Correct installation of pump for system with UFH and radiators for large house

[Samsg30]

Hi,

I am looking for some qualified advise here to deal with a 'noisy' radiator issue (not because of air .. but because of a high flow of water through the radiators due to heavy pump installed by the engineer.

It all started when I got new boiler and plumbing done recently as part of house refurbishment. House has got a large area with wet underfloor heating (UFH) for ground floor and 10 wall radiators for other rooms / areas not covered by UFH and a unvented cylinder.
Boiler is Vaillant 35kwh system boiler

This whole setup is installed in a separate boiler room which is in the garage in one end of the house. House is 2 storey (Ground floor + 1st floor)

The vaillant boiler seems to have a inbuilt pump already. The UFH system also comes with a pump attached to the manifold.
When I was running the Radiator heating, We were not getting 2-3 radiators installed at the extreme end of the property heating up at all.
Plumber (gas safe engineer) suggested that the internal boiler pump is not strong enough to push water so he installed a heavy pump (marked as 1 with orange).
However, he installed pump in the main flow pipe thus, irrespective there's a demand for just hot water, UFH or Radiator or all any combination of these three.. that heavy duty pump turns on. This is in addition to the less heavy duty pump installed in front of manifold for UFH and the internal pump within the boiler.

Now the issue is, when I run both UFH and radiators, all works fine. But as soon as UFH demand is turned off (by thermostat) and only Radiators heating demand is on, the water flow noise in the radiator is immense as if someone is pushing water with a lot of force.

If I turn down the pump power using the dial (to reduce the water flow noise in the radiator), when both UFH and radiators are on, I can feel that UFH is not heating up as quickly as it should.

So, my question is, should he be installing this pump in the pipe that is only catering for radiator so I can run this pump on minimum settings and this pump should only turn on if there's a demand for Radiator heating.
And if there's a demand for UFH at the same time, the pump next to manifold will turn on. If there's a demand for hot water only, none of these two pumps will turn on and only the internal boiler pump is sufficient.
This way, depending on which of the combination is used, the respective pumps will take care of the water flow.

So, do you think it is the right solution to put that pump 1 in the pipe marked with blue up arrow? Plumber would need to move the zone valve up and install pump before the zone valve.

I think he needs to make some loop as well so that hot water within the pipe can continue flowing if zone valve is shut but pump is running for a while to cool down the water in return and flow?

Appereciate some guidance.

Thanks
Sam

 

[trojanhawrs]

Run 1 on min and raise speed on 2?

 

[Johntheo5]

Hi,

I am looking for some qualified advise here to deal with a 'noisy' radiator issue (not because of air .. but because of a high flow of water through the radiators due to heavy pump installed by the engineer.

It all started when I got new boiler and plumbing done recently as part of house refurbishment. House has got a large area with wet underfloor heating (UFH) for ground floor and 10 wall radiators for other rooms / areas not covered by UFH and a unvented cylinder.
Boiler is Vaillant 35kwh system boiler

This whole setup is installed in a separate boiler room which is in the garage in one end of the house. House is 2 storey (Ground floor + 1st floor)

The vaillant boiler seems to have a inbuilt pump already. The UFH system also comes with a pump attached to the manifold.
When I was running the Radiator heating, We were not getting 2-3 radiators installed at the extreme end of the property heating up at all.
Plumber (gas safe engineer) suggested that the internal boiler pump is not strong enough to push water so he installed a heavy pump (marked as 1 with orange).
However, he installed pump in the main flow pipe thus, irrespective there's a demand for just hot water, UFH or Radiator or all any combination of these three.. that heavy duty pump turns on. This is in addition to the less heavy duty pump installed in front of manifold for UFH and the internal pump within the boiler.

Now the issue is, when I run both UFH and radiators, all works fine. But as soon as UFH demand is turned off (by thermostat) and only Radiators heating demand is on, the water flow noise in the radiator is immense as if someone is pushing water with a lot of force.

If I turn down the pump power using the dial (to reduce the water flow noise in the radiator), when both UFH and radiators are on, I can feel that UFH is not heating up as quickly as it should.

So, my question is, should he be installing this pump in the pipe that is only catering for radiator so I can run this pump on minimum settings and this pump should only turn on if there's a demand for Radiator heating.
And if there's a demand for UFH at the same time, the pump next to manifold will turn on. If there's a demand for hot water only, none of these two pumps will turn on and only the internal boiler pump is sufficient.
This way, depending on which of the combination is used, the respective pumps will take care of the water flow.

So, do you think it is the right solution to put that pump 1 in the pipe marked with blue up arrow? Plumber would need to move the zone valve up and install pump before the zone valve.

I think he needs to make some loop as well so that hot water within the pipe can continue flowing if zone valve is shut but pump is running for a while to cool down the water in return and flow?

Appereciate some guidance.

Thanks
Sam


View attachment 366598

Is that "booster" pump a Wilo??, if so, post a close up view of the pump front and also the exact model, ie Wilo Yonos Pico.

 

[Samsg30]

@Johntheo5 Pump 1 (booster pump) is indeed Wilo Yonos Pico. See the attached photos.
Can you recommend on which settings Pump 1 (booster pump) and pump 2 (UFH pump) ideally should be on?

Booster Pump photo and model:

UFH Pump Model and photo:

 

[omph]

What pump are you using for UFH and what speed is it on ?
Also, how do you use your UFH ? its usually designed to run at lower temps (20-28c) for longer periods (ideally 24/7).

 

[Johntheo5]

Now the issue is, when I run both UFH and radiators, all works fine. But as soon as UFH demand is turned off (by thermostat) and only Radiators heating demand is on, the water flow noise in the radiator is immense as if someone is pushing water with a lot of force.

If I turn down the pump power using the dial (to reduce the water flow noise in the radiator), when both UFH and radiators are on, I can feel that UFH is not heating up as quickly as it should.

View attachment 366598

What is the boiler flow temperature?
What are the UFH manifold flow & return temps?

Not familiar with the UFH circ pump but certainly are with the Wilo as I have one, yours is a 8M (mine is 6M), you have it set to constant speed II which is 5.5M. Does your pump display the flowrate in m3/hr as well as the power in watts?

Would suggest when the RADS & UFH are both running normally and up to temperature, note the pump (Wilo) power W (watts) (& the flowrate, if displayed.)
Then turn the setting knob Anticlockwise?? towards the radiator symbol and briefly stop turning it when the pointer is well into the houses, the set (PP, proportional) pressure will flash for 3 secs or so and then revert to showing the power, W, fine tune turning it until the power is exactly the same as it was in its original setting (also note the flashing pressure when you have achieved the power setting), this should/will give you the exact same head/flow as originally but when either the UFH or rads are turned off then the pump will ramp down and should/might still give enough head to satisfy either the rads or the UFH but without the noise.

 

[Samsg30]

What is the boiler flow temperature?
What are the UFH manifold flow & return temps?

Not familiar with the UFH circ pump but certainly are with the Wilo as I have one, yours is a 8M (mine is 6M), you have it set to constant speed II which is 5.5M. Does your pump display the flowrate in m3/hr as well as the power in watts?

Would suggest when the RADS & UFH are both running normally and up to temperature, note the pump (Wilo) power W (watts) (& the flowrate, if displayed.)
Then turn the setting knob Anticlockwise?? towards the radiator symbol and briefly stop turning it when the pointer is well into the houses, the set (PP, proportional) pressure will flash for 3 secs or so and then revert to showing the power, W, fine tune turning it until the power is exactly the same as it was in its original setting (also note the flashing pressure when you have achieved the power setting), this should/will give you the exact same head/flow as originally but when either the UFH or rads are turned off then the pump will ramp down and should/might still give enough head to satisfy either the rads or the UFH but without the noise.

Thanks @Johntheo5 . I have set this up to medium size home setting within the radiator section which is now giving 1.5m3/h flow with 38-41w power and showing 4.6m. I can see that radiators are not making same noise as earlier and they are getting hot along with the UFH.

Boiler is set as max 66C flow temperature but what I noticed is that it kind of stays at 59C when UFH and radiators are running for 1.5hrs in the morning. As soon as UFH turns off (based on timer) and let radiator run, the flow temperature reaches upto 66C and stays there until all heating demand is off.

UFH is set at MAX (see image) and the pump is on level III

We have setup UFH to come on twice a day (1.5hrs in morning and 1.5hrs in evening) and setup to run Radiators and HW at the same time but for 2 hours.

We are finding it comfortable in house whole day but people have suggested that UFH should be lowered down to temperature like 25c and leave the time ON all the time and let the zone thermostat turn it on/off automatically.
Does that mean less gas bill and boiler will run at lower flow temperature if only UFH is running with this white dial turned down to 25C?

Moreover, do you think pump settings looking OK? Since if only HW is on, still the main pump will push water at 1.5m3/h flow. Not sure if that's an issue. If all good, I won't bother plumber to do any unnecessary plumbing in moving the pump etc.

 

[Exedon]

Assuming your underfloor is a in screed type (not overlay) your not running it correctly.
It should be controlled by room thermostats that have a back set position.
You have a desired temperature when you want rooms heated and a back set temperature for night times or when rooms not occupied. This is typically 4 or 5 °C less than desired temperature.
You can certainly try turning down the blender valve temperature down but without knowing what criteria we're used to calculate your underfloor output its probably a bit suck it and see.

 

[Johntheo5]

Thanks @Johntheo5 . I have set this up to medium size home setting within the radiator section which is now giving 1.5m3/h flow with 38-41w power and showing 4.6m. I can see that radiators are not making same noise as earlier and they are getting hot along with the UFH.
[

That PP setting at (if) 4.6M looks like the pump is producing a 3.6M head to give 1.5m3/hr, you might just check/post the flow rate and watts when running on CH only and UFH only.

What is on when the Wilo is just reading 15W??.