New pump setings

[bikeit]

Had to get a new pump fitted on the central heating / hot water system and the plumber fitted a new Wilo Yonos pump, but when he left he had the red turn knob on the pump set to the bleed function, i would never had know this only we where getting this surging noise and thought i would investigate further so what should it be set to, the system is in a two story house with 8 rads.

http://www.wiloszer.hu/user/YONOS-PICO/WILO-YONOS-PICO-Manual.pdf

 

[D_Hailsham]

Call the installer back and get him to set it correctly - at no cost to you.

 

[bikeit]

I rang him several times and left a few messages for him to contact me, to date only silence. the plumber i normally use was away on holiday so thats was why i used this other plumber,

 

[Gasguru]

What was the old pump (and what speed setting was it on) and what is the new pump exactly...thats the numbers referring to the maximum head pressure.

The pump can operate in two different modes.

If most of the system has thermostatic radiator valves it may be beneficial to run it in the variable pressure mode...that's the left hand side from the middle bleed program setting.

However to keep things simple for now try setting at position 2 (clockwise from the bleed program) and see how it goes...

If the temperature drop across the radiators is excessive wind it round clockwise a little more.

Understanding these high efficiency pumps is difficult to explain over a forum.

 

[bikeit]

The old pump was a Wilo Gold i think, it was approx 20 years old, think it was set to number 3, only one radiator has a thermostatic valve which is in the living room, should have maybe also mentioned there is a room stat in the living room also.

 

[Gasguru]

Wind the setting round fully clockwise then

 

[bikeit]

So fully clockwise is Constant Differential Pressure, can you explain in laymans terms the difference between the two different settings please?

 

[Gasguru]

Variable pressure mode means that as radiator valves are turned down (or off) or TRVs shut down the pump pressure is reduced (it detects the system resistance through the motor current draw). Reducing the differential pressure helps prevent excessive noise across the valves (and in some cases the valve seats knocking).

Constant pressure mode means the pressure remains constant despite valves being shut down or off.

The previous pumps that just had fixed speeds would result in a pressure increase as valves shut down.

Bit more to it than this but that's the basics.

You've also got to consider the boilers minimum flowrates but with your oil boiler the settings probably not so critical.