Diverter Swollen balls (oooh errr!) any advice?

[Bobbbyboy]

Hi all,

I'm hoping a plumber or heating engineer can offer me some advice....

Basically I have an open vented CH system, which uses a Honeywell V4073A 3 port mid-position valve to control heating to water and/or the radiators.

On moving into the house in Oct 2008 a new one was professionally fitted to replace the one that was stuck and was leaking onto the airing cupboard carpet. All was well with the new valve until about after 6 months when the valve started to make what sounded like quite a bang when it had previously been on heating and hot water only was called (note: did not bang moving between any other ports). At that time although the valve was functioning correctly, the bang was niggling at me, and I wondered if it would damage any of the pipework eg due to any water pressure build up etc.

Long story short I read up on the internet and found a few stories where the rubber ball inside the valve swelled up quite a lot which restricted the movement and seating of the valve as it moved between ports. So about 6 weeks ago I plucked up the courage and drained down our system, removed the head, and fitted a new ball and plate. I refilled the system and to my joy the valve was silent again. Comparing the old and new balls, it was clear that the old one was a lot bigger than the new one and wouldn't turn on it's shaft(!)

That is until this week, when now the bang noise is back again, and I assume that the ball has swollen again.

As I don't fancy draining down my system every month and changing the ball and plate, would it cause any damage to leave it as is? the valve itself is working fine and selecting hot water and/or heating correctly with no problem.

Also does anyone have any ideas on what I can do to stop this happening? or is it worth me having a paddle type mid position valve fitted?

Apologies about the long post and any advice would be greatly received....cheers, Rob

 

[mysteryman]

There's probably a compatibility problem between the ball and any corrosion inhibitors in the system. Try a thorough powerflush, rinse, and good quality inhibitor. Are you sure you fitted genuine Honeywell parts?

 

[Bobbbyboy]

There's probably a compatibility problem between the ball and any corrosion inhibitors in the system. Try a thorough powerflush, rinse, and good quality inhibitor. Are you sure you fitted genuine Honeywell parts?

Thanks for the quick response....yes they were genuine honeywell parts.
There may also be something in the inhibitor idea, many people have mentioned on the web that fernox has cuased issues, and I did find a box of Fernox MB1 up near the header tank in the lo#ft, that I assume the previous owner used.

Ok....I guess with xmas up I don't want the hasssle and expense of flushing etc (might odo this next year), will it likely to cause any damage to leave it like it is in the short term at least? I've just paid out for a new pump and new boiler PCB bopard in the last 2 moinths so don't need any more expense for a bit!

Thanks again!

 

[Onetap]

Check the archives, it has been discussed before, e.g.,
http://www.diynot.com/forums/viewtopic.php?p=624484

The MB1/swollen balls problem has apparently been resolved. The box may be a few years old.

 

[kevplumb]

Check the archives, it has been discussed before, e.g.,
http://www.diynot.com/forums/viewtopic.php?p=624484

The MB1/swollen balls problem has apparently been resolved. The box may be a few years old.

i think i would be rephrasing that

 

[Bobbbyboy]

Check the archives, it has been discussed before, e.g.,
http://www.diynot.com/forums/viewtopic.php?p=624484

The MB1/swollen balls problem has apparently been resolved. The box may be a few years old.

That made interesting reading, it would appear that that could be the problem with my system.

So, can anyone answer the following qs:

1. Can I leave well alone and just put up with the small clunking noise of the diverter.
2. Would any additive reverse my swollen balls!?
3. Would fitting a paddle valve that doesnt use a ball go the same way pver time?

Again, thanks for all your help to date.

 

[spraggo]

1. Can I leave well alone and just put up with the small clunking noise of the diverter.
2. Would any additive reverse my swollen balls!?
3. Would fitting a paddle valve that doesnt use a ball go the same way pver time?

Again, thanks for all your help to date.[/quote]

Try turning the regulator down on the central heating pump.

 

[Onetap]

1. Can I leave well alone and just put up with the small clunking noise of the diverter.
2. Would any additive reverse my swollen balls!?
3. Would fitting a paddle valve that doesnt use a ball go the same way pver time?

Again, thanks for all your help to date.

Try turning the regulator down on the central heating pump.[/quote]

1. Why not? You don't even know that the ball has swollen.Unless it stops working properly, there's no need to try to fix it.

2. No, swollen balls are incurable. The only solution is amputation. BES sell replacements for £10 or so.

3. Don't know. I'd flush out the system and start again with fresh inhibitor. The Honeywell valve is OK, usually. If anything I'd prefer the S-plan, 2 x 2-port valves, but some pipe and wiring amendments would be required. I don't know whether they have balls.

 

[mysteryman]

There was a problem years ago with MB1 inhibitor and Honeywell valves. Reducing the pump speed may well help.
I wouldn't change to an S Plan, because you will block off any pump overrun. The balls in the valves are the same anyway.
A good flush may prevent future problems.

 

[Bobbbyboy]

There was a problem years ago with MB1 inhibitor and Honeywell valves. Reducing the pump speed may well help.
I wouldn't change to an S Plan, because you will block off any pump overrun. The balls in the valves are the same anyway.
A good flush may prevent future problems.

Thanks for the info all.

Mysteryman - my pump is set to speed 2 out of 3. Are you suggesting that I lower it to setting 1, can you also explain how that might help? It's a 4 bed detached house, wouldn't that speed be a bit slow, would there be any other implications apart from taking longer to heat the rads etc?

Also the system has been drained a few times and MB1 not readded so I would have thought it is quite dilute now in the system after filling with just water.

 

[Onetap]

3. Would fitting a paddle valve that doesnt use a ball go the same way pver time?

I was just rummaging amongst my random selection of valves. The Danfoss Randall HSV3 3-port valve is a 'rotary shoe' type in which shoe seems to be made of graphite. This should be resistant to chemical attack. Check with the makers. My valve is old, so also check they're still made the same way.

http://danfoss-randall.co.uk/PCMPDF/Introducing Motorised Valves.pdf

All the other ones seem to be paddle types ( including the Honeywell ones with the balls) which use a 'rubber' paddle/ball to seal off the unused port. The rotary shoe types may allow a small leakage to a unused port because the shoe is a hard material.

PS I didn't find what I was looking for either.

 

[spraggo]

Would fitting a paddle valve that doesnt use a ball go the same way pver time?
[/quote]

Hi bobbyboy,
I did not quote the above, I suggested that you tried turning the pump speed down to see if this would stop the banging.
The reason that I suggested this is as follows: The heating circuit has a far greater resistance to water going through it than the hot water circuit.
Therefore the velocity of water flowing through the heating circuit would be slower than if it were flowing through the hot water circuit. So, if the central heating was on and then there was a demand for hot water, the three port valve would go to midi position, allowing the water to be diverted through the cylinder coil and, because of its lower resistance, would cause the velocity of water to increase and cause the banging or water hammer by the sudden increase of water flow forcing the ball to close the hot water port momentarily. This is usually overcome by fitting a gate valve, on the outlet return side of the cylinder, and adjusted to create the required resistance through the hot water circuit. So if this valve is present on your system then it is likely that this is fully open or, the valve on the bypass, if you have one, is fully closed. Phew, worn out now.

Cheers spraggo