Radiator balancing problem

[Jim900]

hello

I am trying to balance my radiators as I have heat on my first and second floors, but completely cold radiators on the ground floor. I'm not a plumber, so have followed instructions from the Internet.

I've bled all the radiators, opened all the lockshield valves to fully open, then noted down the order in which they got hot. I then let them cool down again, went to first radiator and shut the lockshield valve fully, switched on system, and gradually opened the lockshield until I had a 12 degree difference between the flow and return pipes (about 32 degrees c on the flow, 20 on the return)

the problem is that with this 12 degree drop, the radiator just doesn't get very hot - I have to open the lock shield valve further to get any decent heat in it, at which point the flow / return difference drops to almost nothing - about 34 degrees each. Surely that defeats the object of balancing?

I'm accepting that I have to just pay a professional to do it for me, but I'm baffled as to why it doesn't work!

 

[doitmyself]

You need a higher flow temperature when balancing; set it to about 75C.

A 12C difference is OK if you have and old non-condensing boiler, but if it's a condensing boiler aim for 15C to 20C. The boiler manual should tell you which temperature to use.

You must remove the TRV heads while balancing.

Try this method:

1. Set all LSVs to 1/2 turn open

2. (if possible) Adjust pump speed to give approximately the correct temp difference at the boiler.

3. Open or close all LSVs by the same amount until the boiler difference is correct. Open to raise return temp; close to reduce. Adjust by 1/12 turn at a time.

4. Measure the return temp of each rad and write it down.

5. Any rad with a lower return temp than the boiler should not be touched for the moment.

6. Those with a higher return temp than the boiler should have the LS valve closed very slightly, e.g 1/12th of a turn.

7. Wait 5-10 minutes for the system to settle down.

8. Repeat from 2 until all return temps are approximately the same.

DO NOT aim for perfection.

Replace TRV heads and set to required temperature.

Sorry for the poor layout. The instructions should be in a list, but the website is playing up big time.

 

[diamondgas]

Is your heating system old or new?
Is this something new or something that has always been an issue?
are you able to get the downstairs to heat with the upstairs turned off?

A bit more info on your system will benefit a better suggested remedy IMHO

Is it combi or fully pumped? etc...etc...

 

[Jim900]

Is your heating system old or new?
Is this something new or something that has always been an issue?
are you able to get the downstairs to heat with the upstairs turned off?

A bit more info on your system will benefit a better suggested remedy IMHO

Is it combi or fully pumped? etc...etc...

its a new problem, since I had an extension done in the summer. Builders fitted some new radiators but didn't balance them. The water drained out completely a few times due to 'leaks' and I did wonder if I had airlocks, hence I've bled all the radiators repeatedly.

its a fully pumped system, cold water storage tank in roof with red expansion vessel next to it, and hot water cylinder in airing cupboard on first floor. The pump is a grundfos alpha2 15-60. I've left it on the maximum speed setting as in auto mode the boiler kept dying (vaillant). Have got the boiler set to maximum temperature, and the cylinder thermostat is at 65 degrees.

If I switch off every single radiator in the house, I can get one downstairs to go hot, if I switch on all the downstairs ones they go lukewarm at best

 

[Jim900]

Is your heating system old or new?
Is this something new or something that has always been an issue?
are you able to get the downstairs to heat with the upstairs turned off?

A bit more info on your system will benefit a better suggested remedy IMHO

Is it combi or fully pumped? etc...etc...

Its a new problem, since i had an extension over the summer. The builders fitted new radiators but didn't balance them. The water drained out completely a couple of times due to 'leaks', and I wondered if I had airlocks, hence I've bled all the radiators repeatedly.

It's an old system that has been altered over the years - cold water storage tank in roof, with red expansion vessel next to it (new, used to be a header tank), hot water cylinder in airing cupboard, grundfos alpha2 pump (new), vaillant boiler (new). The boiler is set to run at maximum temperature, the hot water cylinder thermostat is set to 65, the pump is set to maximum speed. (I found that in automode the boiler kept dying with an f.23 fault - too little difference between flow and return.)

 

[doitmyself]

The pump is a grundfos alpha2 15-60. I've left it on the maximum speed setting as in auto mode the boiler kept dying (vaillant).

You must have the pump set to a fixed speed (I, II or III) when balancing.

Which Vaillant boiler do you have?

Do you have the 15-50 or 15-60 alpha pump?

I have managed to edit my earlier post so it is easier to read.

 

[diamondgas]

Its a new problem, since i had an extension over the summer. The builders fitted new radiators but didn't balance them. The water drained out completely a couple of times due to 'leaks', and I wondered if I had airlocks, hence I've bled all the radiators repeatedly.

It's an old system that has been altered over the years - cold water storage tank in roof, with red expansion vessel next to it (new, used to be a header tank), hot water cylinder in airing cupboard, grundfos alpha2 pump (new), vaillant boiler (new). The boiler is set to run at maximum temperature, the hot water cylinder thermostat is set to 65, the pump is set to maximum speed. (I found that in automode the boiler kept dying with an f.23 fault - too little difference between flow and return.)

Phewee!! Problems ........! Not an easy one to resolve via this place I'd say. However if you say all worked well prior to the extension then you'd expect all to be back to normal with the radiators turned off in the extension yeh? If this isn't the case then something drastic has happened to the system that is now restricting the flow to the downstairs! I my mind you'd want to get to the bottom of why this has occurred?

Can you get the builder back?

An F23 fault seems weird, by-the-way! However, regardless, I'd want to know F&R temp diffs in different scenarios!

What other work did the builder do? Did they fit the new boiler, pump etc?

From the limited info so far, it sounds like you may have something a bit more amiss than just a balance issue!

 

[Jim900]

Phewee!! Problems ........! Not an easy one to resolve via this place I'd say. However if you say all worked well prior to the extension then you'd expect all to be back to normal with the radiators turned off in the extension yeh? If this isn't the case then something drastic has happened to the system that is now restricting the flow to the downstairs! I my mind you'd want to get to the bottom of why this has occurred?

Can you get the builder back?

An F23 fault seems weird, by-the-way! However, regardless, I'd want to know F&R temp diffs in different scenarios!

What other work did the builder do? Did they fit the new boiler, pump etc?

From the limited info so far, it sounds like you may have something a bit more amiss than just a balance issue!

the builder changed the header tank for an expansion vessel as part of the extension. boiler was done a few years prior to that.

british gas fitted the new pump as the solution to the cold downstairs radiators - when that didn't work they insisted that a powerflush was the answer (at £1200...), and refused to consider any other options unless that was done.

I've heard that powerflushes can cause more harm than good, so reluctant to do that, especially as the water that comes out of the radiators is completely clear.

 

[diamondgas]

I take it you've got a service cover contract with BG? If so use them for free to get to the bottom of the issue. You could insist that they send someone more competent on system design. As long as it doesn't cost you anything put up with their sales objective and use them IMHO.

If you have plenty hot water and the rest of the house heats up okay then I'd be erring towards some physical blockage. It all depends on what is going on in the process of heat-up! Basically the main F&R should maintain roughly 22degC during heating up. Try turning all but the downstairs radiators off, including hot water, and see what main F&R pipe temps at boiler do?

As said before ... hard to diagnose without on site visit! whereabouts you situated?