperatures should be 40 - 45C, with a return of 11C less. So you are not getting the correct flow rate. The big beast with the pump is your pump manifold for the ufh.

Thanks, and my apologies, it is a Heatlink system, I should have said that from the start.

shane0007 wrote: »

Can you hear air in the system and if so, unscrew the cap on the aav and open the other bleed screw with a radiator key to release air.

Sorry for my ignorance, but what is the aav? Is it automatic air vent? Is that the small round item on top of the pump manifold with the screw at the side?

shane0007 wrote: »

It sounds more like a flow rate issue which is set on the blue actuator. This setting will depend on the length of the pipe run within that circuit. You should have a data sheet for the installation, otherwise it will have to be re-calculated.

The pump speed will be relative to the flow and return temperatures but it may be better upgrading it to a modulating pump to allow for open/closed circuits.

Thanks, I presume by blue actuator you mean the blue valves on the return? I will look for a data sheet in the house, there is some documentation left around the place.

JohnnieK wrote: »

You might also consider getting a modern up to date manifold set. When you said the pump gets hot is it scorching hot or just as hot as the pipe's?

Strange the boiler pressure gauge says zero. Are you sure there is one bar in it? One bar when cold!!

The pump wasn't scorching hot but it was hot.

The engineer mentioned that the gauge might be faulty, but as I said it does read over 1 bar when running so I'm not sure if that is the way its ment to work?

shane0007 · 27-03-2012 06:24PM

PaulKK wrote: »

Sorry for my ignorance, but what is the aav? Is it automatic air vent? Is that the small round item on top of the pump manifold with the screw at the side?

Yes an AAV is an automatic air vent. It is located on the return manifold in brass with a black plastic cap, although the cap seems to be missing on yours. The other vent is on the return manifold but is similar to a radiator vent.

PaulKK wrote: »

Thanks, I presume by blue actuator you mean the blue valves on the return? I will look for a data sheet in the house, there is some documentation left around the place.

Yes that is correct. The numbers 1-12 correspond to the set flow rate. They will be determined by the length pipe on that circuit and the type of use of the room it serves.

PaulKK wrote: »

The pump wasn't scorching hot but it was hot.

The engineer mentioned that the gauge might be faulty, but as I said it does read over 1 bar when running so I'm not sure if that is the way its ment to work?

It should read 1.0 to 1.5 bar when cold, higher when at full temperature. Always check this pressure when the system is cold.
I would also change your pump/mixing system as Johnniek states. You don't have to change the ufh manifold just remove the pump mixer and re-pipe to encorporate a more effective one.
Incidently the adjustment on the top of that mixer is bypass circuit between the flow and return and should not be adjusted.

sullzz · 27-03-2012 07:38PM

I would also check why you don't have actuators fitted to the other zones on the manifold as there are seven pipe runs connected to the manifold , id say if you were to check you probably have seven room stats , with them red caps fitted where the actuated should be they are possibly holding the pins down preventing circulation on them circuits .

PaulKK · 27-03-2012 08:06PM

shane0007 wrote: »

Yes an AAV is an automatic air vent. It is located on the return manifold in brass with a black plastic cap, although the cap seems to be missing on yours. The other vent is on the return manifold but is similar to a radiator vent.

So to bleed the system I can open this radiator-like vent on the return manifold? I presume the automatic vent is to relieve pressure in an over pressure situation?

shane0007 wrote: »

I would also change your pump/mixing system as Johnniek states. You don't have to change the ufh manifold just remove the pump mixer and re-pipe to encorporate a more effective one.
Incidently the adjustment on the top of that mixer is bypass circuit between the flow and return and should not be adjusted.

Thanks, what would you suggest to change it to? Would you know what the handle/lever on the side of the mixer is for? Adjusting the hot/cold mix?

sullzz wrote: »

I would also check why you don't have actuators fitted to the other zones on the manifold as there are seven pipe runs connected to the manifold , id say if you were to check you probably have seven room stats , with them red caps fitted where the actuated should be they are possibly holding the pins down preventing circulation on them circuits .

Yes I have 7 stats, 3 downstairs and 4 upstairs. Would you suggest removing the red caps in this case to allow the pins to rise and open that zone?

Thanks again for your help lads, it really is appreciated.

shane0007 · 27-03-2012 08:44PM

AAV's is not release pressure but only to release trapped air within the system. Open and re-tighten once air passes and you have water coming out.

The red caps are open loops. They will be uncontrolled loops, in that heat will circulate through them when any of the other 3 call in heat. I would certainly wire the system through motorized valves as this will eliminate these when another heat source is calling in heat, for example hot water or another manifold, etc. Your system will be based on 12v or 24v so this will have to wired through relays. Eliminate the set back mode within the heatlink system and wire in a separate timeclock to control each manifold.

You could remove the red cap and press the pin to ensure they are moving freely. Also remove each actuator and check pins there also. However, I do not think this is your problem. You have heat at 42C going in and only 24C coming out so the heat is going somewhere. Again, I think it is a flow rate issue and/or air. The basis of the heatlink system is basically ok but much improvements can be made. In short, you could easily half your fuel comsumption at the same time as increasing your heat output but some investment would have to be made.

Re: the handle, it looks like an adjustment lever to balance the flow and return temperatures. You could tinker with it but if you do not know what results to expect from an adjustment, then you should not touch it. With ufh, each slight adjustment within the parameters of the system will take a reaction time of approx 4 - 6 hours and therefore it can take considerable time to tweek a system with no design parameters. For example, by adjusting the flow rates on a circuit, with a flow temperature of 42C, it can take up to 6 hours for the return temperature to settle to its reaction temperature in full.

PaulKK · 27-03-2012 09:24PM

Thank you Shane, that is excellent advice.

I will definitely look into completely controlling each loop in time. I had thought the system was originally designed to be run like that and in fact I think this was even ment to be able to be controlled by sms etc when the houses were first advertised.

I am sure since there are 7 stats that there must be wiring for actuators in the vicinity of the manifold also.

I am hoping to get the keys officially tomorrow or Thurs so I will try out your advice re bleeding and testing the actuators and report back.

shane0007 · 28-03-2012 09:35PM

Everything will be wired back to a black wiring centre on a metal track pipe. This will be located close to the manifold as the actuators wire directly to it. The setback timeclock is also attached to this and it can be easily detached by sliding to the side.
Heatlinks are generally poorly installed by can be corrected fairly easily.

PaulKK · 28-03-2012 10:36PM

Thanks Shane, got in again today but didn't get a chance to turn it on.

The pressure is now reading 1 bar when the system is off:

I presume I can bleed the flow manifold with this:

Here is a pic of an actuator that was being held down by those red screw caps:

Also discovered two spare thermostat wires coming through the wall

I presume I can wire these into the control unit and then control the manifold with some electronic actuators at some stage?

What I am going to do tomorrow is turn it on, bleed the flow manifold, and leave off the red caps. Hopefully she heats up for me

PaulKK · 28-03-2012 10:48PM

Here is what those actuators are wired to:

shane0007 · 28-03-2012 10:50PM

Actuator pin is stuck closed.
From that pic, wiring looks a mess.
Check pressure gauge is working. Does it rise when heating is on for a bit?
Yes you can bleed air from that manifold there but also from the AAV.

shane0007 · 28-03-2012 10:51PM

Yes that is the wiring centre. There should also be a timeclock adjoining it, usually on the downstairs wiring centre. The upstairs wiring centre will also be wired back to the downstairs centre. You should also have a red & white control centre.

PaulKK · 28-03-2012 10:54PM

shane0007 wrote: »

Actuator pin is stuck closed.
From that pic, wiring looks a mess.
Check pressure gauge is working. Does it rise when heating is on for a bit?
Yes you can bleed air from that manifold there but also from the AAV.

How do I go about opening the pins? They are all like that (when system is off).

Yea its messy alright, bit all over the place, the cover for that box is broken too.

Pressure rises to approx 1.5 bar when system is on for a while.

I looked at the AAV and it doesn't look like it opens, its just a threaded piece of steel or something? Do I unscrew the entire brass piece?

PaulKK · 28-03-2012 10:56PM

shane0007 wrote: »

Yes that is the wiring centre. There should also be a timeclock adjoining it, usually on the downstairs wiring centre. The upstairs wiring centre will also be wired back to the downstairs centre. You should also have a red & white control centre.

There is an adjoining control box to the one above but I did not take a pic. My apologies.

Thanks again your advice is really excellent.

shane0007 · 28-03-2012 10:58PM

The cap is missing.
Pressure seems ok. I don't think there is a pressure issue.
How long has the heating being off? If it has been off for a long period, it will take a long time for it to get up to temperature, depending also on how good the floor & perimeter insulation is. It soulds like your flow temperature is good and the return temp is low because the slab is cold and taking the heat.

PaulKK · 28-03-2012 11:02PM

shane0007 wrote: »

The cap is missing.
Pressure seems ok. I don't think there is a pressure issue.
How long has the heating being off? If it has been off for a long period, it will take a long time for it to get up to temperature, depending also on how good the floor & perimeter insulation is. It soulds like your flow temperature is good and the return temp is low because the slab is cold and taking the heat.

It was off for approx 6 months, but was tested by an engineer 2 months ago who said it was working fine.

I had it on for about 3 hours the other day, the flow pipes got warm after a while but the returns were stone cold to the touch.

I had fairly hot water in the cylinder also after about an hour.

The floors were stone cold in every room though, no heat at all in them.

House is ICF construction and air tightness is good (no wall vents etc).

shane0007 · 28-03-2012 11:04PM

After 6 months, you won't get a decent reaction in 3 hours. Seems within the realms of it's parameters to me. You will need to test for longer.

Just concentrate on better controls.

PaulKK · 28-03-2012 11:07PM

shane0007 wrote: »

After 6 months, you won't get a decent reaction in 3 hours. Seems within the realms of it's parameters to me. You will need to test for longer.

Just concentrate on better controls.

Wow that's surprising, I thought it would have heated up in that length.

I should probably mention tat he had it on for a full day when testing.

Thanks, I'll leave it on for a longer period on Friday and see what happens then.

shane0007 · 28-03-2012 11:15PM

Also actuators pin is stuck. You will need to free that and check all others.

PaulKK · 28-03-2012 11:29PM

shane0007 wrote: »

Also actuators pin is stuck. You will need to free that and check all others.

I actually think this is the problem. They are all pressed down. How do i free them? Do i need to replace each valve? Sorry for all the questions.

shane0007 · 29-03-2012 08:45AM

You can try moving them with something narrow and blunt or they can be dismantled. If the latter, you will need to isolate the circuit, make note of the number on the blue actuator, then turn to zero and then you can unscrew the actuator head. Once re-instated, re-set the blue head setting to the previous setting and repeat for the others.

tinofapples · 25-09-2012 01:37PM

Have your issues been resolved? We have UFH downstairs in our house and am frustrated by it's preformance, would love to callback the installer/plumber but that's a non-starter. He has since left the business.My main issue is some small areas seems to heat alot better than the floor as a whole, surely this shouldn't be the case ? Just looking at the manifold today and reading this has also made me realise something is missing from the manifold , what is possible called an actuator or at least an actuator ring.What does this missing mean for my setup ? Would it cause my system to call for heat constantly for that particular zone ?

Here's the manifold:

I think i may need to purchase one of these babies :
http://www.pulsar.ie/alpha-actuator-replacement-ring-moh.html

Do Pulsar sell to Joe Public ?

tinofapples · 25-09-2012 08:31PM

Can someone tell from my picture where I can remove an airlock from my system if one existed ?

tinofapples · 26-09-2012 12:37PM

Anyone ?

PaulKK · 20-10-2012 07:40PM

Just saw this now, got it resolved, the system just needed to be on for about 4 hours. I also checked the pins for each zone and a couple were stuck.

The heat is also a little patchy on tiled floors but im presuming thats the nature of the system.

Delighted with it at the moment only costing about 50e a month on gas.

Have it set for 20 min top up in morning and 2 hours every evening. Havent touched it for months now and its performing very well.

Underfloor heating problem

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