Noisy CH system

[bikeit]

I recently got a new pump and motorized valve fitted to my central heating system, but since there are noises coming from the rads and valves, the noise coming from the rads sounds like gushing water and a kettle boiling, and the noise coming from the valves sounds like a whistling noise, i tried adjusting the pump settings from no 1 to 2 and three, when at no 1 one rad does heat up but there is no noise, at no 2 and 3 the noises return, can someone please offer me any help.

http://www.screwfix.com/p/wilo-yonos-central-heating-pump-6m/59045
http://www.uk-plumbing.com/myson-2-port-power-extra-22mm-zone-valve-p-1430.html

 

[D_Hailsham]

Was the old pump a 6 metre one?

If not, why did you buy a 6m pump?

Have you tried the pump on the variable speed setting?

How many rads on your system?

 

[bikeit]

Not sure if the old one was 6 metres it was a Wilo gold pump, what does the 6 metres mean?
What does the variable speed selection do?
There are eight rads on the system two are double rads.

 

[D_Hailsham]

What does the 6 metres mean?

6 metres is the maximum pressure the pump can deliver.

A heating circuit offers resistance to the water flow due to the size of the pipes, number of bends etc. The pump has to be sized so that, at the required flow rate, it can provide sufficient pressure to overcome the circuit resistance.

When you say that you set the pump to 1 and only one rad heated up, do you mean that you set it to 1.0m? If so, 1.0m is the maximum pressure the pump will be able to deliver. An eight rad system will be more than that.

Do you have TRV's on your rads? If so, remove all the heads, so the TRVs will not shut off the rads. Now slowly increase the pump pressure (starts at 1.0m and goes up in steps of 0.1m) until all rads are heating up. The pump is now set to deliver the correct flow rate when all rads are working at full output.

Replace all TRV heads, set them to maximum and check that the rads are still heating up OK. If necessary adjust the pressure.

With the TRV heads in place and set to the required setting (3 or 4 for a living room), the flow rate and pressure offered by the circuit will change as the TRVs open and close. You therefore need to set the pump to Variable Differential Pressure, so it automatically adjusts the pump output to meet the changing requirements.

 

[bikeit]

When the pump is set to no 1 all but one rad heats up but it takes a while, only one rad has a TRV valve which is in the living room, not sure if this makes any difference but there is a room stat also in the living room.

D-Hailsham wrote:
Now slowly increase the pump pressure (starts at 1.0m and goes up in steps of 0.1m) until all rads are heating up. The pump is now set to deliver the correct flow rate when all rads are working at full output.

Is this setting on the right or the left hand side of the red turn knob on the pump?

 

[D_Hailsham]

When the pump is set to no 1 all but one rad heats up but it takes a while, only one rad has a TRV valve which is in the living room, not sure if this makes any difference but there is a room stat also in the living room.

I see. I think you left 'not' out of this: when at no 1 one rad does not heat up

As all rads but one heat up with it set to 1.0m, you should only need to increase the pressure a little.

TRVs and room stats in the same room are not advisable as they can conflict. Set TRV to 25C and room stat to 21C - result the room will never reach 25 as the room stat turns the boiler off at 21C, Set TRV to 21C and room stat to 25C - result the TRV turns the rad off at 21 C, so the room stat never reaches 25C,which means the boiler will never turn off.

The solution, in your case, is to set the TRV in the room to its maximum (about 28C),. The room stat then has full control.

Is this setting on the right or the left hand side of the red turn knob on the pump?

On the left side.

PS Has your system been balanced?

 

[bikeit]

I balanced the system the first rad on the system to heat up is in our sons bedroom i opened both valves a quarter turn, the next rad to heat up is our bedroom i opened both the valves half turn and so on until i got to the last rad to heat up which is in the hall and i opened it fully both sides and its that rad that does not heat up.
What side on the red turn knob on the pump do i need to adjust left or right hand side

 

[D_Hailsham]

I balanced the system the first rad on the system to heat up is in our sons bedroom I opened both valves a quarter turn, the next rad to heat up is our bedroom I opened both the valves half turn and so on until I got to the last rad to heat up which is in the hall and I opened it fully both sides and its that rad that does not heat up.

I'm sorry to say that your system is not properly balanced. How far away the rad is from the pump is only part of the story, the size of the rad is also relevant.

Here's a quick method, which will give reasonable results.

Remove TRV head and set valve at opposite end to one-third turn open.

On the other rads:

Identify which side of each rad is the hotter and set the valve fully open; set the valve at the opposite end one-third of a turn open. If you find that the LS cap is on the 'hot' end, you will probably be able to just swap the cap with the wheel head at the other end.

Set the pump to constant pressure by turning pump knob to the right and raise the pressure (the 'm' setting) until the last rad is warm.
Let the system warm up and temperatures stabilize.

Repeat the following for all rads until you are satisfied
Feel the return (cooler) pipe on each rad and compare it to the last rad. If the return is warmer, close the LS valve by a very small amount; if it's cooler, open by a very small amount. You will find that the temperature of the last rad changes as you alter the earlier rads in the change. The amount of change you should make is minimal.

Let the system temperatures stabilize.

Recheck the pump setting - you may be able to lower the pressure.
End of repeat

Replace TRV head and set to required setting.
Set the wheel valves (hotter side) of all other rads as required.

What side on the red turn knob on the pump do i need to adjust left or right hand side

When you have finished balancing the system, turn the knob to the left and set the pressure to the value you had when balancing was finished.

NOTE
For balancing you turn the knob to the right to set the pressure; when the system is running you turn it to the left to set the pressure.

 

[bikeit]

Thanks mate i really do appreciate your advise, i will try it at the weekend as i dont get home from work till late in the evening, its a pity you don't live closer to me i could give you a job.

 

[bikeit]

Update.
Before i started i checked all the rads for air two had some air the rest where fine, so i done as you advised and the rads are all balanced and they are all heating up nicely, the noises in the rads are all now gone and the reading on the left hand side of the pump is 9 so is this now job done?

 

[D_Hailsham]

the reading on the left hand side of the pump is 9

It sounds as if the job is done, but I don't understand the 9. Is it 9 with a W or 0.9 with an M?

If you can post a pic it would help.

 

[bikeit]

I think the reading is .9M ??

 

[D_Hailsham]

I think the reading is .9M ??

Certainly looks like it. It's a very good result - possibly too good.

If you find that the rads furthest from the boiler do not heat up properly when it is very cold you should try increasing this setting a bit at a time until the rads are heating up properly.

 

[bikeit]

When you say "It's a very good result possibly too good" what do you mean?

 

[D_Hailsham]

When you say "It's a very good result possibly too good" what do you mean?

Just that it is a very low pressure loss round the system. But that couold be due to the fact that it has been corectly designed and the right size pipes used. Most systems have a loss of about 3m.

It's nothing to worry about. In fact, it's a good thing as it means the pump will be using very little electricity to circulate the water.