Bang from V4073 Mid Position valve

Bennachie · 13 Oct 2015

Hello!

The aforementioned mid position valve has been replaced on an open vented, Y plan system with 22mm primaries and 8mm feeds to radiators from manifolds (I know).
The system is clean and all radiators are new. Heating and DHW are fine, both work as required and provide required heat. However, if CH and DHW are on together, there is a significant 'thunk' from the valve when DHW is satisfied. This did not happen with the previous Honeywell valve (still going strong after 28 years) which was changed out as it seemed like the right thing to do as the system was being upgraded. Gas Safe Register man fitted a new boiler (GW HSX) and a replacement Grundfos Alpha 2L 15-60 Pump (which, incidentally is not intelligent enough) to replace the 28 year old 15-50 which, was not quite man enough for the 28 year old Glow Worm Fuel Saver when the thermostat was turned right up.......

There is no 'balancing valve' in the DHW circuit, which is completely 22mm pipe.

I am assuming that the clunk is caused by unrestricted flow through the 22mm heating pipes slamming the Honeywell ball closed as there is much more resistance in the heating circuit than there is in the DHW.

My question is therefore, is there a simple solution to this problem?
Will a valve swap to a shoe type solve the issue?
The radiators are uncontrolled by TRVs
There is no ABV fitted. If it should have one where can it 'return' to? Take off space is OK but return is a nightmare.

Many thanks

Gasop · 13 Oct 2015

Has the new valve been fitted correctly?
Does the A port go to heating and B port to hot water?

Bennachie · 13 Oct 2015

Yes, the valve if fitted correctly both mechanically and electrics.. AB from pump A to CH and B to DHW

DP · 14 Oct 2015

Shoe type will resolve the problem

Bennachie · 14 Oct 2015

Any preference as to manufacturer? I see there are also paddle type valves. I assume they are similar to the Honeywell ball.......

45yearsagasman · 14 Oct 2015

I like Honeywell as a first choice, but a Drayton MA1 3 port takes second place. The 22mm is available for £55 from outlets including Screwfix.

vulcancontinental · 14 Oct 2015

Shoe type I've found (Tower) is usually the cause of the problem. Only time I've had it with HW is when the inhibitors were mixed and didn't like each other making the ball soft and springy.

Bennachie · 14 Oct 2015

Tower is a budget Honeywell and is made in the same factory......and has a ball. That is the problem.
I believe Myson, Sunvic and Drayton offer shoe valves - Drayton also offer a paddle valve.

Complicated isnt it? I used a Honeywell as replacement as my old one was a Honeywell and was perfect for 28 years. The new one bangs. They have changed something I feel. Certainly the castings are 'lighter' and the top seal is a cast ribbed plate as opposed to the flat rolled plate of old. I wonder if the seats are slightly different?
I can't believe that I am actively considering replacing a new valve with a 28 year old item to improve performance..................

DP · 14 Oct 2015

Bennachie said:
Tower is a budget Honeywell and is made in the same factory......and has a ball. That is the problem.
I believe Myson, Sunvic and Drayton offer shoe valves - Drayton also offer a paddle valve.

Complicated isnt it? I used a Honeywell as replacement as my old one was a Honeywell and was perfect for 28 years. The new one bangs. They have changed something I feel. Certainly the castings are 'lighter' and the top seal is a cast ribbed plate as opposed to the flat rolled plate of old. I wonder if the seats are slightly different?
I can't believe that I am actively considering replacing a new valve with a 28 year old item to improve performance..................

Old valve will not have replaceable actuator. New one does. Old ones can be upgraded by replacing the top plate

vulcancontinental · 14 Oct 2015

In the past Tower were a different valve with a different paddle

Bennachie · 15 Oct 2015

DP - old valve is probably one of the first replaceable head models.
Having inspected the old and the new it would appear that the old one has a pivot that is not completely perpendicular to the top plate. It is about one degree out, which means that when the ball closes to the seat it does not immediately seal but is 'helped' that little bit further by pump pressure and seals. Whether this is by accident or design is debatable as the old valve is nearly 30 years old and will have wear characteristics - however, there appear to very few of them. In fact apart from the patina of age internally from hot water and inhibitor it appears as new.
I should still like to get to the bottom of this noise generation however...........

Bennachie · 15 Oct 2015

OK, if I have to provide a by pass with ABV...........
The take off after the pump is no problem but getting the return in will be difficult without extensive pipework.

Can the return go as the ALT. ABV POS in the diagram?

DP · 15 Oct 2015

If you have one radiator without trv, I would not bother fitting a bypass

Steelmasons · 15 Oct 2015

Faulty batch of valves , either replace valve or stretch spring.
If a lock shield on cylinder primary return then throttle it down.

simond · 15 Oct 2015

Why not partially close the balancing valve on the DHW?

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Bang from V4073 Mid Position valve

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