Techy query - bad vibrations!

I did say I'd report back on this one, so better late than never. I ended up attaching an anti-shock (mini expansion) vessel to the flow pipe where it connected to the cylinder coil. This dampened most of the vibrations, although there is sometimes some residual noise. The posting above suggests that there is a design flaw with the heat exchanger coil of the Telford Tempest.
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In all seriousness, im fitting 2 of these things next week so will let you know if i get the same problem .
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I hope to report back later today on where I get with Telford.

The vibrations are all in the heat exchanger coil with no other vibrations anywhere else in the system. And yes, there are pipe clips at regular intervals on all pipe runs.


PS. What was the antishock mini expansion vessel that you used (should I need to work around the problem)
I have spoken to Telford technical support.

They seemed to admit that this is because the heat exchanger coil is profiled and is more likely to resonate when there are pressure shocks in the system.

This is apparently most likely to happen when the heat supply primary circuit is short - in my case I am currently only using my boiler to drive this hot water heating circuit (I have no radiator circuit currently).

I have the primary heating circuit pressurised to 1 Bar with a small expansion vessel).

They are clearly aware of this resonanation problem as an issue.

They suggested the following (that I have not yet tried but that sounds similar in many regards to what has been suggested in this forum)

- Reduce the pressure on the primary heating cirucit feed into the coil to 0.1 to 0.2 of a Bar.
- Use an expansion vessel on this circuit (I already have) and reduce the pressure in teh expansion vessel to this lower pressure.
- They claim that the problem will be much reduced when radiator / underfoor heating circuits are included into the feed

Any thoughts on this?

It seems as if the profiles stainless steel heat exchanger coil is at the heart of the problem and that setting low pressures in teh primary circuit and any pressure shock absortion vessels is critical in achieving a noise free heating solution.
I have reduced the pressure in the primary heating circuit that feeds the heat exchanger coil to about 0.5 Bar.

All is now quiet.

Would be interested to hear how others got along.

It appears that by reducing teh pressure th primary heat feed is not pushing through the coil and hence why teh noise had goen away.

I will be getting back to Telford.
Thanks for the feedback Ben. At least Telford are now acknowledging that there is a problem!

I have to admit that I don't quite follow what you are saying about reducing the pressures. When Telford say reduce the pressures into the coil to 0.1 to 0.2 of a bar, are they talking about the differential pressure across the coil? That is distinct from the system pressure of 1.0 bar or thereabouts. I don't understand why reducing the system pressure to 0.5 bar (which is below what is normally recommended) should make any difference to the differential pressure across the coil.

The idea that the differential pressure across the coil is the problem doesn't fit with my experience reported earlier, where the vibrations were generated only at a very low pump speed, presumably due to resonance with that frequency.
This vibration should only happen on hot water only and its the flow of water on the intergrom coil. fit a gatevalve as a bypass to relieve flow slightly and noise should disappear.
If I had spent serious money on one of these units I would be on the Phone to Telford's Service department to offload the problem onto their Warranty department!! ;)
Is there any particular reason your replying to a thread the is 3 years old? I reckon they have probably sorted out the problem by now.
its a problem i've come across and thought i'd share what i found worked. had't even loked at dates. sorry. r.i.p

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