Underfloor heating

Mach Two

What is the maximum I can set the mixer valve rate to for the underfloor heating to. It goes from 30-55.

Doorcase

Hi. Quick question. Haveunderfloor heating and upstairs is very slow to heat. I have two loops into each bedroom. Not sure on length cause installers were a disaster. Any tips on flow rate liters/min I should be running. Liquid screed with laminate flooring. Thanks

Dr4gul4

Mach Two wrote: »

What is the maximum I can set the mixer valve rate to for the underfloor heating to. It goes from 30-55.

Difficult say for sure, I have both floors done here with UFH, 42 down starts, 35 upstairs. they could be generic.. 

Doorcase wrote: »

Hi.  Quick question.  Haveunderfloor heating and upstairs is very slow to heat.  I have two loops into each bedroom.  Not sure on length cause installers were a disaster.  Any tips on flow rate liters/min I should be running.  Liquid screed with laminate flooring.  Thanks

Distance, and floor area make up the flow rate i believe, as an example, my landing is 17 m2 just one circuit, my flow rate is 2.2 for this zone.

hatchman

U may be able to increase flow rate to upstairs by reducing flow to all other areas

Doorcase

hatchman wrote: »

U may be able to increase flow rate to upstairs by reducing flow to all other areas

I’ll have them all set around 2 l/min now. I know that’s not ideal but it’s the best for now. Seems to work ok at that downstairs although that is tiled.

Doorcase

I looked at my flow and return temputures on lcd and they are the same almost. There should be a difference of at least 5 degrees. Anyone have a idea why so. If flow meters are set low this should not happen surely. Causes heatpp to stop heating water.

Dr4gul4

Doorcase wrote: »

I looked at my flow and return temputures on lcd and they are the same almost.  There should be a difference of at least 5 degrees.  Anyone have a idea why so.  If flow meters are set low this should not happen surely.  Causes heatpp to stop heating water.

I assume you mean the flow and return at the boiler ?  whats the temps at the manifold ?

Doorcase

ok so here is what I make of my problem. If my flow rates are to low my return temputure is to high and Daikin Altherma can not keep 5 degrees between flow and return. Delta T. So turns pump off. So I increased flow rates which fixed problem a good bit. But if I want to heat one room it’s not enough to keep the 5 degrees difference. If I heat a few rooms it’s ok as the return temp is lower. Any soloutions ?

John.G

Doorcase wrote: »

ok so here is what I make of my problem. If my flow rates are to low my return temputure is to high and Daikin Altherma can not keep 5 degrees between flow and return. Delta T. So turns pump off. So I increased flow rates which fixed problem a good bit. But if I want to heat one room it’s not enough to keep the 5 degrees difference. If I heat a few rooms it’s ok as the return temp is lower. Any soloutions ?

I take that your heat pump requires a minimum DeltaT of 5C? one would think that increasing the flow rate would reduce the DeltaT or/and is there a maximum return temperature specified as well before the heat pump cuts out?.

I don,t know anything about UFH but mathematically, I (or anybody) can certainly calculate the heat emitted based on the flow rate and delta T between the flow and return temperatures.
Heat emitted, KW = Flow rate in LPM x 60 X Delta T between Flow & return temperatures / 860
So KW = LPM*60*DeltaT/860
So @ 2 LPM & 5C DeltaT, KW = 2*60*5/860 = 0.7 Kw, if for example you had 10 rooms all set to have a flow rate of 2 LPM and IF (unlikely) they all had a DeltaT of 5C then he total heat requirement would be 10*0.7 = 7.0 KW.
IMO the only way one can increase the heat emitted to any room is either to increase the flowrate (which reduces the DeltaT) or increase the flow temperature at the same flowrate (which increases the DeltaT).
It follows from the above that if a heat pump requires a minimum DeltaT of 5C then the only way to avoid going below this minimum is to either increase the flow temperature at the same flow rate or decrease the flow rate at the same flow temperature or increase the flow rate and the flow temperature but ensuring that the DeltaT doesn,t fall below 5C.

Dr4gul4

Doorcase wrote: »

ok so here is what I make of my problem.  If my flow rates are to low my return temputure is to high and Daikin Altherma can not keep 5 degrees between flow and return. Delta T.  So turns pump off. So I increased flow rates which fixed problem a good bit.   But if I want to heat one room it’s not enough to keep the 5 degrees difference.  If I heat a few rooms it’s ok as the return temp is lower. Any soloutions ?

Whats the boiler heating the flow temp to ? and whats your mixer valve set to ?

Doorcase

I think my flow value that installer put in has stuck or something. That would explain the hot return. He installed it cause there was not enough flow. Must be to much getting through now

Dr4gul4

Doorcase wrote: »

I think my flow value that installer put in has stuck or something.  That would explain the hot return.  He installed it cause there was not enough flow.  Must be to much getting through now

Can you provide a photo of it ?

Doorcase

At work here. It’s just a screw valve between flow and return on upstairs manifold.

Dr4gul4

Doorcase wrote: »

At work here.  It’s just a screw valve between flow and return on upstairs manifold.

I assume it's something as per the attached ?

Doorcase

ALTECNIC ERES 22MM STRAIGHT BYPASS VALVE

Dr4gul4

Doorcase wrote: »

ALTECNIC ERES 22MM STRAIGHT BYPASS VALVE

That's your Bypass valve,  look at the pipes entering the manifolds, and the pump the drives the water in on the hot side. perhaps you have something like the attached. 
That's the mixer valve just below the pump.

Doorcase

Dr4gul4 wrote: »

That's your Bypass valve,  look at the pipes entering the manifolds, and the pump the drives the water in on the hot side. perhaps you have something like the attached. 
That's the mixer valve just below the pump.

No I don’t think so. It’s a combo unit so all is inside unit. Would the bypass valve be open to much hence the hot water that did not go into the zones bypass straight into the return pipe. So if I have only one zone open it’s mainly hot water returning?

Dr4gul4

Doorcase wrote: »

Dr4gul4 wrote: »

That's your Bypass valve,  look at the pipes entering the manifolds, and the pump the drives the water in on the hot side. perhaps you have something like the attached. 
That's the mixer valve just below the pump.

No I don’t think so. It’s a combo unit so all is inside unit. Would the bypass valve be open to much hence the hot water that did not go into the zones bypass straight into the return pipe. So if I have only one zone open it’s mainly hot water returning?

It's possible the bypass valve is allowing to much back. As you have a heat pump, I'm not 100% sure on the use of the return, the theory of ufh is, thermo calling for heat, zone opens, heat flows in, mixes, the return hits the blend valve, and based on temp,goes back to the boiler/heat pump, or stays in the manifold untill the return temp on the return side of the manifold is lower than expected. And then returns to the boiler/heat pump.

A by pass value is used to reduce the load on the pumps when no circuits are open.

Can you provide a snap of your manifold

Doorcase

Yeah I think I need to adjust bypass from what I have read as it adjusts return temputure. If that’s unsuccessful I’ll post a pic. Thanks for your help. Hopefully this sorts it. Cheers

Latro

Doorcase wrote: »

ok so here is what I make of my problem. If my flow rates are to low my return temputure is to high and Daikin Altherma can not keep 5 degrees between flow and return. Delta T. So turns pump off. So I increased flow rates which fixed problem a good bit. But if I want to heat one room it’s not enough to keep the 5 degrees difference. If I heat a few rooms it’s ok as the return temp is lower. Any soloutions ?

Is your heat pump inverter type or constant speed?

Is the circulation pump inside the monoblock/hydroblock unit or is it somewhere outside?

Can your heat pump modulate speed of water flow or is it up to you how you set it?

Doorcase

Pretty sure bypass valve is screwed. It’s the only explanation. Will get plumber to change it