Honeywell v4073a valve noise

[Bennachie]

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. GSR 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 solve the issue?
Should there be a 'balance' on the dhw circuit?

Many thanks

 

[DirksPlumbing]

Just another thought, what is your system pressure?

 

[Bennachie]

Open system...............

 

[DirksPlumbing]

System is balanced (I believe)
Was Fuelsaver 45ff is now Ultracom HSX18
[snip]

A Glow-worm Ultracom HSX18 then? Can you post the GC Number? :rolleyes2:

 

[Bennachie]

My error, 18 HXI

 

[doitmyself]

To squeeze the water through DN6 and then still throttle the flow even further down does not make the slightest sense at all.

Who said anything about squeezing water through pipe? The purpose of balancing is to get the correct flow through every radiator. The fact that each radiator is fed by a separate pipe helps but a 500W rad still needs half the flow rate of a 1kW rad.

Grundfos does do great webinars and courses regarding balancing for free.

Links please.

The TRVs are the best balancing in such a system. All lock shields fully open.

I doubt if Drayton and Honeywell would agree with you.

 

[DirksPlumbing]

Who said anything about squeezing water through pipe? The purpose of balancing is to get the correct flow through every radiator. The fact that each radiator is fed by a separate pipe helps but a 500W rad still needs half the flow rate of a 1kW rad.

I doubt if Drayton and Honeywell would agree with you.

Water has roughly 1.163 Wh/kg/K and 1kg/l.

At DeltaT 10K that is 11.63 Wh/l.

That gives you 43 l/h.

DN6 has 0.028 l/m. Resulting in 0.42 m/s.

But to KISS it: 500W / (11Wh/l *3600) = 0.0126 l/s.

My flow resistance table goes up to 0.025 kg/s for DN6.

Meaning your comparably tiny rad of 6x6 K2 will result in > 0.566 m head per meter.
At a 5m distance from your manifold this is > 5.66m head.

Or in other words, to use this radiator as per design it needs a separate Alpha2L 15/50 for itself.

I am not saying it does not get heat as the resistance per meter drops quickly. Are you sure that Drayton and Honeywell will tell me that physics are not valid for plumbers?

As for the balancing I have to apologise. Grundfos Ecademy does not provide these courses for UK.

 

[DirksPlumbing]

It was Danfoss E-Learning. http://learning.danfoss.com/NR/rdon...earningHeatingCourseCatalogue_UK_05082014.pdf

 

[DirksPlumbing]

As for the correct flow on a microbore system you will end up with a great mixture of temperature spreads as you cannot get more than the pipes will deliver. How that could be correct, I do not know. But it definitely will not be balanced.

Glow-worm specifies a maximum spread of 20K in some manuals. On lower temperature specs (higher efficiencies) you usually design the 10K only anyway.

Gone are the days of 90/70/20 for most gas appliances.

 

[Bennachie]

So, Dirks, what setting should my 'intelligent' pump be on? The boiler requires 780 l/hr min if I remember correctly. This is all doing my head in.
Dodgy valve emits a dull, damped, rubber thunk even when no pump running and just the spring return to DHW only.........

 

[DirksPlumbing]

I have noticed I had mixed up DN6 calculations and 6mm copper pipe resistances.

What the pump should be set to? Honestly I do not know. But typically the variable pressure modes do not work all to well on microbore systems. Is your pump wired into the boiler pump port? There are so many things I do not know about this system, how could I be able to say this or that?

It is indeed mysterious how this valve can cause so much noise even when the pump does not even run. Change the valve, fit the automatic bypass and a balancing valve and lets see.

 

[DirksPlumbing]

Grundfos Product Center

This is roughly the same curve as on the Alpha 2L 15/60.

 

[DirksPlumbing]

As you can see, the high constant pressure setting limits to 4.5m head and the lower constant pressure setting to 3m head.

 

[Bennachie]

Thanks for your time....and sage words. It is appreciated.
I shall go back to basics and work everything out.
The valve will get changed soon and the bypass will go in.
I'll let you know.

It is weird that it thunks even just on spring pressure. I have a theory about it but it is just that, concerning the seating of the ball within the valve. I think the newer ones contact all of the seat immediately whereas the older ones contact the periphery initially then settle onto the seat, thus giving a 'gentler' shut off.

Trawling the net has brought up a number of similar threads concerning Honeywell valves in particular making this noise, so..........................hey ho.

Constant pressure setting is ok for an open vent system I assume
Thanks again.

 

[doitmyself]

I have noticed I had mixed up DN6 calculations and 6mm copper pipe resistances.

Can't see what relevance DN6 and 6mm has? The OP has 8mm pipe -presumably copper considering the age of the installation - approx 28 years.

A 500W rad with a 10K differential will require 0.012 kg/sec so 8mm pipe will have a resistance of approx 0.033 metres/metre length, i.e, 0.3m for a rad 5m from the manifold. The water velocity would be only 0.3 metres/sec, which is just about acceptable if sludge deposits are to be avoided.

 

[DirksPlumbing]

Can't see what relevance DN6 and 6mm has? The OP has 8mm pipe -presumably copper considering the age of the installation - approx 28 years.

A 500W rad with a 10K differential will require 0.012 kg/sec so 8mm pipe will have a resistance of approx 0.033 metres/metre length, i.e, 0.3m for a rad 5m from the manifold. The water velocity would be only 0.3 metres/sec, which is just about acceptable if sludge deposits are to be avoided.

Okay, given a property of 28 years with 3 bedrooms, one bath, one living room, a hall and a utility. That's 7 to 8 rads. How many of them are likely to be 6x4 P+?

Thinking about 18kW (the boiler) then that would be an interesting sight of ~30 radiators of 500W throughout the house .

DN6 is "diamètre nominal" and 8mm copper pipe has 6.4 mm and is very close to DN6. By latest once you got an 0.2mm oxide layer inside it definitely is.
And the 10mm plastic pipes are playing in the same league if at all.

On balancing your worst radiator determines the settings for all others (logically as you can only throttle). This may be your 6x16 K2 at ~2800W with 0.068 l/sec and roughly 12m microbore 8mm. That is a gently 2.1 m/sec and therefore a good speed well under 2.5 m/sec.
Looking in the table the pipe resistance is: oops , we do not know as it's outwith the specs in accordance to the table. But lets assume 0.4 meter head per meter x 12 its 4.8m head.
Now the boiler requires a minimum flow of 773.86 l/min. Adding 1.4 meter head for the boiler as per MI and another meter for the rest of the pipework and fittings we are now at 7.2 meter head loss at ~774 l/min. You need a Magna 25/80 to allow that system to run half decent once it's balanced.

I am sure the customer will be totally happy about the savings he is going to acquire after the pump and installation cost (~1k?) and the rise in electricity costs. Grundfos estimates "only" 68.2 W for the required setting.

And after a while the customer will not even notice the valve noises anymore as he got used to it. Hopefully. Would a pump like this push 22mm 2port or diverter valves open? But hey you won't need an automatic bypass then.