New UPS3 pump too powerful ?

[Graham1737]

Hi,
I have just had my central heating system "upgraded" for a four bed-roomed detached house. The heating company recommended going from the open vented system to sealed / pressurized system, new pump ( UPS3 Grundfos ) all new plastic pipework ( extending ) the 22mm feed and return pipes so no more than three rads on any 15mm pipework, new vertical steel coloume rads to ground floor and conventional horizontal rads upstairs. All fitted with Dryton TRV4s. Three motorized valves ( ground floor, upstairs and hot water) with two wall thermostats. The existing Valiant eco tech plus boiler and Magnaclean filter retained with new auto air vents and bypass valve.

Issues I am encountering are :

Noisy TRVs ( hissing ) assuming water rush ?.
TRVs on coloume rads not allowing the room to go beyond 20 degrees even at highest settings. (radiant heat issue ?. )
Hot water circuit also suffering from water rush (opening the valve on hot water tank inlet seems to ease this).

5 rads downstairs and 4 upstairs plus towel rail.

The heating company did return and drop the pump speed from 3 to 1 and re bled the system which helped but not significantly.

The pump is set on speed 1.

Is it possible that the pump upgrade in conjunction to longer 22mm pipping is pushing the water around with too much pressure ?.

What should the pump setting be ?.

Any help or advice gratefully received.

 

[John.g]

Set it to proportional pressure PP2 or constant pressure CP1.

 

[Graham1737]

Set it to proportional pressure PP2 or constant pressure CP1.

Thanks John.g. I will give setting PP2 a try.

Graham1737

 

[John.g]

If you find that setting a bit on the "weak" side, all rads not heating etc, change to CP1 which at a constant 3M head should be OK.

 

[Graham1737]

If you find that setting a bit on the "weak" side, all rads not heating etc, change to CP1 which at a constant 3M head should be OK.

I have also been looking at the Grundfos website for setting up the UPS3 and they recommend PP2 to reduce valve noise.

 

[Last Plumber]

You will only get around 45000 Btu through 22 mm plastic and around 20000 Btu through 15 mm plastic.
It sounds on the face of it that the pipework could be undersized.
It depends on the installation of course. I haven't seen it.

 

[John.g]

I have also been looking at the Grundfos website for setting up the UPS3 and they recommend PP2 to reduce valve noise.

It will, unfortunately Grundfoss PP settings are allways on the low side, the UPS2 were abysmally low. The UPS3 is certainly a big improvement, based on my own requirements (10 rads) of ~ 15LPM at a 3.5M head the UPS3 PP2 setting would give me 12.4LPM at a 2.40M head, if your system is a little less restrictive at say 15LPM at a 3.0M head then you will circulate 12.45LPM at a 2.45M head but if its more restrictive, say requires a 4.0M head at 15LPM then PP2 will "only" give 11.5LPM at a 2.35M head so maybe OKish, On my pump (Wilo Yonos Pico) you can incrementally change the CP or PP heads in 0.1M steps to give allmost any desired flow.

 

[Graham1737]

Would you know the technical support email for Grundfos UK ?. I have been going round in circles on their website trying to find it !

 

[John.g]

No, havn't got it unfortunately.

 

[Zippymark]

A simple thing i'd probably check is the locksheild valves on the rads. I've installed a tall column rad right next to the boiler before, and it was quite noisy, i turned the locksheild right down until the noise went, it had to be almost off.

I've found some column/designer rads are directional, i.e. the the flow and return have to be on the right side, which is ridiculous to me, as for some of them you can't just flip the radiator round and so if your flow and return are the opposit to what the radiator says, you're stuck.