Central Heating Balancing query

[Longclough]

I have a few questions about balancing a central heating system.

The main reason I think that there is a problem is that when both CH and HW is ON, one of the radiators does not get no where near as hot as the others. When HW is off it gets warm, all be it it takes longer than the others and doesn't get as hot.

1) The system has 2 x 2port valves. on the other side of the valve is shut off taps. For both the CH/HW they are both fully open. Is this correct?

2) There is a Mix TRV and non TRV radiators. Should all TRV radiators have there lockshields fully open and controlled via the TRV. Should the non TRV be fully open at the non lock shield end and then temp set using the lockshield?

3) Is self balancing without radiator thermometers easy enough do and how? what would someone charge to do the balancing?

 

[xr4x4]

rads may require balancing if you have TRV's or not.

question to ask, is if your boiler is up to the job.

 

[D_Hailsham]

1) The system has 2 x 2port valves. on the other side of the valve is shut off taps. For both the CH/HW they are both fully open. Is this correct?

It sounds as if the flow through the cylinder has not been balanced.

Are the "shut off" taps just on/off taps (similar to washing machine taps) or are they gate valves?

Is there a valve on the return from the HW cylinder?

Should all TRV radiators have there lockshields fully open and controlled via the TRV. Should the non TRV be fully open at the non lock shield end and then temp set using the lockshield?

You have to balance the system for all rads using the LS valve.

Is self balancing without radiator thermometers easy enough do and how? what would someone charge to do the balancing?

Ideally you need thermometers (a single infrared thermometer can be used), but it is possible to do it by feel. A heating engineer could take a day balancing a system and there's no guarantee he will do it properly. He may even say that you don't need to balance rads fitted with TRVs.

Read How to balance a CH system.

 

[Longclough]

Thanks for your response so far.

The shut off is a gate valves. I believe that there is only one gate valve.

I have been trying to understand how the system works. As pipe work is in the airing cupboard I am not sure that can see it all. What is visible is pipe that comes into pump, feeds 3 pipes on other side of pump. 2 with valves, 1 for HW and then 1 for CH. On the other side of the valves are gates valves. I don't know what the other pipe is (is it a return pipe to boiler).

You have read the balancing guide and I am pretty sure. I have only checked a few radiators, but the lockshields were open way more than 1 1/2 turns. The last radiator is fully open as much as it can be opened.

Is there a major advantage to balancing the system?

 

[xr4x4]

Is there a major advantage to balancing the system?

yes you get more heat to the bigger rads that are further away by restricting the flow to the smaller rads.

 

[D_Hailsham]

The shut off is a gate valves. I believe that there is only one gate valve.

The you can use the gate valve on the HW pipe to balance the flow though the cylinder.

pipe that comes into pump

That's the flow from the boiler.

feeds 3 pipes on other side of pump. ... I don't know what the other pipe is (is it a return pipe to boiler).

If the third pipe is before either of the motorized valves, it's a bypass connecting the flow to the return. It's there to provide a path for the water when both motorized valves are shut but the pump is still running. There should be either a gate valve or an auto bypass valve on the pipe.

I have only checked a few radiators, but the lockshields were open way more than 1 1/2 turns. The last radiator is fully open as much as it can be opened.

Then the system has not been properly balanced. The typical valve is fully open at 1 1/2 turns.

Is there a major advantage to balancing the system?

1. It ensures all rads are giving the correct output.

2. A correctly balanced system may be able to run with the pump on a lower setting.

 

[Longclough]

D_Hailsham Thanks for your info.

I had a look at the pipework and see that it is a bypass pipe which also has a gate vlave connected to it (Which is fully opened).

The pump speed is set to 3 for the system. I have tried turning it down in the past to 2 (Due to the vibrating noise it makes) but one radiator did not warm at all.

I think my system does need balancing or I may just try and restrict the flow to certain radiators to see if this helps. Trail and Error or is not the best thing to try initially?

I read somewhere about balncing a HW cylinder that you should fully close the gate valve and then open it by half a turn at a time. Is this correct and what are checking for. Differential between flow and return to the cylinder?

Thanks again for everyones help

 

[xr4x4]

your gate valve bypass shouldnt be fully open.

 

[Agile]

The gate valve bypass is a cheap bodge and an auto is the correct component to be used. However it should be opened just enough to create a small flow through it. Start with system cold and turn on heating and adjust bypass FROM closed until just a little warmth is felt on the return side of the valve.

The pump should work fine on "2" if the system is properly balanced.

The cylinder gate can be closed and opened 1 1/4 turns as a starting point.

You have not told us what boiler you have so I cannot advise you on the differential to be aimed for. So for the time being hope for the cyl return being a bit cooler than its flow!

Tony

 

[Longclough]

Thanks Agile for your reply.

The boiler is a Potterton Suprima 40L (Temp setting at 60% ish). Pump is Wilco Gold 50. Tank is unvented Santon 150 Litre.

Before closing bypass I wanted to check that I is a bypass, I believe it is. I have attached an image.

Untitled

• Longclough
• 14 Jan 2011
• 1

All 3 gate valves are fully open. Do I shut the closest one (Bypass Return)

Also I have closed the LS valves on the 1st 2 radiators closest to the pump and then opened them by 1/4 turn. Both appear to heat before. Is this advisable or should I apply a more scientific method before trying anymore radiators.

 

[Longclough]

Over the weekend I attempted to balance my radiators as follows:

Work out order radiators warmed up. Closed lock shields on all radiators. Open the 1st 3 radiators by 1/4 turn, next so many be 1/2 a turn up to last radiator which is open 2 turns. I then turned on central heating and walked round the radiators in order and felt them warm up and adjsted LS so that all radiators warmed up at roughly the same rate.

Questions:

1) For the LS to physically fully open, it would be opened by 7 turns. However my range of LS open is 1/4 turn to 2 turns, is this correct or should I adjusted them all so the 2 turn radiator is open fully and 1/4 turn radiator is open 2 turns or is this incorrect!

2) Now I have balanced radiators I need to balance HW cylinder. Could someone explain how I do this, based on picture in previous post.

3) Agile mentioned about my by-pass and said that the gate valve should not be fully open. Can someone confirm whether it is a bypass (see pciture in previous post) and how I should adjust it!

 

[Agile]

The right hand valve seems to be the system bypass. Adjust as I explained before with HW off and CH on !

Adjust HW as I explained before to 1 1/2 turns open, wait 10 minutes and then feel or measure the flow and return to the cylinfer WHEN its reheating from nearly cold to be about a 10° C differential when both CH and HW are on together.

You dont seem very good at reading and doing what we suggest as you appear to prefer to do your own choice of different things and then forget what we have asked you to do. Either you are just disorganised or dont value our advice!

Tony

 

[D_Hailsham]

Over the weekend I attempted to balance my radiators as follows:

Not a bad first attempt, but you should read How to balance a CH system.

For the LS to physically fully open, it would be opened by 7 turns. However my range of LS open is 1/4 turn to 2 turns, is this correct or should I adjusted them all so the 2 turn radiator is open fully and 1/4 turn radiator is open 2 turns or is this incorrect!

The design of the typical LS means that you get full flow when it is about 2 turns open.

 

[Longclough]

Agile, thanks again.

I do value all your advice. I wanted to make sure that it was a bypass before adjusting it. I will follow your advice for the cylinder 1 1/2 turns and check after 10 mins when both HW. Expecting Cylinder return to approx 10 degrees cooler. Adjust bypass as per your post. It is better to fit an auto bypass and how?

In terms of radiator balancing I wasn't sure whether or not I have done it correctly as I did it starting with the 1st radiator 1/4 open and then adjusting the other radiators so that all heated up at approx the same rate. D_hailsham said a typical valve was fully open at 1 1/2 turns, whereas mine can be turned up to approx 7 turns, sowasn't sure if I was restricting all of them too much or not!

I mentioned the boiler was a potterton Suprima 40L in my previous post as requested

 

[Longclough]

To update,

I have closed the gate valve on the bypass, its now open about 2 turns. I was conservative. All radiators get warm still. Not balanced the cylinder yet, but dropped the pump speed to 2 and all radiators still get warm.

I think I should balance the radiators properly, rather than the method I have used, by being approximate. Where could I get some ok temperatures to measure inlet outlet temperature?